Cumulative dose of bevacizumab associates with albuminuria rather than podocyturia in cancer patients

Differential effects of cyclo-oxygenase 1 and 2 inhibition on angiogenesis inhibitor-induced hypertension and kidney damage

Vascular endothelial growth factor antagonism with angiogenesis inhibitors in cancer patients induces a ‘preeclampsia-like’ syndrome including hypertension, proteinuria and elevated endothelin (ET)-1. Cyclo-oxygenase (COX) inhibition with aspirin is known to prevent the onset of preeclampsia in high-risk patients. In the present study, we hypothesised that treatment with aspirin would prevent the development of angiogenesis inhibitor-induced hypertension and kidney damage. Our aims were to compare the effects of low-dose (COX-1 inhibition) and high-dose (dual COX-1 and COX-2 inhibition) aspirin on blood pressure, vascular function, oxidative stress, ET-1 and prostanoid levels and kidney damage during angiogenesis-inhibitor therapy in rodents. To this end, Wistar Kyoto rats were treated with vehicle, angiogenesis inhibitor (sunitinib) alone or in combination with low- or high-dose aspirin for 8 days (n=5–7/group). Our results demonstrated that prostacyclin (PGI₂) and ET-1 were increased during angiogenesis-inhibitor therapy, while thromboxane (TXA₂) was unchanged. Both low- and high-dose aspirin blunted angiogenesis inhibitor-induced hypertension and vascular superoxide production to a similar extent, whereas only high-dose aspirin prevented albuminuria. While circulating TXA₂ and prostaglandin F_2α levels were reduced by both low- and high-dose aspirin, circulating and urinary levels PGI₂ were only reduced by high-dose aspirin. Lastly, treatment with aspirin did not significantly affect ET-1 or vascular function. Collectively our findings suggest that prostanoids contribute to the development of angiogenesis inhibitor-induced hypertension and renal damage and that targeting the prostanoid pathway could be an effective strategy to mitigate the unwanted cardiovascular and renal toxicities associated with angiogenesis inhibitors.

Novel function of adrenocorticotropic hormone in the stimulation of vascular endothelial growth factor release in healthy children and adolescents: a proof-of-concept study

PURPOSE

To assess the effect of adrenocorticotropic hormone (ACTH) on plasma vascular endothelial growth factor (VEGF) levels in healthy children and adolescents and to inform future work on the effects of ACTH on VEGF in bone.

METHODS

An Institutional Review Board-approved prospective study of 10 healthy subjects, ages 9-17, was conducted to assess the effect of ACTH on plasma VEGF levels. VEGF levels were collected at baseline and every 30 minutes for 3 hours. Cosyntropin (a synthetic ACTH analogue) was administered at a low-dose (1 μg) given at t=0 minutes and a high-dose (250 μg) given at t=60 minutes. A Friedman test was performed comparing baseline to peak VEGF levels after stimulation with low-dose and high-dose cosyntropin.

RESULTS

Peak plasma VEGF levels significantly increased after high-dose cosyntropin compared with baseline (P=0.042). Peak plasma VEGF levels did not significantly increase after low-dose cosyntropin compared to baseline.

CONCLUSION

To our knowledge, this is the first study to demonstrate that ACTH administration causes a significant increase in plasma VEGF levels in humans. This finding may have important implications in the protective effects of ACTH on bone. Decreased bone mineral density and adrenal suppression are common side effects of glucocorticoid use in pediatrics. VEGF increases vascularity and may play a role in reducing glucocorticoid-induced bone disease. Animal studies have shown that ACTH stimulates release of VEGF in osteoblasts, though this effect has yet to be evaluated in humans.