Qatar Foundation Annual Research Conference Proceedings Volume 2016 Issue 1

Background

Long-term peritoneal dialysis (PD) is associated with distinct peritoneal structural changes characterized by thickening of the sub-mesothelial cell layer, fibrosis and angiogenesis. These changes were assumed to be the cause for peritoneal membrane dysfunction and technique failure that was observed in some long-term PD patients. However, this assumption was refuted by the findings from animal models of chronic PD that showed the exact structural phenotype of the long-term PD, and yet a normal peritoneal function. This study was set to determine that the peritoneal microvascular and interstitial changes associated with long-term PD in rats produce peritoneal dysfunction by uremia related mechanisms. Our studies have demonstrated that acute exposure of the peritoneum to glucose-based PD solutions produces rapid and sustained visceral peritoneal microvascular vasodilation via the nitric oxide (NO) pathway. At present, there is no literature data on the reactivity of these peritoneal microvessels after long-term exposure of the peritoneum to PD solutions. NO as the mediator of the peritoneal microvascular reactivity to PD solutions is also involved in angiogenesis. Angiogenesis is initiated by proliferation of endothelial cells, which penetrate into the surrounding tissue, and is tightly regulated by growth factors and inhibitors. Matrix metalloproteinases (MMPs) regulate angiogenesis, on the one hand by facilitating extracellular matrix (ECM) degradation to allow new vessel expansion, and on the other hand, by interfering with angiogenesis through the production of angiostatin. Angiostatin is generated by the proteolytic cleavage of plasminogen by MMP-2, -7, -9, and -12. Angiogenesis was observed in patient undergoing PD as proven by peritoneal biopsy studies and in animal models of chronic PD. As a possible mechanistic explanation, angiogenesis and vasodilation increase the peritoneal surface area available for exchange, for rapid dissipation of the osmotic gradient, and hence, peritoneal membrane dysfunction.

Methodology

Rat studies were done on old animals as typical in chronic PD models because of the time required to develop the animal model. Three animal groups were used: Group - I: Chronic PD solution infusion: Interventions included indwelling peritoneal catheter placement and daily infusion of a glucose-based clinical PD solution for one month. Group – II: Interventions included renal injury and indwelling peritoneal catheter placement: Renal injury was induced by unilateral nephrectomy and ipsilateral kidney injury by cryosurgery. Group – III: Interventions included induction of uremia and indwelling peritoneal catheter placement: Uremia was induced by 5/6 nephrectomy. In all groups, procedures for animal model development including surgery were conducted under anesthesia and according to standard aseptic techniques. Studies on each animal were conducted after complete healing of the surgical incisions. These include: 1) Peritoneal equilibration test (PET-test) to assess the peritoneal transport properties; 2) Intravital microscopy to assess the visceral peritoneal microvascular reactivity to a clinical glucose-based PD solution, and endothelial functions of these visceral peritoneal micro vessels; 3) Assess the NO pathway via immunoblotting. Endothelial nitric oxide synthase (eNOS) which releases NO was measured via western blot. eNOS is activated by serine/threonine protein kinase Akt protein and itself activates matrix metalloprotease 2 (MMP2). Akt is activated by shear stress through activation of PI3K. Protein expression of eNOS, MMP-2 and Akt was assessed.

Results

Uremia caused a remarkable increase in the reactivity of the visceral peritoneal microvasculature to the dialysis solution as compared with the renal injury and the chronic infusion groups. Inversely, Uremia markedly decreased the sensitivity and reactivity of the visceral peritoneal microvasculature to the exogenous endothelium-dependent receptor-dependent Acetylcholine to indicate marked endothelial cell dysfunction. A subset of uremic animals exhibited very high net ultrafiltration which seems to correlate with a phenotype of extensive angiogenesis and uremia-induced hypertension. However, this high net ultrafiltration was not seen in any of our normotensive non-uremic animals that were subjected to indwelling peritoneal catheter placement and daily infusion of a dialysis solution for one month. Arterioles from the renal injury group reacted similarly to the arterioles from the chronic infusion animals. On the animals that showed prolific angiogenesis, expression of Akt and eNOS was elevated as compared with the animals that had kidney injury or control animals. MMP-2 showed elevated expression in animals with angiogenesis compared to animals with kidney injury. That is confirmation in molecular level that angiogenesis occurs in animals that display uremic phenotype. Control animals exhibited a significantly reduced MMP levels, indicating impaired angiogenesis process. Unlike in the naïve control animals, experimental groups demonstrated significant activation of MMP-2. In addition, Enos was found to be upregulated in the experimental groups, as compared with the naïve controls.

Conclusions

Four major conclusions were drawn from this study. 1) Aging is an independent risk factor for peritoneal microvascular endothelial cell dysfunction; 2) indwelling peritoneal catheter placement compounds a pre-existing age-related endothelial cell dysfunction; 3) Uremia unlike reduction in renal mass and injury causes marked peritoneal microvascular endothelial cell dysfunction as proven by the measurement of proteins involved in the vasodilation and angiogenesis pathways; 4) Uremia unlike aging or indwelling peritoneal catheter enhances the basic permeably of the peritoneal membrane for small solute transport.

Introduction

A medication error can be defined as “any error occurring in the medication use process” and focuses on problems with the delivery of medication to a patient [1]. Medication errors are a complex and ongoing issue that are of concern in all health care institutions [1]. Such errors range in severity but have been associated with an increased mortality and morbidity rate, as well as resulting in significant health care cost for both adult and pediatric populations [2,3]. Evidence from the literature indicates that more complex medical problems in patients who require multiple medications are more likely to experience medication errors during their hospitalization [3,4]. Since the release of the report “To err is human” by the Institute of Medicine (IOM) in 1999, the importance of good patient safety management has become a major focus of many health care professionals throughout the world [2]. Neonates, as a population, do not appear at a particularly high risk of experiencing medication errors as the vast majorities are not born preterm and often do not require a significant number of medications within the first month of life. Premature newborns in the neonatal intensive care unit (NICU) however are much more vulnerable to medication errors as they often require many different medications, are of small size, are physiologically immature, and may be lacking in the abilities to compensate for the effects of such errors [5].

Methods

A cross-sectional retrospective study investigating medication error reports submitted by healthcare professionals in an online database was completed. Medication error reports developed from January 1st of 2014 until April 14th of 2015 at a large, tertiary care NICU were reviewed. Medication error reporting within the hospital is policy driven and has migrated from a paper-based to a computer-based system that is accessible to all healthcare professionals. A data collection tool was developed based on three sources: literature review, National Coordinating Council for Medication Error Reporting and Prevention (NCC-MERP) classifications and a medication error sample report from the tertiary care hospital. This tool included demographics, personnel and practice event details including date and time, contributing factors, error category, and medications involved. Phase validation of the data collection tool was completed by study investigators and an external expert in medication error reporting. The modified version of the tool was then piloted using ten medication error reports completed by two investigators. Inconsistencies in data collection were discussed openly and final clarifications were made to the data collection tool. Data collection from all medication error reports were completed by two investigators. Medication errors reports included in this study were analyzed using Statistical Package for Social Sciences SPSS version 22. Frequencies were described using qualitative variables. Chi squared test was applied on categorical variables.

