Background Vascular dysfunction in atherosclerosis and diabetes, as observed in the aging population of developed societies, is associated with vascular DNA damage and cell senescence. We hypothesized that cumulative DNA damage during aging contributes to vascular dysfunction. Methods and Results In mice with genomic instability due to the defective nucleotide excision repair genes ERCC1 and XPD (Ercc1d/− and XpdTTD mice), we explored age-dependent vascular function as compared to wild-type mice. Ercc1d/− mice showed increased vascular cell senescence, accelerated development of vasodilator dysfunction, increased vascular stiffness and elevated blood pressure at very young age. The vasodilator dysfunction was due to decreased endothelial eNOS levels as well as impaired smooth muscle cell function, which involved phosphodiesterase (PDE) activity. Similar to Ercc1d/− mice, age-related endothelium-dependent vasodilator dysfunction in XpdTTD animals was increased. To investigate the implications for human vascular disease, we explored associations between single nucleotide polymorphisms (SNPs) of selected nucleotide excision repair genes and arterial stiffness within the AortaGen Consortium, and found a significant association of a SNP (rs2029298) in the putative promoter region of DDB2 gene with carotid-femoral pulse wave velocity. Conclusions Mice with genomic instability recapitulate age-dependent vascular dysfunction as observed in animal models and in humans, but with an accelerated progression, as compared to wild type mice. In addition, we found associations between variations in human DNA repair genes and markers for vascular stiffness which is associated with aging. Our study supports the concept that genomic instability contributes importantly to the development of cardiovascular disease.

Abstract-Angiogenesis inhibition is an established treatment for several tumor types. Unfortunately, this therapy is associated with adverse effects, including hypertension and renal toxicity, referred to as "preeclampsia." Recently, we demonstrated in patients and in rats that the multitarget tyrosine kinase inhibitor sunitinib induces a rise in blood pressure (BP), renal dysfunction, and proteinuria associated with activation of the endothelin system. In the current study we investigated the effects of sunitinib on rat renal histology, including the resemblance with preeclampsia, as well as the roles of endothelin 1, decreased nitric oxide (NO) bioavailability, and increased oxidative stress in the development of sunitinib-induced hypertension and renal toxicity. In rats on sunitinib, light and electron microscopic examination revealed marked glomerular endotheliosis, a characteristic histological feature of preeclampsia, which was partly reversible after sunitinib discontinuation. The histological abnormalities were accompanied by an increase in urinary excretion of endothelin 1 and diminished NO metabolite excretion. In rats on sunitinib alone, BP increased (⌬BP: 31.6Ϯ0.9 mm Hg). This rise could largely be prevented with the endothelin receptor antagonist macitentan (⌬BP: 12.3Ϯ1.5 mm Hg) and only mildly with Tempol, a superoxide dismutase mimetic (⌬BP: 25.9Ϯ2.3 mm Hg). Both compounds could not prevent the sunitinib-induced rise in serum creatinine or renal histological abnormalities and had no effect on urine nitrates but decreased proteinuria and urinary endothelin 1 excretion. Our findings indicate that both the endothelin system and oxidative stress play important roles in the development of sunitinib-induced proteinuria and that the endothelin system rather than oxidative stress is important for the development of sunitinib-induced hypertension. (Hypertension. 2011;58:295-302.) • Online Data Supplement

Sunitinib induces hypothyroidism due to alterations in T(4)/T(3) metabolism as well as thyroid capillary regression.

