State of the Art Review: Vascular Remodeling in Hypertension

Intraluminal pressure triggers a rapid and persistent reinforcement of endothelial barriers

In response to mechanical cues, endothelial cells elicit highly sensitive cellular response pathways that contribute to the regulation of the physiology and disorders of the vascular system. However, it remains relatively unexplored how endothelial tissues process and integrate the intraluminal pressure, and in turn regulate the permeation flow across the vessel wall. Leveraging a tissue engineering approach to create microvessels (MVs), we measured real-time permeation flow induced by intraluminal pressures ranging from 0.1 to 2.0 kPa. Our findings reveal that mechanically stimulated MVs strengthen their barrier function within seconds of exposure to pressures below 1 kPa, with this enhanced barrier function persisting for 30 minutes. We demonstrate that this barrier reinforcement is linked to the closure of paracellular gaps. Additionally, we observe that it is associated with, and depends on, actin cytoskeleton reorganization, including the accumulation of stress fibers near intercellular junctions and the broadening of adherence junction protein localization. These findings provide insights into the ability of endothelial tissues to regulate interstitial fluid flow in response to sudden increases in blood pressure.

Superior cervical ganglionectomy attenuates vascular remodeling in spontaneously hypertensive rats

BACKGROUND

Sympathetic hyperactivity contributes to the pathogenesis of hypertension. However, it is unclear whether the excessive sympathetic activity is an independent and crucial factor for vascular remodeling in hypertension. This study focused on the effect of local sympathetic denervation with superior cervical ganglionectomy (SCGx) on vascular remodeling.

METHODS

Surgical bilateral SCGx was performed in 9-week-old male Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). Control rats received sham-operation without SCGx. All measurements were made 4 weeks after the surgery.

RESULTS

The effectiveness of SCGx was confirmed by the eye features of Horner syndrome, greatly reduced tyrosine hydroxylase (TH) contents in the superior cervical ganglion (SCG)-innervated arteries in the head. Although SCGx had no significant effects on blood pressure and heart rate in WKY and SHR, it attenuated vascular remodeling of facial artery and superficial temporal artery in SHR, two representative SCG-innervated extracranial arteries, without significant effects on non-SCG-innervated thoracic aorta and mesenteric artery. SCGx-treated SHR had more auricular blood flow and retina microvasculature than sham-operated SHR. However, SCGx had only a mild effect in attenuating the vascular remodeling of basilar artery and middle cerebral artery, two representative SCG-innervated intracranial arteries, in SHR. SCGx-treated SHR exhibited upregulation of α-smooth muscle actin, downregulation of proliferating cell nuclear antigen, and attenuation of oxidative stress and inflammation in facial artery and superficial temporal artery.

CONCLUSIONS

Sympathetic denervation by SCGx in SHR attenuated local vascular remodeling, suggesting that sympathetic overactivity is a crucial pathogenic factor of vascular remodeling in SHR.

Impact of hypertension on mortality in patients with ST-elevation myocardial infarction undergoing primary angioplasty: insights from the international multicenter ISACS-STEMI registry

BACKGROUND

Hypertension is the most prevalent cardiovascular risk factor, with several detrimental effects on the cardiovascular system. Contrasting results have been reported so far on its prognostic role in patients admitted for ST-segment elevation myocardial infarction (STEMI). Therefore, we investigated the impact of hypertension on short-term mortality in a large multicenter contemporary registry of STEMI patients, including patients treated during COVID-19 pandemic.

METHODS

The ISACS-STEMI COVID-19 was a retrospective registry that included STEMI patients treated with primary percutaneous coronary intervention (PCI) between March and June of 2019 and 2020 in 109 high-volume primary PCI centers from 4 continents. We collected data on baseline, clinical and procedural characteristics, in-hospital outcome and 30-day mortality. For this analysis patients were grouped according to history of hypertension at admission.

