HIV and haematopoiesis.

Human immunodeficiency virus (HIV) infection not only leads to a compromised immune system, but also disrupts normal haematopoiesis, resulting in the frequent manifestation of cytopenias (anaemia, thrombocytopenia and neutropenia). Although there is a definite association between the severity of cytopenia and HIV disease stage, this relationship is not always linear. For example, cytopenias such as thrombocytopenia may occur during early stages of infection. The aetiology of these haematological abnormalities is complex and multifactorial, including drug-induced impaired haematopoiesis, bone marrow suppression due to infiltration of infectious agents or malignant cells, HIV-induced impaired haematopoiesis, and several other factors. In this review, we describe the frequencies of anaemia, thrombocytopenia and neutropenia reported for HIV-infected, treatment-naïve cohorts studied in eastern and southern sub-Saharan African countries. We present a rational approach for the use of diagnostic tests during the workup of HIV-infected patients presenting with cytopenia, and discuss how HIV impacts on haematopoietic stem/progenitor cells (HSPCs) resulting in impaired haematopoiesis. Finally, we describe the direct and indirect effects of HIV on HSPCs which result in defective haematopoiesis leading to cytopenias.

HIV and haematopoiesis

Human immunodeficiency virus (HIV) infection not only leads to a compromised immune system, but also disrupts normal haematopoiesis, resulting in the frequent manifestation of cytopenias (anaemia, thrombocytopenia and neutropenia). Although there is a definite association between the severity of cytopenia and HIV disease stage, this relationship is not always linear. For example, cytopenias such as thrombocytopenia may occur during early stages of infection. The aetiology of these haematological abnormalities is complex and multifactorial, including drug-induced impaired haematopoiesis, bone marrow suppression due to infiltration of infectious agents or malignant cells, HIV-induced impaired haematopoiesis, and several other factors. In this review, we describe the frequencies of anaemia, thrombocytopenia and neutropenia reported for HIV-infected, treatment-naïve cohorts studied in eastern and southern sub-Saharan African countries. We present a rational approach for the use of diagnostic tests during the workup of HIV-infected patients presenting with cytopenia, and discuss how HIV impacts on haematopoietic stem/progenitor cells (HSPCs) resulting in impaired haematopoiesis. Finally, we describe the direct and indirect effects of HIV on HSPCs which result in defective haematopoiesis leading to cytopenias

Structural vascular disease in Africans: Performance of ethnic-specific waist circumference cut points using logistic regression and neural network analyses: The SABPA study.

A recently proposed model for waist circumference cut points (RPWC), driven by increased blood pressure, was demonstrated in an African population. We therefore aimed to validate the RPWC by comparing the RPWC and the Joint Statement Consensus (JSC) models via Logistic Regression (LR) and Neural Networks (NN) analyses. Urban African gender groups (N=171) were stratified according to the JSC and RPWC cut point models. Ultrasound carotid intima media thickness (CIMT), blood pressure (BP) and fasting bloods (glucose, high density lipoprotein (HDL) and triglycerides) were obtained in a well-controlled setting. The RPWC male model (LR ROC AUC: 0.71, NN ROC AUC: 0.71) was practically equal to the JSC model (LR ROC AUC: 0.71, NN ROC AUC: 0.69) to predict structural vascular -disease. Similarly, the female RPWC model (LR ROC AUC: 0.84, NN ROC AUC: 0.82) and JSC model (LR ROC AUC: 0.82, NN ROC AUC: 0.81) equally predicted CIMT as surrogate marker for structural vascular disease. Odds ratios supported validity where prediction of CIMT revealed -clinical -significance, well over 1, for both the JSC and RPWC models in African males and females (OR 3.75-13.98). In conclusion, the proposed RPWC model was substantially validated utilizing linear and non-linear analyses. We therefore propose ethnic-specific WC cut points (African males, ≥90 cm; -females, ≥98 cm) to predict a surrogate marker for structural vascular disease.

Cardiovascular, cortisol and coping responses in urban Africans: the SAPBA study.

OBJECTIVES: To assess the relationships between progression of target-organ damage and cardiovascular, cortisol and coping responses in black urban Africans. METHODS: Urban black African gender groups (n = 200) aged 21-62 years from the Sympathetic Activity and Ambulatory Blood Pressure in Africans study were stratified into normotensive and hypertensive groups. Resting and reactivity Finometer blood pressure, fasting sodium fluoride glucose and salivary cortisol values were obtained before and after applying the Stroop and cold pressor tests. Coping strategies were determined and high-resolution ultrasound carotid intima-media scans were done to determine progression of target-organ damage. RESULTS: A trend of high-normal resting cortisol values during sampling time 1 was demonstrated in all hypertensive men. Both hypertensive gender groups showed increased vascular responses during both mental stressors. During the cold pressor test, vascular responses predicted sub-clinical atherosclerosis in all hypertensive men, independent of sampling time. CONCLUSION: Early morning vascular responses in all the hypertensive men could have occurred secondarily to the permissive effect of cortisol on norepinephrine secretion, with subsequent α-adrenergic vasoconstriction. Their α-adrenergic vascular responses during the cold pressor test, however, predicted sub-clinical atherosclerosis, independent of sampling time and cortisol level.

