Salt Sensitivity of Blood Pressure.

The year 2024 marks the centennial of the initiation of the American Heart Association. Over the past 100 years, the American Heart Association has led groundbreaking discoveries in cardiovascular disease including salt sensitivity of blood pressure, which has been studied since the mid-1900s. Salt sensitivity of blood pressure is an important risk factor for cardiovascular events, but the phenotype remains unclear because of insufficient understanding of the underlying mechanisms and lack of feasible diagnostic tools. In honor of this centennial, we commemorate the initial discovery of salt sensitivity of blood pressure and chronicle the subsequent scientific discoveries and efforts to mitigate salt-induced cardiovascular disease with American Heart Association leading the way. We also highlight determinants of the pathophysiology of salt sensitivity of blood pressure in humans and recent developments in diagnostic methods and future prospects.

HIV-Associated Hypertension: Risks, Mechanisms, and Knowledge Gaps.

HIV type 1 (HIV-1) is the causative agent of AIDS. Since the start of the epidemic, HIV/AIDS has been responsible for ≈40 million deaths. Additionally, an estimated 39 million people are currently infected with the virus. HIV-1 primarily infects immune cells, such as CD4+ (cluster of differentiation 4+) T lymphocytes (T cells), and as a consequence, the number of CD4+ T cells progressively declines in people living with HIV. Within a span of ≈10 years, HIV-1 infection leads to the systemic failure of the immune system and progression to AIDS. Fortunately, potent antiviral therapy effectively controls HIV-1 infection and prevents AIDS-related deaths. The efficacy of the current antiviral therapy regimens has transformed the outcome of HIV/AIDS from a death sentence to a chronic disease with a prolonged lifespan of people living with HIV. However, antiviral therapy is not curative, is challenged by virus resistance, can be toxic, and, most importantly, requires lifelong adherence. Furthermore, the improved lifespan has resulted in an increased incidence of non-AIDS-related morbidities in people living with HIV including cardiovascular diseases, renal disease, liver disease, bone disease, cancer, and neurological conditions. In this review, we summarize the current state of knowledge of the cardiovascular comorbidities associated with HIV-1 infection, with a particular focus on hypertension. We also discuss the potential mechanisms known to drive HIV-1-associated hypertension and the knowledge gaps in our understanding of this comorbid condition. Finally, we suggest several directions of future research to better understand the factors, pathways, and mechanisms underlying HIV-1-associated hypertension in the post-antiviral therapy era.

The Interplay of HIV and Long COVID in Sub-Saharan Africa: Mechanisms of Endothelial Dysfunction.

PURPOSE OF REVIEW: Long COVID affects approximately 5 million people in Africa. This disease is characterized by persistent symptoms or new onset of symptoms after an acute SARS-CoV-2 infection. Specifically, the most common symptoms include a range of cardiovascular problems such as chest pain, orthostatic intolerance, tachycardia, syncope, and uncontrolled hypertension. Importantly, these conditions appear to have endothelial dysfunction as the common denominator, which is often due to impaired nitric oxide (NO) mechanisms. This review discusses the role of mechanisms contributing to endothelial dysfunction in Long COVID, particularly in people living with HIV. RECENT FINDINGS: Recent studies have reported that increased inflammation and oxidative stress, frequently observed in Long COVID, may contribute to NO dysfunction, ultimately leading to decreased vascular reactivity. These mechanisms have also been reported in people living with HIV. In regions like Africa, where HIV infection is still a major public health challenge with a prevalence of approximately 26 million people in 2022. Specifically, endothelial dysfunction has been reported as a major mechanism that appears to contribute to cardiovascular diseases and the intersection with Long COVID mechanisms is of particular concern. Further, it is well established that this population is more likely to develop Long COVID following infection with SARS-CoV-2. Therefore, concomitant infection with SARS-CoV-2 may lead to accelerated cardiovascular disease. We outline the details of the worsening health problems caused by Long COVID, which exacerbate pre-existing conditions such as endothelial dysfunction. The overlapping mechanisms of HIV and SARS-CoV-2, particularly the prolonged inflammatory response and chronic hypoxia, may increase susceptibility to Long COVID. Addressing these overlapping health issues is critical as it provides clinical entry points for interventions that could improve and enhance outcomes and quality of life for those affected by both HIV and Long COVID in the region.

High salt intake and HIV infection on endothelial glycocalyx shedding in salt-sensitive hypertension.