RESULTS

A total of 16083 patients were assessed, including 8813 (54.8%) with history of hypertension. These patients were more often elderly, with a worse cardiovascular risk profile, but were less frequently active smoker. Some procedural differences were observed between the two groups, including lower rate of thrombectomy and use of glycoprotein IIb/IIIa inhibitors or cangrelor but more extensive coronary disease in patients with hypertension. Between patients with and without hypertension, there was no significant difference in SARS-CoV-2 positivity. Hypertensive patients had a significantly higher in-hospital and 30-day mortality, similarly observed in both pre-COVID-19 and COVID-19 era, and confirmed after adjustment for main baseline differences and propensity score (in-hospital mortality: adjusted odds ratio (OR) [95% confidence interval (CI)] =1.673 [1.389-2.014], P  < 0.001; 30-day mortality: adjusted hazard ratio (HR) [95% CI] = 1.418 [1.230-1.636], P  < 0.001).

CONCLUSION

This is one of the largest and contemporary study assessing the impact of hypertension in STEMI patients undergoing primary angioplasty, including also the COVID-19 pandemic period. Hypertension was independently associated with significantly higher rates of in-hospital and 30-day mortality.

Association between pathological scar and hypertension: A two-sample Mendelian randomization study

Observational studies have linked pathological scars to hypertension; however, the causality remains ambiguous. In this study, we aimed to explore this issue using Mendelian randomization (MR). We obtained genome-wide association study data for hypertrophic scar and hypertension from the IEU Open genome-wide association study project [hypertension (containing 9851,867 SNPs, observation group of 124,227, and control group of 337,653), hypertrophic scars (containing 16,380,443 SNPs with a sample mass of 207,482), and keloids (containing 24,197,210 SNPs and sample volume of 481,912)]. The inverse variance weighted method and MR-Egger test were used, followed by a sensitivity analysis. With hypertension as the exposure and hypertrophic scar as the outcome, we obtained the IVW analysis results (OR = 0.264, 95% CI = 0.098-0.709, P = .008) and the MR-Egger test results (OR = 0.036, 95% CI = 0.002-0.544, P = .017); for keloid as the outcome, the results of IVW analysis showed OR = 0.592, 95% CI = 0.293-1.195, P = .143. Contrary to the findings of observational studies, our results revealed hypertension as a protective factor against hypertrophic scarring, and was unrelated to keloids.

Molecular Links and Clinical Effects of Inflammation and Metabolic Background on Ischemic Stroke: An Update Review

Stroke is a major global health concern, with 12.2 million new cases and 6.6 million deaths reported in 2019, making it the second leading cause of death and third leading cause of disability worldwide. Ischemic stroke, caused by blood vessel occlusion, accounts for 87% of stroke cases and results in neuronal death due to oxygen and nutrient deprivation. The rising global stroke burden is linked to aging populations and increased metabolic risk factors like high blood pressure, obesity, and elevated glucose levels, which promote chronic inflammation. This article explores the intricate molecular and clinical interplay between inflammation and metabolic disorders, emphasizing their role in ischemic stroke development, progression, and outcomes.

Reduced systemic microvascular function in patients with resistant hypertension and microalbuminuria: an observational study

Resistant hypertension (RH) may be associated with microalbuminuria (MAU), a marker of cardiovascular risk and target organ damage, and both may be related to microvascular damage. Laser speckle contrast imaging (LSCI) is an innovative approach for noninvasively evaluating systemic microvascular endothelial function useful in the context of RH with or without MAU. Microalbuminuria was defined as a urine albumin-to-creatinine ratio between 30 and 300 mg/g. Microvascular reactivity was evaluated using LSCI to perform noninvasive measurements of cutaneous microvascular perfusion changes. Pharmacological (acetylcholine [ACh], or sodium nitroprusside [SNP]) and physiological (postocclusive reactive hyperemia [PORH]) stimuli were used to evaluate vasodilatory responses. Thirty-two patients with RH and a normal urine albumin-to-creatinine ratio (RH group) and 32 patients with RH and microalbuminuria (RH + MAU) were evaluated. Compared with patients without MAU, patients with RH + MAU showed reduced endothelial-dependent systemic microvascular reactivity, as demonstrated by an attenuation of microvascular vasodilation induced by PORH. On the other hand, ACh-induced vasodilation did not differ between groups. The results also revealed reduced endothelial-independent (SNP-induced) microvascular reactivity in hypertensive patients with MAU compared with patients without MAU. In this study, there was evidence of endothelial dysfunction associated with impaired microvascular smooth muscle function in patients with RH + MAU. This may suggest that patients with RH need more intensive therapeutic strategies for the control of blood pressure to avoid further vascular damage and the resulting consequences.The study was registered at ClinicalTrials.gov ( https://register.clinicaltrials.gov ) under protocol # NCT05464849, initial release 12/07/2022.

