Determinants of the haemoglobin level in patients with sickle cell disease living in sub-Saharan Africa: Major impact of the country of residence and independent effects of leucocyte and platelet counts and haemolysis.

The degree of anaemia in sickle cell disease (SCD) is a well-known contributor to morbidity and mortality. We aimed to explore the factors affecting haemoglobin (Hb) level in African SCD patients, considering haemolysis biomarkers (LDH and bilirubin level, and reticulocyte count), leucocyte and platelet counts and socio-demographic characteristics (gender, age group, country of residence and BMI). The research was part of the CADRE multinational cohort and involved 3699 SCD patients living in Mali, Senegal, Ivory Coast, Democratic Republic of Congo, Gabon and Cameroon: 2936 SS/Sß0, 587 SC and 176 Sß + patients with median Hb level of 8, 11.3 and 11.2 g/dL respectively (p < 0.001). In multivariate analysis conducted in 1394 SS/Sß0 patients, living in Cameroon, female gender, lower BMI, higher haemolysis markers (especially LDH) and higher leucocyte and platelet counts were independently associated with lower Hb level (all p < 0.05). In 497 SC and 156 Sß + patients, female gender (p < 0.001), lower BMI (p < 0.05) and higher platelet counts (p < 0.001) were independently associated with lower Hb level. Anaemia in African SCD patients is not only associated with haemolysis but also with the country of residence, lower BMI and leucocyte or platelet counts which might reflect inflammation related to infectious burden in the region.

Metabolic Profile of Individuals with and without Type 2 Diabetes from Sub-Saharan Africa.

Epidemiological data predicts that sub-Saharan Africa will have the largest increase in type 2 diabetes (T2D) prevalence over the next two decades. Metabolomics studies have identified biomarkers that could improve T2D diagnosis and follow-up. However, no studies have characterized the metabolome of people from sub-Saharan Africa. Plasma samples from Senegalese individuals with T2D (n = 31) or without T2D (n = 34) were compared using measures of oxidative stress damage and plasma antioxidant enzyme activity and mass-spectrometry-based metabolomics analyses. Results showed that glucose, lactate, and tricarboxylic acid metabolites (fumarate, malate, and succinate) were increased in the T2D group, suggesting alterations in glycolysis and mitochondrial dysfunction. Several amino acids (leucine, isoleucine, valine, and tryptophan) and long-to-very-long-chain fatty acids were higher in the T2D group. Finally, elevated levels of ketone bodies and acylcarnitines were observed along with increased levels of oxidative stress damage and antioxidant activity. In conclusion, the T2D group exhibited modifications in metabolites previously shown to be associated with T2D risk in populations from other areas of the world. Future studies should seek to test whether these metabolites could be used as predictors for T2D-related complications in people from sub-Saharan Africa.

Association of haemolysis markers, blood viscosity and microcirculation function with organ damage in sickle cell disease in sub-Saharan Africa (the BIOCADRE study).

Sickle cell anaemia (SCA) is a monogenic disease with a highly variable clinical course. We aimed to investigate associations between microvascular function, haemolysis markers, blood viscosity and various types of SCA-related organ damage in a multicentric sub-Saharan African cohort of patients with SCA. In a cross-sectional study, we selected seven groups of adult patients with SS phenotype in Dakar and Bamako based on the following complications: leg ulcer, priapism, osteonecrosis, retinopathy, high tricuspid regurgitant jet velocity (TRV), macro-albuminuria or none. Clinical assessment, echocardiography, peripheral arterial tonometry, laboratory tests and blood viscosity measurement were performed. We explored statistical associations between the biological parameters and the six studied complications. Among 235 patients, 58 had high TRV, 46 osteonecrosis, 43 priapism, 33 leg ulcers, 31 retinopathy and 22 macroalbuminuria, whereas 36 had none of these complications. Multiple correspondence analysis revealed no cluster of complications. Lactate dehydrogenase levels were associated with high TRV, and blood viscosity was associated with retinopathy and the absence of macroalbuminuria. Despite extensive phenotyping of patients, no specific pattern of SCA-related complications was identified. New biomarkers are needed to predict SCA clinical expression to adapt patient management, especially in Africa, where healthcare resources are scarce.

