Citations

The diaphragm muscle (DIAm) is the major inspiratory muscle. Neural control of DIAm activation involves recruitment of phrenic motor neurons. Activation of the DIAm during breathing involes recruitment of fatigue resistant motor units comprising smaller PhMNs and type I and IIa muscle fibers. More force, but infrequent non-ventilatory behaviors of the DIAm involes the recruitment of fatigable motor units comprising larger PhMNs and type IIx/IIb fibers. This study investigated the role of brain derived neurotrophic factor (BDNF) signaling, through its high-affnity receptor, tropomyosin receptor kinase B (TrkB.FL), in the survival of PhMNs in young (6 months old) and old (24 months old) Sprague Dawley rats. Previous research in Fischer 344 rats revealed an age-related loss of larger PhMNs. We hypothesize that both BDNF/TrkB signaling and PhMN activity are crucial for PhMN survival, but that the influence of BDNF/TrkB decreases with age due to reduced TrkB.FL expression. PhMNs were retrogradely labeled and imaged using 3D confocal microscopy in both young and old rats. We found a similar reduction in larger PhMNs in Sprague Dawley rats as previously observed in Fischer 344 rats. In contrast to younger rats, intrathecal BDNF treatment did not induce phosphorylation of the transcription factor CREB at Serine133 in older rats, consistent with reduced TrkB.FL expression and signaling in older rats. In both old age and following TrkB kinase inhibition, smaller PhMNs survived perhaps due to the continued activation driving pCREB, while larger PhMNs may require BDNF/TrkB signaling to maintain pCREB and survival. Research Supported by NIH R01 grants AG44615, HL146114 and R56-HL166204. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Lipoprotein Lipase (LPL) hydrolyzes plasma triglycerides into free fatty acids in the circulation for use and/or storage in tissues (i.e., adipose tissue, skeletal muscle). Impaired LPL activity (LPLa) is associated with unfavorable health outcomes, such as elevated plasma triglyceride concentrations. We sought to determine how plasma LPLa relates to body composition measurements in individuals with varying degrees of adiposity. Eighteen subjects (ages 19 to 45 years) with body mass index (BMI) between 18 and 45 kg/m2 had their body composition measured by dual-energy X-ray absorptiometry (DEXA) and insulin sensitivity estimated from an oral glucose tolerance test by using the Matsuda Index (MI). Subjects ingested a bolus of 5g fat (i.e., whipping cream, 0.2 g fat/kg fat free mass), followed by small boluses of fat over the course of a 3-hour experimental period. This experimental protocol allows for the induction of a postprandial state without perturbation of the plasma triglyceride or insulin concentrations. LPLa was measured in the presence of increased plasma insulin induced by intravenous insulin infusion during the last 30 mins of the 3-hour experimental protocol. Insulin was infused at a rate of 0.5 mU/kg/min for subjects with MI-determined insulin sensitivity < 4 and 1 mU/kg/min for those with MI-determined insulin sensitivity > 4, in order to produce comparable levels of plasma insulin concentrations across subjects. To release endothelial-bound LPL, subjects received an injection of intravenous heparin (75 UI/kg) at the end of the plasma insulin infusion. Plasma samples were collected 10 minutes after the heparin infusion and analyzed for LPL concentration (LPLc) and LPLa using commercially available ELISA kits. Person’s correlation was used to evaluate relationships between several body composition parameters and LPLc as well as LPLa. LPLc was not correlated (P >0.05) with BMI (r = 0.03), total lean body mass (r = -0.20), total body fat (r = -0.02), or android fat (r = - 0.08). However, LPLa was positively correlated (P <0.05) with BMI (r = 0.49) and total lean body mass (r = 0.58), as well as total body fat (r = 0.54, P = 0.02) and android fat (r = 0.58, P = 0.01). In conclusion, increased body fat, including android fat, are associated with increased intravascular LPLa in the presence of insulin. Greater insulin-stimulated intravascular LPLa can enhance the release of triglyceride-associated free fatty acids and their uptake by tissues, resulting in insulin resistance as documented in individuals with increased android fat distribution. American Diabetes Association Grant #7-12-CT-40. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

This article addresses clinical challenges of photon-counting detector (PCD) CT in pediatric patients by outlining fundamental terminology, explaining technical aspects, and providing protocol guidance for the first commercially available PCD CT scanner.