Transient cerebral ischaemia alters mesenteric arteries in hypertensive rats: Limited reversal despite suberoylanilide hydroxamic acid cerebroprotection

Stroke induces brain injury, especially severe in hypertensive patients, and elevates mortality rates through non-neurological complications. However, the potential effects of a transient ischaemic episode on the peripheral vasculature of hypertensive individuals remain unclear. We investigated whether transient cerebral ischaemia (90 min)/reperfusion (1 or 8 days) induces alterations in mesenteric resistance artery (MRA) properties in adult male spontaneously hypertensive rats (SHR). In addition, we assessed whether the reported cerebroprotective effects of suberoylanilide hydroxamic acid (SAHA; 50 mg/kg; administered intraperitoneally at 1, 4, or 6 h after reperfusion onset) extend over several days and include beneficial effects on MRAs. Functional and structural properties of MRAs were examined at 1- and 8-days post-stroke. Nuclei distribution, collagen content, and oxidative stress were assessed. Ischaemic brain damage was evaluated longitudinally using magnetic resonance imaging. Following stroke, MRAs from SHR exhibited non-reversible impaired contractile responses to the thromboxane A2 receptor agonist U46619. Stroke increased the MRA cross-sectional area, wall thickness, and wall/lm ratio due to augmented collagen deposition. These changes were partially sustained 8 days later. SAHA did not improve U46619-induced contractions but mitigated stroke-induced oxidative stress and collagen deposition, preventing MRA remodelling at 24 h of reperfusion. Furthermore, SAHA induced sustained cerebroprotective effects over 8 days, including reduced brain infarct and oedema, and improved neurological scores. However, SAHA had minimal impact on chronic MRA contractile impairments and remodelling. These findings suggest that stroke causes MRA changes in hypertensive subjects. While SAHA treatment offers sustained protection against brain damage, it cannot fully restore MRA alterations.

Asprosin contributes to vascular remodeling in hypertensive rats via superoxide signaling

OBJECTIVE

Proliferation and migration of vascular smooth muscle cells (VSMCs) contribute to vascular remodeling. Asprosin, a newly discovered protein hormone, is involved in metabolic diseases. Little is known about the roles of asprosin in cardiovascular diseases. This study focused on the role and mechanism of asprosin on VSMC proliferation and migration, and vascular remodeling in a rat model of hypertension.

METHODS AND RESULTS

VSMCs were obtained from the aortic media of 8-week-old male Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). Asprosin was upregulated in the VSMCs of SHR. For in vitro studies, asprosin promoted VSMC proliferation and migration of WKY and SHR, and increased Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) activity, NOX1/2/4 protein expressions and superoxide production. Knockdown of asprosin inhibited the proliferation, migration, NOX activity, NOX1/2 expressions and superoxide production in the VSMCs of SHR. The roles of asprosin in promoting VSMC proliferation and migration were not affected by hydrogen peroxide scavenger, but attenuated by superoxide scavenger, selective NOX1 or NOX2 inhibitor. Toll-like receptor 4 (TLR4) was upregulated in SHR, TLR4 knockdown inhibited asprosin overexpression-induced proliferation, migration and oxidative stress in VSMCs of WKY and SHR. Asprosin was upregulated in arteries of SHR, and knockdown of asprosin in vivo not only attenuated oxidative stress and vascular remodeling in aorta and mesentery artery, but also caused a subsequent persistent antihypertensive effect in SHR.