Results

During this study period, a total of 201 medication error reports were collected and reviewed. All errors were identified and reported by pharmacists. 51.8% of reports involved male patients. 27.4% of error reports developed from the NICU occurred in patients from birth to one day of age while 42.3% of error reports occurred in patients during the first week of life. The three most frequent categories of medication errors included wrong dose of medication (45.5%), wrong dosing frequency (31%) and documentation error (24%). Wrong frequencies were significantly associated with newborns on days 0–1 of life (p < 0.05). None of the medication errors identified reached the patient. 98.5% of medication errors were classified as causing no harm to the patient involved while the remaining 1.5% were re-evaluated as medication discrepancies after further review. A majority of medication errors were identified as being made by the primary prescriber (98.5%) while the remaining medication errors were identified as being made by the primary nurse in charge of the patient at the time the error was made. 98.5% of errors were stated to have occurred at the stage of prescribing while the remaining 1.5% of errors occurred at the dispensing, administration and transcribing stages. In 194/201 (96.5%) of medication errors, primary physicians were notified to modify the related prescription. The most common causes of medication errors included: calculation errors (118/201; 58.7%), documentation errors (35/201; 17.4%) and protocol errors (16/201; 8%). The class of medication resulting in the greatest number of medication errors were antibiotics (38.8%) while within this class, amikacin, gentamicin, and teicoplanin were the most likely medications to be involved in the error. The second most frequent medication classes resulting in medication errors were supplements (14.4%) including ferrous sulfate and vitamin D. Intravenous additives were the third most frequent class of medications that resulted in medication errors (8%). The most common days of the week for medication errors to be reported occurred on Wednesday (37 errors), Sunday (36 errors), and Thursday (35 errors). The days of the week with the fewest medication error reports generated were Friday and Saturday with 16 reports each. The time range where the greatest number of medication errors was identified was between 09:00 – 12:00 (37.8%). The fewest medication errors were identified between 03:01 – 06:00 (2.0% each). There was no association between the type of medication error and the time with which it occurred.

Discussion

Several studies have described the frequency and preventability of medication errors in the NICU [6]. This is the first study in Qatar that focuses on this area. We identified several deficiencies with the current error reporting system in that much of the demographic information useful for medication error reporting in neonates (ie. weight, gestational age, and diagnosis) are not necessary to complete the report. As only pharmacists completed all medication error reports it appears that education and training of other health care professionals may be needed to improve overall reporting. Reporters are also not anonymous which may contribute to underreporting. The most common medications involved in errors were antibiotics which is similar to existing studies [7]. Some limitations of this study included the inability to calculate the rate of errors occurring per patient or prescription as the total number of prescriptions written in the unit during this time was not available. Also, due to the retrospective nature of this study, there is the limitation of underrepresentation of medication errors as investigators were only able to describe medication errors that were reported through the online reporting system and did not use other sources for identifying medication errors in the unit.

Conclusion

Based on the reports generated through this online reporting system, medication errors that do occur in the NICU appear to be identified before they reach the patient. However, it is difficult to determine if underreporting does occur. Special care must be taken when selecting doses and frequencies of medications for patients in the NICU. Education and training on medication error reporting would likely have a positive influence on reporting by other health care professionals in the NICU.

References

[1] Bates DW, Boyle DL, Vander Vliet MB, Schneider J, Leape L. Relationship between medication errors and adverse drug events. J Gen Intern Med. 1995;10(4):199–205.

[2] Kohn LT, Corrigan JM, Donaldson MS (Eds): Institute of Medicine Committee on Quality of Health Care in America: To Err is Human: Building a Safer Health System. Washington DC, National Academy Press, 2000.

[3] Slonim AD, Tian J, Lafleur B, et al: Hospital reported medical errors in children. Pediatrics 2003; 111:617–621.

[4] Slonim AD, Tian J, Lafleur B, et al: Patient characteristics associated with the occurrence of hospital-reported medical errors in children. Pediatr Res 2001; 49:A127.

[5] Kanter DE, Turenne W, Slonim AD. Hospital-reported medical errors in premature neonates. Pediatr Crit Care Med 2004;5:119–23.

[6] Santesteban E, Arenas S, Campino A. Medication errors in neonatal care: A systematic review of types of errors and effectiveness of preventive strategies. J Neonat Nurs 2015;21(5):200–8.

[7] Jain S, Basu S, Parmar VR. Medication errors in neonates admitted in intensive care unit and emergency department. Indian J Med Sci. 2009;63:145–51.

Background

Traumatic exsanguination leading to class IV hemorrhagic shock as defined by the Committee on Trauma of the American College of Surgeons requires aggressive resuscitation with crystalloids and packed cells together with the temporary administration of either norepinephrine or vasopressin to manage a persistent hypotension that is not corrected by aggressive fluid resuscitation. However, the use of vasopressors in the resuscitation from hemorrhagic hypovolemic shock is controversial as these drugs may worsen the pre-existing splanchnic hypoperfusion by virtue of their vascular action. In previous intravital microscopy studies of the terminal ileum in rats, we demonstrated that adequate resuscitation which restores and maintains central hemodynamics, as clinical end-points of resuscitation, does not restore or maintain splanchnic tissue perfusion, which instead exhibits a persistent and progressive intestinal microvascular vasoconstriction and end-organ tissue hypoperfusion. In other intravital microscopy studies we have shown that resuscitation from hemorrhagic shock with small volumes of hypertonic saline does not restore or maintain the pre-hemorrhage blood pressure, but selectively prevent the post-resuscitation vasoconstriction of the pre-mucosal pre-capillary arterioles of the terminal ileum. In contrast, the replenishment of the hemorrhage-induced depletion of endothelial energy stores with vitasol, restored the pre-hemorrhage arterial pressure and selectively prevented the post-resuscitation vasoconstriction of the pre-mucosal pre-capillary arterioles suggesting a positive inotropic effect of vitasol. Therefore, such inotropic action merits the administration of vitasol during fluid resuscitation from severe hemorrhagic shock. It is well established that hemorrhagic shock profoundly depletes cellular adenosine nucleotides. This depletion occurs as the hemorrhage-induced splanchnic hypoperfusion decreases the supply of oxygen to end-organ tissue and cells, resulting in failure of ATP generation by oxidative phosphorylation and the activation of the alternative cellular ATP generation from the low yield anaerobic glycolysis pathway. Studies designed to directly assess the status of the splanchnic microcirculation during severe hemorrhage shock and its resuscitation is scant. As the ischemic hypoperfused gut is central in the pathophysiology of shock and largely determine resuscitation outcome, we were prompted to use our intravital microscopy technology to directly examine the intestinal microvasculature response to traumatic exsanguinations and during their resuscitations with either norepinephrine or vasopressin as opposed to direct cytosolic energy replenishment.