Metabolic syndrome indicators and target organ damage in urban active coping African and Caucasian men: the SABPA study.

Psychosocial stress relating to an urban environment or acculturation increases the prevalence of metabolic syndrome (MetS). The objectives of this study were firstly to indicate and compare differences regarding appraisal of stress or active coping responses in urban African (n=88) and Caucasian (n=101) male teachers of South Africa, in accord with the prevalence of MetS indicators. And secondly to investigate the extent to which utilisation of active coping responses, together with MetS indicators, predict target organ damage, in these men. The Coping Strategy Indicator determined high and low active coping responses in male teachers from the Sympathetic Activity and Ambulatory Blood Pressure in Africans (SABPA) study. SABPA inclusion and exclusion criteria were used. Additionally, diabetic medication users (n=8), and participants with renal impairment (n=2) or HIV positive (n=13), were excluded. MetS indicators included glucose, triglyceride, high-density lipoprotein cholesterol, blood pressure, and waist circumference, independent of confounders (age, physical activity, gamma glutamyl transferase). Microalbuminuria and carotid intima-media thickness indicated target organ damage. More MetS indicators exceeded the IDF cut-off points in high active coping African men (14.71%) than in their Caucasian counterparts (3.33%), as determined from χ² analyses. Furthermore, stepwise regressions indicated that more MetS indicators predicted endothelial dysfunction, especially in the high active coping African men. High active coping African men showed more manifestation of MetS, compared to their Caucasian counterparts, and revealed progress towards endothelial dysfunction.

Determining the waist circumference cut off which best predicts the metabolic syndrome components in urban Africans: the SABPA study.

Various studies have shown that the relationship between waist circumference (WC) and abdominal obesity is age, gender as well as ethnicity-dependent. WC criteria for Sub Saharan Africans have not been defined by the International Diabetes Federation (IDF). The aim was to determine which WC cut off best predicted Metabolic Syndrome (MetS) in a group of urban African teachers (80 males and 93 females). We determined sphygmomanometer blood pressure, WC, glucose, high density lipoprotein cholesterol (HdL) and triglyceride (TRIG) values. The males' MetS profile was less favourable as their glucose, TRIG and blood pressure levels were higher than the proposed cut off for MetS. The females could be classified as obese, based on their mean BMI (32.78±6.36) and WC (93.48±15.68). Receiver operating characteristic (ROC) WC cut offs of 90, 91, 94 and 96 cm for the respective MetS components in males (blood pressure, HdL, glucose and TRIG) were suggested. In the females, cut offs of 92, 98, 94 and 94 cm for TRIG, blood pressure, HdL and glucose respectively, were put forward. Odds ratios revealed that increased blood pressure best predicted ROC WC in both males (OR 9.59; 95% CI 3.14-29.32) and females (OR 3.11; 95% CI 1.30-7.42) irrespective of age. We suggest that the optimal cut off point for the males be set at 90 cm, as opposed to the current 94 cm; whilst the female cut off be set at 98 cm as opposed to the existing cut off of 80 cm. Larger sample groups are recommended to justify our data.

Cardiovascular function and psychological distress in urbanised black South Africans: the SABPA study.

OBJECTIVE: The increased prevalence of cardiovascular disease risk factors in sub-Saharan Africa has increased the incidence of cardiovascular disease in this region but whether psychological distress contributes to this observed increased risk remains largely unclear. The aim of this study was to investigate the association between cardiovascular function and psychological distress in urbanised black South African men (n = 101) and women (n = 99). METHODS: Resting cardiovascular variables were obtained by making use of the Finometer device and 24-hour ambulatory blood pressure (BP) measurements with the Cardiotens apparatus. Psychological questionnaires assessed the perception of health (General Health questionnaire) and depression status (DSM-IV criteria). The resting ECG (NORAV PC-1200) was used to determine left ventricular hypertrophy (LVH) by making use of the Cornell product. Confounders included age, obesity, alcohol intake, smoking and physical activity. RESULTS: The hypertensive groups were overweight, with lower vascular compliance and higher LVH (only men) compared to the normotensive groups. In hypertensive men, perception of health (somatic symptoms) was positively associated with blood pressure, while in hypertensive women it was associated with heart rate. Major depression was associated with LVH in hypertensive men and mean arterial pressure in hypertensive women. LVH and depression showed odds ratios of 1.02 (95% CI: 0.997-1.05) and 1.15 (95% CI: 1.01-1.32), respectively, in predicting hypertension in women. CONCLUSIONS: Psychological distress was associated with higher blood pressure in hypertensive African men but also with the development of left ventricular hypertrophy in hypertensive African men and women.