CONCLUSIONS

Asprosin promotes VSMC proliferation and migration via NOX-mediated superoxide production. Inhibition of endogenous asprosin expression attenuates VSMC proliferation and migration, and vascular remodeling of SHR.

Asprosin promotes vascular inflammation via TLR4-NFκB-mediated NLRP3 inflammasome activation in hypertension

Objective

and design Mild vascular inflammation promotes the pathogenesis of hypertension. Asprosin, a newly discovered adipokine, is closely associated with metabolic diseases. We hypothesized that asprosin might led to vascular inflammation in hypertension via NLRP3 inflammasome formation. This study shows the importance of asprosin in the vascular inflammation of hypertension.

Methods

Primary vascular smooth muscle cells (VSMCs) were obtained from the aorta of animals, including spontaneously hypertensive rats (SHR), Wistar-Kyoto rats (WKY), NLRP3-/- and wild-type mice. Studies were performed in VSMCs in vitro, as well as WKY and SHR in vivo.

Results

Asprosin expressions were up-regulated in VSMCs and media of arteries in SHR. Asprosin overexpression promoted NLRP3 inflammasome activation via Toll-like receptor 4 (TLR4), accompanied with activation of NFκB signaling pathway in VSMCs. Exogenous asprosin protein showed similar roles in promoting NLRP3 inflammasome activation. Knockdown of asprosin restrained NLRP3 inflammasome and p65-NFκB activation in VSMCs of SHR. NLRP3 inhibitor MCC950 or NFκB inhibitor BAY11-7082 attenuated asprosin-caused VSMC proliferation and migration. Asprosin-induced interleukin-1β production, proliferation and migration were attenuated in NLRP3-/- VSMCs. Local asprosin knockdown in common carotid artery of SHR attenuated inflammation and vascular remodeling.

Conclusions

Asprosin promoted NLRP3 inflammasome activation in VSMCs by TLR4-NFκB pathway, and thereby stimulates VSMCs proliferation, migration, and vascular remodeling of SHR.

Vasomotion heterogeneity and spectral characteristics in diabetic and hypertensive patients

Vasomotion refers to the spontaneous oscillation of blood vessels within a frequency range of 0.01 to 1.6 Hz. Various disease states, including hypertension and diabetes, have been associated with alterations in vasomotion at the finger, indicating potential impairment of skin microcirculation. Due to the non-linear nature of human vasculature, the modification of vasomotion may vary across different locations for different diseases. In this study, Laser Doppler Flowmetry was used to measure blood flow motion at acupoints LU8, LU5, SP6, and PC3 among 49 participants with or without diabetes and/or hypertension. Fast Fourier Transformation was used to analyze noise type while Hilbert-Huang Transformation and wavelet analysis were applied to assess Signal Noise Ratio (SNR) results. Statistical analysis revealed that different acupoints exhibit distinct spectral characteristics of vasomotion not only among healthy individuals but also among patients with diabetes and/or hypertension. The results showed strong heterogeneity of vasomotion among blood vessels, indicating that the vasomotion measured at a certain point may not reflect the real status of microcirculation.

