Distinct inflammatory mediator patterns in young black and white adults: The African-predict study

The Africa non-communicable diseases (NCD) Open Lab: Impact of a portfolio of clinical studies to deepen the understanding of NCDs in sub-Saharan Africa

Background

Clinical research in sub-Saharan Africa (SSA) has often focussed on communicable diseases. However, with the increasing burden of non-communicable diseases (NCDs), there is a need for Africa-specific NCD research.

Methods

GSK established the Africa NCD Open Lab in 2014. Three calls for proposals were advertised through various media channels. An external independent scientific advisory board, predominantly representing African scientists and NCD experts, reviewed and selected projects to receive funding. An additional programme in the Africa NCD Open Lab was designed to build statistical capability by supporting training initiatives. We assessed the impact of the Africa NCD Open Lab in three ways: scientific quality with impact; research training and professional development; and research environments. We captured metrics through regular reports/interactions with researchers; via a final report; and through exit interviews with principal investigators.

Results

Twenty projects in 11 African countries were funded; reports from 18 completed projects are available (data capture is ongoing). Overall, 139 articles have been published in peer-reviewed journals and other data have been presented at conferences and other forums. Most completed projects led to positive outcomes, such as further research, informing policy, or positively impacting clinical care, including three projects that saw changes to regional or national practice guidelines: the CREOLE study in Nigeria; the African Severe Asthma Program in Uganda; and the African Prospective Study on the Early Detection and Identification of Cardiovascular Disease and Hypertension in South Africa. Participation in the Africa NCD Open Lab led to the award of 34 grants related to or influenced by increased research capacity or experience. Significant professional development related to the projects also occurred with higher-level degrees being awarded, including 30 MScs, 30 PhDs, and nine postdoctoral fellowships. Through these projects, research capacity was strengthened across the region by equipping core research facilities, training research staff, strengthening research support services, and supporting the expansion of investigator networks.

Conclusions

The completed Africa NCD Open Lab projects demonstrate high-quality research outcomes addressing important health challenges with potential benefits to African populations. Based on the success of the Africa NCD Open Lab, additional funding has been secured to extend the Open Lab initiative.

Inflammatory proteins are associated with mortality in a middle-aged diverse cohort

BACKGROUND

Recent data indicate a decline in overall longevity in the United States. Even prior to the COVID-19 pandemic, an increase in midlife mortality rates had been reported. Life expectancy disparities have persisted in the United States for racial and ethnic groups and for individuals living at low socioeconomic status. These continued trends in mortality indicate the importance of examining biomarkers of mortality at midlife in at-risk populations. Circulating levels of cytokines and inflammatory markers reflect systemic chronic inflammation, which is a well-known driver of many age-related diseases.

METHODS

In this study, we examined the relationship of nine different inflammatory proteins with mortality in a middle-aged socioeconomically diverse cohort of African-American and White men and women (n = 1122; mean age = 47.8 years).

RESULTS

We found significant differences in inflammatory-related protein serum levels between African-American and White middle-aged adults. E-selectin and fibrinogen were significantly higher in African-American adults. IFN-γ, TNF-α trimer, monocyte chemoattractant protein-1 (MCP-1), soluble receptor for advanced glycation end-products (sRAGE) and P-selectin were significantly higher in White participants compared to African-American participants. Higher levels of E-selectin, MCP-1 and P-selectin were associated with a higher mortality risk. Furthermore, there was a significant interaction between sex and IL-6 with mortality. IL-6 levels were associated with an increased risk of mortality, an association that was significantly greater in women than men. In addition, White participants with high levels of sRAGE had significantly higher survival probability than White participants with low levels of sRAGE, while African-American participants had similar survival probabilities across sRAGE levels.

CONCLUSIONS

These results suggest that circulating inflammatory markers can be utilized as indicators of midlife mortality risk in a socioeconomically diverse cohort of African-American and White individuals.

Epidemiology of interleukin-6: the 30-year follow-up of the 1982 Pelotas (Brazil) birth cohort study

BACKGROUND

Cardiovascular diseases are the main cause of death globally. Interleukin-6 (IL-6) is a biomarker of cardiovascular risk.

AIM

To investigate factors associated with IL-6 concentration in serum, from early life up to 30 years of age.

SUBJECTS AND METHODS

In the 2012-2013 follow-up, IL-6 was measured in 2809 participants of the 1982 Pelotas Birth Cohort (1369 males). Multivariable linear regressions, stratified by sex, were performed to evaluate the associations of African ancestry, family income and maternal education at birth, monthly income and education at 30 years, smoking status, harmful alcohol intake, physical activity, and body composition with IL-6, considering a conceptual hierarchical framework.

RESULTS

Males with low educational levels and current smokers had the highest mean IL-6. Among females, African ancestry and low monthly income were associated with the highest mean values for the outcome. Physical activity had an inverse association with IL-6 concentration among females. A direct relationship was observed between the measures of adiposity on IL-6, in both sexes.

CONCLUSION

Body composition was the main predictor for the outcome evaluated in males and females. Thus, the avoidance of overweight remains an important strategy for the prevention and control of cardiovascular risk and biomarkers associated with these diseases.

Inflammation and hypertension development: A longitudinal analysis of the African-PREDICT study

Background

The role of inflammation in the development of hypertension remains incompletely understood. While single inflammatory mediators have been shown to associate with changes in blood pressure (ΔBP), the role of clusters of inflammatory mediators has been less comprehensively explored. We therefore determined whether individual or clusters of inflammatory mediators from a large biomarker panel were associated with ΔBP over 4.5 years, in young healthy adults.