Methods

Anesthetized male Sprague-Dawley rats underwent initial venous withdrawal of 30% of the calculated animal's blood volume over 15 min (shed blood preserved in heparin-rinsed syringe for later resuscitation). This was followed by phase-2 of uncontrolled hemorrhage as induced by transection of the splenic parenchyma at the two ends of the organ and severing one of the branches of the splenic artery. The transected organ was returned to the abdominal cavity for free arterial and venous bleeding until class IV hemorrhage is achieved [defined by persistent mean arterial pressure, MAP <  40 mmHg, and a shock index (ratio of heart rate and systolic arterial pressure), SI ≥  5 for successive 10 minutes during the period of active uncontrolled bleeding]. Following this, homeostasis was established by rapid ligation of the splenic pedicle and the animals were assigned to 4 resuscitation groups: 1) Conventional resuscitation (shed blood returned+double the shed blood volume as lactated Ringers, CR); or adjuvant resuscitations with: 2) CR+norepinephrine; 3) CR+vasopressin; and 4) CR+vitasol. Four-level, A1 through A4 arterioles in the terminal ileum were examined with Intravital Microscopy and their diameters timely measured at baseline, during shock, and during 2h post-resuscitation.

Results

There were no differences between the four groups in pre-hemorrhage baseline metabolic parameters, blood gases and acid base status. In all four groups, class IV hemorrhagic shock remarkably decreased hemoglobin, hematocrit and produced a metabolic acidosis characterized by low pH, PCO2, HCO3, TCO2 and an increase in the base deficit as compared with the baseline pre-hemorrhage levels. None of the four resuscitation methods restored parameters of the metabolic panel or blood gases and acidosis to pre-hemorrhage baseline levels. Class IV hemorrhagic shock caused differential arteriole responses with vasoconstriction from baseline of A1 and A2 ( − 22.1 ± 1.9%), and vasodilation of the A3 and A4 arterioles (+22.2 ± 2.8%). Resuscitation initially restored A1 and A2 diameters to near baseline. This was followed by post-resuscitation A1 and A2 vasoconstriction in all groups except in the vitasol group ( − 8.1 ± 3.4%). The hemorrhage-induced vasodilation of the A3 and A4 arterioles was maintained during the post-resuscitation observation period in the CR (+55.3 ± 6.4%) and the vitasol groups (+39.5 ± 5.2%), but remarkably attenuated in the norepinephrine (+9.6 ± 5.8%) and vasopressin (+9.4 ± 8.8) groups.

Conclusions

The temporary administration of norepinephrine or vasopressin as adjuvants to fluid resuscitation from severe hemorrhagic shock has deleterious effects on the splanchnic microcirculation. Endothelial cell resuscitation by cytosolic energy replenishment produces better metabolic and microvascular profiles as compared with adjuvant vasopressor resuscitation.

Background

Natural Killer (NK) cells are critical mediators of tumor immunosurveillance. In humans, clinically relevant NK-dependent anti-leukemia effects have been originally demonstrated in the context of hematopoietic stem cell transplantation from HLA-haploidentical related donors. More recently, adoptive transfer of allogeneic NK cells has been recognized as a potentially successful immunotherapeutic strategy allowing for leukemia allorecognition without transplantation-related mortality. Several sources of allogeneic NK cells for adoptive immunotherapy have been described. Among these, hematopoietic progenitor cells from cord blood (HPC-CB) represent an emerging “off-the-shelf” source of NK cells potentially capable of leukemia allorecognition. Various methods for in vitro differentiation of HPC-CB into NK cells have been reported. However, such methods have been generally unable to propagate large numbers of mature NK cells with enhanced alloreactivity, a critical requirement for NK-based immunotherapy. IL-15, a critical factor for survival, proliferation and activation of NK cells, is physiologically delivered in combination with a high affinity IL-15 binding protein (IL-15 receptor alpha or IL-15Ra), a mechanism known as IL-15 trans-presentation. To mimic this mechanism, pre–B-lymphocyte BaF/3 cells have been double-transfected with IL-15Ra and IL-15 (BaF/3 IL-15Ra/IL-15). When used as feeders, these cells can trans-present IL-15, thereby inducing extensive NK cell propagation independent of exogenous soluble cytokines. We have recently set up the BaF/3 co-culture system with the purpose of obtaining large-scale generation of HPC-CB-derived NK cells with potent leukemia alloreactivity.

Methods

BaF/3 IL-15Ra/IL-15 were maintained in RPMI 1640 supplemented with 10% FCS, 100 U/ml penicillin, 0.1 mg/ml streptomycin. One day prior use in co-culture, BaF/3 IL-15Ra/IL-15 were incubated with 10 ug/ml mitomycin C to inhibit proliferation. NK cells were cultured in 24-well plates containing SCGM medium supplemented by 10% heat-inactivated human serum. BaF/3 IL-15Ra/IL-15 transfectants at 1:1 or 1:2 effector: feeder (E:F) ratio (5 × 10⁵ or 1 × 10⁶) were added at D1 and every five days thereafter until D15. On D19, cultured cells were screened by flow cytometry to determine NK number, viability, purity and receptor expression. On D20, NK cytotoxicity to the K562 and U937 myeloid leukemia lines was determined by a non-radioactive calcein AM release assay.

Results

Nineteen days after co-culture start, we obtained 4.35 × 10⁶ from 5 × 10⁵ starting NK cells (8.7-fold increase) in the presence of a 1:2 E:F ratio. A 1:1 E:F ratio allowed for less extensive NK cell propagation. Regardless of the E:F ratio, harvested NK cells were >94% pure and expressed high levels (58–90%) of activating natural cyctotoxicity receptors (NCR) (NKp46, NKp44, NKp30) and NKG2D. Expression of inhibitory killer immunoglobulin-like receptors (KIR) was comparatively lower (0–30%). Consistent with this data, NK cells displayed potent and similarly high cytotoxicity to K562 and U937 AML lines, namely 69–82% at 20:1 effector:target ratio.

Conclusions

We show here that IL-15 trans-presentation may support efficient propagation of polyclonal NK cell with enhanced anti-leukemia functional capabilities. These results provide strong mechanistic rationale for studies exploring the effects of IL-15 trans-presentation delivery to HPC-CB-derived NK cells. Our next objective is to induce differentiation of NK cells (CBNK) from CBSC, and then enhance the cytotoxicity of differentiated NK cell using a secondary culture system based on IL-15 trans-presentation with the scope of generating high numbers of NK cells with anti-leukemia reactivity.

Background

Our immune system is composed of an innate (germ-line encoded) and adaptive (acquired) arm. It involves specialized hematopoietic cells but also cell-intrinsic (non-hematopoietic) mechanisms, antigen-specific receptors