History of the cutaneous microcirculation from antiquity to modern times

 This review spans a wide arc from the first observations of the early anatomists to the present day. William Harvey was the first to describe the heart as the centre of the large and small circulatory system. He thus replaced the previously valid system of Galenos, It was Marcello Malpighi who first described that the capillary system connects the arteries with the veins. In 1688 Antoni van Leeuwenhoek (1632-1686) confirmed these results with a paper on capillary perfusion in the caudal fin of the glass eel. It was then Hermann Boerhave (1668-1738, Leiden) who was the first to carry out microcirculation tests on patients. He studied the microcirculation in the human bulbar conjunctiva. Even today, microcirculation studies in the conjunctiva bulbi of patients are carried out today. Until 1831, it was never quite clear whether the observations reported belonged mainly to the field of microcirculation, which had not yet been defined. This was done in Great Britain by Marshall Hall (1790-1857). Technical Improvements allowed increasingly sophisticated studies of the morphological structure of the terminal vasculature. According to Gustav Ricker (1870-1948, Vienna), the terminal vasculature comprises the functional unit of the smallest arteries, arterioles, capillaries and venules. In 1921 it was still thought that the blood circulation was the sole response to the pumping action of the heart. Even the classic work by Bayliss on the myogenic hypothesis (later referred to as "blood flow autoregulation") initially received little attention. More strikingly, even the findings of August Krogh, for which he received the Nobel Prize in Medicine in 1920 (for his discovery of the mechanisms of capillary motor regulation), were ignored. During an outstanding autoregulation symposium held in 1963 a broad consensus was reached on active and passive mechanisms, which is more or less valid till today. The mechanisms of regulation of capillary blood flow are now largely understood, although not completely resolved. The development of video systems with recording capability and automated off-line recording of capillary erythrocyte velocities allowed the application of morphological and dynamic studies of cutaneous capillaries in humans. These reopened the field of physiological or pathophysiological questions again for many groups worldwide. Since 1955, many publications on "microcirculation (5423)" and "capillary microscopy (2195)" have been listed in pubmed.

Proposal of a Modified Classification of Hypertensive Crises: Urgency, Impending Emergency, and Emergency

Systemic arterial hypertension (HTN) is the main cause of morbidity and mortality, and HTN crises contribute significantly to an unfavourable clinical course. For decades, HTN crises have been dichotomized into hypertensive emergency (HTN-E) and hypertensive urgency (HTN-U). The main difference between the two is the presence of acute hypertension-mediated organ damage (HMOD) - if HMOD is present, HTN crisis is HTN-E; if not, it is HTN-U. Patients with HTN-E are in a life-threatening situation. They are hospitalized and receive antihypertensive drugs intravenously (IV). On the other hand, patients with HTN-U are usually not hospitalized and receive their antihypertensives orally. We suggest a modification of the current risk stratification scheme for patients with HTN crises. The new category would be the intermediate risk group, more precisely the 'impending HTN-E' group, with a higher risk in comparison to HTN-U and a lower risk than HTN-E. 'Impending HMOD' means that HMOD has not occurred (yet), and the prognosis is, therefore, better than in patients with ongoing HMOD. There are three main reasons to classify patients as having impending HTN-E: excessively elevated BP, high-risk comorbidities, and ongoing bleeding/high bleeding risk. Their combinations are probable. This approach may enable us to prevent some HTNEs by avoiding acute HMOD using a timely blood pressure treatment. This treatment should be prompt but controlled.

MiR-21-3p in extracellular vesicles from vascular fibroblasts of spontaneously hypertensive rat promotes proliferation and migration of vascular smooth muscle cells

Enhanced proliferation and migration of vascular smooth muscle cells (VSMCs) contributes to vascular remodeling in hypertension. Adventitial fibroblasts (AFs)-derived extracellular vesicles (EVs) modulate vascular remodeling in spontaneously hypertensive rat (SHR). This study shows the important roles of EVs-mediated miR-21-3p transfer in VSMC proliferation and migration and underlying mechanisms in SHR. AFs and VSMCs were obtained from aorta of Wistar-Kyoto rat (WKY) and SHR. EVs were separated from AFs culture with ultracentrifugation method. MiR-21-3p content in the EVs of SHR was increased compared with those of WKY. MiR-21-3p mimic promoted VSMC proliferation and migration of WKY and SHR, while miR-21-3p inhibitor attenuated proliferation and migration only in the VSMCs of SHR. EVs of SHR stimulated VSMC proliferation and migration, which were attenuated by miR-21-3p inhibitor. Sorbin and SH3 domain containing 2 (SORBS2) mRNA and protein levels were reduced in the VSMCs of SHR. MiR-21-3p mimic inhibited, while miR-21-3p inhibitor promoted SORBS2 expressions in the VSMCs of both WKY and SHR. EVs of SHR reduced SORBS2 expression, which was prevented by miR-21-3p inhibitor. EVs of WKY had no significant effect on SORBS2 expressions. SORBS2 overexpression attenuated the roles of miR-21-3p mimic and EVs of SHR in promoting VSMC proliferation and migration of SHR. Overexpression of miR-21-3p in vivo promotes vascular remodeling and hypertension. These results indicate that miR-21-3p in the EVs of SHR promotes VSMC proliferation and migration via negatively regulating SORBS2 expression.

