bioRxiv - Physiology最新文献

{"title":"Unraveling cysteine deficiency-associated rapid weight loss","authors":"Alan Varghese, Ivan Gusarov, Begona Gamallo-Lana, Daria Dolgonos, Yatin Mankan, Ilya Shamovsky, Mydia Phan, Rebecca Jones, Maria Gomez-Jenkins, Eileen White, Rui Wang, Drew Jones, Thales Papagiannakopoulos, Michael E. Pacold, Adam C Mar, Dan R Littman, Evgeny Nudler","doi":"10.1101/2024.07.30.605703","DOIUrl":"https://doi.org/10.1101/2024.07.30.605703","url":null,"abstract":"Forty percent of the US population and 1 in 6 individuals worldwide are obese, and the incidence of this disease is surging globally1,2. Various dietary interventions, including carbohydrate and fat restriction, and more recently amino acid restriction, have been explored to combat this epidemic3-6. We sought to investigate the impact of removing individual amino acids on the weight profiles of mice. Compared to essential amino acid restriction, induction of conditional cysteine restriction resulted in the most dramatic weight loss, amounting to 20% within 3 days and 30% within one week, which was readily reversed. This weight loss occurred despite the presence of substantial cysteine reserves stored in glutathione (GSH) across various tissues7. Further analysis demonstrated that the weight reduction primarily stemmed from an increase in the utilization of fat mass, while locomotion, circadian rhythm and histological appearance of multiple other tissues remained largely unaffected. Cysteine deficiency activated the integrated stress response (ISR) and NRF2-mediated oxidative stress response (OSR), which amplify each other, leading to the induction of GDF15 and FGF21, hormones associated with increased lipolysis, energy homeostasis and food aversion8-10. We additionally observed rapid tissue coenzyme A (CoA) depletion, resulting in energetically inefficient anaerobic glycolysis and TCA cycle, with sustained urinary excretion of pyruvate, orotate, citrate, α-ketoglutarate, nitrogen rich compounds and amino acids. In summary, our investigation highlights that cysteine restriction, by depleting GSH and CoA, exerts a maximal impact on weight loss, metabolism, and stress signaling compared to other amino acid restrictions. These findings may pave the way for innovative strategies for addressing a range of metabolic diseases and the growing obesity crisis.","PeriodicalId":501557,"journal":{"name":"bioRxiv - Physiology","volume":"151 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141868396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gene transfer of human cardiomyopathy beta-MyHC mutant R403Q directly alters intact cardiac myocyte calcium homeostasis and causes hyper-contractility","authors":"Todd J Herron, Eric Devaney, Guadalupe Guerrero-Serna, Lakshmi Mundada, Joseph M Metzger","doi":"10.1101/2024.07.31.605903","DOIUrl":"https://doi.org/10.1101/2024.07.31.605903","url":null,"abstract":"The R403Q mutation of human cardiac beta-myosin heavy chain was the first missense mutation of a sarcomeric protein identified as being causal for hypertrophic cardiomyopathy\u0000(HCM), in humans. The direct effect of the R403Q mutant myosin on intracellular calcium homeostasis and contractility is not fully known. Here we have used in vitro gene transfer of the R403Q mutant human beta-myosin to study its direct effects on single intact adult cardiac myocyte contractility and calcium homeostasis. In the first experiments, adult cardiac myocytes transduced with the R403Q mutant myosin recombinant viral vectors were compared to myocytes transduced with wild-type human beta-myosin (wtMYH7). Efficiency of gene transfer was high in both groups (>98%) and the degree of stoichiometric myofilament incorporation of either the mutant or normal myosin was comparable at ~40% in quiescent myocytes in primary culture. Sarcomere structure and cellular morphology were unaffected by R403Q myosin expression and myofilament incorporation. Functionally, in electrically paced cardiac myocytes, the R403Q mutant myosin caused a significant increase in intracellular calcium concentration and myocyte hyper-contractility. At the sub-cellular myofilament level, the mutant myosin increased the\u0000calcium sensitivity of steady state isometric tension development and increased isometric crossbridge cycling kinetics. R403Q myocytes became arrhythmic after beta-adrenergic stimulation with spontaneous calcium transients and contractions in between electrical stimuli. These results\u0000indicate that human R403Q mutant myosin directly alters myofilament function and intracellular calcium cycling. Elevated calcium levels may provide a trigger for the ensuing hypertrophy and susceptibility to arrhythmia that are