Association between the MTNR1B, HHEX, SLC30A8, and TCF7L2 single nucleotide polymorphisms and cardiometabolic risk profile in a mixed ancestry South African population.

Single nucleotide polymorphisms of the TCF7L2, HHEX, SLC30A8, MTNR1B, SLC2A2 and GLIS3 genes are well established candidate genes for cardiometabolic diseases (CMDs) across different ethnic populations. We investigated their association with CMDs in a mixed ancestry population of South Africa. rs10830963, rs1111875, rs11920090, rs13266634, rs7034200 and rs7903146 SNPs were genotyped by quantitative real time PCR in 1650 participants and Hardy-Weinberg equilibrium (HWE) analyses performed on the SNPs. Diabetes, obesity, hypertension and cardiometabolic traits were compared across genotypes of SNPs in HWE. Linear and logistic regressions adjusting for age, gender and body mass index were used to determine the risk of T2DM, obesity and hypertension. rs7903146 (p = 0.055), rs1111875 (p = 0.465), rs13266634 (p = 0.828), and rs10830963 (p = 0.158) were in HWE. The rs10830963 recessive genotype was able to predict FPG, insulin and HOMA-IR, while the rs1111875 recessive genotype was able to predict total cholesterol, triglyceride, LDL cholesterol and FPG. The rs7903146 recessive genotype was able to predict SBP and LDL cholesterol. The recessive genotypes of MTNRIB and HHEX SNPs were associated with T2DM traits in the study population and could partially explain the high prevalence of T2DM. Further studies are required to confirm these findings and establish candidate genes in the African population.

A Review of the Relationship between the Immune Response, Inflammation, Oxidative Stress, and the Pathogenesis of Sickle Cell Anaemia.

Sickle cell anaemia (SCD) is a life-threatening haematological disorder which is predominant in sub-Saharan Africa and is triggered by a genetic mutation of the ß-chain haemoglobin gene resulting in the substitution of glutamic acid with valine. This mutation leads to the production of an abnormal haemoglobin molecule called haemoglobin S (HbS). When deoxygenated, haemoglobin S (HbS) polymerises and results in a sickle-shaped red blood cell which is rigid and has a significantly shortened life span. Various reports have shown a strong link between oxidative stress, inflammation, the immune response, and the pathogenesis of sickle cell disease. The consequence of these processes leads to the development of vasculopathy (disease of the blood vessels) and several other complications. The role of the immune system, particularly the innate immune system, in the pathogenesis of SCD has become increasingly clear in recent years of research; however, little is known about the roles of the adaptive immune system in this disease. This review examines the interaction between the immune system, inflammation, oxidative stress, blood transfusion, and their effects on the pathogenesis of sickle cell anaemia.

Circulating miR-30a-5p and miR-182-5p in Prediabetes and Screen-Detected Diabetes Mellitus.

BACKGROUND: microRNAs (miRNAs) have been touted as potential diagnostic and prognostic biomarkers for various diseases. The aim of the present study was to evaluate the diagnostic value of miR-30a-5p and miR-182-5p for prediabetes and screen-detected type 2 diabetes mellitus (T2DM). METHODS: The study included 1270 participants (207 prediabetes, 94 screen-detected diabetes and 969 normotolerant) from the Vascular and Metabolic Health (VMH) study. Whole blood levels of miR-30a-5p and miR-182-5p were quantitated by RT-qPCR. Multivariable logistic regressions were used to relate miRNAs with prediabetes or T2DM and receiver operating characteristic (ROC) curves were used to evaluate the ability of each miRNA to diagnose these conditions. RESULTS: Both miRNAs were significantly highly expressed in individuals with prediabetes or T2DM (both ≥3.2-fold, and p<0.001). We also observed significant under-expression in T2DM relative to prediabetes for miR-182-5p (0.49-fold, p=0.001). Age, sex and BMI-adjusted partial correlation coefficient analysis revealed a significant correlation between the two miRNAs across glucose tolerance statuses (r≥0.932, p<0.001). In normotolerant individuals, both miRNAs showed a negative correlation with waist circumference and positive correlation with HDL-cholesterol whilst in T2DM they correlated positively with hip circumference, 2-hour insulin, HDL- and LDL-cholesterol. Multivariable logistic regressions revealed both miRNAs to be consistently and continuously associated with prediabetes or T2DM (OR≥1.18, 95% 95% CI: 1.10-1.28, p<0.001), while only miR-182-5p associated with a reduced prevalence of T2DM relative to prediabetes (OR: 0.89, 95% CI: 0.83-0.96, p=0.003). In ROC analyses, miR-182-5p almost outperformed HbA1c in diagnosing prediabetes; area under the curve 0.74 vs 0.69. CONCLUSION: Our findings demonstrate that miR-30a-5p and miR-182-5p are associated with dysglycaemia and could potentially predict prediabetes, particularly miR-182-5p.