Cell-derived microparticles and sickle cell disease chronic vasculopathy in sub-Saharan Africa: A multinational study.

Although most individuals with sickle cell disease (SCD) live in sub-Saharan Africa, the natural history of the disease on this continent remains largely unknown. Intravascular haemolysis results in activation of circulating blood cells and release of microparticles (MPs) that exert pro-inflammatory effects and contribute to vascular damage. We designed a case-control study nested in the CADRE cohort (Coeur-Artère-DRÉpanocytose, clinical trials.gov identifier NCTO3114137) and based on extreme phenotypes, to analyse blood cell-derived MPs in 232 adult SS patients at steady state in Bamako and Dakar. Thirty-six healthy adult controls matched by age and sex were recruited in Bamako. The MPs concentrations were higher in SS patients compared to AA controls with a predominance of erythrocyte- and reticulocyte-derived MPs. These erythroid-derived MPs were significantly lower in patients with retinopathy (P = 0·022). Reticulocyte-derived MPs were significantly negatively and positively associated with a history of priapism (P = 0·020) and leg ulcers (P = 0·041) respectively. We describe for the first time the comparative patterns of plasma MPs in healthy subjects and patients with SCD living in sub-Saharan Africa and exhibiting various complications. Because our present results show no clear pattern of correlation between erythroid MPs and the classical hyper-haemolytic complications, we hypothesise a weak relevance of the hyper-haemolysis versus hyper-viscous paradigm in Africa.

Altered blood rheology and impaired pressure-induced cutaneous vasodilation in a mouse model of combined type 2 diabetes and sickle cell trait.

OBJECTIVE: Type 2 diabetes (T2D)-related vascular dysfunction and hemorheological abnormalities could possibly be amplified by sickle cell trait (SCT). These alterations could potentially increase the risk of vascular complications in individuals with combined T2D and SCT. Therefore, this study used a mouse model to determine whether vascular function and blood rheology were more severely altered in combined T2D and SCT than in T2D or SCT alone. METHODS: Townes transgenic mice with or without SCT received a 12-week high fat high sucrose or standard diet to create models of combined T2D-SCT, T2D, SCT, and controls. Pressure-induced vasodilation (PIV) and sodium nitroprusside (SNP)-mediated vasodilation in-vivo, and hemorheological parameters were measured. RESULTS: No significant differences in blood viscosity, hematocrit, erythrocyte deformability, or PIV were observed between the control and T2D mice, or the control and SCT mice. However, blood viscosity, erythrocyte deformability, and PIV were significantly altered in the T2D-SCT mice compared to the control mice. There were no differences in SNP response between the groups. CONCLUSIONS: Although neither T2D nor SCT alone had significant effects on blood rheology parameters or vascular function, combined T2D-SCT mice had significantly altered blood rheology and significantly impaired vascular function.

[Prevalence of smoking among 741 High school students from Dakar. Carbon monoxide measurement]. / Prevalence du tabagisme parmi 741 Lycéens de Dakar : Intérêt de la mesure du monoxide de carbone.

BACKGROUND: Tobacco consumption is a net increase in our areas. In Senegal, as in other African countries, sponsorship of cultural and sporting events in schools promote tobacco use among schoolchildren. Our objective was to assess the prevalence of tobacco in the French School of Jean Mermoz of Dakar by a survey completed by a measurement of carbon monoxide (CO) in expired air. METHODS: seven hundred forty-one students (n = 402 girls and n = 339 boys), aged 11 to 18 years of French and African cultures, participated in the study. A questionnaire with several items of smoking has been distributed to them . Two weeks after the collection of questionnaires, the CO measuring for all students was conducted. RESULTS: The prevalence of smoking in High School was 23.1% and smoking was found more in boys according to the questionnaire and piCO+TM with 13.7% and 7.1% respectively. It affected over the upper age class or equal to fifteen years. The most mentioned reason for the initiation of smoking (45.4% of smokers) was curiosity with a need to be free, followed by the influence of the environment famial (44.4%) and friendly (20.5%). The measurement of carbon monoxide showed that 12.4% of our subjects had a smoking profile with 8% light smoking, 1% moderate smoking, and severe smoking was 3% of our students. A significant difference (p = 0.0021) between the two prevalences was found. CONCLUSION: The carbon monoxide intoxication by tobacco use is responsible for microcirculatory accidents such as tissue hypoxia, whereas smoking affects young students, in which the phenomenon is more precocious. Thus it is urgent to establish a policy of tobacco control in schools.

