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Artificial intelligence–derived immune phenotypes for prediction of prognosis in patients with stage III colon cancer (NCCTG N0147; Alliance).
Ardestani, Bahar Saberzadeh, Nelson, Garth D. , Segovia, Diana I. , Yan, Dongyao , Shanmugam, Kandavel , Park, Gahee , Lim, Yoojoo , Alberts, Steven R. , Shi, Qian , Ock, Chan‐Young , Sinicrope, Frank A.

Journal of Clinical Oncology | June 4, 2023 | Volume: 41 | Issue: 16_suppl | Pages: 3542-3542

10.1200/jco.2023.41.16_suppl.3542 Get It

3542 Background: Solid tumors can be characterized by distinct immune phenotypes based on the level of T cell infiltration in the tumor microenvironment (TME) which may provide prognostic information and also inform strategies to restore the anti-tumor immune response. Immune phenotypes were determined using an artificial intelligence (AI) algorithm in digitized whole-slide images (WSI) of tumors with deficient (d) mismatch repair (MMR) vs proficient (p) MMR. Methods: Stage III colon carcinomas (N = 401; 393 met QC) from participants in a phase III trial of FOLFOX-based adjuvant chemotherapy were analyzed including all available tumors with dMMR (n = 196) and a randomly selected cohort of pMMR tumors (n = 195). Using an AI algorithm (Lunit SCOPE) previously trained on solid tumors, digitized tumors were categorized into three immune phenotypes based on epithelial and stromal TIL data-driven cutpoints in dMMR and pMMR (inflamed: TIL high in epithelium (> upper 25%); excluded: TIL high in stroma (>lower 25%), low in epithelium; and desert: TIL low in epithelium and stroma). Phenotypes were then examined in relationship to disease-free survival (DFS) using Kaplan-Meier methodology. Results: Of the 3 immune phenotypes in dMMR tumors, 25% were inflamed, 50% were immune-excluded, and 25% were immune-desert. Based on univariate results, multivariable modeling was performed incorporating immune phenotype in addition to age, histological grade, N stage, T stage, performance status, treatment arm, BRAF and KRAS status and identified immune phenotypes and N stage to be significantly associated with DFS. Among dMMR tumors, immune desert phenotype was associated with the poorest DFS (Desert: HR adj 1.95, 95%CI (1.01, 3.80); Excluded: HR adj 0.89, 95%CI (0.47, 1.69); Inflamed: ref; p:0.01). When compared to immune desert tumors, immune-excluded tumors had significantly better DFS (HR adj 0.49, 95%CI (0.27, 0.88), p:0.01). At a median follow-up of 60 months, 3-year DFS of patients with dMMR was 71.2% with Immune inflamed, 78.5% with Excluded, and 54.5% with Desert phenotypes. In contrast to dMMR, univariate analyses of data-driven cutpoints in pMMR tumors was not prognostic. Using a different data-driven cutpoint (15%), the revised immune phenotypes remained non-significant for DFS within pMMR tumors. Conclusions: Distinct AI-derived immune phenotypes in the TME were identified that were significantly prognostic in patients with dMMR, but not pMMR colon cancers. A data-driven immune-desert phenotype was identified in dMMR tumors that was associated with significantly poorer survival. Further investigation of the potential predictive utility of these phenotypes for immunotherapy are planned. Support: https://acknowledgments.alliancefound.org . ClinicalTrials.gov Identifier: NCT00079274 .
Association of Medicaid expansion with treatment receipt, delays in treatment initiation, and survival among young adult women with breast cancer.
Shi, Kewei Sylvia , Ruddy, Kathryn J. , Mertens, Ann C. , Yabroff, K. Robin , Ji, Xu , Yabroff, K Robin , Han, Xuesong , Zhao, Jingxuan , Castellino, Sharon M.