Mechanical forces on the airway can contribute to altered contractility and remodeling in airway diseases, but the mechanisms are not clearly understood. Using human airway smooth muscle cells exposed to cyclic forces with static stretch to mimic breathing and static pressure, we found that the effects of stretch are mediated through STIM1, resulting in the activation of multiple pathways, including Piezo channels and the inflammasome, with potential downstream influences on contractility and remodeling.

The current study establishes functional links between endoplasmic reticulum (ER) stress and cellular senescence per se in the specific context of aging human lung fibroblasts. Recognizing that the process of aging per se is complex, modulated by the myriad of lifelong and environmental exposures, it is striking to note that chronic ER stress may play a crucial role in the establishment and maintenance of cellular senescence in lung fibroblasts.

ABSTRACT Chronic wound infections can be difficult to treat and may lead to impaired healing and worsened patient outcomes. Novel treatment strategies are needed. This study evaluated the effects of intermittently produced hydrogen peroxide (H 2 O 2 ) and hypochlorous acid (HOCl), generated via an electrochemical bandage (e-bandage), against methicillin-resistant Staphylococcus aureus biofilms in an agar membrane biofilm model. By changing the working electrode potential, the e-bandage generated either HOCl (1.5 V Ag/AgCl ) or H 2 O 2 (−0.6 V Ag/AgCl ). The degree of biocidal activity of intermittent treatment with HOCl and H 2 O 2 correlated with HOCl treatment time; HOCl treatment durations of 0, 1.5, 3, 4.5, and 6 hours (with the rest of the 6-hour total treatment time devoted to H 2 O 2 generation) resulted in mean biofilm reductions of 1.36 ± 0.2, 2.22 ± 0.16, 3.46 ± 0.38, 4.63 ± 0.74, and 7.66 ± 0.5 log CFU/cm 2 , respectively, vs. non-polarized controls, respectively. However, application of H 2 O 2 immediately after HOCl treatment was detrimental to biofilm removal. For example, 3 hours HOCl treatment followed by 3 hours H 2 O 2 resulted in a 1.90 ± 0.84 log CFU/cm 2 lower mean biofilm reduction than 3 hours HOCl treatment followed by 3 hours non-polarization. HOCl generated over 3 hours exhibited biocidal activity for at least 7.5 hours after e-bandage operation ceased; 3 hours of HOCl generation followed by 7.5 hours of non-polarization resulted in a biofilm cell reduction of 7.92 ± 0.12 log CFU/cm 2 vs. non-polarized controls. Finally, intermittent treatment with HOCl (i.e., interspersed with periods of e-bandage non-polarization) for various intervals showed similar effects (approximately 6 log CFU/cm 2 reduction vs. non-polarized control) to continuous treatment with HOCl for 3 hours, followed by 3 hours of non-polarization. These findings suggest that timing and sequencing of HOCl and H 2 O 2 treatments are crucial for maximizing biofilm control when using an e-bandage strategy.