(T and B cell receptors/immunoglobulins), microbial sensors (pattern recognition receptors), and a complex network of signaling molecules that cooperatively work together to prevent or control infection by invading microorganisms via a variety of effector mechanisms. Both innate and adaptive immune defense mechanisms are tightly regulated, to avoid potentially harmful consequences such as tissue damage to the host, and to maintain tolerance to self as well as to harmless foreign antigens. An imbalance or insufficiency of these immune defense and regulatory mechanisms becomes apparent as clinical disease, either in the form of symptomatic infections (in which case the host immune defense was insufficient to prevent or control infection, dysregulated, or even deficient), or during autoimmune disease (indicating an overly and inappropriate reaction of the immune system to harmless or self antigens). The immune defense and regulatory mechanisms are highly age-dependent, reflecting the different environmental challenges and requirements during the prenatal and postnatal period, and throughout life. Not surprisingly, these age-specific differences are most profound either very early in life (generally described as the ontogeny and maturation of the immune system), or late in life (referred to as immunosenescence). Infants and young children rely heavily on cell-intrinsic and innate immune defenses to control infection. This is because their adaptive immune system has yet to fully mature, and antigen-specific effector B and T cells are absent during the early course of primary infection (the first exposure to a given pathogen). Moreover, we [1–3] and other groups [4–12] have shown substantial age- and gestational age-dependent differences in the innate immune function in early life, which may explain the vulnerability of some newborns, infants and young children to particular pathogens. Indeed, infants and young children are disproportionally burdened by severe infections with a variety of common viruses and bacteria that they become exposed to during birth (e.g. Group B streptococci), in the first few months of life (e.g. respiratory syncytial virus and other ‘common cold’ viruses), or even in utero (e.g. cytomegalovirus). It should be noted that most microorganisms associated with severe diseases in early childhood (or late in life) are common, can also be isolated from asymptomatic individuals and/or individuals with mild disease, and are in most cases unknowingly transmitted through the contact with infected family members or caregivers. It remains largely unclear why some children develop severe clinical illness following exposure to these microbes, while most others exposed to the same microbes develop only mild symptoms. This knowledge gap has been a major obstacle for the development of neonatal vaccines and therapeutic interventions for young pediatric patients. Various studies have indicated an important role of germline genetics (i.e. inborn errors), as well as developmental factors (i.e. epigenetics) in the clinical outcome of primary infection. Here we focus on developmental factors, specifically on age-dependent differences in the genome-wide expression profiles (transcriptome) of whole blood, blood mononuclear cells, or specific blood cell subsets that play an important role in immunity of neonates to infection. To gain further insight into the function and regulation of the immune system in early life, we applied a recently developed web-based systems immunology toolkit [13] to allow the visualization and analysis of a collection of datasets publically available in the Gene Expression Omnibus (GEO) database of the US National Center for Biotechnology Information (NCBI).

Material and Methods

Human neonatal immune defenses are most commonly studied by utilizing placenta-derived cord blood, because it is relatively easy to obtain in larger quantities, and the collection is non-invasive. Less frequently, peripheral blood samples are also obtained from healthy or sick neonates, or fetal blood samples are utilized, in order to study the ontogeny of the immune system. To harness available transcriptomics data and to allow a ‘cross-study’ comparison in order to reveal novel insights from publically available collective data, we queried NCBI's GEO database for search terms “neonate”, “neonatal”, “fetal” or “cord”, as well as “blood”, “PBMC”, “lymphocyte”, “B cell”, ”plasma cell”, ”T cell”, “Treg”, “monocyte”, “dendritic”, ”DC”, “natural killer”, “NK”, NKT”, “ neutrophil”, “erythroblast”, “erythroid”, or lineage markers CD19, CD20, CD3, CD4, CD8, or CD71. Data sets were restricted to those generated from human samples using expression profiling by array or high throughput sequencing. Data sets with keywords including “cancer”, “leukemia”, “lymphoma”, “cell line”, “myeloma”, “hepatocyte”, “mesenchymal” or “endothelial” were excluded. Further, the generated list of data sets using this query was manually curated to exclude studies that are unlikely to reveal insights into neonatal or fetal immune function and regulation. For refining and curating the query result, we used an alternative search engine to NCBI, namely GEOmetadb [14]. This search engine allows the use of SQL language to query a local copy of NCBI's GEO database, and to export any metadata field that is needed for the manual curation of the query result. Next, we adopted a novel approach to knowledge discovery and hypotheses generation for future mechanistic studies [15]. In brief, we first performed a screen aimed at identifying knowledge gaps in one of the above identified data sets that was retrieved from GEO (GSE25087), where the authors generated global gene expression data using sort-purified human fetal and adult T cell subsets, including CD4+CD25+ regulatory T cells (Tregs) and naïve CD4+ T cells [16]. The primary objective of the original study was to assess lineage differences in adult and fetal T cells. Here, we re-assessed data set GSE25087 by ranking the genes according to differential gene expression between fetal and adult Tregs, in order to reveal as yet unknown genes that are involved in immune regulation in early life. Of the genes that ranked among the top 20, we computed a knowledge gap score (KGS) as follows: Existing knowledge was numerated for each of the top-ranking genes by querying NCBI's National Library of Medicine's Pubmed search engine using the official gene symbol, name, as well as aliases. A knowledge gap score was then calculated by dividing the sum of publications with the sum of publications using the same query AND a keyword plus 1 [KGS =  number the Sum(publications)/ (Sum(publications) AND keyword)+1]. For this particular data set, we used “Treg” or “neonatal” as keywords for the denominator, because our objective was to reveal genes that have not yet been associated with Treg function, or with immune regulation during fetal or neonatal life. A high KGS indicated a knowledge gap, whereas a low KGS indicated that the gene in question had already been described to play a functional and/or regulatory role in immunity.

Results and Conclusion

The query of NCBI's GEO database using the keywords and restrictive criteria listed above generated a list of >400 data sets, a selection of our curated data set collection is available at http://developmentalimmunology.gxbsidra.org/dm3/geneBrowser/list (including data set GSE25087). This website is running an instance of an open source web tool called gene expression browser (GXB) [13], which hosts the curated data set. Interestingly, our knowledge gap assessment on data set GSE25087 revealed a high KGS for PMCH, a gene encoding a precursor of melanin-concentrating hormone (MCH), a cyclic neuropeptide. PMCH expression profiles and results from previous studies primarily suggested a neurotransmitter or neuromodulator role for MCH in a broad array of neuronal functions directed toward the regulation of behavior. We further assessed the expression of PMCH in a selection of other GEO data sets that we had identified with the query described above. This revealed PMCH to also be selectively expressed in immature erythroid cells, which were sort-purified from cord blood samples of healthy neonates along with a broad panel of other hematopoietic cell subsets (GSE24759). These immature (nucleated) red blood cells are found in high frequencies in human cord blood samples but decline rapidly in frequency in the first few days of life [17]. Recent studies have shown an important immunosuppressive role of CD71+ erythroid cells, which was associated with increased susceptibility to Listeria monocytogenes and Escherichia coli infection in a mouse model [7, 18]. Our findings indicate that PMCH is expressed by two important immune regulatory cell types of hematopoietic origin and may play a critical, as yet unrecognized role in immune suppression and tolerance during fetal development, which may in turn render newborns vulnerable to infection. To our knowledge, a role of PMCH in immune regulation has not been described, apart from two studies. One of these studies reported PMCH to be induced by TH2 cytokines in human vascular endothelial cells from normal lung blood vessels, suggesting a role in asthma development [19]. The other study found PMCH to be expressed in human Th2 cells which was activation responsive and paralleled with the expression of Th2 cytokine genes [20]. In conclusion, we employed a web-based systems immunology application that allows the visualization and comparative analysis of a collection of public human functional genomics data sets. This proved to be a powerful approach for new discoveries and hypothesis generation, which can then be further validated with in-depth mechanistic ‘wet laboratory’ studies.

References

[1] Marr, N., et al., J Immunol, 2014. 192(3): p. 948–57.

[2] Sharma, A.A., et al., Neonatology, 2014. 106(1): p. 1–9.

[3] You, D., et al., J Leukoc Biol, 2013. 93(6): p. 933–42.

[4] Dowling, D.J. and O. Levy, Trends Immunol, 2014. 35(7): p. 299–310.

[5] Zhang, X., et al., PLoS One, 2013. 8(1): p. e52003.