A clinical audit of the utilisation of red cell products in elective total hip replacement surgery.

BACKGROUND: Previous studies have documented a marked variation in transfusion practice for total hip replacement (THR) surgery. OBJECTIVE: To audit red cell product utilisation for THR at two Western Cape tertiary referral hospitals (HY and HG). METHODS: The folders of 207 consecutive patients undergoing elective THR surgery from January 2013 to December 2013 were reviewed. Information relating to age, sex, clinical observations, indications for surgery, pre- and postoperative haemoglobin (Hb) values, comorbidities, length of hospital stay and transfusion history was recorded. RESULTS: The transfusion rate at HY (41.6%) was significantly higher than that at HG (10.0%). The mean postoperative Hb in the transfused patients at HG was 8.3 g/dL v. 9.1 g/dL at HY. Females had a significantly higher transfusion rate (33.0%) than males (15.0%) (p<0.05), and the mean age of transfused patients was significantly greater than that of untransfused patients (p<0.005). Although patients with comorbidities had a higher transfusion rate than those without, this did not reach statistical significance. Of 120 patients with complete data, 113 (94.2%) had a blood bank order, of which the vast majority, 102/113 (90.3%), were group-and-screen (G&S) requests; 29/113 (25.7%) were converted to a full crossmatch. CONCLUSIONS: Overall, the transfusion rate for both hospitals was 25.8%, which is well within published rates. A guideline Hb trigger of 8.0 g/dL is recommended as per published guidelines, with the caveat that the clinical judgement of the attending clinician whether a transfusion is indicated is paramount. Causes of preoperative anaemia should be investigated and treated. Routine cross-matching preoperatively is unnecessary, and a G&S order is sufficient.

A Clinical Audit of the Utilisation of Red Cell Products in Elective Total Hip Replacement Surgery

Background. Previous studies have documented a marked variation in transfusion practice for total hip replacement (THR) surgery.Objective. To audit red cell product utilisation for THR at two Western Cape tertiary referral hospitals (HY and HG).Methods. The folders of 207 consecutive patients undergoing elective THR surgery from January 2013 to December 2013 were reviewed. Information relating to age; sex; clinical observations; indications for surgery; pre- and postoperative haemoglobin (Hb) values; comorbidities; length of hospital stay and transfusion history was recorded.Results. The transfusion rate at HY (41.6%) was significantly higher than that at HG (10.0%). The mean postoperative Hb in the transfused patients at HG was 8.3 g/dL v. 9.1 g/dL at HY. Females had a significantly higher transfusion rate (33.0%) than males (15.0%) (p0.05); and the mean age of transfused patients was significantly greater than that of untransfused patients (p0.005). Although patients with comorbidities had a higher transfusion rate than those without; this did not reach statistical significance. Of 120 patients with complete data; 113 (94.2%) had a blood bank order; of which the vast majority; 102/113 (90.3%); were group-and-screen (GetS) requests; 29/113 (25.7%) were converted to a full crossmatch.Conclusions. Overall; the transfusion rate for both hospitals was 25.8%; which is well within published rates. A guideline Hb trigger of 8.0 g/dL is recommended as per published guidelines; with the caveat that the clinical judgement of the attending clinician whether a transfusion is indicated is paramount. Causes of preoperative anaemia should be investigated and treated. Routine cross-matching preoperatively is unnecessary; and a GetS order is sufficient

The evaluation of platelet function in HIV infected, asymptomatic treatment-naïve individuals using flow cytometry.

