Transforming growth factor-β (TGF)-β signaling plays a crucial role in the development and maintenance of various organs, including the vasculature. Accordingly, the mutations in TGF-β signaling pathway-related genes cause heritable disorders of the connective tissue, such as Marfan syndrome (MFS), Loeys-Dietz syndrome (LDS), and Shprintzen-Goldberg syndrome (SGS), and these syndromes may affect skeletal, ocular, pulmonary, and cardiovascular systems. Aortic root aneurysms are common problems that can result in aortic dissection or rupture, which is the leading cause of sudden death in the natural history of MFS and LDS, and recent improvements in surgical treatment have improved life expectancy. However, there is currently no genotype-specific medical treatment. Accumulating evidence suggest that not only structural weakness of connective tissue but also increased TGF-β signaling contributes to the complicated pathogenesis of aortic aneurysm formation, but a comprehensive understanding of governing molecular mechanisms remains lacking. Inhibition of angiotensin II receptor signaling and endothelial dysfunction have gained attention as a possible MFS treatment strategy, but interactions with TGF-β signaling remain elusive. Heterozygous loss-of-function mutations in TGF-β receptors 1 and 2 (TGFBR1 and TGFBR2) cause LDS, but TGF-β signaling is activated in the aorta (referred to as the TGF-β paradox) by mechanisms yet to be elucidated. In this review, we present and discuss the current understanding of molecular mechanisms responsible for aortopathies of MFS and related disorders.
Study Design: A time series design was used, with the dependent variable being gastrocnemius muscle temperature at a depth of 3 cm. Objectives: To determine the rate of temperature rise and the rate of post-treatment temperature decline in skeletal muscle following the application of pulsed short-wave diathermy (PSWD). Background: Data on PSWD rate and longevity of heating are 20 years old and outdated. With the recent introduction of advanced diathermy equipment, results of our study would provide clinicians with much needed information regarding treatment duration. Methods and Measures: A 23-gauge thermistor was inserted into the center of the medial head of the anesthetized gastrocnemius muscle, 3 cm below the skin's surface of 20 subjects. The PSWD (27.12 MHz frequency) was applied using the following parameters: 800 bursts per second; 400 psecond burst duration; 850 pecond interbunt interval; with a peak root mean square (RMS) amplitude of 150 W per burst and an average RMS output of 48 W. Temperature changes were documented every 5 minutes during the treatment and additionally at 5 and 10 minutes following treatment.Results: The average baseline and peak temperatures were 35.84 2 0.93OC and 39.80 + 0.83"C, respectively. Mean temperature increases were: 1.36 + 0.90°C (5 min); 2.87 2 1.44"C (10 min); 3.78 2 1 .lg°C (1 5 min); 3.49 + 1.13"C (20 min). After the treatment terminated, intramuscular temperature dropped 0.97 + 0.68"C in 5 minutes and 1.78 + 0.69" in 10 minutes. Conclusions: PSWD is an effective modality if temperature elevation of deep tissue over a large area is the clinical objective. ) Orthop Sports Phys 7her 1999;29:13-22.
Background: In the wake of the coronavirus disease 2019 (COVID-19) pandemic, people need to practice social distancing in order to protect themselves from SARS-CoV-2 infection. In such stressful situations, remote cardiac rehabilitation (CR) might be a viable alternative to the outpatient CR program. Methods: We prospectively investigated patients hospitalized for heart failure (HF) with a left ventricular ejection fraction of < 50%. As for patients who participated in the remote CR program, telephone support was provided by cardiologists and nurses who specialized in HF every 2 weeks after discharge. The emergency readmission rate within 30 days of discharge was compared among the outpatient CR, remote CR, and non-CR groups, and the EQ-5D score was compared between the outpatient CR and remote CR groups. Results: The participation rate of HF patients in our remote CR program elevated during the COVID-19 pandemic. As observed in the outpatient CR group (n = 69), the emergency readmission rate within 30 days of discharge was lower in the remote CR group (n = 30) than in the non-CR group (n = 137) (P = 0.02). The EQ-5D score was higher in the remote CR group than in the outpatient CR group (P = 0.03) 30 days after discharge. Conclusions: Remote CR is as effective as outpatient CR for improving the short-term prognosis of patients hospitalized for heart failure post-discharge. This suggests that the remote CR program can be provided as a good alternative to the outpatient CR program.
SummaryMarfan syndrome (MFS) is an autosomal dominant heritable disorder of connective tissue that affects the cardiovascular, skeletal, ocular, pulmonary, and nervous systems and is usually caused by mutations in the FBN1 gene, which encodes fibrillin-1. MFS is traditionally considered to result from the structural weakness of connective tissue. However, recent investigations on molecular mechanisms indicate that increased transforming growth factor-β (TGF-β) activity plays a crucial role in the pathogenesis of MFS and related disorders, such as Loeys-Dietz syndrome (LDS), which is caused by mutation in TGF-β signaling-related genes. In addition, recent studies show that angiotensin II type 1 receptor (AT1R) signaling enhances cardiovascular pathologies in MFS, and the angiotensin II receptor blocker losartan has the potential to inhibit aortic aneurysm formation. However, the relationship between TGF-β and AT1R signaling pathways remains poorly characterized. In this review, we discuss the recent studies on the molecular mechanisms underlying cardiovascular manifestations of MFS and LDS and the ensuing strategies for management. (Int Heart J 2016; 57: 271-277)
Most seven transmembrane receptors (7TMRs) are G protein-coupled receptors; however, some 7TMRs evoke intracellular signals through β-arrestin as a biased receptor. As several β-arrestin-biased agonists have been reported to be cardioprotective, we examined the role of the chemokine receptor CXCR7 as a β-arrestin-biased receptor in the heart. Among 510 7TMR genes examined, Cxcr7 was the most abundantly expressed in the murine heart. Single-cell RNA-sequencing analysis revealed that Cxcr7 was abundantly expressed in cardiomyocytes and fibroblasts. Cardiomyocyte-specific Cxcr7 null mice showed more prominent cardiac dilatation and dysfunction than control mice 4 weeks after myocardial infarction. In contrast, there was no difference in cardiac phenotypes between fibroblast-specific Cxcr7-knockout mice and control mice even after myocardial infarction. TC14012, a specific agonist of CXCR7, significantly recruited β-arrestin to CXCR7 in CXCR7-expressing cells and activated extracellular signal-regulated kinase (ERK) in neonatal rat cardiomyocytes. Cxcr7 expression was significantly increased and ERK was activated in the border zone of the heart in control, but not Cxcr7 null mice. These results indicate that the abundantly expressed CXCR7 in cardiomyocytes may play a protective role in the heart as a β-arrestin-biased receptor and that CXCR7 may be a novel therapeutic target for myocardial infarction.
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