Introduction: Non-alcoholic fatty liver disease (NAFLD), spanning from non-alcoholic steatohepatitis (NASH) to liver fibrosis, poses a global health challenge amid rising obesity and metabolic syndrome rates. Effective pharmacological treatments for NASH and liver fibrosis are limited. Objective: This study systematically reviews and meta-analyzes the safety and efficacy of resmetirom, a selective thyroid hormone receptor-β agonist, in NASH and liver fibrosis treatment. By analyzing data from clinical trials, we aim to offer evidence-based recommendations for resmetirom’s use in managing these conditions and identify avenues for future research. Methods: Electronic databases (PubMed, Scopus, Science Direct, Google Scholar, ClinicalTrials.gov, and Cochrane CENTRAL) were systematically searched, supplemented by manual screening of relevant sources. Only English-language randomized controlled trials were included. Data extraction, risk of bias assessment, pooled analyses, and meta-regression were performed. Results: Three randomized controlled trials involving 2231 participants were analyzed. Resmetirom demonstrated significant reductions in hepatic fat fraction [standardized mean difference (SMD) −4.61, 95% CI −6.77 to −2.44, P < 0.0001], NASH resolution without worsening fibrosis [risk ratio (RR) 2.51, 95% CI 1.74–3.64, P = 0.00001), and liver fibrosis improvement (RR 2.31, 95% CI 1.20–4.44, P = 0.01). Secondary outcomes showed significant improvements in lipid profiles, liver enzymes, and NASH biomarkers with resmetirom treatment. Meta-regression revealed associations between covariates and primary outcomes. Conclusion: Resmetirom exhibits promising efficacy in reducing hepatic fat, improving NASH resolution, and ameliorating liver fibrosis with a favorable safety profile. Further research is warranted to validate findings and optimize therapeutic strategies for NASH and liver fibrosis management.

With improved medical treatments, the prognosis for many malignancies has improved, and more patients are presenting for transplant evaluation with a history of treated cancer. Solid organ transplant (SOT) recipients with a prior malignancy are at higher risk of posttransplant recurrence or de novo malignancy, and they may require a cancer surveillance program that is individualized to their specific needs. There is a dearth of literature on optimal surveillance strategies specific to SOT recipients. A working group of transplant physicians and cancer-specific specialists met to provide expert opinion recommendations on optimal cancer surveillance after transplantation for patients with a history of malignancy. Surveillance strategies provided are mainly based on general population recurrence risk data, immunosuppression effects, and limited transplant-specific data and should be considered expert opinion based on current knowledge. Prospective studies of cancer-specific surveillance models in SOT recipients should be supported to inform posttransplant management of this high-risk population.

Background. Minority race, ethnicity, and financial barriers are associated with lower rates of living donor (LD) kidney transplantation (LDKT). Financial reimbursement for LD costs may impact social determinants of health and, therefore, impact disparities in access to LDKT. Methods. Among US LDKTs, we studied associations between racial and ethnic minority status and utilization of the National Living Donor Assistance Center (NLDAC), a means-tested reimbursement program for nonmedical LD costs. We analyzed demographic, clinical, income, and survey data from NLDAC and the Scientific Registry of Transplant Recipients (January 1, 2011, to December 31, 2022) to identify predictors of NLDAC utilization. Results. Among 70 069 US LDKTs, 6093 NLDAC applicants were identified (9% of US LDKTs). Racial and ethnic minorities were over-represented in NLDAC-supported LDKTs compared with non-NLDAC US LDKTs (Black donors 12% versus 9%; Black recipients 15% versus 12%; Hispanic donors 21% versus 14%; Hispanic recipients 23% versus 15%; all P < 0.001). Among preemptive transplants, use of NLDAC by donors to Hispanic recipients (11%) was nearly twice as high as that of non-Hispanic recipients (6%) (P < 0.001). At time of NLDAC application, 72% stated NLDAC “will make it possible” to donate; higher proportions of minority applicants agreed (Black 80%, White 70%, P < 0.001; Hispanic 79%, non-Hispanic 70%, P < 0.001). Racial and ethnic minority-concordant transplants were significantly more likely to use NLDAC (donor/recipient: Black/Black risk-adjusted odds ratio [OR], 1.85, other/other OR 2.59, Hispanic/Hispanic OR 1.53; all P < 0.05). Conclusions. Reduction of LD financial barriers may increase access to LDKT, particularly in racial and ethnic minority communities.