Early vessel destabilization mediated by Angiopoietin-2 and subsequent vessel maturation via Angiopoietin-1 induce functional neovasculature after ischemia.

We assessed whether Angiopoietin-2 (Ang2), a Tie2 ligand and partial antagonist of Angiopoietin-1 (Ang1), is required for early vessel destabilization during postischemic angiogenesis, when combined with vascular growth factors. In vitro, matrigel co-cultures assessed endothelial-cell tube formation and pericyte recruitment after stimulation of VEGF-A, Apelin (APLN), Ang1 with or without Ang2. In a murine hindlimb ischemia model, adeno-associated virus (rAAV, 3×10(12) virusparticles) transduction of VEGF-A, APLN and Ang1 with or without Ang2 (continuous or early expression d0-3) was performed intramuscularly (d-14). Femoral artery ligation was performed at d0, followed by laser doppler perfusion meassurements (LDI) 7 and 14. At d7 (early timepoint) and d14 (late timepoint), histological analysis of capillary/muscle fiber ratio (CMF-R, PECAM-1) and pericyte/capillary ratio (PC-R, NG2) was performed. In vitro, VEGF-A, APLN and Ang1 induced ring formation, but only APLN and Ang1 recruited pericytes. Ang2 did not affect tube formation by APLN, but reduced pericyte recruitment after APLN or Ang1 overexpression. In vivo, rAAV.VEGF-A did not alter LDI-perfusion at d14, consistent with an impaired PC-R despite a rise in CMF-R. rAAV.APLN improved perfusion at d14, with or without continuous Ang2, increasing CMF-R and PC-R. rAAV.Ang1 improved perfusion at d14, when combined with rAAV.Ang2 (d0-3), accompanied by an increased CMF-R and PC-R. The combination of early vessel destabilization (Ang2 d0-3) and continuous Ang1 overexpression improves hindlimb perfusion, pointing to the importance of early vessel destabilization and subsequent vessel maturation for enhanced therapeutic neovascularization

Overweight, obesity and perceptions about body weight among primary schoolchildren in Dar es Salaam, Tanzania

The increasing prevalence of overweight and obesity among children has become a public health concern both in developing and developed countries. Previous research studies have shown that favourable perception of one’s body weight is an important factor in weight control. This study determined prevalence of overweight and obesity and assessed perception about body weight among primary schoolchildren in Dar es Salaam, Tanzania. In this cross sectional study, nine schools were selected randomly from a list of all primary schools in Dar es Salaam. A structured questionnaire was used to collect data on socio-demographic characteristics and lifestyle information including perception about body weight. Height and weight were measured following standard procedures. Chi-square tests and multiple logistic regressions were used to determine factors which influence perceptions about body weight. A total of 446 children were included into the study. The mean body mass index (BMI) was 16.6±4.0kg/m2 (16.1±4.0 for males and 17.0±4.0 for females). Prevalence of overweight and obesity was 9.8% and 5.2%, respectively. The prevalence of overweight and obesity was significantly higher among girls, 13.1% and 6.3% compared to  boys with 6.3% and 3.8%  overweight and obese respectively (P=0.0314). Overall, the prevalence of overweight and obesity was 15.0% (10.1% among boys and 19.4% among girls).  One-third (33.3%) of the children perceived their body weight as overweight or obese. Among overweight and obese children, 35.4% had unfavourable perception of their body weights. There was a statistically significant difference between perceived body weight and actual body weight as indicated by BMI for both boys and girls (P<0.05). Age of the child (AOR=O.55 95%CI 0.36-0.85) and area of residence (COR=0.64 95% CI 0.44-0.95) were found to be significant predictors of   favourable perception of one’s body weight. In conclusion, the prevalence of overweight and obesity is not very high in this population. However over a third of overweight and obese children, had unfavourable perception of their body weights. We recommend targeted educational programmes about overweight and obesity and the associated health effects in order to instill a behavior of self consciousness on overweight and obesity among children in Tanzania

Capillary growth and maturation profile of VEGF-A, APLN and Ang1 with or without Ang2 in vitro.

<p><b>(A)</b> Capillary-like tube formation was enhanced by VEGF-A alone transfection in HMECs (1×10⁴ per well of μ-slide angiogenesis plate) on 2D-matrigel. <b>(B)</b> 1×10³ Pericytes labeled by DiO (green) are plated after capillary-like tube formation of HMECs with DiD labeling (red). 24 h later, co-cultures reveal a low rate of pericytes attraction by VEGF-A, which was unaffected by Ang2. <b>(C)</b> Apelin (APLN) promoted tube formation with or without Ang2. <b>(D)</b> Pericyte recruitment was enhanced by Apelin, an effect attenuated by Ang2. <b>(E)</b> Ang1 induced tubes formationin the absence of Ang2. <b>(F)</b> However, the tube maturation provided by Ang1 was abolished in the presence of Ang2. (MEAN ± SEM, n = 5, ** p<0.01).</p

The failed therapeutic neovascularization after VEGF-A overexpression in the early stage (7 day) of mouse hindlimb ischemia model.