[6] Corbett, N.P., et al., PLoS One, 2010. 5(11): p. e15041.

[7] Elahi, S., et al., Nature, 2013. 504(7478): p. 158–62.

[8] Ghazal, P., et al., Curr Opin Infect Dis, 2013. 26(3): p. 213–8.

[9] Kollmann, T.R., et al., J Immunol, 2009. 183(11): p. 7150–60.

[10] Kollmann, T.R., et al., Immunity, 2012. 37(5): p. 771–83.

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[12] Lissner, M.M., et al., PLoS One, 2015. 10(7): p. e0132061.

[13] Speake, C., et al., J Transl Med, 2015. 13: p. 196.

[14] Zhu, Y., et al., Bioinformatics, 2008. 24(23): p. 2798–2800.

[15] Rinchai, D., et al. [version 1; referees: 3 approved with reservations], 2015. 4:89 (doi: 10.12688/f1000research.6241.1)

[16] Mold, J.E., et al., Science, 2010. 330(6011): p. 1695–9.

[17] Hermansen, M.C., Arch Dis Child Fetal Neonatal Ed, 2001. 84(3): p. F211–5.

[18] Elahi, S., Front Immunol, 2014. 5: p. 376.

[19] Orihara, K., et al., J Allergy Clin Immunol, 2009. 124(3): p. 612–4, 614 e1–2.

[20] Sandig, H., et al., Proc Natl Acad Sci U S A, 2007. 104(30): p. 12440–4.

Objective

To study the prevalence of neonatal complications among pregnancies complicated by polyhydramnios of unidentified prenatal cause and their outcome in an attempt to introduce more active antenatal/postnatal evaluation and aid the counseling.

Methods

A retrospective descriptive study to identify all the cases of idiopathic polyhydramnios for whom there was causes between 2002 and June 2014. All the cases of polyhydramnios during the study period were reviewed and only those with no obvious antenatal cause were included in the study. Only cases where polyhydramnios diagnosed using Deepest Vertical Pocket were included. The exclusion criteria are; diabetic pregnant patients, fetus who were diagnosed antenataly with congenital/genetic anomalies, Polyhydramnios diagnosed using Amniotic Fluid Index and those with incomplete data. We look for the rate of preterm delivery, IUFD, rate of cesarean section, low APGAR score admission to NICU and neonatal complications. We also use this study as an audit to identify those cases for which a genetic/congenital anomaly identified; making a proper antenatal work up as a crucial step in dealing with such cases. The collected data were put into Excel sheet (Microsoft Office 2013) and professional statistical tools were used (provided by StatPages.org), P value of 0.05 was taken as the limit for statistical significance.

Results

Total of 66 case of idiopathic polyhydramnios identified in the period from 2002 to med-2014, which account for about 0.4 in 1000 (total number of deliveries during this period was around 180000 deliveries). There were 58 cases (87.9%) with mild polyhydramnios (defined as deepest pocket of 8 to 11 cm, and 8 (12.1%) cases of moderate polyhydramnios (from 11.1 to 15 cm) the mean of amniotic fluid Deepest Pocket was 9.6 cm (SD 1.%). Maternal age was variable among the cases [range from 20 to 52 years (median of 30 years, and mean of 30.2 years (SD 5.7)], and those above 35 years [8 cases (12%)] all of them are mild polyhydramnios, so the degree of hydramnios does not direcetly correlate with advanced maternal age. 39 cases were diagnosed before 37 weeks (59.1%), of them 32 cases had mild Idiopathic Polyhydramnios ranging from 8–11 cm with no direct correlation of increasing Mild amniotic fluid DP and decreasing gestational age as the relation was variable. 5 patients who were diagnosed before 37 weeks were of Moderate Idiopathic Polyhydramnios, although the number is small but it seems Moderate IP is more prone to be present at early GA, however comparing both groups; there was no statistical significance [p value 0.17] Over all, the rate of preterm delivery was 10.6% (7 cases), 4 cases among mild IP (6.7%) and 3 cases among moderate IP (37.5%). As in the graphs the GA at delivery decreases as the deepest pool increases and that most prominent in moderate IP, less relevant in mild form. 22 cases had a cesarean sections (33%) which relatively high compared to the overall cesarean section rate of 25%. 8 of them where as an emergency setting; 4 were in Labour and taken for failed progress, 2 for fetal distress and 2 were previous cesarean came in labor and requested repeated cesarean. The remaining 14 cesarean were due to placenta previa (2 cases), repeated cesarean sections (7 cases), big baby (3 cases), transverse lie (1 case) and previous 2 shoulder dystocia (1 case). The rate of emergency cesarean section among mild IP was 8.8% (5 cases) compared to 12.5% (1 case) in the Moderate IP group, however there is no statistical significant difference between the 2 groups [p value of 0.73]. Overall rate of spontaneous labor noticed in 37 cases (56.1 %) Induction of Labour was significantly high (13 cases; 19.7%), mainly due to polyhydramnios (11 cases; 16.7%), only 2 cases due to High BP. Worth noticing that despite the high rate of Induction, however the rate of cesarean among induced patient was low (only 2 case; 15.4%) comparable to those who came in spontaneous labour (4 cases out of 37 patients; 10.8%). There is no statistical significant difference between the 2 groups [p value of 0.66] The rate of operative delivery was 7.7% (5 cases). All of them among those who came into spontaneous labor. On the other hand the operative delivery was noticed in 4 cases (7%) of mild IP compared to 1 case in moderate IP (12.5%), but no statistical significant difference between the 2 groups [p value of 0.59]. Over all Mean birth weight was 3503.4 grams (SD 645.4). Among the Mild IP group the mean birth weight was 3185.7 grams (SD 898.9), compared to the Moderate IP group whch was 3185.7 grams (SD 898.9); there was no statistical significant difference between the 2 groups [p value of 0.36]; however the rate of big babies (>4000 grams) was high among Mild IP (15 cases; 25.9%), the mean birth weight in such subgroup was 4175 grams (SD 229.5), there were no big babies among the moderate IP. Low birth weight ( = < 2500 grams) found in 6 cases (10.4%) of Mild IP (mean of 2166.6 (SD 367)) and 1 case (12.5%) of Moderate IP (1300 grams), there was no statistical significant difference between the 2 groups [p value of 0.85]. Low APGAR score (0–3 in the 1st 5 minutes) was found in 1 case of Mild IP (1.7%) and 1 case of moderate IP (12.5%), with no statistical significant difference between the 2 groups [p value of 0.096]. overall low APGAR score was 3%. MICU admission was 22.7 % (15 cases). 2 cases ended in neonatal death (3%), the degree of polyhydramnios did not increase NND the as in each group there is one case.Conclusion; Idiopathic polyhydramnios is an important pregnancy complication. It warrant detailed antenatal assessment, including ultrasound and repeated GTT. It also urges the postnatal examination of the baby for undiscovered pathology. We recommend taking care of such pregnancies in tertiary care center.