Microcirculation in Hypertension: A Therapeutic Target to Prevent Cardiovascular Disease?

Arterial hypertension is a common condition worldwide and an important risk factor for cardio- and cerebrovascular events, renal diseases, as well as microvascular eye diseases. Established hypertension leads to the chronic vasoconstriction of small arteries as well as to a decreased lumen diameter and the thickening of the arterial media or wall with a consequent increased media-to-lumen ratio (MLR) or wall-to-lumen ratio (WLR). This process, defined as vascular remodeling, was firstly demonstrated in small resistance arteries isolated from subcutaneous biopsies and measured by micromyography, and this is still considered the gold-standard method for the assessment of structural alterations in small resistance arteries; however, microvascular remodeling seems to represent a generalized phenomenon. An increased MLR may impair the organ flow reserve, playing a crucial role in the maintenance and, probably, also in the progressive worsening of hypertensive disease, as well as in the development of hypertension-mediated organ damage and related cardiovascular events, thus possessing a relevant prognostic relevance. New non-invasive techniques, such as scanning laser Doppler flowmetry or adaptive optics, are presently under development, focusing mainly on the evaluation of WLR in retinal arterioles; recently, also retinal microvascular WLR was demonstrated to have a prognostic impact in terms of cardio- and cerebrovascular events. A rarefaction of the capillary network has also been reported in hypertension, which may contribute to flow reduction in and impairment of oxygen delivery to different tissues. These microvascular alterations seem to represent an early step in hypertension-mediated organ damage since they might contribute to microvascular angina, stroke, and renal dysfunction. In addition, they can be markers useful in monitoring the beneficial effects of antihypertensive treatment. Additionally, conductance arteries may be affected by a remodeling process in hypertension, and an interrelationship is present in the structural changes in small and large conductance arteries. The review addresses the possible relations between structural microvascular alterations and hypertension-mediated organ damage, and their potential improvement with antihypertensive treatment.

Unattended versus Attended Blood Pressure Measurement: Relationship with Retinal Microcirculation

Though the relationship between both “attended” and “unattended” BP and several forms of target organ damage have been evaluated, data on retinal arteriolar alterations are lacking. The aim of our study was to evaluate the relationship between “attended” or “unattended” BP values and retinal arteriolar changes in consecutive individuals undergoing a clinical evaluation and assessment of retinal fundus at an ESH Excellence Centre. An oscillometric device programmed to perform 3 BP measurements, at 1 min intervals and after 5 min of rest was used on all individuals to measure BP with the patient alone in the room (“unattended”) or in the presence of the physician (“attended”) in the same day in a random order. The retinal arteriole’s wall thickness (WT) was measured automatically by a localization algorithm as the difference between external (ED) and internal diameter (ID) by adaptive optics (RTX-1, Imagine Eyes, Orsay, Francia). Media-to-lumen ratio (WLR) of the retinal arterioles and cross-sectional area (WCSA) of the vascular wall were calculated. Results: One-hundred-forty-two patients were examined (mean age 57 ± 12 yrs, 48% female, mean BMI 26 ± 4). Among them, 60% had hypertension (84% treated) and 11% had type 2 diabetes mellitus. Unattended systolic BP (SBP) was lower as compared to attended SBP (129 ± 14.8. vs. 122.1 ± 13.6 mmHg, p < 0.0001). WLR was similarly correlated with unattended and attended SBP (r = 0.281, p < 0.0001 and r = 0.382, p < 0.0001) and with unattended and attended diastolic BP (r = 0.34, p < 0.001 and r = 0.29, p < 0.0001). The differences between correlations were not statistically significant (Steiger’s Z test). Conclusion: The measurement of “unattended” or “attended” BP provides different values, and unattended BP is lower as compared to attended BP. In this study a similar correlation was observed between attended and unattended BP values and structural changes of retinal arterioles.