Journal of Clinical Oncology | June 4, 2023 | Volume: 41 | Issue: 16_suppl | Pages: 1509-1509

10.1200/jco.2023.41.16_suppl.1509 Get It

1509 Background: Medicaid expansion under the Affordable Care Act has been shown to increase insurance coverage and early-stage cancer diagnoses for young adults (YAs), the age group with the highest uninsured rate. We examined whether Medicaid expansion was associated with increased receipt of timely, guideline-concordant treatment and survival among YA women newly diagnosed with breast cancer, the most common YA cancer diagnosis. Methods: Using the National Cancer Database, we identified 51,675 women aged 18-39 years who were diagnosed with breast cancer in 2011-2018. We applied the difference-in-differences (DD) method to estimate outcome changes pre vs. post Medicaid expansion, in expansion- vs. non-expansion states. Linear probability models estimated associations of Medicaid expansion with receipt of guideline-concordant treatment – including any endocrine therapy among women with ER-positive or PR-positive breast cancer, and any chemotherapy or targeted therapy among women with ER-negative and PR-negative breast cancer – and initiation of guideline-concordant treatment (surgery, chemotherapy, or targeted therapy for stage I-III diagnoses, and systemic therapy for stage IV diagnoses) <60 days after diagnosis. Flexible parametric survival models were used to estimate 2-year overall survival. DD models also adjusted for age, race/ethnicity, rurality, zip code-level income, comorbidity, and diagnosis year, with standard errors clustered at the state level. Analyses were stratified by stage at diagnosis (stage I-III vs. IV). Results: Of the subset of women with stage I-III ER-positive or PR-positive breast cancer, the percentage receiving endocrine therapy increased in expansion states (85.20% pre-expansion to 86.46% post-expansion), but decreased in non-expansion states (84.32% to 82.79%), resulting in a net increase of 2.42 percentage points (ppt; 95% CI = 0.56 to 4.28) associated with Medicaid expansion in the adjusted DD model. Among all women with stage I-III breast cancer, the percentage with treatment initiation <60 days after diagnosis decreased less in expansion states (84.10% pre-expansion to 82.36% post-expansion) than in non-expansion states (86.95% to 83.98%), resulting in a net reduction of 1.61 ppt (95% CI = 0.05 to 3.18) in treatment delays associated with Medicaid expansion. Notably, the 2-year overall survival increased in expansion states (96.84% pre-expansion to 96.99% post-expansion), but decreased in non-expansion states (97.24% to 96.30%), resulting in a net survival increase of 1.00 ppt (95% CI = 0.21 to 1.79) associated with Medicaid expansion. Conclusions: Among YA women with stage I-III breast cancer, Medicaid expansion was associated with increased receipt of guideline-concordant treatment, reduced delays in treatment initiation, and improved 2-year survival.
Association of tumor-infiltrating lymphocytes (TILs) with clinicopathologic characteristics and prognosis in young women with HR+/HER2- breast cancer (BC).
Tesch, Megan E. , Arocho, Yaileen D Guzman, Collins, Laura C. , Heng, Jan, Tayob, Nabihah , Rosenberg, Shoshana M. , Ruddy, Kathryn J. , Schapira, Lidia , Peppercorn, Jeffrey , Come, Steven E. , Zheng, Yue , Tamimi, Rulla M. , Borges, Virginia F. , Snow, Craig , Mittendorf, EA , Partridge, Ann H.

Journal of Clinical Oncology | June 4, 2023 | Volume: 41 | Issue: 16_suppl | Pages: 505-505

