Inhibition of tumor necrosis factor-alpha improves physiological angiogenesis and reduces pathological neovascularization in ischemic retinopathy

The present study was undertaken to test whether inhibition of the proangiogenic inflammatory cytokine tumor necrosis factor (TNF)-alpha can modulate retinal hypoxia and preretinal neovascularization in a murine model of oxygen-induced retinopathy (OIR). OIR was produced in TNF-alpha-/- and wild-type (WT) control C57B6 neonatal mice by exposure to 75% oxygen between postnatal days 7 and 12 (P7 to P12). Half of each WT litter was treated with the cytokine inhibitor semapimod (formerly known as CNI-1493) (5 mg/kg) by daily intraperitoneal injection from the time of reintroduction to room air at P12 until P17. The extent of preretinal neovascularization and intraretinal revascularization was quantified by image analysis of retinal flat-mounts and retinal hypoxia correlated with vascularization by immunofluorescent localization of the hypoxia-sensitive drug pimonidazole (hypoxyprobe, HP). HP adducts were also characterized by Western analysis and quantified by competitive enzyme-linked immunosorbent assay. TNF-alpha-/- and WT mice showed a similar sensitivity to hyperoxia-induced retinal ischemia at P12. At P13 some delay in early reperfusion was evident in TNFalpha-/- and WT mice treated with semapimod. However, at P17 both these groups had significantly better vascular recovery with less ischemic/hypoxic retina and preretinal neovascularization compared to untreated retinopathy in WT mice. Immunohistochemistry showed deposition of HP in the avascular inner retina but not in areas underlying preretinal neovascularization, indicating that such aberrant vasculature can reduce retinal hypoxia. Inhibition of TNF-alpha significantly, improves vascular recovery within ischemic tissue and reduces pathological neovascularization in OIR. HP provides a useful tool for mapping and quantifying tissue hypoxia in experimental ischemic retinopathy.

Numerical simulation of separation factor of NaCl in surface force pore flow model

This work deals with modelling and experimental verification of desalination theory (surface force pore flow) . The work has direct application in desalination of sea water.

Association between polymorphism in regulatory region of gene encoding tumour necrosis factor alpha and risk of Alzheimer's disease and vascular dementia: a case-control study

BACKGROUND: Deposition of beta-amyloid in the brains of patients with Alzheimer's disease is thought to precede a chain of events that leads to an inflammatory response by the brain. We postulated that genetic variation in the regulatory region of the gene for the proinflammatory cytokine tumour necrosis factor alpha (TNF-alpha) leads to increased risk of Alzheimer's disease and vascular dementia. METHODS: A polymorphism in the regulatory region of the TNF-alpha gene was analysed in a case-control study. The polymorphism (C-850T) was typed in 242 patients with sporadic Alzheimer's disease, 81 patients with vascular dementia, 61 stroke patients without dementia, and 235 normal controls. These groups of individuals were also genotyped for the apolipoprotein E polymorphism, and the vascular dementia and stroke groups were typed at the HLA-DR locus. FINDINGS: The distribution of TNF-alpha genotypes in the vascular dementia group differed significantly from that in the stroke and normal control groups, giving an odds ratio of 2.51 (95% CI 1.49-4.21) for the development of vascular dementia for individuals with a CT or TT genotype. Logistic regression analysis indicated that the possession of the T allele significantly increased the risk of Alzheimer's disease associated with carriage of the apolipoprotein E epsilon4 allele (odds ratio 2.73 [1.68-4.44] for those with apolipoprotein E epsilon4 but no TNF-alpha T, vs 4.62 [2.38-8.96] for those with apolipoprotein E epsilon4 and TNF-alpha T; p=0.03). INTERPRETATION: Possession of the TNF-alpha T allele significantly increases the risk of vascular dementia, and increases the risk of Alzheimer's disease associated with apolipoprotein E. Although further research is needed, these findings suggest a potential role for anti-inflammatory therapy in vascular dementia and Alzheimer's disease, and perhaps especially in patients who have had a stroke.

A switch in the cellular localization of macrophage migration inhibitory factor in the rat testis after ethane dimethane sulfonate treatment.

Macrophage migration inhibitory factor (MIF), one of the first cytokines to be discovered, has recently been localized to the Leydig cells in adult rat testes. In the following study, the response of MIF to Leydig cell ablation by the Leydig cell-specific toxin ethane dimethane sulfonate (EDS) was examined in adult male rats. Testicular MIF mRNA and protein in testicular interstitial fluid measured by ELISA and western blot were only marginally reduced by EDS treatment, in spite of the fact that the Leydig cells were completely destroyed within 7 days. Immunohistochemistry using an affinity-purified anti-mouse MIF antibody localized MIF exclusively to the Leydig cells in control testes. At 7 days post-EDS treatment, there were no MIF immunopositive Leydig cells in the interstitium, although distinct MIF immunostaining was observed in the seminiferous tubules, principally in Sertoli cells and residual cytoplasm, and some spermatogonia. A few peritubular and perivascular cells were also labelled at this time, which possibly represented mesenchymal Leydig cell precursors. At 14 and 21 days, Sertoli cell MIF immunoreactivity was observed in only a few tubule cross-sections, while some peritubular and perivascular mesenchymal cells and the re-populating immature Leydig cells were intensely labeled. At 28 days after EDS-treatment, the MIF immunostaining pattern was identical to that of untreated and control testes. The switch in the compartmentalization of MIF protein at 7 days after EDS-treatment was confirmed by western blot analysis of interstitial tissue and seminiferous tubules separated by mechanical dissection. These data establish that Leydig cell-depleted testes continue to produce MIF, and suggest the existence of a mechanism of compensatory cytokine production involving the Sertoli cells. This represents the first demonstration of a hitherto unsuspected pattern of cellular interaction between the Leydig cells and the seminiferous tubules which is consistent with an essential role for MIF in male testicular function.