characteristic of HCM.","PeriodicalId":501557,"journal":{"name":"bioRxiv - Physiology","volume":"79 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141881433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic Manipulation of Caveolin-1 in the Mouse Model of Marfan Syndrome Associated Aortic Root Aneurysm: Effects on Endothelial and Smooth Muscle Function","authors":"Tala Curry-Koski, Brikena Gusek, Ross M Potter, T. Bucky Jones, Raechel Dickman, Nathan Johnson, Johana Vallejo-Elias, Mitra Esfandiarei","doi":"10.1101/2024.07.29.605631","DOIUrl":"https://doi.org/10.1101/2024.07.29.605631","url":null,"abstract":"Marfan Syndrome (MFS) is a systemic connective tissue disorder caused by mutations in the gene encoding for the large glycoprotein Fibrillin-1 (Fbn1), leading to wide-spectrum clinical manifestations, with the most life-threatening being aortic root aneurysm. MFS aortic aneurysm is known to be associated with reduced endothelial nitric oxide synthase (eNOS)-mediated nitric oxide (NO) production. Previous studies have shown that caveolin-1 (Cav1), a coat protein of caveolae structure on the plasma membrane, acts as a negative regulator of eNOS activity. This suggests that Cav1 may play a role in the development of aortic root aneurysm in MFS by modulating eNOS activity. In this study, we investigated the role of Cav1 in regulating aortic smooth muscle and endothelial function, aortic wall elasticity, and wall strength by generating MFS mice (FBN1+/Cys1041Gly) lacking Cav1 gene expression (MFS/Cav1KO). Our data show that ablation of the Cav1 gene results in a significant decrease in aortic smooth muscle contraction in response to the vasoconstricting agent phenylephrine seemingly due to a marked increase in NO production within the aortic wall. We also showed that acetylcholine-induced vasorelaxation was increased in MFS/Cav1KO mice potentially through the endothelial nitric oxide-dependent mechanism, further confirming inhibitory role of Cav1 on endothelial NO production. In addition, aortic wall elastin fiber structure and strength were markedly improved in male MFS/Cav1KO mice. This study demonstrates the regulatory role of Cav1 during the development of aortic root aneurysm in MFS mice through its effects on smooth muscle and endothelial functions in an NO-dependent manner.","PeriodicalId":501557,"journal":{"name":"bioRxiv - Physiology","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141868616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Remote organ cancer adversely alters renal function and induces kidney injury, inflammation, and fibrosis.","authors":"Dana Hammouri, Andrew Orwick, Mark Doll, Dianet Sanchez Vega, Parag P Shah, Christopher J Clarke, Brian Clem, Levi J Beverly, Leah Jean Siskind","doi":"10.1101/2024.07.29.605635","DOIUrl":"https://doi.org/10.1101/2024.07.29.605635","url":null,"abstract":"Approximately 30% of cancer patients experience kidney complications, which hinder optimal cancer management, imposing a burden on patients quality of life and the healthcare system. The etiology of kidney complications in cancer patients is often attributed to nephrotoxic oncological therapies. However, the direct impact of cancer on kidney health is underestimated, as most nephrotoxic oncological therapies have been studied in animal models that do not have cancer. Our previous study demonstrated that metastatic lung cancer adversely alters kidney physiology and function, and exacerbates chemotherapy-induced nephrotoxicity, indicating lung cancer-kidney crosstalk. The current study examines whether this phenomenon is specific to the employed cancer model. Female and male mice of various strains were injected with different cell lines representing human and mouse lung cancer, breast cancer, and melanoma, and their kidney tissues were analyzed for toxicity and fibrosis. The impact of cancer on the kidney varied by cancer type. Breast cancer and specific subtypes of lung cancer, including KRAS- and EGFR-mutant cancer, pathologically altered kidney physiology and function in a manner dependent on the metastatic potential of the cell line. This was independent of mouse strain, sex, and cancer cell line origin. Moreover, tumor DNA was not detected in the renal tissue, excluding metastases to the kidney as a causative factor for the observed pathological alterations. Lewis lung carcinoma and B16 melanoma did not cause nephrotoxicity, regardless of the tumor size. Our results confirm cancer-kidney crosstalk in specific cancer types and highlight gaps in understanding the risk of renal complications in cancer patients. In the era of precision medicine, further research is essential to identify at-risk oncology populations, enabling