Vascular permeability, blood pressure, and organ damage in primary hypertension

Prognostic value of morning blood pressure surge in chronic kidney disease

This was a retrospective study. This study investigated the occurrence of a composite endpoints (cardiovascular and cerebrovascular events, end-stage renal disease, and death) in 153 patients (aged ≥ 18 years) with a diagnosis of in chronic kidney disease (CKD). Based on morning blood pressure surge (MBPS) defined as ≥35 mm Hg, patients were divided into two groups: with MBPS (n = 50) and without MBPS (n = 103). All patients were followed up for at least 1 year. Baseline demographic, laboratory and follow-up data were collected. The clinical characteristics of the two groups were compared. The relationships between MBPS and endpoint events were analyzed using the Kaplan-Meier method and Cox regression model. In total, 153 patients (mean age 41.8 years; 56.86% males) were included in this study. During the follow-up period (mean 4.3 years), 34 endpoint events occurred. After adjustment for the covariates, the risk of cardiovascular and cerebrovascular events, end-stage renal disease and death remained significantly higher in patients with MBPS (hazard ratio [HR] and 95% confidence interval [CI] 3.124 [1.096-9.130]]) Among the other variables, systolic blood pressure, and night-time and daytime pulse pressures remained significantly associated with outcome in patients of CKD (1.789 [1.205-2.654], 1.710 [1.200-2.437], and 1.318 [1.096-1.586], respectively]. In conclusions, MBPS was identified as an independent prognostic factor for composite endpoint events (cardiovascular and cerebrovascular events, end-stage renal disease and death) patients with chronic kidney disease patients.

Comparative analysis of hypertensive nephrosclerosis in animal models of hypertension and its relevance to human pathology. Glomerulopathy

Current research on hypertension utilizes more than fifty animal models that rely mainly on stable increases in systolic blood pressure. In experimental hypertension, grading or scoring of glomerulopathy in the majority of studies is based on a wide range of opinion-based histological changes that do not necessarily comply with lesional descriptors for glomerular injury that are well-established in clinical pathology. Here, we provide a critical appraisal of experimental hypertensive glomerulopathy with the same approach used to assess hypertensive glomerulopathy in humans. Four hypertensive models with varying pathogenesis were analyzed–chronic angiotensin II infused mice, mice expressing active human renin in the liver (TTRhRen), spontaneously hypertensive rats (SHR), and Goldblatt two-kidney one-clip rats (2K1C). Analysis of glomerulopathy utilized the same criteria applied in humans–hyalinosis, focal segmental glomerulosclerosis (FSGS), ischemic, hypertrophic and solidified glomeruli, or global glomerulosclerosis (GGS). Data from animal models were compared to human reference values. Kidneys in TTRhRen mice, SHR and the nonclipped kidneys in 2K1C rats had no sign of hyalinosis, FSGS or GGS. Glomerulopathy in these groups was limited to variations in mesangial and capillary compartment volumes, with mild increases in collagen deposition. Histopathology in angiotensin II infused mice corresponded to mesangioproliferative glomerulonephritis, but not hypertensive glomerulosclerosis. The number of nephrons was significantly reduced in TTRhRen mice and SHR, but did not correlate with severity of glomerulopathy. The most substantial human-like glomerulosclerotic lesions, including FSGS, ischemic obsolescent glomeruli and GGS, were found in the clipped kidneys of 2K1C rats. The comparison of affected kidneys to healthy control in animals produces lesion values that are numerically impressive but correspond to mild damage if compared to humans. Animal studies should be standardized by employing the criteria and classifications established in human pathology to make experimental and human data fully comparable for comprehensive analysis and model improvements.

Microvascular and lymphatic dysfunction in HFpEF and its associated comorbidities

Heart failure with preserved ejection fraction (HFpEF) is a complex heterogeneous disease for which our pathophysiological understanding is still limited and specific prevention and treatment strategies are lacking. HFpEF is characterised by diastolic dysfunction and cardiac remodelling (fibrosis, inflammation, and hypertrophy). Recently, microvascular dysfunction and chronic low-grade inflammation have been proposed to participate in HFpEF development. Furthermore, several recent studies demonstrated the occurrence of generalized lymphatic dysfunction in experimental models of risk factors for HFpEF, including obesity, hypercholesterolaemia, type 2 diabetes mellitus (T2DM), hypertension, and aging. Here, we review the evidence for a combined role of coronary (micro)vascular dysfunction and lymphatic vessel alterations in mediating key pathological steps in HFpEF, including reduced cardiac perfusion, chronic low-grade inflammation, and myocardial oedema, and their impact on cardiac metabolic alterations (oxygen and nutrient supply/demand imbalance), fibrosis, and cardiomyocyte stiffness. We focus primarily on HFpEF caused by metabolic risk factors, such as obesity, T2DM, hypertension, and aging.