Because of the presence of the blood-brain barrier, brain renin-angiotensin system activity should depend on local (pro)renin synthesis. Indeed, an intracellular form of renin has been described in the brain, but whether it displays angiotensin (Ang) I-generating activity (AGA) is unknown. Here, we quantified brain (pro)renin, before and after buffer perfusion of the brain, in wild-type mice, renin knockout mice, deoxycorticosterone acetate salt-treated mice, and Ang II-infused mice. Brain regions were homogenized and incubated with excess angiotensinogen to detect AGA, before and after prorenin activation, using a renin inhibitor to correct for nonrenin-mediated AGA. Renin-dependent AGA was readily detectable in brain regions, the highest AGA being present in brain stem (>thalamus=cerebellum=striatum=midbrain>hippocampus=cortex). Brain AGA increased marginally after prorenin activation, suggesting that brain prorenin is low. Buffer perfusion reduced AGA in all brain areas by >60%. Plasma renin (per mL) was 40× to 800× higher than brain renin (per gram). Renin was undetectable in plasma and brain of renin knockout mice. Deoxycorticosterone acetate salt and Ang II suppressed plasma renin and brain renin in parallel, without upregulating brain prorenin. Finally, Ang I was undetectable in brains of spontaneously hypertensive rats, while their brain/plasma Ang II concentration ratio decreased by 80% after Ang II type 1 receptor blockade. In conclusion, brain renin levels (per gram) correspond with the amount of renin present in 1 to 20 μL of plasma. Brain renin disappears after buffer perfusion and varies in association with plasma renin. This indicates that brain renin represents trapped plasma renin. Brain Ang II represents Ang II taken up from blood rather than locally synthesized Ang II.

Abstract-Renin/prorenin binding to the (pro)renin receptor ([P]RR) results in direct (angiotensin-independent) secondmessenger activation in vitro, whereas in vivo studies in rodents overexpressing prorenin (Ϸ400-fold) or the (P)RR do not support such activation. To solve this discrepancy, DNA synthesis, extracellular signal-regulated kinase 1/2 phosphorylation, and plasminogen-activator inhibitor 1 release were evaluated in wild-type and human (P)RRoverexpressing vascular smooth muscle cells after their incubation with 1 to 80 nmol/L of (pro)renin. Human prorenin (4 nmol/L, ie, Ϸ800-fold above normal) ϩ angiotensinogen increased DNA synthesis in human (P)RR cells only in an angiotensin II type 1 receptor-dependent manner. Prorenin at this concentration also increased plasminogen-activator inhibitor 1 release via angiotensin. Prorenin alone at 4 nmol/L was without effect, but at 20 nmol/L (Ϸ4000-fold above normal) it activated extracellular signal-regulated kinase 1/2 directly (ie, independent of angiotensin). Renin at concentrations of 1 nmol/L (Ϸ2000-fold above normal) and higher directly stimulated DNA synthesis, extracellular signal-regulated kinase 1/2 phosphorylation, and plasminogen-activator inhibitor 1 release in wild-type and human (P)RR cells, and similar effects were seen for rat renin, indicating that they were mediated via the rat (P)RR. In conclusion, angiotensin generation depending on prorenin-(P)RR interaction may occur in transgenic rodents overexpressing prorenin several 100-fold. Direct (pro)renin-induced effects via the (P)RR require agonist concentrations that are far above the levels in wild-type and transgenic rats. Therefore, only prorenin (and not [P]RR) overexpression will result in an angiotensin-dependent phenotype, and direct renin-(P)RR interaction is unlikely to ever occur in nonrenin-synthesizing organs. (Hypertension. 2011;58:1111-1119.)Key Words: prorenin Ⅲ DNA synthesis Ⅲ transgenic Ⅲ (pro)renin receptor Ⅲ renin Ⅲ plasminogen activator inhibitor 1 Ⅲ ERK1/2 S ince the discovery of the (pro)renin receptor ([P]RR), 1 many investigators have attempted to unravel its relationship with the renin-angiotensin (Ang) system. Its overexpression resulted in elevated blood pressure, a rise in plasma aldosterone levels, increased renal cyclooxygenase 2 expression, and glomerulosclerosis, albeit in the absence of changes in renin-Ang system component levels. 2,3 Vice versa, prorenin overexpression, elevating plasma prorenin levels Յ400-fold, did raise blood pressure in an Ang-dependent manner. Yet, it did not result in fibrosis and/or glomerulosclerosis, 4 -6 although this was expected on the basis of in vitro studies showing that direct prorenin-(P)RR interaction (ie, independent of Ang) results in activation of the extracellular signalregulated kinase (ERK) 1/2 pathway, thereby upregulating profibrotic genes like transforming growth factor-␤ 1 (TGF-␤ 1 ) and plasminogen-activator inhibitor 1 (PAI-1) and increasing cell proliferation. [7][8][9][10][11] The (P)RR colocalizes with vacuolar H...