Urinary metabolomics, dietary salt intake and blood pressure: the African-PREDICT study

In Black populations excessive salt intake may exacerbate the genetic predisposition to hypertension and promote the early onset of cardiovascular disease. Ethnic differences in the interaction between sodium intake and the metabolome may play a part in hypertension and cardiovascular disease development. We determined (1) urinary amino acid and acylcarnitine profiles of young Black and White adults according to low, moderate, and high dietary salt intake, and (2) investigated the triad of salt intake, systolic blood pressure (SBP), and the associated metabolomics profile. This study included 447 White and 380 Black adults aged 20-30 years from the African-PREDICT study. Estimated salt intake was determined from 24-hour urinary sodium levels. Urinary amino acids and acylcarnitines were measured using liquid chromatography-tandem mass spectrometry. Black adults exhibited no significant differences in SBP, amino acids, or acylcarnitines across low (<5g/day), moderate (5-10g/day), and high (>10g/day) salt intake. White adults with a high salt intake had elevated SBP compared to those with low or moderate intakes (p < 0.001). Furthermore, gamma-aminobutyric acid (GABA) (q = 0.020), citrulline (q = 0.020), glutamic acid (q = 0.046), serine (q = 0.054) and proline (q = 0.054) were lowest in those with higher salt intake. Only in White and not Black adults did we observe inverse associations of clinic SBP with GABA (Adj. R2 = 0.34; Std. β = -0.133; p = 0.003), serine (Adj. R2 = 0.33; Std. β = -0.109; p = 0.014) and proline (Adj. R2 = 0.33; Std. β = -0.109; p = 0.014). High salt intake in White, but not in black adults, were related to metabolomic changes and may contribute to pathophysiological mechanisms associated with increased BP.

Elevated blood pressure positively associates with alpha-1 microglobulin in prepubescent children: the ExAMIN Youth SA study

OBJECTIVES AND METHODS

Hypertension is a growing health concern in childhood populations and individuals of African descent. As the kidneys play a significant role in blood pressure regulation, we compared alpha-1 microglobulin (A1M) as a marker of proximal tubular function between young healthy black and white children (n = 957; aged: 5-9 years) and explored its association with blood pressure.

RESULTS

The black children had higher levels of A1M (P < 0.001) and higher DBP (P < 0.001) when compared with their white counterparts. In multiple regression analysis, SBP (adj. R2 = 0.173, β = 0.151; P < 0.001) and DBP (adj. R2 = 0.110, β = 0.179; P < 0.001) associated positively with A1M in the black children. In binary logistic regression, each standard deviation increase in A1M increased the odds of having elevated blood pressure by 28% (P = 0.002) in the black group, independent of age, sex, BMI z-score and body height. No significance was reached in the white children.

CONCLUSION

Our findings highlight the importance of a marker of proximal tubular function, especially in children of black ethnicity, in the setting of elevated blood pressure. Early childhood screening for elevated blood pressure remains essential in order to promote primary prevention of hypertension and early onset kidney damage in children.

Urinary proteomics combined with home blood pressure telemonitoring for health care reform trial: rational and protocol

BACKGROUND

Hypertension and diabetes cause chronic kidney disease (CKD) and diastolic left ventricular dysfunction (DVD) as forerunners of disability and death. Home blood pressure telemonitoring (HTM) and urinary peptidomic profiling (UPP) are technologies enabling prevention.

METHODS

UPRIGHT-HTM (Urinary Proteomics Combined with Home Blood Pressure Telemonitoring for Health Care Reform [NCT04299529]) is an investigator-initiated 5-year clinical trial with patient-centred design, which will randomise 1148 patients to be recruited in Europe, sub-Saharan Africa and South America. During the whole study, HTM data will be collected and freely accessible for patients and caregivers. The UPP, measured at enrolment only, will be communicated early during follow-up to 50% of patients and their caregivers (intervention), but only at trial closure in 50% (control). The hypothesis is that early knowledge of the UPP risk profile will lead to more rigorous risk factor management and result in benefit. Eligible patients, aged 55-75 years old, are asymptomatic, but have ≥5 CKD- or DVD-related risk factors, preferably including hypertension, type-2 diabetes, or both. The primary endpoint is a composite of new-onset intermediate and hard cardiovascular and renal outcomes. Demonstrating that combining UPP with HTM is feasible in a multicultural context and defining the molecular signatures of early CKD and DVD are secondary endpoints.

