Publications

Vitamin D deficiency has been associated with cardiovascular dysfunction. We evaluated the role of the vitamin D receptor (VDR) in vascular endothelial function, a marker of cardiovascular health, at baseline and in the presence of angiotensin II, using an endothelial-specific knockout of the murine VDR gene. In the absence of endothelial VDR, acetylcholine-induced aortic relaxation was significantly impaired (maximal relaxation, endothelial-specific VDR knockout=58% versus control=73%; P<0.05). This was accompanied by a reduction in endothelial NO synthase expression and phospho-vasodilator-stimulated phosphoprotein levels in aortae from the endothelial-specific VDR knockout versus control mice. Although blood pressure levels at baseline were comparable at 12 and 24 weeks of age, the endothelial VDR knockout mice demonstrated increased sensitivity to the hypertensive effects of angiotensin II compared with control mice (after 1-week infusion: knockout=155±15 mm Hg versus control=133±7 mm Hg; P<0.01; after 2-week infusion: knockout=164±9 mm Hg versus control=152±13 mm Hg; P<0.05). By the end of 2 weeks, angiotensin II infusion-induced, hypertrophy-sensitive myocardial gene expression was higher in endothelial-specific VDR knockout mice (fold change compared with saline-infused control mice, type-A natriuretic peptide: knockout mice=3.12 versus control=1.7; P<0.05; type-B natriuretic peptide: knockout mice=4.72 versus control=2.68; P<0.05). These results suggest that endothelial VDR plays an important role in endothelial cell function and blood pressure control and imply a potential role for VDR agonists in the management of cardiovascular disease associated with endothelial dysfunction.

PURPOSE

Increasing evidence of a link between erectile dysfunction and cardiovascular disease suggests a shared vascular etiology with endothelial dysfunction as a plausible underlying biological mechanism. To our knowledge whether this association is different for large arterial endothelium compared to microvascular endothelium has not yet been established. We investigated the association of erectile dysfunction with macrovascular and microvascular endothelial function.

MATERIALS AND METHODS

A sample of 390 men with a mean age of 55.5 years was recruited from the BACH survey, a population based survey of urological symptoms. Erectile dysfunction was assessed using IIEF-5. The percent of brachial artery flow mediated dilatation, a measure of macrovascular function, and hyperemic flow velocity in cm per second, a measure of microvascular function, were assessed by ultrasound. Linear regression was used to assess the association of erectile dysfunction and endothelial function, and adjust for potential confounders.

RESULTS

Reactive hyperemia was lower in men with vs without erectile dysfunction (mean ± SE 97.1 ± 2.5 vs 106.0 ± 1.6 cm per second, p = 0.003). However, the difference in flow mediated dilatation between men with vs without erectile dysfunction was statistically nonsignificant (mean 6.6% ± 0.33% vs 7.2% ± 0.24%, p = 0.147). The association of erectile dysfunction with reactive hyperemia was attenuated but it remained statistically significant in men with moderate to severe erectile dysfunction (IIEF-5 less than 12) after adjusting for traditional cardiovascular risk factors (p = 0.038).

CONCLUSIONS

These results provide evidence of greater microvascular than macrovascular endothelial dysfunction as a potential contributor to erectile dysfunction and an underlying mechanism linking erectile dysfunction and cardiovascular disease.

Mycobacterium bovis bacillus Calmette-Guerin (BCG), the only vaccine currently used against tuberculosis, is an attenuated derivative of M. bovis that has been propagated in vitro for more than 40 years. We have previously reported that the experimentally-verified human T cell epitopes of the M. tuberculosis complex (MTBC) are the most conserved elements of the genome; whether immune recognition is the force driving the conservation of epitopes in the MTBC is unknown. Therefore, we sequenced the genomes of 12 BCG strains to determine whether T cell epitopes were under selection pressure during BCG in vitro evolution. We constructed a genome-wide phylogeny and refined the previously-determined BCG phylogeny. Notably, we identified a new cluster between BCG Japan and BCG Russia, and repositioned the relationships of several strains within the lineage. We also compared the sequence diversity of 1530 experimentally verified human T cell epitopes in the BCG vaccines with those in the MTBC. We found 23% of the known T cell epitopes are absent, and that the majority (82%) of the absent epitopes in BCG are contained in 6 proteins encoded in 2 regions of difference (RD) unique to BCG strains. We also found that T cell epitope sequences in BCG are more conserved than non-epitope sequences in the same gene. Finally, we find evidence that epitope sequence variation in BCG potentially affects human T cell recognition. These findings provide new insight into sequence variation in a slow-growing bacterium closely related to the MTBC that has been subjected to prolonged passage outside of a mammalian host, and indicate little difference in the extent of variation in vivo and in vitro.