Tissue factor expression on monocyte subpopulations during normal pregnancy.

Pregnancy is often referred to as a hypercoaguable state due to changes in the haemostatic system. Tissue factor (TF) is the initiator of blood clotting in vivo. The effect of pregnancy on monocyte TF expression was determined in a longitudinal case control study, (89 pregnant, 39 non-pregnant). Using whole blood flow cytometry and CD14 as a monocyte marker, TF expression was measured on all CD14 positive, CD14Bright and CD14Dim cells. TF expression was significantly lower in pregnant women than in non-pregnant control subjects, on all CD14 positive cells at 20 and 35 weeks, on CD14Bright cells at 12 and 35 weeks and on CD14Dim cells at 20 weeks. Additionally, we report that a higher percentage of CD14Dim than CD14Bright cells express TF. These results suggest that, in order to maintain homeostasis in haemostasis in an otherwise hypercoaguable state, monocyte TF expression is reduced during normal pregnancy.

Glycemic State Regulates Brain-Derived Neurotrophic Factor Responsiveness of Neurons in the Paraventricular Nucleus of the Hypothalamus

Brain derived neurotrophic factor (BDNF) is a member of the family of neurotrophins and binds to the tropomyosin-related kinase B (TrkB) receptor. Like other neurotrophic factors, BDNF is involved in the development and differentiation of neurons. Recently, studies have suggested important roles for BDNF in the regulation of energy homeostasis. The paraventricular nucleus (PVN) is critical for normal energy balance contains high levels of both BDNF and TrkB mRNA. Studies have shown that microinjections of BDNF into the PVN increase energy expenditure, suggesting BDNF plays a role in energy homeostasis through direct actions in this hypothalamic nucleus. We used male Sprague-Dawley rats to perform whole-cell current-clamp experiments from PVN neurons in slice preparation. BDNF was bath applied at a concentration of 2nM and caused depolarizations in 54% of neurons (n = 25; mean change in membrane potential: 8.9 ± 1.2 mV), hyperpolarizations in 23% (n = 11; mean change in membrane potential: -6.7 ± 1.4 mV), while the remaining cells tested were unaffected. Previous studies showing effects of BDNF on γ-aminobutyric acid type A (GABAA) mediated neurotransmission in PVN led us to examine if these BDNF-mediated changes in membrane potential were maintained in the presence of tetrodotoxin (TTX) sodium channel blocker (N = 9; 56% depolarized, 22% hyperpolarized, 22% non-responders) and bicuculline (GABAA antagonist) (N = 12; 42% depolarized, 17% hyperpolarized, 41% non-responders), supporting the conclusion that these effects on membrane potential were postsynaptic. We also evaluated the effects of BDNF on these neurons across varying physiologically relevant extracellular glucose concentrations. At 10 mM 23% (n = 11; mean: -6.7 ± 1.4 mV) of PVN neurons hyperpolarized in response to BDNF treatment, whereas at 0.2 mM glucose, 71% showed hyperpolarizing effects (n = 12; mean: -6.3 ± 2.8 mV). Our findings reveal that BDNF has direct impacts on PVN neurons and that these neurons are capable of integrating multiple sources of metabolically relevant input. Our analysis regarding glucose concentrations and their effects on these neurons’ response to other metabolic signals emphasizes the importance of using physiologically relevant conditions for study of central pathways involved in the regulation of energy homeostasis.

Deletion of complement factor H-related genes CFHR1 and CFHR3 is associated with atypical hemolytic uremic syndrome.

Atypical hemolytic uremic syndrome (aHUS) is associated with defective complement regulation. Disease-associated mutations have been described in the genes encoding the complement regulators complement factor H, membrane cofactor protein, factor B, and factor I. In this study, we show in two independent cohorts of aHUS patients that deletion of two closely related genes, complement factor H-related 1 (CFHR1) and complement factor H-related 3 (CFHR3), increases the risk of aHUS. Amplification analysis and sequencing of genomic DNA of three affected individuals revealed a chromosomal deletion of approximately 84 kb in the RCA gene cluster, resulting in loss of the genes coding for CFHR1 and CFHR3, but leaving the genomic structure of factor H intact. The CFHR1 and CFHR3 genes are flanked by long homologous repeats with long interspersed nuclear elements (retrotransposons) and we suggest that nonallelic homologous recombination between these repeats results in the loss of the two genes. Impaired protection of erythrocytes from complement activation is observed in the serum of aHUS patients deficient in CFHR1 and CFHR3, thus suggesting a regulatory role for CFHR1 and CFHR3 in complement activation. The identification of CFHR1/CFHR3 deficiency in aHUS patients may lead to the design of new diagnostic approaches, such as enhanced testing for these genes.