Methods

We included 358 adults (white, n = 156; black, n = 202) with detailed information on ambulatory blood pressure (BP) at baseline and follow-up. Baseline blood samples were analysed for 22 inflammatory mediators using multiplexing technology. Principal component analysis was used to study associations between clusters of inflammatory mediators and ΔBP.

Results

In the total cohort in multivariable-adjusted regression analyses, percentage change in 24hr systolic BP associated positively with Factors 1 (Interferon-gamma, interleukin (IL)-4, IL-7, IL-10, IL-12, IL-17A, IL-21, IL-23, macrophage inflammatory protein (MIP)-1α, MIP-1β, TNF-α, granulocyte-macrophage colony-stimulating factor (GM-CSF)) and 2 (IL-5, IL-6, IL-8, IL-13). Change in daytime systolic BP associated positively with Factors 1, 2 and 3 (C-Reactive protein, IL-1β, IL-2, MIP-3α). Subgroup analysis found these findings were limited to white study participants. Numerous associations were present between individual inflammatory mediators (Interferon-gamma, GM-CSF, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-17A, IL-21, IL-23, MIP-1α and MIP-1β) and ΔBP in the white but not black subgroups.

Conclusion

We found independent relationships between numerous inflammatory mediators (individual and clusters) and ΔBP over 4.5 years. The relationship between inflammatory markers and ΔBP was only found in white participants. ClinicalTrials.gov (Identifier: NCT03292094)..

Von Willebrand factor, its cleaving protease (ADAMTS13), and inflammation in young adults: The African-PREDICT study

BACKGROUND

The role of inflammation in the early development of vascular dysfunction remains complex. Interleukin-6 (IL-6) and C-reactive protein (CRP) can cause an acute imbalance in the von Willebrand factor (vWF)-ADAMTS13 interaction, indicating a possible link between markers of haemostasis and low-grade inflammation. To better understand these inter-relationships in the early phases of disease development, we investigated whether vWF and ADAMTS13 associate with the pro-inflammatory markers, IL-6 and CRP in healthy young adults. We considered the role of blood types, sex and race on these relationships.

METHODS

In healthy black and white men and women (n = 1113; 24 ± 5 years; no previous diagnosis or medication use for chronic diseases) we analysed von Willebrand factor antigen (vWF_ag), ADAMTS13, IL-6 and CRP, and grouped blood types as non-O (A, B and AB) and O. Covariates included socioeconomic status, age, estimated glomerular filtration rate, 24-hour systolic blood pressure, waist circumference, glucose, total cholesterol, platelet count, γ-glutamyl transferase and total energy expenditure.

RESULTS

In the total group, vWF_ag was highest in the third tertile of both IL-6 and CRP (p ≤ 0.014), while ADAMTS13 was lowest in the third compared to the first IL-6 tertile (p = 0.006). In multivariate regression, vWF_ag associated positively with IL-6 (Adj R² = 0.169; β = 0.123; p = 0.001) and CRP (Adj R² = 0.163; β=0.094; p = 0.019) in the total group, in the O blood group (all p ≤ 0.051) and white men (all p ≤ 0.035). ADAMTS13 associated negatively with IL-6 (Adj R² = 0.053; β = -0.154; p = 0.015) and CRP (Adj R² = 0.055; β = -0.177; p = 0.009), only in the O blood group.

CONCLUSIONS

Markers of haemostasis associated independently with low-grade inflammation in the O type blood group and white men. An interplay between the haemostatic and inflammatory systems may already exist in young healthy adults and is dependent on blood groups, sex and race. This extends our understanding on the role of inflammation in the early development of vascular dysfunction prior to cardiovascular compromise.

Inflammation and salt in young adults: the African-PREDICT study

PURPOSE

Low-grade inflammation and a diet high in salt are both established risk factors for cardiovascular disease. High potassium (K⁺) intake was found to counter increase in blood pressure due to high salt intake and may potentially also have protective anti-inflammatory effects. To better understand these interactions under normal physiological conditions, we investigated the relationships between 22 inflammatory mediators with 24-h urinary K⁺ in young healthy adults stratified by low, medium and high salt intake (salt tertiles). We stratified by ethnicity due to potential salt sensitivity in black populations.

METHODS

In 991 healthy black (N = 457) and white (N = 534) adults, aged 20-30 years, with complete data for 24-h urinary sodium and K⁺, we analysed blood samples for 22 inflammatory mediators.

RESULTS

We found no differences in inflammatory mediators between low-, mid- and high-sodium tertiles in either the black or white groups. In multivariable-adjusted regression analyses in white adults, we found only in the lowest salt tertile that K⁺ associated negatively with pro-inflammatory mediators, namely interferon gamma, interleukin (IL) -7, IL-12, IL-17A, IL-23 and tumour necrosis factor alpha (all p ≤ 0.046). In the black population, we found no independent associations between K⁺ and any inflammatory mediator.

CONCLUSION

In healthy white adults, 24-h urinary K⁺ associated independently and negatively with specific pro-inflammatory mediators, but only in those with a daily salt intake less than 6.31 g, suggesting K⁺ to play a protective, anti-inflammatory role in a low-sodium environment. No similar associations were found in young healthy black adults.