Endocannabinoid receptor blockade increases vascular endothelial growth factor and inflammatory markers in obese women with polycystic ovary syndrome.

Context: Animal studies suggest that cannabinoid receptor-1 (CB-1) blockade reduces inflammation and neovascularization by decreasing vascular endothelial growth factor (VEGF) levels associated with a reduction in inflammatory markers, thereby potentially reducing cardiovascular risk.

Objective: To determine the impact of CB1 antagonism by rimonabant on VEGF and inflammatory markers in obese PCOS women.

Design: Randomized, open-labelled parallel study.

Setting: Endocrinology outpatient clinic in a referral centre.

Subjects: Twenty patients with PCOS (PCOS) and biochemical hyperandrogenaemia with a body mass index of ≥30 kg/m were recruited. Patients were randomized to 1·5 g daily of metformin or 20 mg daily of rimonabant.

Main Outcome Measures: Post hoc review to detect VEGF and pro-inflammatory cytokines TNF-α, IL-1β, IL-1ra, IL-2, IL6, IL-8, IL-10 and MCP-1 before and after 12 weeks of treatment.

Results: After 12 weeks of rimonabant treatment, there was a significant increase in VEGF (99·2 ± 17·6 vs 116·2 ± 15·8 pg/ml, P < 0·01) and IL-8 (7·4 ± 11·0 vs 18·1 ± 13·2 pg/ml, P < 0·05) but not after metformin (VEGF P = 0·7; IL-8 P = 0·9). There was no significant difference in the pro-inflammatory cytokines TNF-α, IL-1β, IL-1ra, IL-2, IL6, IL-8, IL-10 and MCP-1 following either treatment.

Conclusion: This study suggests that rimonabant CB-I blockade paradoxically raised VEGF and the cytokine IL-8 in obese women with PCOS that may have offset the potential benefit associated with weight loss.