Effects of hydration and water deprivation on blood viscosity during a soccer game in sickle cell trait carriers.

The present study compared the changes in blood viscosity, hydration status, body temperature and heart rate between a group of sickle cell trait (SCT) carriers and a control (Cont) group before and after a soccer game performed in two conditions: one with water offered ad libitum (hydration condition; Hyd) and the other one without water (dehydration condition; Dehyd). Blood viscosity and haematocrit per blood viscosity ratio (HVR; an index of red blood cell oxygen transport effectiveness) were measured before and at the end of each game. Resting blood viscosity was greater in the SCT carriers than in the Cont group. The increase of blood viscosity over baseline at the end of the game in the Cont group was similar in the two conditions. In contrast, the change in blood viscosity occurring in SCT carriers during soccer games was dependant on the experimental condition: (1) in Dehyd condition, blood viscosity rose over baseline; (2) in Hyd condition, blood viscosity decreased below resting level reaching Cont values. The Cont group had higher HVR than SCT carriers at rest. HVR remained unchanged in the Cont group at the end of the games, whatever the experimental condition. Although HVR of SCT carriers decreased below baseline at the end of the game performed in Dehyd condition, it increased over resting level in Hyd condition reaching the values of the Cont group. Our study demonstrated that ad libitum hydration in exercising SCT carriers normalises the blood hyperviscosity.

Strengthening and utilizing response groups for emergencies flagship: a narrative review of the roll out process and lessons from the first year of implementation.

The World Health Organization Regional Office for Africa (WHO/AFRO) faces members who encounter annual disease epidemics and natural disasters that necessitate immediate deployment and a trained health workforce to respond. The gaps in this regard, further exposed by the COVID-19 pandemic, led to conceptualizing the Strengthening and Utilizing Response Group for Emergencies (SURGE) flagship in 2021. This study aimed to present the experience of the WHO/AFRO in the stepwise roll-out process and the outcome, as well as to elucidate the lessons learned across the pilot countries throughout the first year of implementation. The details of the roll-out process and outcome were obtained through information and data extraction from planning and operational documents, while further anonymized feedback on various thematic areas was received from stakeholders through key informant interviews with 60 core actors using open-ended questionnaires. In total, 15 out of the 47 countries in WHO/AFRO are currently implementing the initiative, with a total of 1,278 trained and validated African Volunteers Health Corps-Strengthening and Utilizing Response Groups for Emergencies (AVoHC-SURGE) members in the first year. The Democratic Republic of Congo (DRC) has the highest number (214) of trained AVoHC-SURGE members. The high level of advocacy, the multi-sectoral-disciplinary approach in the selection process, the adoption of the one-health approach, and the uniqueness of the training methodology are among the best practices applauded by the respondents. At the same time, financial constraints were the most reported challenge, with ongoing strategies to resolve them as required. Six countries, namely Botswana, Mauritania, Niger, Rwanda, Tanzania, and Togo, have started benefiting from their trained AVoHC-SURGE members locally, while responders from Botswana and Rwanda were deployed internationally to curtail the recent outbreaks of cholera in Malawi and Kenya.

Plasma Levels of Acyl-Carnitines and Carboxylic Acids Correlate With Cardiovascular and Kidney Function in Subjects With Sickle Cell Trait.

