In conclusion, the results of linkage and association analyses suggest that in hypertensive pedigrees of French-Canadian origin, the TNF-alpha gene locus contributes to the determination of obesity and obesity-associated hypertension.
However, although they do not reach statistical significance (which may be due to the relatively restricted number of subjects included in this study), the distribution differences (in normotensives and hypertensives) observed in the cases of EGF and TNF-alpha reflect trends that could be expected from a mechanistic explanation of the pathways that underlie the patho-physiology of hypertension.
Multivariate logistic regression analysis with adjustment for age, body mass index, and the prevalence of smoking, diabetes mellitus, hypercholesterolemia, and hyperuricemia revealed that 2 polymorphisms (825C-->T in the G protein beta3 subunit gene and 190G-->A in the CC chemokine receptor 2 gene) were significantly associated with hypertension in men and that one polymorphism (-238G-->A in the tumor necrosis factor alpha gene) was significantly associated with hypertension in women.
These findings have raised the possibility that decreased expression of adrenomedullin by tumor necrosis factor-alpha may be related to the increased risk of hypertension and other cardiovascular diseases in obese subjects.
We demonstrated in rodents that stimulation of sensory neurons reduces hypertension, stress-induced gastric mucosal injury, reperfusion-induced liver injury, and endotoxin-induced shock responses by attenuating inflammatory responses such as increases in both tissue levels of tumor necrosis factor (TNF) and tissue accumulation of neutrophils.
After stratification according to risk factors for CAD, our analysis revealed that CAD patients with diabetes (p=0.042) and CAD patients without hypertension (p= 0.0495) displayed a higher frequency of the TNF -308 AA genotype compared with healthy controls.
These data support the hypothesis that endogenous TNF-alpha is an important stimulus for ET-1 in response to placental ischemia and is important in mediating endothelial cell activation and hypertension during pregnancy.
We examined the association of insulin resistance and enhanced TNF pathway with severe hypertension and the association of a microsatellite polymorphism of the TNFR2 gene with severe hypertension.
Infusion of Ang II increased blood pressure (p < 0.001) but decreased vascular relaxation in response to acetylcholine, endothelial nitric oxide synthase (eNOS) and phosphorylated eNOS (peNOS) levels, and renal and plasma levels of adiponectin (p < 0.05); in contrast, plasma tumor necrosis factor-α and monocyte chemoattractant protein-1 levels increased.
TNF-α neutralization reduced hypertension, albuminuria and renal inflammation and fibrosis, which were coupled to a reduction in renal NF-ĸB activation, inflammatory markers expression, TGF-β1 and ET-1 production, and an increase in NO release.
Our results suggest that the G-308A polymorphism of the TNF-α gene may be independently associated with hypertension, leptin level and hypercholesterolemia leading to metabolic syndrome independent of Insulin resistance and hyperglycemia.
Our study suggests that epigenetic mechanisms and release of tumor necrosis factor-α by infiltrating neutrophils could contribute to the increased expression of thromboxane synthase in maternal systemic blood vessels, contributing to the hypertension and coagulation abnormalities associated with preeclampsia.
Hence, central leptin employs TNFα to mediate the diurnal blood pressure elevation in physiology while enhancement of this mechanism can contribute to hypertension development.
The maternal endothelium is targeted by placental and adipose tissue-derived factors like sFlt-1 and TNF-α that promote hypertension during pregnancy, resulting in vascular dysfunction and hypertension.
Our results also showed the transversal importance of proinflammatory cytokines in different stages of atherogenesis, with special relevance of IL6 (OR, 1.39; 95% CI, 0.56-3.49) and TNF (OR, 1.40; 95% CI, 0.92-2.15) related to hypercholesterolemia and hypertension.