early detection and management of renal complications.","PeriodicalId":501557,"journal":{"name":"bioRxiv - Physiology","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141868481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Longitudinal Decline of Exercise Capacity in Male and Female Mice","authors":"Megan L Pajski, Rosario Maroto, Chris Byrd, Ted G Graber","doi":"10.1101/2024.07.29.605646","DOIUrl":"https://doi.org/10.1101/2024.07.29.605646","url":null,"abstract":"The population of older adults is exponentially expanding. Alongside aging comes the onset of chronic disease, decline of functional capacity, and reduced quality of life. Thus, this population increase will stress the capacity and financial viability of health and long-term care systems. Developing pre-clinical models for age-related functional decline is imperative to advancing therapies that extend healthspan and prolong independence. Previously in a cross-sectional study, we established a powerful composite scoring system we termed CFAB (comprehensive functional assessment battery). CFAB measures physical function and exercise capacity using well-validated determinants to measure overall motor function, fore-limb strength, four-limb strength/endurance, aerobic capacity, and volitional exercise/activity rate. In the current work, we used CFAB to track cohorts of male and female C57BL/6 mice over the lifespan (measuring CFAB at 6, 12, 18, 24, and 28 months of age). Overall, we found statistically significantly declining function as the mice aged, with some differences between males and females in trajectory and slope. We also determined that body mass changes presented differently between sexes, and tracked body composition (fat percentage, using magnetic resonance imagery) in females. In a subset of mice, we tracked in vivo contractile physiology noting declines in plantar flexor maximum isometric torque. In summary, our data suggest that males and females declined at different rates. We confirmed the efficacy of CFAB to track longitudinal changes in exercise capacity and physical fitness in both males and females, further validating the system to track age-related functional decline.","PeriodicalId":501557,"journal":{"name":"bioRxiv - Physiology","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141868617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MACanalyzeR: scRNA-seq Analysis Tool Reveals PPARγHI Lipid-Associated Macrophages Facilitate Thermogenic Expansion in BAT","authors":"Andrea Ninni, Fabio Zaccaria, Luca Verteramo, Francesca Sciarretta, Loreana Sanches Silveira, Jose Cesar Rosa-Neto, Paolo Grumati, Giuseppe Rizzo, Clement Cochain, Jesse W Williams, Stoyan Ivanov, Beiyan Zhou, Katia Aquilano, Daniele Lettieri-Barbato","doi":"10.1101/2024.07.29.605588","DOIUrl":"https://doi.org/10.1101/2024.07.29.605588","url":null,"abstract":"Macrophages in brown adipose tissue (BAT) play a complex role in regulating its activity. However, the role of macrophages in regulating BAT activation/deactivation has not yet been comprehensively characterized. To elucidate this, we developed MACanalyzeR, a scRNAseq-based tool specifically designed to explore the macrophage features at molecular and metabolic level. MACanalyzeR was applied in scRNA-seq datasets obtained from BAT with thermogenic loss (db/db mice) and activation (High Fat Diet, HFD). Our computational approach revealed that macrophages accumulating in BAT upon these conditions resemble lipid-associated macrophages (LAMs) with foaming-like features. BAT LAMs also show a significant enrichment of genes associated with mitochondria and lysosomes. Interestingly, LAMs identified in BAT from HFD mice positively correlate with thermogenic genes and exhibit an enrichment in PPARγ signaling pathway, with an activated mitochondrial metabolism. Cell dynamic strategy, revealed that LAM with high Pparg expression levels (PpargHIGH) progressively accumulate during skeletal muscle regeneration, suggesting a potential role for this LAM subcluster in maintaining tissue homeostasis. Our findings suggest PpargHIGH LAMs as a subclass of macrophages potentially contributing in preserving tissue homeostasis associated with high energy demand conditions such as thermogenic and regenerative stimuli.","PeriodicalId":501557,"journal":{"name":"bioRxiv - Physiology","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141868618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rapid oxygen titration following cardiopulmonary resuscitation mitigates cerebral overperfusion and striatal mitochondrial dysfunction in asphyxiated newborn lambs","authors":"Shiraz Badurdeen, Robert Galinsky, Calum Roberts, Kelly J Crossley, Valerie Zahra, Alison