Subjects with sickle cell trait (SCT) carry one copy of mutated ß-globin gene at position E6V at the origin of the production of sickle hemoglobin (HbS). Indeed, individuals with SCT have both normal hemoglobin and HbS, in contrast to patients with sickle cell disease who inherited of two copies of the mutated gene. Although SCT is generally benign/asymptomatic, carriers may develop certain adverse outcomes such as renal complications, venous thromboembolism, exercise-induced rhabdomyolysis … However, little is known about whether similar metabolic pathways are affected in individuals with SCT and whether these metabolic derangements, if present, correlate to clinically relevant parameters. In this study, we performed metabolomics analysis of plasma from individuals with sickle cell trait (n = 34) compared to healthy controls (n = 30). Results indicated a significant increase in basal circulating levels of hemolysis markers, mono- (pyruvate, lactate), di- and tri-carboxylates (including all Krebs cycle intermediates), suggestive of systems-wide mitochondrial dysfunction in individuals with SCT. Elevated levels of kynurenines and indoles were observed in SCT samples, along with increases in the levels of oxidative stress markers (advanced glycation and protein-oxidation end-products, malondialdehyde, oxylipins, eicosanoids). Increases in circulating levels of acyl-carnitines and fatty acids were observed, consistent with increased membrane lipid damage in individuals with sickle cell trait. Finally, correlation analyses to clinical co-variates showed that alterations in the aforementioned pathways strongly correlated with clinical measurements of blood viscosity, renal (glomerular filtration rate, microalbuminuria, uremia) and cardiovascular function (carotid-femoral pulse wave velocity, blood pressure).

Gender gap in annual preventive care services in France.

Background: In France, screening for cardiovascular risk factors is recommended during annual preventive visits. However, data are lacking on the temporal trend in women's uptake to preventive care services, and in cardiovascular and mortality outcomes. The aim of the study was to investigate the participation and mortality of women in annual preventive care services in a major preventive medicine center in France. Method: Ee conducted repeated cross-sectional studies including a total of 366,270 individuals who had a first examination at the Centre d'Investigations Préventives et Cliniques, France, between January 1992 and December 2011. Findings: Women's participation was low below 50 years of age, then increases from 50 to 70 years, and is lower for women older than 70 years. The gap in female participation was more pronounced among individuals with high education, low social deprivation, and no depressive symptoms. Compared with the general population, the screened population had significantly lower standardized mortality ratios (SMRs) among both men and women, for all age ranges. Screened women aged 18-49 years showed a lower mortality gain compared with men of the same age; SMRs did not differ significantly by sex for individuals over 50 years. Interpretation: In this community-based sample, compared with men, women's participation to annual preventive care services was lower, and screened women had a lower mortality gain. Despite the demonstrated benefit of annual check-ups on health, there is a gender gap in adherence to preventive programs and in efficiency of screening programs, especially in the young age range. This gap in cardiovascular disease prevention may result in poorer cardiovascular health in women. Urgent adaptations to overcome this gender gap in preventive screening in France are warranted. Funding: Bamba Gaye is supported by the Fondation Recherche Médicale grant.

Mild haemorheological changes induced by a moderate endurance exercise in patients with sickle cell anaemia.

The levels and duration of physical activity that can be considered as completely safe in patients with sickle cell anaemia (SCA) is unknown. The present study compared the haemorheological and haematological profile, cell density distribution and basic biochemistry between a group of 17 patients with SCA and 21 healthy subjects before and after a 20 min duration submaximal cycling exercise at the same absolute workload. Blood was sampled at rest and 3 min after the end of exercise for measurement of biological parameters. Exercise did not affect the haematocrit and blood viscosity in the two groups. Plasma viscosity was not different between the two groups at rest and similarly increased with exercise. The proportion of intermediary dense cells (with density between 1·11 and 1·12 g/ml) decreased with exercise in the SCA group resulting in an increase in the proportion of red blood cells with a density >1·12 g/ml. No change was observed in the control group. The present study suggests that mild-moderate exercise is not very harmful for SCA patients. The haemorheological and haematological changes were very mild, except for the formation of dense cells but no clinically significant signs of medical complication were present in any of the patients.

Effects of hydration and dehydration on blood rheology in sickle cell trait carriers during exercise.