10.1200/jco.2023.41.16_suppl.505 Get It

505 Background: Increased TILs are associated with better prognosis in triple-negative BC, including in patients (pts) age < 40. However, the role of TILs remains unclear in HR+/HER2- BC and little data exist in young pts, in whom immune microenvironment could be altered by age-related host/tumor differences. We assessed the extent and composition of immune infiltration in HR+ tumors of young women and correlated with clinicopathologic features and survival outcomes. Methods: From a prospective cohort study of women with BC diagnosed age ≤40, we identified those with stage I-III HR+/HER2- BC and available pre-treatment (tx) tumor tissue. Multiplexed immunofluorescence was used to quantify cytotoxic T (CD8+), T helper (Th, CD3+CD8-), T regulatory (Tregs, FOXP3+CD3+) and exhausted T (PD1+CD8+) cells in stroma and tumor. Univariate analyses tested associations between clinicopathologic variables and immune markers by high or low expression, divided based on median. High vs. low TILs were evaluated in Cox regression analyses for invasive breast cancer-free survival (iBCFS), distant disease-free survival (DDFS) and overall survival (OS). Results: In 390 pts, median age was 37 years (21-40), most had grade 2 (51%), T1 (65%), N0 (63%) tumors and 67% received adjuvant chemotherapy. Black pts (n = 17) had higher expression of stromal CD8+ ( P= .010), FOXP3+CD3+ ( P= .027) and PD1+CD8+ TILs ( P= .043); intratumoral TILs did not differ by race. Older age (36-40) was associated with high expression of CD8+ ( P= .033) and PD1+CD8+ TILs ( P= .031) within stroma and CD3+CD8- TILs within tumor ( P= .046). Grade 3 tumors had higher stromal and intratumoral expression of CD3+CD8- ( P= .002; P< .001) and FOXP3+CD3+ TILs ( P= .020; P< .001). No differences in TILs were seen according to recency of pregnancy, BRCA1/2 status or T/N stage. Over a median follow up of 8 years, 85 iBCFS events, 64 DDFS events and 37 deaths occurred. High stromal expression of CD3+CD8- TILs was associated with better iBCFS (HR 0.49, P= .002) and DDFS (HR 0.57, P= .046), which remained significant when adjusted for T/N stage, grade and chemotherapy (iBCFS HR 0.41, P< .001; DDFS HR 0.45, P= .008). High stromal expression of CD3+CD8- and FOXP3+CD3+ TILs was associated with better OS (HR 0.47, P= .038) and iBCFS (HR 0.58, P= .018), respectively, on adjusted analyses only. High intratumoral expression of CD3+CD8- and FOXP3+CD3+ TILs was associated with better iBCFS (HR 0.59, P= .025; HR 0.63, P= .043) after adjustment only. Conclusions: The distribution of TIL subtypes in young women’s HR+ BC varied according to race, age and grade. High stromal and intratumoral expression of Th and Tregs was associated with improved BC outcomes. Characterization of immune cell subsets could help refine the prognostic value of TILs in HR+ BC, particularly in young pts who may benefit from individualized escalated/de-escalated tx strategies.
Rho-associated protein kinase 1 inhibition in hepatocytes attenuates nonalcoholic steatohepatitis
Dohnálková, Ester , Bayer, Rachel L., Guo, Qianqian , Lee, Hyun Se Kim , Valenzuela-Pérez, Lucía , Krishnan, Anuradha , Pavelko, Kevin D. , Guisot, Nicolas E. S. , Bunyard, Peter, Ibrahim, Samar H. , Bamidele, Adebowale O , Kim Lee, Hyun Se , Pavelko, Kevin D , Kim, Young-Bum , Ibrahim, Samar H , Hirsova, Petra , Guo, Qianqian , Bamidele, Adebowale O. , Gores, Gregory J. , Valenzuela-Pérez, Lucía

Hepatology Communications | June 2, 2023 | Volume: 7 | Issue: 6 | Pages: No page available