Thiel, Yen Pham, Peter Davis, Stuart B. Hooper, Graeme Polglase, Emily Camm","doi":"10.1101/2024.07.27.603805","DOIUrl":"https://doi.org/10.1101/2024.07.27.603805","url":null,"abstract":"Asphyxiated neonates must have oxygenation rapidly restored to limit ongoing hypoxic-ischemic injury. However, the effects of transient hyperoxia after return of spontaneous circulation (ROSC) are poorly understood. We randomly allocated acutely asphyxiated, near-term lambs to cardiopulmonary resuscitation in 100% oxygen (standard oxygen, n=8) or air (n=7) until 5 minutes after ROSC, or to resuscitation in 100% oxygen immediately weaned to air upon ROSC (rapid-wean, n=7). From 5 minutes post-ROSC, oxygen was titrated to target preductal oxygen saturation between 90-95%. Cerebral tissue oxygenation was transiently but markedly elevated following ROSC in the standard oxygen group compared to the air and rapid-wean groups. The air group had a delayed rise in cerebral tissue oxygenation from 5 minutes after ROSC coincident with up-titration of oxygen. These alterations in oxygen kinetics corresponded with similar overshoots in cerebral perfusion (pressure and flow), indicating a physiological mechanism. Transient cerebral tissue hyperoxia in the standard oxygen and air groups resulted in significant alterations in mitochondrial respiration and dynamics, relative to the rapid-wean group. Overall, rapid-wean of oxygen following ROSC preserved striatal mitochondrial respiratory function and reduced the expression of genes involved in free radical generation and apoptosis, suggesting a potential therapeutic strategy to limit cerebral reperfusion injury.","PeriodicalId":501557,"journal":{"name":"bioRxiv - Physiology","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141868625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chromatin Remodeling by the Histone Methyltransferase SETD2 Drives Lipotoxic Injury in Cardiometabolic Heart Failure with Preserved Ejection Fraction","authors":"Samuele Ambrosini, Sarah Costantino, Shafeeq Ahmed Mohammed, Era Gorica, Melissa Herwig, Loek van Heerebeek, Alessandro Mengozzi, Gergely Karsai, Thorsten Hornemann, Omer Dzemali, Frank Ruschitzka, Nazha Hamdani, Francesco Paneni","doi":"10.1101/2024.07.25.605217","DOIUrl":"https://doi.org/10.1101/2024.07.25.605217","url":null,"abstract":"Background: Cardiometabolic heart failure with preserved ejection fraction (cHFpEF) is highly prevalent and associates with a poor outcome. Pathological gene expression in heart failure is accompanied by changes in active histone marks without major alterations in DNA methylation. Histone 3 trimethylation at lysine 36 (H3k36me3) - a chromatin signature induced by the histone methyltransferase SETD2 - strongly correlates with changes in gene expression in human failing hearts; however, its role is poorly understood. Here we investigate the role of SETD2 in cHFpEF. Methods: Mice with cardiomyocyte-specific deletion of SETD2 (c-SETD2-/-) were generated and subjected to high fat diet feeding and L-NAME treatment for 15 weeks to induce cHFpEF. Cardiac function and exercise tolerance were assessed by echocardiography and Treadmill exhaustion test. Chromatin immunoprecipitation assays (ChIP) were performed to investigate SETD2/H3k36me3 enrichment on gene promoters. SETD2 gain- and loss-of-function experiments were performed in cultured cardiomyocytes (CMs) exposed to palmitic acid (PA). SETD2 expression was also investigated in left ventricular (LV) myocardial specimens from patients with cHFpEF and control donors. Results: SETD2 was upregulated in cHFpEF mouse hearts and its chromatin mark H3k36me3 was enriched on the promoter of sterol regulatory element-binding transcription factor 1 (SREBP1) gene. SETD2 activation in cHFpEF led to SREBP1 upregulation, triglyceride accumulation and lipotoxic damage. Of note, cardiomyocyte-specific deletion of SETD2 in mice prevented HFpEF-related hypertrophy, diastolic dysfunction and lung congestion while improving exercise tolerance. SETD2 deletion blunted H3K36me3 enrichment on SREBP1 promoter thus leading to a marked rewiring of the cardiac lipidome and restoration of autophagic flux. SETD2 depletion in PA-treated CMs prevented SREBP1 upregulation, whereas SETD2 overexpression recapitulated lipotoxic damage. Finally, SETD2 was upregulated in LV specimens from cHFpEF patients and its pharmacological inhibition by EZM0414 attenuated CM stiffness. Conclusions: Therapeutic modulation of SETD2/H3k36me3 axis might prevent lipotoxic injury and cardiac dysfunction in cHFpEF.","PeriodicalId":501557,"journal":{"name":"bioRxiv - Physiology","volume":"42 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141783073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Alleviation