This study compared the hemorheological responses of a group of sickle cell trait (SCT) carriers with those of a control (Cont) group in response to 40 min of submaximal exercise (exercise intensity, 55% aerobic peak power) performed in two conditions: one with water offered ad libitum, i.e., the hydration (Hyd) condition, and one without water, i.e., the dehydration (Dehyd) condition. Blood and plasma viscosities, as well as red blood cell rigidity, were determined at rest, at the end of exercise, and at 2 h recovery with a cone plate viscometer at high shear rate and 37 degrees C. The SCT and Cont groups lost 1 +/- 0.7 and 1.6 +/- 0.6 kg of body weight, respectively, in the Dehyd condition, indicating a significant effect of water deprivation compared with the Hyd condition, in which body weight remained unchanged. Plasma viscosity increased with exercise and returned to baseline during recovery independently of the group and condition. As previously demonstrated, resting blood viscosity was greater in the SCT carriers than in the Cont group. Blood viscosity increased by the end of exercise and returned to baseline at 2 h recovery in the Cont group in both conditions. The blood viscosity of SCT carriers did not change in response to exercise in the Dehyd condition and remained elevated at 2 h recovery. This extended hyperviscosity, in association with other biological changes induced by exercise, could be considered as a risk factor for exercise-related events in SCT carriers, similar to vasoocclusive crises, notably during the recovery. In contrast, the Hyd condition normalized the hyperviscosity and red blood cell rigidity of the SCT carriers, with blood viscosity values reaching the same lower values as those found in the Cont group during the recovery. Adequate hydration of SCT carriers should be strongly promoted to reduce the clinical risk associated with potential hyperviscosity complications.

In-situ fluorescence spectroscopy indicates total bacterial abundance and dissolved organic carbon.

We explore in-situ fluorescence spectroscopy as an instantaneous indicator of total bacterial abundance and faecal contamination in drinking water. Eighty-four samples were collected outside of the recharge season from groundwater-derived water sources in Dakar, Senegal. Samples were analysed for tryptophan-like (TLF) and humic-like (HLF) fluorescence in-situ, total bacterial cells by flow cytometry, and potential indicators of faecal contamination such as thermotolerant coliforms (TTCs), nitrate, and in a subset of 22 samples, dissolved organic carbon (DOC). Significant single-predictor linear regression models demonstrated that total bacterial cells were the most effective predictor of TLF, followed by on-site sanitation density; TTCs were not a significant predictor. An optimum multiple-predictor model of TLF incorporated total bacterial cells, nitrate, nitrite, on-site sanitation density, and sulphate (r2 0.68). HLF was similarly related to the same parameters as TLF, with total bacterial cells being the best correlated (ρs 0.64). In the subset of 22 sources, DOC clustered with TLF, HLF, and total bacterial cells, and a linear regression model demonstrated HLF was the best predictor of DOC (r2 0.84). The intergranular nature of the aquifer, timing of the study, and/or non-uniqueness of the signal to TTCs can explain the significant associations between TLF/HLF and indicators of faecal contamination such as on-site sanitation density and nutrients but not TTCs. The bacterial population that relates to TLF/HLF is likely to be a subsurface community that develops in-situ based on the availability of organic matter originating from faecal sources. In-situ fluorescence spectroscopy instantly indicates a drinking water source is impacted by faecal contamination but it remains unclear how that relates specifically to microbial risk in this setting.

Evaluation of agreement between hemoglobin A1c, fasting glucose, and fructosamine in Senegalese individuals with and without sickle-cell trait.

