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Impaired microvascular dilatation and capillary rarefaction in young adults with a predisposition to high blood
J P Noon1, B R Walker, D J Webb
1Department of Medicine, University of Edinburgh, Western General Hospital, United Kingdom.
Insights
Men with a family history of high blood pressure show impaired dermal vasodilation and reduced capillaries. This suggests defective blood vessel growth may contribute to inherited hypertension.
Area of Science:
- Cardiovascular physiology
- Hypertension research
- Vascular biology
Background:
- Essential hypertension involves increased vascular resistance primarily in microvessels.
- The role of microvascular abnormalities as a cause or consequence of high blood pressure (BP) remains unclear.
- Familial predisposition to high BP is linked to genetic factors influencing vascular health.
Purpose of the Study:
- To investigate microvascular function in men with a familial predisposition to high BP.
- To determine if impaired vasodilation and capillary density are associated with inherited hypertension.
- To explore the potential role of defective angiogenesis in the etiology of hypertension.
Main Methods:
- Studied 105 men (aged 23-33 yr) categorized by their BP and parental BP.
- Assessed dermal vasodilation in the forearm using laser Doppler flowmetry after ischemia and heating.
- Quantified capillary density on the dorsum of the finger using microscopy.
Main Results:
- Men with high BP and a parental history of high BP exhibited significantly impaired dermal vasodilation compared to other groups (P < 0.0001).
- These individuals also showed reduced capillary density on the finger dorsum (P < 0.003).
- No significant differences were observed in other hemodynamic indices like cardiac output or forearm vascular resistance, apart from BP itself.
Conclusions:
- Microvascular abnormalities, including increased minimum resistance and capillary rarefaction, are present in men with a familial predisposition to high BP.
- Defective angiogenesis may be an etiological factor in the inheritance of high blood pressure.
- These findings highlight potential early vascular changes contributing to inherited hypertension.
Abstract:
Increased vascular resistance in essential hypertension occurs mainly in microvessels with luminal diameters < 100 microm. It is not known whether abnormalities in these vessels are a cause or consequence of high blood pressure (BP). We studied 105 men (aged 23-33 yr) in whom predisposition to high blood pressure has been characterized by both their own BP and those of their parents. Factors that are secondary to high BP correlate with offspring BP irrespective of parental BP, but factors that are components of the familial predisposition to high BP are more closely associated with higher BP in offspring whose parents also have high BP. Offspring with high BP whose parents also have high BP had impaired dermal vasodilatation in the forearm following ischemia and heating (289+/-27 [n = 25] versus 529+/-40 [n = 26], 476+/-38 [n = 30], and 539+/-41 flux units [n = 24] in other groups; P < 0.0001) and fewer capillaries on the dorsum of the finger (23+/-0.8 capillaries/0.25 mm2 versus 26+/-0.8 in all other groups; P < 0.003). Except for BP, other hemodynamic indices (including cardiac output and forearm vascular resistance) were not different. The dermal vessels of men who express a familial predisposition to high BP exhibit increased minimum resistance and capillary rarefaction. Defective angiogenesis may be an etiological component in the inheritance of high BP.