Paradoxical sex differences in a hamster model of angiotensin II-dependent hypertension and associated renal injury.

BACKGROUND: Biological sex is a critical determinant in cardiovascular and renal disease outcomes. Although angiotensin II (Ang II) infusion is widely used to model hypertension in mice and rats, little is known about its effects in the Syrian hamster, a small rodent increasingly used for translational research. This study aimed to develop a model of chronic Ang II-induced hypertension in Syrian hamsters and investigate sex-specific differences in blood pressure, renal pathology, and components of the renin-angiotensin system (RAS). METHODS: Male and female Syrian hamsters (8-9 weeks old) were infused subcutaneously with Ang II (200 ng/kg/min) or saline via osmotic minipumps for four weeks. Mean arterial pressure (MAP) and kidney wet weight were determined on the euthanasia day. The kidneys were analyzed for renal pathology; renal RAS enzymes (ACE and ACE2) were measured by colorimetric assay and qPCR; cytokines (IL-6 and IL-1β) were measured by qPCR; and the angiotensin receptor type 1 (AT1R) was measured by radioligand binding and qPCR. RESULTS: Ang II infusion increased MAP in both sexes but elicited a significantly greater response in females (+ 50 mmHg) than males (+ 27 mmHg, p < 0.005). Female hamsters exhibited pronounced kidney injury, including acute tubular necrosis, glomerular sclerosis, and vascular fibrinoid necrosis, along with a 2-fold increase in kidney weight normalized to body weight. Ang II significantly downregulated renal ACE, ACE2, and AT1R expression and activity in females but not in males. Renal IL-6 and IL-1β mRNA levels were elevated 20-fold and 3.9-fold, respectively, in females, compared to modest increases in males. CONCLUSIONS: Female Syrian hamsters exhibit heightened vulnerability to Ang II-induced hypertension and renal damage compared to males, marked by exaggerated blood pressure elevation, enhanced renal inflammation, and suppression of classical RAS components. This novel hamster model provides a unique platform for studying sex-specific mechanisms of hypertension and renal pathology, with translational relevance for subpopulations of women who are at increased risk of Ang II-dependent hypertension-associated renal disease.