Fasting glucose (FG) and glycated hemoglobin A1c (HbA1c) perform sub-optimally in people of African origin, especially in individuals with sickle-cell trait (SCT). The purpose of this study was to compare the relationships between HbA1c, FG, and fructosamine in individuals from Senegal with and without SCT. HbA1c, FG, and fructosamine were measured in 203 adults from Senegal (100 control: 45 with type 2 diabetes (T2D); 103 SCT: 51 with T2D). Significant, positive correlations were observed between HbA1c and FG, fructosamine and FG, and fructosamine and HbA1c in both groups. The limits of agreement were inappropriately large in both groups for the Bland-Altman plots of HbA1c and FG (control: -95.97 to 83.97%; SCT: -115.9 to 91.52%), fructosamine and FG (control: -100.6 to 99.89%; SCT: -105.6 to 100.6%), and fructosamine and HbA1c (control: -52.03 to 38.98%; SCT: -88.04 to 71.41%). In both groups, the greatest proportion of subjects were considered above the clinical cut-point for hyperglycemia when fructosamine was used as the criterion (control: 33%; SCT: 44.6%), and the lowest percentage of subjects were classified as over the clinical cut-point when HbA1c was used as the criterion (control: 21%; SCT: 27.7%).Substantial disparities between HbA1c, FG, and fructosamine were observed in both groups, and these differences were exaggerated in the SCT group. Therefore, these three biomarkers should not be considered to be interchangeable measures of glycemic control. These biomarkers should be used thoughtfully, and special care should be taken when using them in individuals with SCT.

Pulse wave velocity is lower in trained than in untrained sickle cell trait carriers.

BACKGROUND: Sickle cell trait (SCT) is a benign condition of sickle cell disease. Nevertheless, previous reports showed that SCT carriers have increased blood viscosity and decreased vascular reactivity compared to non-SCT carrier. The benefit of regular exercise on vascular function has been well documented in the general population but no study focused on the SCT population. PURPOSE: The aim of our study was to compare arterial stiffness and blood viscosity between trained and untrained SCT carriers, as well as a group of untrained non-SCT. METHODS: Arterial stiffness (finger-toe pulse wave velocity) and blood viscosity were evaluated in untrained non-SCT carriers (n = 10), untrained SCT carriers (n = 23) and trained SCT carriers (n = 17) who reported at least 10 hours of physical exercise per week. RESULTS: Untrained SCT carriers had higher pulse wave velocity (p = 0.032) and blood viscosity (p < 0.001) than their trained counterparts. In addition, untrained SCT carriers had higher blood viscosity (p < 0.001) than the untrained non-SCT group. A positive association was noted between blood viscosity and pulse wave velocity in the whole study population. CONCLUSION: Our study suggests that regular exercise may be beneficial for the vascular function of SCT carriers.

Increased Prevalence of Type 2 Diabetes-Related Complications in Combined Type 2 Diabetes and Sickle Cell Trait.

OBJECTIVE: The prevalence of type 2 diabetes (T2D) is rapidly increasing in sub-Saharan Africa, where sickle cell trait (SCT) is also frequent. Although SCT is generally considered a benign condition, evidence suggests that SCT could exaggerate vascular dysfunction in T2D. However, it remains unclear whether SCT could increase the risk of the development of T2D complications. Therefore, this study was conducted to determine whether T2D complications were more prevalent among Senegalese individuals with SCT and T2D than among those with T2D only. RESEARCH DESIGN AND METHODS: Rates of hypertension, retinopathy, peripheral neuropathy, peripheral artery disease, and impaired renal function as well as arterial stiffness, blood rheology, and concentrations of plasma advanced glycation end products (AGEs) and cytokines were compared between groups of Senegalese individuals with combined SCT and T2D (T2D-SCT) (n = 60), T2D (n = 52), SCT (n = 53), and neither T2D nor SCT (control) (n = 56). Human aortic endothelial cell (HAEC) expression of inflammatory and adhesion factors was measured after treatment with tumor necrosis factor-α and subjects' plasma. Effects of AGE inhibition or tiron on HAEC expression of E-selectin were measured. RESULTS: Retinopathy, hypertension, and reduced renal function were more prevalent, and arterial stiffness, blood viscosity at high shear rates, and thixotropic index were higher, in the SCT group compared with the other groups. Multivariable analysis showed that plasma AGE concentration was significantly associated with arterial stiffness. E-selectin expression was elevated in HAECs treated with T2D-SCT plasma compared with the other groups, but AGE inhibition reversed this. CONCLUSIONS: SCT could potentially augment the risk of the development of T2D-related complications, including retinopathy, nephropathy, and hypertension.

Glycemic Control in a Clinic-Based Sample of Diabetics in M'Bour Senegal.