Introduction

The aim of prenatal diagnosis is to detect fetal structural and genetic abnormalities. Some changes can be registered on chromosome level (chromosome mutations) or at the level of DNA (genetic or genomic mutations), which in turn can produce somatic malformations. When amniocentesis for fetal karyotyping was first performed it was limited to gestations at or beyond 16 weeks because it was associated with higher failure rate in obtaining amniotic fluid at earlier gestation. A major disadvantage of second trimester amniocentesis is late diagnosis beyond 17 weeks' gestation, when surgical termination of pregnancy becomes risky. Earlier options include chorionic villus sampling (CVS) and early amniocentesis. Early amniocentesis (9 to 14 weeks' gestation) was introduced in the late 1980s. It is technically the same as a ‘late’ procedure, except that less amniotic fluid is removed which reported to result in laboratory failure varied between 0% and 20%, however such observation decreased with advanced genetic technologies and experience of the practetioners.

Objectives

To study the feasibility and reproducibility of early amniocentesis (define as below 15 weeks) by studying the failure rate of the Amniocytes culture and the need to repeat the procedure. The aim is to fine an alternative way of invasive testing in case of difficult CVS and need for early diagnosis. Material and methods. It is a retrospective study. Diamniotic twins case were collected in the period from of September 2003 to October 2014, these cases were seen in the Feto-Maternal Unit which I specialized unit in the Obstetrics and Gynecology department started on 2003 and serving high risk pregnancies, including fetal anomalies, maternal diseases and prenatal intervention.. etc After obtaining permission for the Medical Research Center. The ultrasound data was collected form the ultrasound software (Astraia. Astraia Software GmbH Occamstr.20, 80802 Munich Germany). Data were collected and kept in password protected Excel sheet (© 2010 Microsoft Corporation) and the analysis carried using online statistics tools (http://www.numberempire.com/statisticscalculator.php, http://www.evanmiller.org/ab-testing/), P value below 0.05 was considered for statistical significance.

Results

Total of 1263 amniocentesis was done during the study period, of them 50 cases was done before 15 weeks (encompass), 9 case excluded due to incomplete data. The mean gestational age at the procedure was 14 weeks and 2 day (SD of 4 days), median was 14 weeks and 3 days (Range of 2 weeks and 5 days). There were 11 cases (26.8%) under 14 weeks (between 12 weeks+1 day and 13 weeks+6 days. The indications of the prenatal testing was high nuchal translucency or cystic hygroma in 32%, fetal anomaly in 27%, previous baby with genetic disease (mainly trisomy 21, Thalasimia, sickle cell disease, …etc) in 19%, Maternal age (more than 40 years) in 17 %, and family history of genetic diseases in 5% (Mucolipidosis, Hematological diseases) Placenta was anterior in 22 cases (53.6%) and posterior in 19 (46.4%) with no statistical deference (p value 0.51), however the approach was Transamniotic in 33 cases (80.5%) and Transplacental in 8 cases (19.6%). Among all the case only one case (2.4%) of Amniocytes culture failure was reported with need to repeat the test after 15 weeks, she had a family history of thalassemia and the procedure was Transplacental with bloody stained fluid; processed in the genetic lab and the results were inconclusive. The rest was reproducible with 13 cases showed abnormal karyotype and managed accordingly. There were no reported cases of miscarriages after the procedure (excluding 10 cases “those who had an elective termination due to positive genetic diseases after ethical committee approval)

Conclusion

Early amniocentesis is a feasible and reproducible procedure with very minimal failure rate and in an experienced hand and with advanced genetic technology can substitute difficult CVS after proper counseling.

Introduction

Metabolomics is a study of small molecule (metabolite) composition in the body fluids, tissue or cell culture samples. Depending on the study objective we can apply non-targeted metabolomics (metabolic profiling), which provides a semi-quantitative, global overview of the organisms metabolic composition, or targeted-metabolomics, which offers quantitative measurements of a given set of metabolites. Until today, valuable samples collected in Qatar were shipped to centers abroad for both targeted and non-targeted metabolomics studies. Using our previous experience from development of a metabolomics platform in Germany, we now introduce a targeted-metabolomics platform in Qatar (MetaQ). By a model cooperation between the interim Translational Research Institute (iTRI) of Hamad Medical Corporation (HMC), which provided hardware components of the platform, and the Virtual Metabolomics Core of Weill Cornell Medicine in Qatar (WCM-Q), providing know-how and data analysis support, MetaQ (based on the AbsoluteIDQ p150 assay Biocrates Life Sciences AG) is offering in-house, quantitative measurements of 163 metabolites including amino acids, carnitines, phosphatidylcholines, and sphingomyelins from different sample types (plasma, dry blood spots, tissue samples and cell culture). To validate the MetaQ platform we used plasma samples which were collected in Qatar in the framework of the QMDiab study. Those samples were previously measured by a well-established metabolomics core at Helmholtz Zetrum Munich in Germany.

Materials and Methods

We used 80 plasma samples from de-identified subjects previously enrolled in the QMDiab study. For targeted metabolomics profiling we used the AbsoluteIDQ p150 assay (Biocrates Life Sciences AG). Samples preparation and metabolite detection was performed at the iTRI, according to the manufacturer instructions (Biocrates Life Sciences AG). Briefly, 10 μL of plasma samples were pipetted onto the kit filter plate and evaporated. Evaporation was performed by using evaporator (Organomotion Microvap 118) under nitrogen atmosphere in the chemical fume hood. Dried plasma samples were derivatized with 5% phenylisothiocyanate for 20 minutes followed by second round of evaporation. In the next step sample metabolites together with internal standards were extracted with methanol and filtrated by centrifugation. The sample extract was transferred into a new deep well plate and diluted with running solvent. Sample injection was performed automatically with the auto sampler (Eksigent EkspertUltraLC100) and the metabolite detection was performed using FIA-MS/MS system on a QTRAP4500 triple quadrupole (ABSciex). Evaluation of the mass spectrometry data was performed using MetIDQ software package (integral part of the Absolute IDQ assay). Statistical data analysis was performed using R-Studio.

Results

The major objective was to introduce and validate a functional, targeted metabolomics platform in Qatar. We used the iTRI in-house workhorse for mass spectrometry, the QTRAP4500 triple quadrupole system equipped with liquid chromatography EkspertUltraLC100. As a method of quality control, after sample measurement, we tested the correlation between samples measured in Qatar and previously in Germany. Correlation between subjects was very high: R² > 0.98. Furthermore, 2/3 of the evaluated metabolites also had a high correlation: R² > 0.5. Among the poorly correlating metabolites, which were mainly below the detection limit, correlation was not expected. In this group several carnitines were found. These results show that the introduced platform is robust, especially given that the measurements were performed 2 years after the initial study in Germany, using different version of the equipment. Moreover, this pilot trial was performed completely manually, which might introduce some variation. Therefore, we are currently procuring a robotic system that will allow high throughput with low variability.

Conclusion

Within the cooperation of an Academic Health System between two leading scientific institutions in Qatar (HMC and Weill Cornell Medical) we established and validated a non-targeted metabolomics platform – MetaQ – which now can serve as a hub for targeted metabolomics studies for researchers of various areas in Qatar. Moreover Biocrates Life Sciences AG also offers assays for bile acids, steroids and biogenic amines that can also be processed on this platform.

