Blood pressure and TNF-α act synergistically to increase leucocyte CD11b adhesion molecule expression in the BELFAST study: implications for better blood pressure control in ageing.

Hypertension, a key risk factor for stroke, cardiovascular disease and dementia, is associated with chronic vascular inflammation, and although poorly understood, putative mechanisms include pro-inflammatory responses induced by mechanical stretching, with cytokine release and associated up-regulated expression of adhesion molecules. Because blood pressure increases with age, we measured baseline and tumour necrosis alpha (TNF-α)-stimulated CD11b/CD18 adhesion molecule expression on leucocytes to assess any association between the two. In 38 subjects (mean age 85 years), consecutively enrolled from Belfast Elderly Longitudinal Free-Living Aging Study (BELFAST), baseline and TNF-α-stimulated CD11b/CD18 expression on separated monocytes and neutrophils increased with systolic blood pressure >120 mmHg (p = 0.05) and for lymphocytes, with diastolic blood pressure >80 mmHg (p < 0.05).These findings show increased potential stickiness of intravascular cells with increasing blood pressure which is accentuated by TNF-α, and suggest mechanistic reasons why better hypertension control is important.

Interleukin-6-gene C/G 174 polymorphism in nonagenarian and octogenarian subjects in the BELFAST study. Reciprocal effects on IL-6, soluble IL-6 receptor and for IL-10 in serum and monocyte supernatants.

In this study, we have assessed any change in the frequency of the GG homozygotes of the 174 IL-6 polymorphism with increasing age, arguing that if IL-6 tracks with functional disability and age-related diseases, then there may be attrition or reduction in the frequency of homozgyous subjects, who produce higher levels of IL-6 in serum, in older survivors in a population. We have tested this hypothesis in a large group of free-living, mentally competent, nonagenarian and octogenarian subjects from the Belfast Elderly Longitudinal Ageing Study-BELFAST study and found that the frequency of GG homozygotes with IL-6-174C/G polymorphism decreases with age by about 10%, compared with young controls. In addition we find that CC homozygotes have higher serum levels of IL-6 levels compared with GG (P=0.055), with reciprocal and significant changes in the anti-inflammatory IL-10 (P=0.05). Both IL-6 and IL-10 were spontaneously produced from separated mononuclear cell monolayers in elderly subjects, with significantly higher levels of secreted IL-10 supernatant levels (P=0.05) at 20 h, for G allele subjects carrying the IL-6-174C/G polymorphism. In conclusion, in the BELFAST study, there appears to be a reduction in the frequency of GG homozygotes in the octo/nonagenarian age group and a higher serum IL-6 level associated with CC homozygotes with reciprocal changes for the anti-inflammatory cytokine IL-10.