The interstitium in cardiac repair: role of the immune-stromal cell interplay

Cardiac regeneration, that is, restoration of the original structure and function in a damaged heart, differs from tissue repair, in which collagen deposition and scar formation often lead to functional impairment. In both scenarios, the early-onset inflammatory response is essential to clear damaged cardiac cells and initiate organ repair, but the quality and extent of the immune response vary. Immune cells embedded in the damaged heart tissue sense and modulate inflammation through a dynamic interplay with stromal cells in the cardiac interstitium, which either leads to recapitulation of cardiac morphology by rebuilding functional scaffolds to support muscle regrowth in regenerative organisms or fails to resolve the inflammatory response and produces fibrotic scar tissue in adult mammals. Current investigation into the mechanistic basis of homeostasis and restoration of cardiac function has increasingly shifted focus away from stem cell-mediated cardiac repair towards a dynamic interplay of cells composing the less-studied interstitial compartment of the heart, offering unexpected insights into the immunoregulatory functions of cardiac interstitial components and the complex network of cell interactions that must be considered for clinical intervention in heart diseases

Acute effects of whole-body vibration with resistance exercise on postexercise blood pressure and oxygen consumption in prehypertensive adults

Background/Objective: Research on the acute health effects of whole-body vibration with resistance exercise (WBV + RE) for clinical populations is limited. This randomized crossover trial evaluated postexercise hypotension and excess postexercise oxygen consumption (EPOC) in response to three conditions: WBV + RE, RE alone, and control (CON) in 11 prehypertensive (systolic/diastolic blood pressure: 120–139/80–89 mmHg) adults. Methods: Following a 12-hour fast with no exercise for the previous 24 hours, resting VO2 and blood pressure (BP) were measured. WBV + RE was performed while standing barefoot on a vibration platform (Pneumex Pro-Vibe) and lifting a bar of 10% body weight. Fifteen repetitions of nine exercises were performed using a 1-minute–to-30-second exercise:rest ratio. RE was identical to WBV + RE but without vibration. During CON, participants remained seated for 15 minutes. Following exercise, VO2 was measured continuously and BP every 15 minutes for 3 hours. Results: Postexercise hypotension and EPOC were significantly different for WBV + RE compared with RE and CON (p <0.001). Postexercise systolic BP was significantly lower for WBV + RE as compared with RE or CON, while diastolic BP was lower for both WBV + RE and RE compared with CON (p < 0.001; WBV + RE: 124 ± 2/72 ± 6 mmHg; RE: 126 ± 2/71 ± 6 mmHg; CON: 128 ± 2/73 ± 6 mmHg). EPOC was significantly (p < 0.001) higher at 15 minutes postexercise for WBV + RE as compared with RE. Conclusion: Compared with RE alone, a single bout of WBV + RE resulted in a greater postexercise hypotension response and higher EPOC

Lateral Posterior Tibial Slope in Male and Female Athletes Sustaining Contact Versus Noncontact Anterior Cruciate Ligament Tears: A Prospective Study

Background: Lateral posterior tibial slope (PTS) has been identified as a risk factor for primary anterior cruciate ligament (ACL) tears. Purpose/Hypothesis: The purpose was to prospectively determine if there was a difference in lateral PTS between male and female athletes sustaining contact ACL tears as compared with a group of sex-, age-, and activity-matched athletes who sustained noncontact ACL tears. It was hypothesized that there would be no difference in degree of lateral PTS between contact and noncontact mechanisms among patients sustaining primary ACL tears in sports. Study Design: Cohort study; Level of evidence, 3. Methods: Data from patients who underwent primary ACL reconstruction without posterior cruciate ligament injury between 2016 and 2018 by a single surgeon were prospectively analyzed. Measurements of lateral PTS were performed on magnetic resonance imaging. Mean values of lateral PTS were compared between the ACL tear groups. Additionally, a group of patients with intact knee ligaments were matched to patients with ACL tears to serve as controls. Results: A total of 245 patients had complete primary ACL tears during the inclusion period. Of these, 56 (23%) reported a contact mechanism of injury at the time of ACL tear, and 56 patients who sustained noncontact ACL tears were matched to the contact ACL tear group. There were no significant differences in sex (P≥ .999), age (P = .990), or body mass index (P = .450) between the patient groups. The mean lateral PTS was 9.1°± 2.9° for the ACL contact and 9.9°± 3.0° for the ACL noncontact group (P = .180). There was a significant difference in mean lateral PTS between the ACL tear groups (noncontact and contact: 9.5°± 3.0°) and matched control group (5.6°± 1.9°, P = .0001). Conclusion: The lateral PTS was significantly increased among patients with contact and noncontact ACL tears as compared with controls. However, there were no differences in lateral PTS between patients who sustained contact and noncontact ACL tears. Lateral PTS measured on magnetic resonance imaging does not appear to be predictive of the mechanism of injury type among patients who sustain a contact or noncontact primary ACL tear