10.1097/hc9.0000000000000171 | PMID 37267252 Get It

Background: NASH is the progressive form of NAFLD characterized by lipotoxicity, hepatocyte injury, tissue inflammation, and fibrosis. Previously, Rho-associated protein kinase (ROCK) 1 has been implicated in lipotoxic signaling in hepatocytes in vitro and high-fat diet-induced lipogenesis in vivo. However, whether ROCK1 plays a role in liver inflammation and fibrosis during NASH is unclear. Here, we hypothesized that pathogenic activation of ROCK1 promotes murine NASH pathogenesis. Methods and Results: Patients with NASH had increased hepatic ROCK1 expression compared with patients with fatty liver. Similarly, hepatic ROCK1 levels and activity were increased in mice with NASH induced by a western-like diet that is high in fat, fructose, and cholesterol (FFC). Hepatocyte-specific ROCK1 knockout mice on the FFC diet displayed a decrease in liver steatosis, hepatic cell death, liver inflammation, and fibrosis compared with littermate FFC-fed controls. Mechanistically, these effects were associated with a significant attenuation of myeloid cell recruitment. Interestingly, myeloid cell-specific ROCK1 deletion did not affect NASH development in FFC-fed mice. To explore the therapeutic opportunities, mice with established NASH received ROCKi, a novel small molecule kinase inhibitor of ROCK1/2, which preferentially accumulates in liver tissue. ROCK inhibitor treatment ameliorated insulin resistance and decreased liver injury, inflammation, and fibrosis. Conclusions: Genetic or pharmacologic inhibition of ROCK1 activity attenuates murine NASH, suggesting that ROCK1 may be a therapeutic target for treating human NASH.
An ERK5-NRF2 Axis Mediates Senescence-Associated Stemness and Atherosclerosis
Abe, Jun‐ichi , Imanishi, Masaki , Li, Shengyu , Zhang, Aijun , Ko, Kyung Ae , Samanthapudi, Venkata Subrahman K, Lee, Ling-Ling, Bojorges, Angelica Paniagua, Gi, Young Jin , Hobbs, Brian P. , Herrmann, Joerg , Chini, Eduardo N. , Shen, Ying H. , Schadler, Keri , Nguyen, Thi-Hong-Minh, Gupte, Anisha A. , Reyes‐Gibby, Cielito C. , Abe, Rei , Pownall, Henry J. , Yoshimoto, Momoko , Fujiwara, Keigi , Hamilton, Dale J. , Le, Nhat-Tu , Kotla, Sivareddy , Li, Shengyu , Deswal, Anita M , Shen, Ying H , Reyes-Gibby, Cielito , Abe, Rei J , Dantzer, Robert , Palaskas, Nicolas L , Cooke, John P , Pownall, Henry J , Yoshimoto, Momoko , Fujiwara, Keigi , Hamilton, Dale J , Burks, Jared K , Wang, Guangyu , Kotla, Sivareddy , Abe, Jun-Ichi , Li, Shengyu , Zhang, Aijun , Lin, Steven H. , Schadler, Keri , Yeung, Sai‐Ching J. , Olmsted‐Davis, Elizabeth A. , Krishnan, Sunil , Cooke, John P. , Wang, Guangyu