Elevated blood pressure and illness beliefs: a cross-sectional study of emergency department patients in Jamaica

BACKGROUND

Elevated blood pressure (BP) is common among emergency department (ED) patients. While some data exist on the association between ED BP and hypertension (HTN) in the USA, little is known about this relationship in Afro-Caribbean nations. The aim of the study was to evaluate the relationship between elevated systolic BP in the ED and a previous diagnosis of HTN, accounting for potential factors that could contribute to poor HTN control among those with a previous diagnosis: socioeconomic status, health-seeking behavior, underlying HTN illness beliefs, medication adherence, and perceived adherence self-efficacy.

METHODS

This was a cross-sectional survey over 6 weeks, from November 19 through December 30, 2014. Those surveyed were non-critically ill or injured adult ED patients (≥ 18 years) presenting to an Afro-Caribbean hospital. Descriptive statistics were derived for study patients as a whole, by HTN history and by presenting BP subgroup (with systolic BP ≥ 140 mmHg considered elevated). Data between groups were compared using chi-square and t tests, where appropriate.

RESULTS

A total of 307 patients were included: 145 (47.2%) had a prior history of HTN, 126 (41.4%) had elevated BP, and 89 (61.4%) of those presenting with elevated blood pressure had a previous diagnosis of HTN. Those with less formal education were significantly more likely to present with elevated BP (52.1 vs. 28.8% for those with some high school and 19.2% for those with a college education; p = 0.001). Among those with a history of HTN, only 56 (30.9%) had a normal presenting BP. Those with a history of HTN and normal ED presenting BP were no different from patients with elevated BP when comparing the in duration of HTN, medication compliance, location of usual follow-up care, and HTN-specific illness beliefs.

CONCLUSIONS

In this single-center study, two out of every five Jamaican ED patients had elevated presenting BP, the majority of whom had a previous diagnosis of HTN. Among those with a history of HTN, 60% had an elevated presenting BP. The ED can be an important location to identify patients with chronic disease in need of greater disease-specific education. Further studies should evaluate if brief interventions provided by ED medical staff improve HTN control in this patient population.

An in vivo assay to test blood vessel permeability

This method is based on the intravenous injection of Evans Blue in mice as the test animal model. Evans blue is a dye that binds albumin. Under physiologic conditions the endothelium is impermeable to albumin, so Evans blue bound albumin remains restricted within blood vessels. In pathologic conditions that promote increased vascular permeability endothelial cells partially lose their close contacts and the endothelium becomes permeable to small proteins such as albumin. This condition allows for extravasation of Evans Blue in tissues. A healthy endothelium prevents extravasation of the dye in the neighboring vascularized tissues. Organs with increased permeability will show significantly increased blue coloration compared to organs with intact endothelium. The level of vascular permeability can be assessed by simple visualization or by quantitative measurement of the dye incorporated per milligram of tissue of control versus experimental animal/tissue. Two powerful aspects of this assay are its simplicity and quantitative characteristics. Evans Blue dye can be extracted from tissues by incubating a specific amount of tissue in formamide. Evans Blue absorbance maximum is at 620 nm and absorbance minimum is at 740 nm. By using a standard curve for Evans Blue, optical density measurements can be converted into milligram dye captured per milligram of tissue. Statistical analysis should be used to assess significant differences in vascular permeability.

Microvascular responses to cardiovascular risk factors

Hypertension, hypercholesterolemia, diabetes, and obesity are among a growing list of conditions that have been designated as major risk factors for cardiovascular disease (CVD). While CVD risk factors are well known to enhance the development of atherosclerotic lesions in large arteries, there is also evidence that the structure and function of microscopic blood vessels can be profoundly altered by these conditions. The diverse responses of the microvasculature to CVD risk factors include oxidative stress, enhanced leukocyte- and platelet-endothelial cell adhesion, impaired endothelial barrier function, altered capillary proliferation, enhanced thrombosis, and vasomotor dysfunction. Emerging evidence indicates that a low-grade systemic inflammatory response that results from risk factor-induced cell activation and cell-cell interactions may underlie the phenotypic changes induced by risk factor exposure. A consequence of the altered microvascular phenotype and systemic inflammatory response is an enhanced vulnerability of tissues to the deleterious effects of secondary oxidative and inflammatory stresses, such as ischemia and reperfusion. Future efforts to develop therapies that prevent the harmful effects of risk factor-induced inflammation should focus on the microcirculation.