Low serum testosterone and increased diastolic ocular perfusion pressure: a risk for retinal microvasculature

Malan, Nico T; Smith, Wayne; von Känel, Roland; Hamer, Mark; Schutte, Alta E; Malan, Leoné (2015). Low serum testosterone and increased diastolic ocular perfusion pressure: a risk for retinal microvasculature. Vasa - European journal of vascular medicine, 44(6), pp. 435-443. Huber 10.1024/0301-1526/a000466

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BACKGROUND Low levels of testosterone in men and changes in retinal microvascular calibre are both associated with hypertension and cardiovascular disease risk. Sex hormones are also associated with blood flow in microvascular beds which might be a key intermediate mechanism in the development of hypertension. Whether a direct association between endogenous testosterone and retinal microvascular calibre exists is currently unknown. We aimed to determine whether testosterone is independently associated with ocular perfusion via a possible association with retinal vascular calibre or whether it plays only a secondary role via its effect on blood pressure in a bi-ethnic male cohort. PROBANDS AND METHODS A total of 72 black and 81 white men (28-68 years of age) from the follow-up phase of the Sympathetic activity and Ambulatory Blood Pressure in Africans (SABPA) study were included in this sub-study. Ambulatory pulse pressure and intraocular perfusion pressures were obtained, while metabolic variables and testosterone were measured from fasting venous blood samples. Retinal vascular calibre was quantified from digital photographs using standardised protocols. RESULTS The black men revealed a poorer cardiometabolic profile and higher pulsatile pressure (>50 mm Hg), intraocular pressure and diastolic ocular perfusion pressure than the white men (p≤0.05). Only in the white men was free testosterone positively associated with retinal calibre, i.e. arterio-venular ratio and central retinal arterial calibre and inversely with central retinal venular calibre. These associations were not found in the black men, independent of whether pulse pressure and ocular perfusion pressure were part of the model. CONCLUSIONS These results suggest an independent, protective effect of testosterone on the retinal vasculature where an apparent vasodilatory response in the retinal resistance microvessels was observed in white men.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Pre-clinic Human Medicine > BioMedical Research (DBMR) > DCR Unit Sahli Building > Forschungsgruppe Neurologie

UniBE Contributor:

von Känel, Roland

Subjects:

600 Technology > 610 Medicine & health

ISSN:

0301-1526

Publisher:

Huber

Language:

English

Submitter:

Romina Theiler

Date Deposited:

16 Mar 2016 12:14

Last Modified:

20 Sep 2017 09:09

Publisher DOI:

10.1024/0301-1526/a000466

PubMed ID:

26515220

Uncontrolled Keywords:

Testosterone; diastolic ocular perfusion pressure; intraocular pressure; pulse pressure; retinal microvascular calibre

BORIS DOI:

10.7892/boris.76999

URI:

https://boris.unibe.ch/id/eprint/76999

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