Male gender and not the severity of hypertension is associated with end-organ damage in aged stroke-prone spontaneously hypertensive rats.
BACKGROUND
It is well-known that gender affects the progression of kidney failure. Male patients exhibit faster development of age-dependent renal disease than do women. In the present study, we examined arterial blood pressure (BP), proteinuria, and end-organ damage in male and female retired breeders from our colony of stroke-prone spontaneously hypertensive rats (SHRSP).


METHODS
Male (n = 7) and female (n = 11) SHRSP littermates maintained on Purina Laboratory Chow 5008 and water were studied starting at 53 weeks of age. Systolic BP was measured by tail-cuff plethysmography and 24-h urinary protein excretion was quantified while animals were housed in metabolic cages. Blood was obtained by retro-orbital bleeding. Mean arterial pressure (MAP) was then monitored by radiotelemetry. Organs were preserved for histopathologic assessment.


RESULTS
Tail-cuff systolic BP did not differ between the sexes. Male SHRSP exhibited greater proteinuria (128 +/- 7 mg/d) than females (21 +/- 5 mg/d, P < .001). Blood urea nitrogen was higher in males (22 +/- 2 mg%) v females (15 +/- 1 mg%, P < .005). The MAP by radiotelemetry did not differ between the sexes (179 +/- 3 mm Hg in males v 192 +/- 6 mm Hg in females, 2 weeks after probe implantation). Stroke-related mortality was greater in males (83%) than females (10%). Renal vascular disease including thrombotic microangiopathy affecting glomeruli and microvessels and cardiac damage were more prominent in male SHRSP.


CONCLUSIONS
These findings demonstrate that male gender is a major risk factor for multisystem end-organ damage associated with aging and hypertension in SHRSP, despite comparable degrees of hypertension among males and females.
Masineni
Sreeharsha N
SN
Department of Pharmacology, New York Medical College, Valhalla, New York 10595, USA.
Chander
Praveen N
PN
Singh
Gagan D
GD
Powers
C Andrew
CA
Stier
Charles T
CT
D000375:Aging / Q000473:pathology; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D001806:Blood Urea Nitrogen; D004195:Disease Models, Animal; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006973:Hypertension / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D007668:Kidney / Q000473:pathology; D007676:Kidney Failure, Chronic / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D008297:Male; D009206:Myocardium / Q000473:pathology; D010991:Plethysmography; D051381:Rats; D011918:Rats, Inbred SHR; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors; D013686:Telemetry