The endothelial glycocalyx is closely associated with various physiological and pathophysiological events. Significant modification of the endothelial glycocalyx is an early process in the pathogenesis of cardiovascular disease. High dietary salt and HIV infection damages the endothelial glycocalyx causing endothelial dysfunction and increasing the risk for salt-sensitive hypertension and cardiovascular disease. The two factors, HIV infection and dietary salt are critical independent predictors of hypertension and cardiovascular disease and often synergize to exacerbate and accelerate disease pathogenesis. Salt-sensitive hypertension is more common among people living with HIV and is associated with risk for cardiovascular disease, stroke, heart attack and even death. However, the underlying mechanisms linking endothelial glycocalyx damage to dietary salt and HIV infection are lacking. Yet, both HIV infection/treatment and dietary salt are closely linked to endothelial glycocalyx damage and development of salt-sensitive hypertension. Moreover, the majority of individuals globally, consume more salt than is recommended and the burden of HIV especially in sub-Sahara Africa is disproportionately high. In this review, we have discussed the missing link between high salt and endothelial glycocalyx shedding in the pathogenesis of salt-sensitive hypertension. We have further elaborated the role played by HIV infection and treatment in modifying endothelial glycocalyx integrity to contribute to the development of hypertension and cardiovascular disease.

Erythrocyte glycocalyx sensitivity to sodium is associated with salt sensitivity of blood pressure in women but not men.

Background: While salt sensitivity of blood pressure (SSBP) is a risk factor for hypertension, end-organ damage and death, most studies are conducted in western countries and in White people. We previously found that the prevalence of SSBP in Blacks living in Sub-Saharan Africa is as high as 75-80% like what has been reported in the west. Erythrocyte glycocalyx sensitivity to sodium (eGCSS), a marker of sodium-induced damage to the erythrocyte and vascular endothelial glycocalyx is thought to be related to blood pressure perturbations associated with salt intake. We hypothesized that SSBP correlates with eGCSS differently in men and women in Black people. Methods: We conducted a cross sectional study using data from our recent clinical trial from Livingstone University Teaching Hospital among 117 normotensive young adults. We used a "salt blood test" to determine eGCSS and an immediate pressor response to oral salt (IPROS) for the diagnosis of SSBP. Results: The proportion of males were equal to females and the median age (interquartile range) of the participants was 29 (22-45) years. The eGCSS scores were higher in salt-resistant females compared to salt-sensitive females and males. eGCSS correlated negatively with SSBP (AOR 0.98, 95% CI 0.97-0.99, p = 0.008), however, this relationship was driven by female sex and abrogated by male sex. Although blood pressure elevations exhibited a sustained bimodal pattern in both sexes, in males, systolic and diastolic blood pressure never returned to baseline during the time course as it did in females. Conclusion: In this study, eGCSS correlated negatively with SSBP in black women but not in black men and the pressor response to dietary salt was significantly higher in men compared to women. These results suggest that women tend to have a higher disruption of the vascular endothelial glycocalyx by an acute salt load, implying that acute changes in blood pressure may not be driven directly by the endothelial glycocalyx. Our findings suggest a novel mechanism linking eGCSS and SSBP with potential implications for sex differences in salt-induced cardiovascular disease.Clinical trial registration: https://clinicaltrials.gov/, identifier [NCT04844255].

Mechanisms and Cardiorenal Complications of Chronic Anemia in People with HIV.

Chronic anemia is more prevalent in people living with HIV (PLWH) compared to the general population. The mechanisms that drive chronic anemia in HIV are multifaceted and include functional impairment of hematopoietic stem cells, dysregulation of erythropoietin production, and persistent immune activation. Chronic inflammation from HIV infection adversely affects erythropoiesis, erythrocyte lifespan, and erythropoietin response, leading to a heightened risk of co-infections such as tuberculosis, persistent severe anemia, and increased mortality. Additionally, chronic anemia exacerbates the progression of HIV-associated nephrotoxicity and contributes to cardiovascular risk through immune activation and inflammation. This review highlights the cardinal role of chronic inflammation as a link connecting persistent anemia and cardiovascular complications in PLWH, emphasizing the need for a universal understanding of these interconnected pathways for targeted interventions.

Prevalence and correlates of Human Papillomavirus infection in females from Southern Province, Zambia: A cross-sectional study.