EXPECTED OUTCOMES

The expected outcome is that application of UPP on top of HTM will be superior to HTM alone in the prevention of CKD and DVD and associated complications and that UPP allows shifting emphasis from treating to preventing disease, thereby empowering patients.

3044Exploration of biomarkers for subclinical atherosclerosis in an African population using a proteomics chip targeted at inflammation and cardiovascular disease

Introduction

The evolving use of multiplex proteomic platforms provides an excellent tool for investigating associations between multiple proteins and subclinical atherosclerotic disease. In this study, we evaluated the impact of a multiplex protein panel, on carotid intima-media thickness (cIMT) as a marker of subclinical atherosclerosis.

Purpose

We used a multiplex proteomic platform to identify possible associations between proteins and subclinical carotid atherosclerosis as measured by carotid ultrasound in an African population.

Methods

In the Sympathetic Activity and Ambulatory Blood Pressure in Africans (SABPA) study, 92 proteins from the Proseek Multiplex CVD III 96×96 (Olink Bioscience, Sweden) were analyzed in 378 participants (mean age 44.7±9.6 years, 50.6% women, 10.8% with known cardiovascular disease). Carotid ultrasound was performed for measurements of the carotid intima-media thickness (cIMT, mean 0.663±0.127 mm) and calculation of cross-sectional wall area (CSWA, mean 13.5±4.4mm2), a measure of target organ damage. Possible associations between the proteins, and cIMT and CSWA, respectively, were explored using linear regression models. A two-sided Bonferroni corrected P-value of 0.05/92=5.4x10–4 was considered statistically significant in the crude analysis.

Results

Of 18 proteins (1 standard deviation of change of ln-transformed values) that were Bonferroni-corrected (p≤5.4x10–4) significantly associated with cIMT and/or CWAS in crude analyses, the following remained significant after further adjustment for age, sex, waist circumference, systolic blood pressure, smoking and total cholesterol: growth-differentiation factor-15 (GDF15; β 0.017, p=0.050), E-selectin (SELE; β 0.019, p=0.017), carboxypeptidase A1 (CPA1; β 0.019, p=0.019), C-C motif chemokine 15 (CCL15; β 0.031, p<0.001), chitinase-3-like protein 1 (CHI3L1; β 0.021, p=0.007), the hemoglobin scavenger receptor (CD163; β 0.021, p=0.008) and osteoprotegerin (OPG; β 0.022, p=0.004). As for target-organ damage defined by CSWA, SELE (β 0.459, p=0.018), CCL15 (β 0.398; p=0.032) and CD163 (β 0.541, p=0.005) showed multivariate adjusted significant associations.

Conclusion

In an African population, we could confirm five proteins (GDF15, SELE, CHI3L1, CD163 and OPG) associated with cIMT, but in addition identified two proteins (CPA1 and CCL15) with novel associations with cIMT and/or CSWA.

Acknowledgement/Funding

North-West University; National Research Foundation (NRF); Medical Research Council (MRC-SA); Department of Education North-West Province; ROCHE

Social support in unaccompanied asylum-seeking boys: a case study

BACKGROUND

The situation of unaccompanied asylum-seeking children (UASC) is characterized by a substantial disruption of the social network and loss of parental support, seriously jeopardizing their psychological well-being. However, little is known about the role of social support in the lives of UASC.

METHODS

Twelve UASC completed a social support instrument and interview exploring perceived social support and what this implies for both buffering and main effects of social support.

RESULTS

Asylum centre staff and the ethnic community were the most important resources of support. High importance was ascribed to social companionship as a way of coping. Despite pro-social efforts towards Belgian peers, this group provided hardly any social support.

CONCLUSIONS

The provision of social support could enhance UASC's well-being through buffering effects (e.g. social companionship as avoidant/distractive coping) and main effects (acceptance by Belgian peers enhancing self-esteem). The asylum centre shows a great potential to stimulate UASC's psychological well-being by expanding the psychosocial function of staff members and community treatment.