<p>(A) Laser Doppler Imaging (LDI) measured after right femoral artery ligation and at d7. (B) Quantification of LDI (ischemic versus non-ischemic hindlimb) revealed no significant neovascularization by VEGF-A at low (rAAV.lVEGF-A) or high doses (rAAV.hVEGF-A), but deterioration of perfusion in the rAAV.hVEGF-A+Ang2 group compared vehicle group (#P<0.05, vs. vehicle). (C) Fluorescence microscopy images of gastrocnemius muscle sections from control (rAAV.LacZ) or ischemic hind limb co-stained with DAPI (blue, nucleus), anti-NG2 (green, pericyte) antibody and anti-PECAM-1 (red, endothelial cell) antibody at d 7 after ligation. (D) Quantitative evaluation of capillary/muscle fibre ratio (CMF-R) demonstrated the ability of high VEGF-A with or without Ang2 to induce capillary growth in vivo. (E) Pericyte coverage was unaffected by lVEGF-A, but reduced in hVEGF-Agroup compared to vehicle group and even further reduced through the co-application of rAAV.Ang2. (MEAN ± SEM, n = 7,* p<0.05, ** p<0.01).</p

Apelin did not provide early neovascularization with Ang2.

<p><b>(A, B)</b> LDI of blood reperfusion induced by APLN is enhanced without continuous Ang2 overexpression (rAAV.Ang2), where as the combination of APLN and Ang2 displayed no significant alteration. APLN combined with early Ang2 overexpression (rAAV.Apln+Ang2(d0-3)) induced a trend towards higher perfusion (p = 0.08). <b>(C–E)</b> PECAM-1 positive capillaries were slightly increased by rAAV.APLN, whereas the combination with continuous rAAV.Ang2 or rAAV.Ang2(d0-3) clearly enhaced capillary formation compared to APLN alone. Capillary maturation, indicated by pericyte coverage <b>(E)</b> was enhanced by rAAV.APLN with or without rAAV.Ang2(d0-3), whereas continous Ang2 reduced PC-R. (MEAN ± SEM, n = 7,* p<0.05, ** p<0.01).</p

Apelin did not enhance neovascularization when combined with Ang1.

<p><b>(A, B)</b> rAAV.APLN combined with rAAV. Ang1 was not capable of elevating hindlimb perfusion at d7 or d14 achieved by APLN alone. <b>(C–E)</b> The combination of APLN with Ang1 failed to increase capillary growth at d14, but provided a capillary maturation index (PR-R). (MEAN ± SEM, n = 7,* p<0.05, ** p<0.01).</p

APLN provided late neovascularization, with or without continuous Ang2.

<p><b>(A,B)</b> At d14, LDI indicated an increased perfusion by APLN with or without continuous Ang2 compared to control. Of note, the effect of APLN was prohibited by Ang2(d0-3). <b>(C,D)</b> At d14, rAAV.APLN improved capillary growth (CMF-R), when used alone or in combination with continuous Ang2 overexpression and temporary Ang2 (d0-3). <b>(C,E)</b> Pericyte recruitment was provided by APLN, but not if combined with continuous Ang2 overexpression. (MEAN ± SEM, n = 7,* p<0.05, ** p<0.01).</p

Elevated blood pressure among primary school children in Dar es salaam, Tanzania: prevalence and risk factors

Abstract Background Whilst the burden of non-communicable diseases is increasing in developing countries, little data is available on blood pressure among Tanzanian children. This study aimed at determining the blood pressure profiles and risk factors associated with elevated blood pressure among primary school children in Dar es Salaam, Tanzania. Methods We conducted a cross sectional survey among 446 children aged 6–17 years from 9 randomly selected primary schools in Dar es Salaam. We measured blood pressure using a standardized digital blood pressure measuring machine (Omron Digital HEM-907, Tokyo, Japan). We used an average of the three blood pressure readings for analysis. Elevated blood pressure was defined as average systolic or diastolic blood pressure ≥ 90th percentile for age, gender and height. Results The proportion of children with elevated blood pressure was 15.2% (pre-hypertension 4.4% and hypertension 10.8%). No significant gender differences were observed in the prevalence of elevated BP. Increasing age and overweight/obese children were significantly associated with elevated BP (p = 0.0029 and p < 0.0001) respectively. Similar associations were observed for age and overweight/obesity with hypertension. (p = 0.0506 and p < 0.0001) respectively. In multivariate analysis, age above 10 years (adjusted RR = 3.63, 95% CI = 1.03–7.82) was significantly and independently associated with elevated BP in this population of school age children. Conclusions We observed a higher proportion of elevated BP in this population of school age children. Older age and overweight/obesity were associated with elevated BP. Assessment of BP and BMI should be incorporated in school health program in Tanzania to identify those at risk so that appropriate interventions can be instituted before development of associated complications