Fibromuscular dysplasia (FMD) is a non-atherosclerotic vascular disease that may involve medium-sized muscular arteries throughout the body. The majority of FMD patients are women. Although a variety of genetic, mechanical, and hormonal factors play a role in the pathogenesis of FMD, overall, its cause remains poorly understood. It is probable that the pathogenesis of FMD is linked to a combination of genetic and environmental factors. Extensive studies have correlated the arterial lesions of FMD to histopathological findings of arterial fibrosis, cellular hyperplasia, and distortion of the abnormal architecture of the arterial wall. More recently, the vascular phenotype of lesions associated with FMD has been expanded to include arterial aneurysms, dissections, and tortuosity. However, in the absence of a string of beads or focal stenosis, these lesions do not suffice to establish the diagnosis. While FMD most commonly involves renal and cerebrovascular arteries, involvement of most arteries throughout the body has been reported. Increasing evidence highlights that FMD is a systemic arterial disease and that subclinical alterations can be found in non-affected arterial segments. Recent significant progress in FMD-related research which has led to improved understandings of the disease’s clinical manifestations, natural history, epidemiology, and genetics. Ongoing work continues to focus on FMD genetics and proteomics, physiological effects of FMD on cardiovascular structure and function, and novel imaging modalities and blood-based biomarkers that can be used to identify subclinical FMD. It is also hoped that the next decade will bring the development of multi-centred and potentially international clinical trials to provide comparative effectiveness data to inform the optimal management of patients with FMD.

ObjectivesCOVID-19 is an ongoing global pandemic. There is an urgent need for identification and understanding of clinical and laboratory parameters related to progression towards a severe and fatal form of this illness, often preceded by a so-called cytokine-storm syndrome (CSS). Therefore, we explored the hemocytometric characteristics of COVID-19 patients in relation to the deteriorating clinical condition CSS, using the Sysmex XN-10 hematology analyzer.MethodsFrom March 1st till May 16th, 2020, all patients admitted to our hospital with respiratory complaints and suspected for COVID-19 were included (n=1,140 of whom n=533 COVID-19 positive). The hemocytometric parameters of immunocompetent cells in peripheral blood (neutrophils [NE], lymphocytes [LY] and monocytes [MO]) obtained upon admission to the emergency department (ED) of COVID-19 positive patients were compared with those of the COVID-19 negative ones. Moreover, patients with CSS (n=169) were compared with COVID-19 positive patients without CSS, as well as with COVID-19 negative ones.ResultsIn addition to a significant reduction in leukocytes, thrombocytes and absolute neutrophils, it appeared that lymphocytes-forward scatter (LY-FSC), and reactive lymphocytes (RE-LYMPHO)/leukocytes were higher in COVID-19-positive than negative patients. At the moment of presentation, COVID-19 positive patients with CSS had different neutrophils-side fluorescence (NE-SFL), neutrophils-forward scatter (NE-FSC), LY-FSC, RE-LYMPHO/lymphocytes, antibody-synthesizing (AS)-LYMPHOs, high fluorescence lymphocytes (HFLC), MO-SSC, MO-SFL, and Reactive (RE)-MONOs. Finally, absolute eosinophils, basophils, lymphocytes, monocytes and MO-FSC were lower in patients with CSS.ConclusionsHemocytometric parameters indicative of changes in immunocompetent peripheral blood cells and measured at admission to the ED were associated with COVID-19 with and without CSS.

Renal blood flow, glomerular filtration, and the response to vasoactive substances in kidneys with multifocal FMD are comparable to patients with essential hypertension, suggesting that microvascular function is relatively spared. Renin secretion was not increased and the response to RAS modulation was not affected in kidneys with FMD.

A ngiotensin-(1-7) (Ang-(1-7)) is a vasoactive peptide that plays an important role in the regulation of tissue blood flow.1 It is closely linked to the classical renin-angiotensin system (RAS) because the enzymes producing Ang-(1-7) use angiotensin I and angiotensin II (Ang II) as its substrate. Available data, limited to studies using animal models and human forearm vasculature, predominantly demonstrate a vasodilatory effect of Ang-(1-7).2,3 Human data on the effect of Ang-(1-7) in clinically important vascular beds, such as that of the kidney, are lacking. 4 As the kidney and RAS activation play a key role in blood pressure regulation and the development of hypertension, studying the intrarenal flow effects of Ang-(1-7) in hypertensive patients may lead to new insights in the pathophysiology of hypertension. We hypothesized that, in correspondence to the data currently available, Ang-(1-7) increases renal blood flow in hypertensive humans. For that reason we studied the effect of intrarenal Ang-(1-7) infusion on renal blood flow in hypertensive patients. To assess the influence of the RAS, various states of RAS stimulation were simulated by restriction of dietary sodium intake (inducing endogenous RAS activation) and co-infusion of Ang II (increasing Ang II availability). Methods Participants and ProtocolThis study was performed in 85 hypertensive outpatients (all whites) who were angiographically evaluated for the presence of renovascular abnormalities. Inclusion criteria were difficult-to-treat hypertension (mostly blood pressure remaining above goal in spite of the use of ≥3 full-dose antihypertensive drugs) or clinical suspicion on renovascular abnormalities based on clinical clues (eg, the presence of an abdominal bruit, peripheral vascular disease, or a rise in serum creatinine after treatment with a RAS inhibitor). Patients previously diagnosed with renovascular abnormalities or other secondary causes of hypertension were excluded. Three weeks before the angiography all antihypertensive medication was discontinued to avoid interference with the experiments. Patients in whom interruption of the medication was not possible because of a high risk for acute cardiovascular events (a recent cardiovascular event or [expected] blood pressure >180/110 mm Hg) were excluded from the study. Patients were randomly allocated to adhere to either a sodium-restricted diet (<55 mmol sodium/24 hours) or a sodium-rich diet (>200 mmol sodium/24 hours) during the week preceding the study. The day preceding the angiography study, patients underwent a noninvasive 24-hour ambulatory blood pressure measurement (using SpaceLabs ambulatory blood pressure monitor type 90207 or 90217-b) and collected a 24-hour urine specimen to measure urinary sodium excretion to monitor dietary compliance. All patients gave written Abstract-Current evidence suggests that angiotensin-(1-7) plays an important role in the regulation of tissue blood flow. This evidence, however, is restricted to studies in animals and human forearm. Therefore, we stu...

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These findings argue against the hypothesis that FMD induces hypertension via similar pathophysiological mechanism as in ARAS.

Abnormalities in orthostatic blood pressure changes upon active standing are associated with morbidity, mortality, and reduced quality of life. However, over the last decade, several population-based cohort studies have reported a remarkably high prevalence (between 25 and 70%) of initial orthostatic hypotension (IOH) among elderly individuals. This has raised the question as to whether the orthostatic blood pressure patterns in these community-dwelling elderly should truly be considered as pathological. If not, redefining of the systolic cutoff values for IOH (i.e., a value ≥ 40 mmHg in systolic blood pressure in the first 15 s after standing up) might be necessary to differ between normal aging and true pathology. Therefore, in this narrative review, we provide a critical analysis of the current reference values for the changes in systolic BP in the first 60 s after standing up and discuss how these values should be applied to large population studies. We will address factors that influence the magnitude of the systolic blood pressure changes following active standing and the importance of standardization of the stand-up test, which is a prerequisite for quantitative, between-subject comparisons of the postural hemodynamic response.

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