BACKGROUND: Sub-Saharan Africa (SSA) including Senegal is faced with a significant and increasing burden of type 2 diabetes. However, little information is available about diabetes management among Senegalese diabetics. PURPOSE: The current study aims to describe the level of glycemic control among a convenience sample of diabetics who receive care at the M'Bour Hospital in M'Bour, Senegal. METHODS: A total of 106 type 2 diabetic patients were recruited at the hospital complex of M'Bour, Senegal. Linear regression was employed to assess the relationship between clinical and sociodemographic factors and Hba1c. RESULTS: Only 24.8% of the sample had glycemic control, according to an Hba1c test. Participants who were diagnosed earlier were less likely to have diabetes control (mean = 7.8 years) compared with those who were diagnosed more recently (mean = 6.5 years); p< .05. CONCLUSIONS: We found that glycemic control in our sample was suboptimal. Length of time with diabetes was one of the key factors related to glycemic control. Length of time with diabetes is negatively associated with glycemic control. Early diagnosis and early glycemic control are essential to long-term glycemic control screening, and early detection for diabetes is uncommon given the general lack of health insurance and most people paying out of pocket for medical care. In the absence of universal health insurance, public health programs that provide blood sugar screenings for high-risk individuals would provide preliminary indication of abnormal glucose; however, subsequent diagnostic testing and follow-up may still be cost prohibitive.

Blood viscosity is lower in trained than in sedentary sickle cell trait carriers.

The aim of this study was to compare blood and plasma viscosities, as well as the hematocrit/blood viscosity ratio (HVR), between trained and sedentary SCT carriers. Thirty African male SCT carriers from the city of Dakar (Senegal) participated in the study: one group composed of 15 trained SCT carriers (TSCTc) and one group composed of 15 sedentary individuals (SSCTc). Blood was sampled in resting condition and blood and plasma viscosities were measured using a cone-plate viscometer. After the determination of hematocrit by microcentrifugation, HVR was determined for each subject. Blood and plasma viscosities, as well as hematocrit, were significantly reduced in TSCTc compared to SSCTc. As a consequence, HRV was greater in TSCTc. These findings provide evidence that SCT carriers should be encouraged to practice regular physical activity to limit the cardiovascular strain usually caused by their blood hyperviscosity.

Sickle Cell Trait Worsens Oxidative Stress, Abnormal Blood Rheology, and Vascular Dysfunction in Type 2 Diabetes.

OBJECTIVE: It is predicted that Africa will have the greatest increase in the number of patients with type 2 diabetes mellitus (T2DM) within the next decade. T2DM patients are at risk for cardiovascular disorders. In Sub-Saharan African countries, sickle cell trait (SCT) is frequent. Despite the presence of modest abnormalities in hemorheology and oxidative stress, SCT is generally considered a benign condition. Little is known about vascular function in SCT, although recent studies demonstrated an increased risk of cardiovascular disorders, including venous thromboembolism, stroke, and chronic kidney disease. We hypothesized that SCT could accentuate the vascular dysfunction observed in T2DM. RESEARCH DESIGN AND METHODS: The current study, conducted in Senegal, compared vascular function, hemorheological profile, and biomarkers of oxidative stress, inflammation, and nitric oxide metabolism in healthy individuals (CONT), subjects with T2DM or SCT, and patients with both T2DM and SCT (T2DM-SCT). RESULTS: Flow-mediated dilation was blunted in individuals with T2DM, SCT, and T2DM-SCT compared with CONT, with vascular dysfunction being most pronounced in the latter group. Carotid-femoral pulse wave velocity measurements demonstrated increased arterial stiffness in T2DM-SCT. Oxidative stress, advanced glycation end products, and inflammation (interleukin-1ß) were greater in patients with T2DM-SCT compared with the other groups. Blood viscosity was higher in individuals with TD2M, SCT carriers, and individuals with T2DM-SCT, and the values were further increased in the latter group. CONCLUSIONS: Our results demonstrate severe biological abnormalities and marked vascular dysfunction in patients with both T2DM and SCT. SCT should be viewed as a risk factor for further cardiovascular disorders in individuals with T2DM.