Salt sensitivity, baroreflex sensitivity and vascular resistance in a normotensive young-adult Nigerian Population

Future Physiology 2019 (Liverpool, UK) (2019) Proc Physiol Soc 45, PC03

Poster Communications: Salt sensitivity, baroreflex sensitivity and vascular resistance in a normotensive young-adult Nigerian Population

A. K. Oloyo1, A. Adewusi1, K. Ismail-Badmus1, F. M. Agbaraolorunpo1, A. Adejare1, O. Sofola1

1. Physiology, College of Medicine, University of Lagos, Idi-Araba, Surulere, Lagos, Nigeria.

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Hypertension is a global public health challenge, and a high salt diet is its most important environmental risk factor (Meneton et al., 2005). We have previously reported that about 60% hypertensive and 37% normotensive adult Nigerian population are salt-sensitives (Elias et al., 2014). However, salt-sensitivity increases with age (Weinberger, 2002), therefore this study was designed to evaluate salt-sensitivity and its relationship with baroreflex sensitivity (BRS) and systemic vascular resistance (SVR) in a normotensive young-adult Nigerian population. After an ethical approval from the Health and Research Ethics Committee (HREC) of the College of Medicine, University of Lagos and collection of both written and verbal consent, 24 (12 Males; 12 Females) young-adult [18-35: (26±1.0) years] normotensive [Blood Pressure (BP) < 140/90: 119±2/74±1 mm Hg] participants were salt loaded (200mmol/day x 5), after the collection of anthropometric [Weight (61.71±2.79 Kg) height (165.9±1.74 cm) and BMI (22.30±0.82 kg/m2)] and basal parameters (BP, heart rate (HR), 12- hour urine, BRS, SVR via finger plethysmography and 5ml venous blood for serum measurement of Asymmetric Dimethyl Arginine (ADMA)). On day 6, which is the day 1 post salt-loading, all the above-listed parameters were taken again. Thereafter, collected data before and after salt-loading were analysed using paired t-test. Salt sensitivity was defined as post salt-loading MABP ≥3mm Hg. Differences in parameters between salt sensitive (SS) and salt resistant (SR) participants were analysed using student t-test while confidence interval was placed at p≤0.05. There was no significant difference between the pre and post salt values of MABP (89±1 vs. 88±1mm Hg); HR (73±2 vs. 70±3 beat/min); SVR (0.038±0.006 vs. 0.48±0.007) and Serum ADMA levels (91.07±4.67vs. 96.65±6.05 µg/ml) of the participants. However, about 29% (7/24) of the participants are salt sensitive. In the SS participants, post salt-loading values of MABP (84±3 vs. 89±2mm Hg(p=0.001)); SVR (0.024±0.006 vs. 0.044±0.01 (p=0.008)) and serum ADMA concentration (80.57±5.51 vs. 104±6.73 µg/ml (p=0.01)) are significantly higher when compared to the pre salt values, while the BRS was blunted. These observations are not found in SR participant.Thus, findings from this study suggest that in SS normotensive young-adult Nigerians, salt loading blunted the BRS and impaired the SVR probably by increasing the concentration of ADMA – an endogenous inhibitor of nitric oxide production.



Where applicable, experiments conform with Society ethical requirements.

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