BACKGROUND: Human papillomavirus (HPV) infection is strongly associated with cervical cancer with almost all cases being associated with the infection. Cervical cancer is the leading cause of cancer death among women in Zambia and the fourth leading cause of cancer death in women worldwide. However, there is limited data on the burden and associated factors of HPV in sub-Saharan Africa. This study therefore aimed to determine the prevalence and correlates of HPV infection in the Southern province of Zambia. METHODS: This was a cross-sectional study conducted at Livingstone University Teaching Hospital (LUTH) among 4,612 women from different districts of the southern province being screened for HPV infection between September 2021 and August 2022. Demographic and clinical data were collected from an existing laboratory programmatic database. Multivariable logistic regression was used to estimate the factors associated with HPV infection. RESULTS: The study participants had a median age of 39 years [interquartile range (IQR) 30, 47]. The prevalence of HPV infection was 35.56% (95%CI). At multivariable analysis, the factors associated with a positive HPV result were younger age (adjusted odds ratio (AOR) 0.98; 95% confidence interval (CI) 0.98-0.99; p. value 0.001), having provider collected sample (AOR 2.15; 95%CI 1.66-2.79; p. value <0.001) and living with HIV (AOR 1.77; 95%CI 1.22-2.55; p. value <0.002). CONCLUSION: The prevalence of HPV in women in the southern province of Zambia is high, and likely influenced by age and HIV status. Additionally, the outcome of the HPV test is affected by the sample collection method. Therefore, there is a necessity to enhance HPV and cervical cancer screening, especially among people with HIV.

Recent Advances in Understanding Peripheral and Gut Immune Cell-Mediated Salt-Sensitive Hypertension and Nephropathy.

Hypertension is the primary modifiable risk factor for cardiovascular, renal, and cerebrovascular diseases and is considered the main contributing factor to morbidity and mortality worldwide. Approximately 50% of hypertensive and 25% of normotensive people exhibit salt sensitivity of blood pressure, which is an independent risk factor for cardiovascular disease. Human and animal studies demonstrate that the immune system plays an important role in the etiology and pathogenesis of salt sensitivity of blood pressure, kidney damage, and vascular diseases. Antigen-presenting and adaptive immune cells are implicated in salt-sensitive hypertension and salt-induced renal and vascular injury. Elevated sodium activates antigen-presenting cells to release proinflammatory cytokines including IL (interleukin) 6, tumor necrosis factor-α, IL-1ß, and accumulate isolevuglandin-protein adducts. In turn, these activate T cells release prohypertensive cytokines including IL-17A. Moreover, high-salt intake is associated with gut dysbiosis, leading to inflammation, oxidative stress, and blood pressure elevation but the mechanistic contribution to salt-sensitivity of blood pressure is not clearly understood. Here, we discuss recent advances in research investigating the cause, potential biomarkers, and therapeutic targets for salt-sensitive hypertension as they pertain to the gut microbiome, immunity, and inflammation.

Correlates of hypertension among persons living with HIV at Livingstone Central Hospital: A cross sectional study

Background: Persons living with HIV (PLWH) are more likely to develop hypertension and cardiovascular disease than the HIV-negative population. The new hypertension guidelines by the American Heart Association (AHA) and the American College of Cardiology (ACC) lowered the definition of hypertension from systolic and diastolic blood pressure (BP) of ≥ 140/90mmHg to ≥ 130/80, respectively. This study was aimed at determining the prevalence and factors associated with hypertension in PLWH in Livingstone using the new hypertension diagnostic criteria. Methods: This was a cross-sectional study. We recruited 226 antiretroviral treated PLWH attending routine visits. Socio-demographic, health and clinical data including BP readings were collected. Interviewer-structured questionnaires adapted from the World Health Organization Stepwise approach to Surveillance ( WHO STEPs) and the international physical activity questionnaire (IPAQ) were used to collect data. Statistical evaluations were employed to elucidate relationships between hypertension and all response variables. Results: The prevalence of hypertension using the old and new guidelines was 16% and 42%, respectively. Factors significantly associated with increased and reduced odds of developing hypertension after adjustments in multivariate logistic regression were age, body mass index (BMI), employment status, fasting blood sugar (FBS) and table salt consumption, respectively (p<0.05 for all). Using the new AHA/ACC criteria for hypertension shifted the prevalence from 16% (old criteria) to 42%.Conclusion: The prevalence of hypertension in PLH in Livingstone was 42% and the major risk factors associated with hypertension in PLWH were increasing age, BMI and FBS. We recommend the inclusion of FBS in routine measurements in PLWH. The AHA/ ACC new guidelines should be reenforced in low-cost settings to increase the treatment of hypertension among PLWH.