of salt stress in strawberries by hydrogen-rich water: physiological, transcriptomic and metabolomic responses","authors":"Renyuan Wang, Shaohua Chu, Dan Zhang, Xia Zhang, Yaowei Chi, Xianzhong Ma, Xunfeng Chen, Haiyan Yang, Wenjiang Ding, Ting Zhao, Yongfeng Ren, Xijia Yang, Pei Zhou","doi":"10.1101/2024.07.25.605184","DOIUrl":"https://doi.org/10.1101/2024.07.25.605184","url":null,"abstract":"As climate change and human activities continue to influence the environment, the area of arable land has been decreasing and becoming more susceptible to the impact of salt ions. Consequently, understanding the molecular mechanisms behind hydrogen's mitigation of plant salt tolerance is essential. In this study, strawberries were selected as the test plants, and analyses including physiological, biochemical, transcriptomic, and metabolomic approaches were conducted to elucidate the effects of hydrogen-rich water (HRW) under salt stress. The results indicated that under 100 mM salt stress, HRW significantly promoted plant growth, particularly increasing root biomass by 49.50%. Additionally, HRW regulated the levels of soluble sugars, malondialdehyde (MDA), and antioxidant enzymes, enhancing the cellular uptake of potassium ions and the expulsion of sodium ions. The levels of Ca2+ and Mg2+ in organelles increased by 2.06 and 2.45-fold, respectively. Transcriptomic analysis revealed that HRW substantially altered gene expression in strawberry roots; under salt stress, HRW up-regulated beneficial biological processes. Furthermore, genes related to ion absorption and transport, antioxidant enzymes, and cell wall biosynthesis were screened. Through integrating transcriptomic and metabolomic analyses which identified key common pathways in the differentially expressed metabolites (DEMs) and differentially expressed genes (DEGs) related to phenylpropanoid biosynthesis, alanine, aspartate, and glutamate metabolism, amino sugar and nucleotide sugar metabolism, and galactose metabolism. A molecular mechanism for mitigating salt stress in strawberry seedlings by HRW was provided by the integrated approaches in this research, reflecting the potential applications of hydrogen gas in agriculture.","PeriodicalId":501557,"journal":{"name":"bioRxiv - Physiology","volume":"53 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141783072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In vivo quantification of anterior and posterior chamber volumes in mice: implications for aqueous humor dynamics","authors":"Daniel Kim, Raymond Fang, Pengpeng Zhang, Cheng Sun, Guorong Li, Christa Montgomery, Simon W.M. John, W Daniel Stamer, Hao F. Zhang, C Ross Ethier","doi":"10.1101/2024.07.24.604989","DOIUrl":"https://doi.org/10.1101/2024.07.24.604989","url":null,"abstract":"Purpose: Aqueous humor inflow rate, a key parameter influencing aqueous humor dynamics, is typically measured by fluorophotometery. Analyzing fluorophotometric data depends, inter alia, on the volume of aqueous humor in the anterior, but not the posterior, chamber. Previous fluorophotometric studies of aqueous inflow rate in mice have assumed the ratio of anterior:posterior volumes in mice to be similar to those in humans. Our goal was to measure anterior and posterior chamber volumes in mice to facilitate better estimates of aqueous inflow rates. Methods: We used standard near-infrared optical coherence tomography (OCT) and robotic visible-light OCT (vis-OCT) to visualize, reconstruct and quantify the volumes of the anterior and posterior chambers of the mouse eye in vivo. We used histology and micro-CT scans to validate relevant landmarks from ex vivo tissues to facilitate in vivo measurement. Results: Posterior chamber volume is 1.1 times the anterior chamber volume in BALB/cAnNCrl mice, i.e. the anterior chamber constitutes about 47% of the total aqueous humor volume, which is very dissimilar to the situation in humans. Anterior chamber volumes in 2-month-old BALB/cAnNCrl and 7-month-old C57BL6/J mice were 1.55 +- 0.36 microliters (n=10) and 2.41 +- 0.29 microliters (n=8), respectively. This implies that previous studies likely over-estimated aqueous inflow rate by approximately two-fold. Conclusions: It is necessary to reassess previously reported estimates of aqueous inflow rates, and thus aqueous humor dynamics in the mouse. For example, we now estimate that only 0-15% of aqueous humor drains via the pressure-independent (unconventional) route, similar to that seen in humans and monkeys.","PeriodicalId":501557,"journal":{"name":"bioRxiv - Physiology","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141783031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}