c-Jun N-terminal kinase primes endothelial cells at atheroprone sites for apoptosis

Atherosclerosis can be initiated by pro-inflammatory activation of endothelial cells (EC) which leads to the recruitment of leukocytes to the vessel wall, and also by endothelial apoptosis which elevates the permeability of arteries to lipoproteins. The greater curvature of the aorta is exposed to high shear and is protected from EC apoptosis, inflammation and atherosclerosis, whereas the lesser curvature is exposed to low shear and is susceptible to atherosclerosis. Pro-inflammatory mediators (e.g. TNFα, LPS) trigger phosphorylation of c-Jun N-terminal kinase (JNK) and p38 MAP kinases to positively regulate these process and influence atherosclerosis. I examined the effects of JNK activation on EC physiology at atherosusceptible sites. En face staining revealed that phosphorylation of JNK in EC occurs constitutively at the susceptible site of the murine aortic arch and can be enhanced by LPS treatment. In contrast, JNK activation was suppressed at the protected site by mitogen-activated protein kinase phosphatase-1 (MKP-1), a negative regulator of JNK and p38 MAP kinases. To study the function of JNK and p38 in vascular endothelium, I identified the transcriptional programs that they regulate by applying specific pharmacological inhibitors to cultured EC and assessing the transcriptome using microarrays. Functional annotation revealed that JNK and p38 positively regulate the expression of numerous pro-inflammatory and pro-apoptotic molecules. Subsequent gene silencing studies demonstrated that JNK1 positively regulates pro-apoptotic molecule expression in EC. I validated my findings in vivo by analyzing EC in aortae of wild-type, JNK1-/- and MKP-1-/- mice. I observed that EC at an atherosusceptible site express pro-apoptotic proteins and are primed for apoptosis and proliferation in response to LPS through a JNK1-dependent mechanism, whereas EC at a protected site expressed lower levels of pro-apoptotic molecules and was protected from injury by MKP-1. These findings indicate that the spatial variation of JNK1 activity delineates the spatial distribution of apoptosis and turnover of EC in arteries, and may influence the punctuate development of atherosclerotic lesions

Dexamethasone arterializes venous endothelial cells by inducing mitogen-activated protein kinase phosphatase-1:A novel antiinflammatory treatment for vein grafts?

Background— Vein grafting in coronary artery surgery is complicated by a high restenosis rate resulting from the development of vascular inflammation, intimal hyperplasia, and accelerated atherosclerosis. In contrast, arterial grafts are relatively resistant to these processes. Vascular inflammation is regulated by signaling intermediaries, including p38 mitogen-activated protein (MAP) kinase, that trigger endothelial cell (EC) expression of chemokines (eg, interleukin-8, monocyte chemotactic protein-1) and other proinflammatory molecules. Here, we have tested the hypothesis that p38 MAP kinase activation in response to arterial shear stress (flow) may occur more readily in venous ECs, leading to greater proinflammatory activation. Methods and Results— Comparative reverse-transcriptase polymerase chain reaction and Western blotting revealed that arterial shear stress induced p38-dependent expression of monocyte chemotactic protein-1 and interleukin-8 in porcine jugular vein ECs. In contrast, porcine aortic ECs were protected from shear stress–induced expression of p38-dependent chemokines as a result of rapid induction of MAP kinase phosphatase-1. However, we observed with both cultured porcine jugular vein ECs and perfused veins that venous ECs can be protected by brief treatment with dexamethasone, which induced MAP kinase phosphatase-1 to suppress proinflammatory activation. Conclusions— Arterial but not venous ECs are protected from proinflammatory activation in response to short-term exposure to high shear stress by the induction of MAP kinase phosphatase-1. Dexamethasone pretreatment arterializes venous ECs by inducing MAP kinase phosphatase-1 and may protect veins from inflammation. </jats:sec

Enhanced infection prophylaxis reduces mortality in severely immunosuppressed HIV-infected adults and older children initiating antiretroviral therapy in Kenya, Malawi, Uganda and Zimbabwe: the REALITY trial

Meeting abstract FRAB0101LB from 21st International AIDS Conference 18–22 July 2016, Durban, South Africa. Introduction: Mortality from infections is high in the first 6 months of antiretroviral therapy (ART) among HIV‐infected adults and children with advanced disease in sub‐Saharan Africa. Whether an enhanced package of infection prophylaxis at ART initiation would reduce mortality is unknown. Methods: The REALITY 2×2×2 factorial open‐label trial (ISRCTN43622374) randomized ART‐naïve HIV‐infected adults and children >5 years with CD4 <100 cells/mm3. This randomization compared initiating ART with enhanced prophylaxis (continuous cotrimoxazole plus 12 weeks isoniazid/pyridoxine (anti‐tuberculosis) and fluconazole (anti‐cryptococcal/candida), 5 days azithromycin (anti‐bacterial/protozoal) and single‐dose albendazole (anti‐helminth)), versus standard‐of‐care cotrimoxazole. Isoniazid/pyridoxine/cotrimoxazole was formulated as a scored fixed‐dose combination. Two other randomizations investigated 12‐week adjunctive raltegravir or supplementary food. The primary endpoint was 24‐week mortality. Results: 1805 eligible adults (n = 1733; 96.0%) and children/adolescents (n = 72; 4.0%) (median 36 years; 53.2% male) were randomized to enhanced (n = 906) or standard prophylaxis (n = 899) and followed for 48 weeks (3.8% loss‐to‐follow‐up). Median baseline CD4 was 36 cells/mm3 (IQR: 16–62) but 47.3% were WHO Stage 1/2. 80 (8.9%) enhanced versus 108(12.2%) standard prophylaxis died before 24 weeks (adjusted hazard ratio (aHR) = 0.73 (95% CI: 0.54–0.97) p = 0.03; Figure 1) and 98(11.0%) versus 127(14.4%) respectively died before 48 weeks (aHR = 0.75 (0.58–0.98) p = 0.04), with no evidence of interaction with the two other randomizations (p > 0.8). Enhanced prophylaxis significantly reduced incidence of tuberculosis (p = 0.02), cryptococcal disease (p = 0.01), oral/oesophageal candidiasis (p = 0.02), deaths of unknown cause (p = 0.02) and (marginally) hospitalisations (p = 0.06) but not presumed severe bacterial infections (p = 0.38). Serious and grade 4 adverse events were marginally less common with enhanced prophylaxis (p = 0.06). CD4 increases and VL suppression were similar between groups (p > 0.2). Conclusions: Enhanced infection prophylaxis at ART initiation reduces early mortality by 25% among HIV‐infected adults and children with advanced disease. The pill burden did not adversely affect VL suppression. Policy makers should consider adopting and implementing this low‐cost broad infection prevention package which could save 3.3 lives for every 100 individuals treated