INTRODUCTION: Human immunodeficiency virus (HIV) induces inflammation and platelet activation. People living with HIV are at increased risk of thrombotic events. Activated platelets link inflammation with thrombosis. However platelet function in HIV remains unclear. P-selectin (CD62P), a marker of platelet activation, and platelet glycoprotein GPIV (CD36) a marker of platelet aggregation, can be measured using flow cytometry. We raise a hypothesis that HIV alters the signalling pathways involved in normal platelet function. We evaluated platelet function in HIV using a whole blood platelet flow cytometry based assay. MATERIALS AND METHODS: Fifty-eight antiretroviral therapy naïve HIV infected and 38 HIV negative individuals were recruited in a clinic in Cape Town. Platelet surface CD36 and CD62P were measured using flow cytometry. These were then correlated with CD4 count, viral load and %CD38 on CD8+ T-cells. Platelet function was evaluated using adenosine diphosphate, arachidonic acid and collagen at varying concentrations. RESULTS: The HIV group showed increased levels of %CD62P (median 5.51[3.03- 10.11] vs. Control group 2.14[0.19 - 3.59], p<0.0001. This correlated with Viral load (r=0.336, P=0.008). The HIV group also showed increased levels of platelet %CD36 21.93[11.03-44.92] vs. Control 16.15[2.24-25.37], p=0.0087) which correlated with viral load (r=0.398, p=0.024). The HIV group showed a hyper response to AA and collagen at various concentrations. Notably, the HIV group only showed a hyper response to ADP at a maximal concentration of 20 µM (median CD62P MFI, 1.91[1.64-4.95] vs. Control 1.75[1.45-2.44] p=0.0279. CONCLUSION: The measurement of platelet function using flow cytometry is a rapid technique for the evaluation of platelet signalling pathways that may be modified in HIV infected individuals.

The clonogenic potential of selected CD34+ cells from patients with MDS appear preserved when tested ex vivo.

Our aim was to examine in 17 patients with MDS the effects of PMA activated and non-activated autologous lymphocytes on selected bone marrow CD34+ progenitors, in dose response studies. We used a double layer culture technique. Compared with controls, there was no difference in the colony growth promoting capacity of autologous PMA stimulated or unstimulated blood lymphocytes from MDS patients. In addition, similar to control studies, increasing numbers of lymphocytes, (0, 1×10(5), 1×10(6)) led to a corresponding increase in the number of CFU-GM (p=0.04). We conclude that MDS blood mononuclear cells have the ability to stimulate colony growth of autologous CD34+ cells while these selected progenitors show a proliferative capacity that is similar to normal when they are isolated from the bone marrow accessory cells.

Dendritic cells, T-cells and their possible role in the treatment of leukaemia and lymphoma.

The immune system has the ability to control and destroy malignant calls. This has been demonstrated by the graft versus leukaemia effect and the use of donor lymphocyte infusions in peripheral blood stem cell transplantation. Dendritic cells are potent antigen presenting cells and become activated after phagocytosing and processing antigen. During this process they up-regulate MHC, co-stimulatory and adhesion molecules and have the ability to stimulate naïve T-cells. Recent evidence has shown that dendritic cells can be loaded with tumour specific antigens and can be used to generate specific anti-tumour T-cell responses. Initial clinical studies using this technology have been promising and suggest that dendritic cells and T-lymphocytes can be utilised in developing therapies which target specific malignant clones.

Telomeres and telomerase in leukaemia and lymphoma.

Telomeres are DNA structures which serve to stabilize chromosomes. In human cells telomeres progressively shorten with each cell division leading to eventual chromosome instability and cell death. Telomerase is a DNA polymerase which is required for the maintenance of telomeres. Therefore, telomeres and telomerase play a role in the regulation of the life span of the cell. Human cells express low levels of telomerase, however when telomere length reaches a critical level abnormal activation of telomerase can lead to immortalization and uncontrolled proliferation. This process has been associated with the development of many leukaemias and lymphomas. Understanding these processes in normal and malignant cells could lead to therapies which target the telomere/telomerase complex.