Background

The world's obese population is continuing to grow at an alarming rate and Qatar posts one of the highest obese populations in the Middle East relative to its total population. Data from the supreme council for health shows that 70% of Qataris are either overweight or obese1. This development represents an increased risk for notable complications of obesity such as type 2 diabetes, hypertension and other cardiovascular diseases among the population. Although angiogenesis tries to keep up with the need of the expanding fat, the balance is not always achievable resulting in hypoxia and dysregulated secretory functions2. As a result, a more pro-inflammatory milieu is established with adverse impact on local blood vessels. Thus, vascular dysfunctions account for much of the morbidity of obesity with the vascular endothelium often an early target of the changing metabolic status of the obese individual. In this regard, arteries that supply visceral fat tissues are more prone to dysfunction as we previously showed in omental (OM) arteries from morbidly obese Qataris3.

Endothelial dysfunction typically refers to reduced ability of the endothelium to influence the relaxation of the underlying vascular smooth muscle. This is widely believed to be due to reduction in endothelium-derived dilators particularly nitric oxide (NO) 4. Although a number of potential causes of reduction in NO and other endothelium-derived dilator molecules have been investigated over the years including decrease in eNOS expression and increase in reactive oxygen species, the molecular mechanisms underlying endothelial dysfunction in obesity are still not well understood. In a recent report, it was suggested that enhanced cyclooxygenase (COX) enzyme activity which favour increased formation of vasoconstrictor prostanoids might play a major part in the endothelial dysfunction suffered by blood vessels embedded in the visceral adipose tissue depots of individuals with morbid obesity5. COX converts arachidonic acid into endoperoxide (PGH2), an intermediate in prostanoid biosynthetic pathway, which can either act as an endothelium-derived contracting factor (EDCF) or be further transformed into prostacyclin (PGI2), thromboxane A2 (TXA2) or various other prostaglandins6, 7. In healthy endothelium, the balance is in the favour of relaxing prostanoids mainly prostacyclin8. However, this balance can be reversed in diseases such as hypertension, diabetes and atherosclerosis, in the favour of contractile prostanoids such as TXA2, which otherwise is predominantly formed in platelets. TXA2 and EDCF antagonize relaxation through binding to distinct receptors, the TP receptors expressed on vascular smooth muscle. Although circulating levels of TXA2 are increased in obesity9, the link with endothelial dysfunction has not been fully established. The aim of the current study was therefore to determine the sensitivity of the OM and subcutaneous (SC) arteries from morbidly obese Qataris to TXA2 and to relate this to the functional state of their endothelium.

Methods

A total of 12 obese Qatari male (4) and female (8) patients undergoing bariatric surgery for weight reduction at Hamad general hospital were studied. Their physical (anthropometric) and clinical (blood pressure) parameters were measured. Body Mass Index (BMI) was calculated from their heights and weights using the formula: Weight (Kg)/Square of Height (M). Mean arterial blood pressure (MAP) was calculated with the formula: 1/3 pulse pressure (systolic – diastolic pressures) + diastolic pressure. Blood was collected prior to surgery and separated to obtain plasma or serum. Fasting serum insulin, plasma Il-6 and leptin were measured by Enzyme-linked immunosorbent assay (ELISA, R & D Systems). OM and SC adipose tissue samples were collected during surgery into Cellgro medium. Arteries embedded in the adipose tissues were isolated and cut into segments (∼2 mm long) and mounted on wire myographs in normal physiological solution (PSS) containing (in mM), NaCl 112, KCl 5, CaCl2 1.8, MgCl2 1, NaHCO3 25, KH2PO3 0.5, NaH2PO3 0.5 and glucose 10. The segments were pre-tensioned to an equivalent of 100 mmHg and continuously aerated with 95% O2/5% CO2 to pH 7.4 at 37 °C. An equilibration period of at least 1 h was allowed during which 90 mM KCl was added to test for viability and thereafter 10 μM noradrenaline (NA) to optimize tissue responsiveness. Cumulative concentration-response curves were then constructed for NA (10-9 – 10-4.5 M) and the thromboxane analogue U46619 (10-11 – 10-5.5 M) in separate experiments on the same segments.

Results

The patients were 33 ± 3 years old and had BMI of 51 ± 4 Kg.m^− 2, mean arterial pressure (MAP) 88 ± 3 mmHg, fasting serum insulin of 7.04 (2.27–38.67) miU/ml, plasma Il-6 3.73 (2.70–8.70) pg/ml and plasma leptin 51.33 ± 5.81 ng.ml. Maximum NA contractions of both OM and SC arteries from same patient were similar. In contrast, U46619 contractions were significantly greater in OM compared with SC arteries from same patient (p < 0.01). When contractions to both agonists were compared on the same vessel, differences were only recorded in the OM arteries which were more sensitive to U46619 (log EC50 − 7.81 ± 0.08) compared with NA ( − 6.65 ± 0.13, p < 0.001). In addition, the OM artery curve for U46619 was significantly shifted to the left of the curve for NA (p < 0.001) with Emax for U46619 (0.05 ± 0.005 mN/μm) significantly greater than that for NA (0.03 ± 0.006 mN/μm, p < 0.01). There were no differences in both U46619 and NA contractions of the SC arteries. Emax for U46619 in SC arteries was 0.03 ±  0.008 mN/μm and for NA was 0.03 ± 0.005 mN/μm. There were also no differences in the sensitivities of the SC arteries to U46619 and NA. The log EC50 values for these agonists in the SC arteries were − 7.59 ± 0.19 vs − 6.92 ± 0.35 for U46619 and NA respectively.

Conclusion

The data show that OM arteries are hyper responsive to thromboxane A2 compared with SC arteries. In contrast, the response to noradrenaline was muted in the same arteries. We previously showed that in the Qatari obese population, endothelial dysfunction specifically occurs in OM arteries and not in SC arteries3. Since enhanced COX activity has been demonstrated in OM arteries in obesity5, we hypothesized that under this condition, increased production of contractile prostanoids would contribute to vascular dysfunction. The enhanced responsiveness to thromboxane A2 seen in the current study suggests that contractile prostanoids could indeed contribute to the endothelial dysfunction suffered by OM arteries in morbid obesity. The data also suggests that circulating levels of thromboxane A2 would more likely differentially and adversely impact OM arteries in obesity.

References

[1] Supreme Council for Health, Qatar health report 2012, page 22.

[2] Ouchi N, Parker JL, Lugus JJ, Walsh K. Adipokines in inflammation and metabolic disease. Nat Rev Immunol. 2011; 11(2):85–97.

[3] Nelson Orie Impact Of Metabolic Health On Microvascular Endothelial Function In Morbidly Obese Qataris. DOI:10.5339/qfarf.2013.BIOP-016. Published online: 22 Nov 2013

[4] Lerman A, Burnett JC., Jr Intact and altered endothelium in regulation of vasomotion. Circulation. 1992;86(Suppl III):III-12–III-19

[5] Farb MG1, Tiwari S, Karki S, Ngo DT, Carmine B, Hess DT, Zuriaga MA, Walsh K, Fetterman JL, Hamburg NM, Vita JA, Apovian CM, Gokce N. Cyclooxygenase inhibition improves endothelial vasomotor dysfunction of visceral adipose arterioles in human obesity. Obesity (Silver Spring). 2014 Feb;22(2):349–55

[6] Ge T, Hughes H, Junquero DC, Wu KK, Vanhoutte PM, Boulanger CM. Endothelium-dependent contractions are associated with both augmented expression of prostaglandin H synthase-1 and hypersensitivity to prostaglandin H2 in the SHR aorta. Circ. Res. 1995; 76: 1003–10.

[7] Wong MS, Vanhoutte PM. COX-mediated endothelium-dependent contractions: from the past to recent discoveries. Acta Pharmacologica Sinica (2010) 31: 1095–1102

[8] Moncada S, Gryglewski RJ, Bunting S, Vane JR. An enzyme isolated from arteries transforms prostaglandin endoperoxides to an unstable substance that inhibits platelet aggregation. Nature 1976; 263: 663–65.

[9] Canales A1, Bastida S, Librelottto J, Nus M, Sánchez-Muniz FJ, Benedi J. Platelet aggregation, eicosanoid production and thrombogenic ratio in individuals at high cardiovascular risk consuming meat enriched in walnut paste. A crossover, placebo-controlled study. Br J Nutr. 2009 Jul;102(1):134–41.

Background and Objectives

Walking is the most natural and important activity of daily living as it refers to the primary type of terrestrial human locomotion. Analyses of gait patterns typically examine the speed and manner in which people prefer to walk. Even though humans can walk at speeds ranging from near 0 km/h to 9 km/h, they typically only use a very limited range of speeds around 4.5 km/h in their daily life (Bohannon & Andrews, 2011). The preferred walking speed (PWS) is used in clinical settings as an indicator of a person's mobility. For example, elderly people, or those suffering from osteoarthritis prefer to walk at slower speeds. Therefore, improving their PWS is considered as a significant clinical goal.

Many studies on gait analysis tried to identify the basic parameters of normal unconstrained gait in different populations. Despite the fundamental common shared characteristics, walking patterns may vary from a person to another according to several factors such as age, gender, physical characteristics, etc. In a study examining the “pace” of random pedestrians in 31 cities around the world, differences in the walking speed were found to be linked to parameters such as climate, economic variables, size of population and cities (Levine & Norenzayan, 1999). More recently, a study has put forward the impact of the cultural background on walking norms by revealing several significant differences in basic gait parameters between young Kuwaiti and Swedish adults (Al-Obaidi et al., 2003). Specifically, the authors presented the first evidence concerning walking patterns in a population from the Gulf region and proposed an interpretation to the found differences that is linked to traditional clothing and foot wear. This reveals the need for a specific normative database targeting healthy young Qataris. Creating such databases for Qatar is desirable for rehabilitation purposes for people with impaired walking patterns (e.g., elderly fallers, people suffering from stroke consequences, hemiplegia, Parkinson disease, etc).

For instance, the aim of this study is to evaluate the preferred walking speed and manners in which young male and female Qatari adults walk as compared to non-Qatari participants with similar physical characteristics. To characterize walking patterns we used spatiotemporal kinematic indicators such as stride length, stride frequency and support phase duration. The associated physiological cost and perceived exertion of walking at a preferred pace will also be examined to test for possible differences. We expect to see differences between the preferred walking patterns of Qatari and non-Qatari participants as proposed by Al-Obaidi and collaborators (2003).

Methods

34 healthy volunteers participated in the experiment and were distributed in four groups according to their gender and ethnic cultural background (wearing cultural clothing or not): 9 Qatari females (21.33 ±  2.11 years), 9 Qatari males (24.00 ±  2.40 years), 9 non-Qatari females (22.00 ±  1.49 years) and 7 non-Qatari males (22.83 ±  1.73 years). Participants were asked to perform two sessions on the same visit with a total duration of 1.5 hours. The first session started after 10 minutes of familiarization and warm-up on a medical treadmill (Lode Valiant, the Netherlands) and consisted of a determination test of the preferred walking speed (PWS) using a standardized protocol (Jordan, Challis, and Newell, 2007). In the second session, participants walked at their PWS for three minutes. Using a gas analyzer (Metalyzer 3B, Cortex, Germany) and a synchronized heart rate monitor (Polar, Finland), the relative oxygen uptake (VO2, mlO2/kg/min) and heart rate (HR, beats/min) were collected at the last minute when a steady state was reached and the metabolic cost of transport (MCT, mlO2/kg/km) was computed according to the individual PWS. Furthermore, the rating of perceived exertion (RPE) was collected using the Borg Scale (6–20). Spatiotemporal kinematic data such as stride length (SL, cm/stride), stride frequency (strides/sec) and contact phase duration within a stride (Contact, sec) were computed using a video analysis and modeling tool (tracker 4.91) from 15 strides filmed in the middle of the three-minute trial at PWS with a sampling frequency of 25 Hz. Using independent t-tests, comparisons were made for Qatari men versus non-Qatari men and for Qatari women versus non-Qatari women for each of the eight variables. All statistical analyses were performed in Statistica 7.1 package with a level of significance set at p <  .05.

Results

No significant differences were found in the physical characteristics (i.e., body height and body weight) between Qatari male and non-Qatari male groups or between Qatari female and non-Qatari female groups (Table 1). This validates the fair investigation of differences in other variables. As shown in Table 1, no significant differences in all tested variables were noted between Qatari and non-Qatari female participants. However, results revealed a significantly lower PWS and CPD for Qatari males compared to non-Qatari males (Table 1). Furthermore, Qatari males had a significantly lower SF compared to non-Qatari male participants (Table 1). All other tested variables were non-significantly different between Qatari and non-Qatari male groups.

Table 1

Conclusions

Our results showed significant differences in the preferred walking patterns between Qatari and non-Qatari as expected. Surprisingly, these differences only concerned male groups while female groups exhibited non-significant differences in the speed or the manner in which they preferred to walk. Specifically, the slower walking pattern of Qatari male participants doesn't seem to be explained by any of the tested physiological (metabolic) or perceptual factors. Spatiotemporal parameters however seemed to be better candidates in explaining the discrepancy in the preferred walking speed. Results on stride characteristics indicate that the time required to perform one stride and the time where the foot is in contact with the ground (within one stride) was significantly longer for Qatari male participants compared to non-Qataris in the same gender group. Although all participants were wearing their sports outfits during the experiment, results could be interpreted as long-term adaptations in gait patterns to wearing traditional clothing and/or footwear. Indeed, male (i.e, thobe) and female (i.e., abaya) cultural clothing in Qatar are not similar in their structure and material which might explain why differences were only found in male and not female volunteers. This interpretation was also proposed in a previous study on Kuwaitis walking patterns (Al-Obaidi et al., 2003) that suggested a need to include diverse cultural background when developing databases on normal walking for different ethnic groups. Further investigations would be needed to create a larger database with a bigger sample and extend the findings of this pilot study.

References

Al-Obaidi, S., Wall, J. C., Al-Yaqoub, A., & Al-Ghanim, M. (2003). Basic gait parameters: A comparison of reference data for normal subjects 20 to 29 years of age from Kuwait and Scandinavia. Journal of rehabilitation research and development, 40(4), 361–366.

Bohannon, R. W., Andrews, W. A. (2011). Normal walking speed: a descriptive meta-analysis. Physiotherapy. 97, 182–189.

Jordan, K., Challis, J. H., & Newell, K. M. (2007). Walking speed influences on gait cycle variability. Gait & Posture, 26(1), 128–34.

Levine, R. V., & Norenzayan, A. (1999). The Pace of Life in 31 Countries. Journal of Cross-Cultural Psychology. 30, 178–205.