Circulation Research | June 2, 2023 | Volume: 133 | Issue: 1 | Pages: 25-44

10.1161/circresaha.122.322017 | PMID 37264926 Get It

Background: ERK5 (extracellular signal-regulated kinase 5) is a dual kinase transcription factor containing an N-terminal kinase domain and a C-terminal transcriptional activation domain. Many ERK5 kinase inhibitors have been developed and tested to treat cancer and inflammatory diseases. However, recent data have raised questions about the role of the catalytic activity of ERK5 in proliferation and inflammation. We aimed to investigate how ERK5 reprograms myeloid cells to the proinflammatory senescent phenotype, subsequently leading to atherosclerosis. Methods: A ERK5 S496A (dephosphorylation mimic) knock in (KI) mouse model was generated using CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeat–associated 9), and atherosclerosis was characterized by hypercholesterolemia induction. The plaque phenotyping in homozygous ERK5 S496A KI and wild type (WT) mice was studied using imaging mass cytometry. Bone marrow–derived macrophages were isolated from hypercholesterolemic mice and characterized using RNA sequencing and functional in vitro approaches, including senescence, mitochondria reactive oxygen species, and inflammation assays, as well as by metabolic extracellular flux analysis. Results: We show that atherosclerosis was inhibited in ERK5 S496A KI mice. Furthermore, ERK5 S496 phosphorylation mediates both senescence-associated secretory phenotype and senescence-associated stemness by upregulating AHR (aryl hydrocarbon receptor) in plaque and bone marrow–derived macrophages isolated from hypercholesterolemic mice. We also discovered that ERK5 S496 phosphorylation could induce NRF2 (NFE2-related factor 2) SUMOylation at a novel K518 site to inhibit NRF2 transcriptional activity without altering ERK5 catalytic activity and mediates oxidized LDL (low-density lipoprotein)–induced senescence-associated secretory phenotype. Specific ERK5 kinase inhibitors (AX15836 and XMD8-92) also inhibited ERK5 S496 phosphorylation, suggesting the involvement of ERK5 S496 phosphorylation in the anti-inflammatory effects of these ERK5 kinase inhibitors. Conclusions: We discovered a novel mechanism by which the macrophage ERK5-NRF2 axis develops a unique senescence-associated secretory phenotype/stemness phenotype by upregulating AHR to engender atherogenesis. The finding of senescence-associated stemness phenotype provides a molecular explanation to resolve the paradox of senescence in proliferative plaque by permitting myeloid cells to escape the senescence-induced cell cycle arrest during atherosclerosis formation.
Disproportionate increases in alcohol-associated hepatitis incidence in women and individuals of low socioeconomic status: A population-based study using the Rochester epidemiology project database
Ahn, Joseph , Wi, Chung‐Il , Buryska, Seth , Sivasubramaniam, Priyadharshini , Harmsen, William S. , Kamath, Patrick S. , Juhn, Young J. , Shah, Vijay H. , Ahn, Joseph C , Simonetto, Douglas A , Juhn, Y J , Wi, Chung-Ii , Simonetto, Douglas A.

Hepatology Communications | May 31, 2023 | Volume: 7 | Issue: 6 | Pages: No page available

10.1097/hc9.0000000000000160 | PMID 37255371 Get It

Background: Alcohol-associated hepatitis (AH) is among the deadliest liver diseases, but its incidence is poorly defined. The aim of our study was to define the incidence of AH meeting the National Institute on Alcohol Abuse and Alcoholism criteria and to identify risk factors for AH. Methods: We conducted a retrospective cohort study using the Rochester epidemiology project database on adult patients hospitalized with AH between January 1, 2000 and December 31, 2018. Patients were screened using ICD-9 codes and then included if they met the National Institute on Alcohol Abuse and Alcoholism criteria on manual chart review. Baseline demographics, comorbidities, access to care, liver-related complications, and outcomes were obtained. The HOUsing-based index of SocioEconomic status index was used to measure socioeconomic status. Incidence rates were calculated in cases per 100,000 person-years of follow-up. Results: Among 204 patients, the cumulative AH incidence was 6.8 per 100,000 person-years. Between 2000–2004 and 2015–2018, AH incidence among males increased from 8.4 to 14.7 per 100,000 py, whereas AH incidence among females increased by 7-fold from 0.8 to 5.9 per 100,000 py. Such increases among females were accompanied by increases in comorbid depression and anxiety. The proportion of patients with AH in the lower socioeconomic status quartiles increased from 62.9% between 2000 and 2004 to 73.3% between 2015 and 2019. Conclusions: The incidence of AH is increasing rapidly, especially among females and individuals of lower socioeconomic status. There are areas of unmet need in preventative measures and treatments for comorbid psychiatric disorders in patients at high risk of AH.
Age-Based Versus Young-Adult Thresholds for Nephrosclerosis on Kidney Biopsy and Prognostic Implications for CKD
Asghar, Muhammad Sohaib , Đenić, Aleksandar , Mullan, Aidan F. , Moustafa, Amr A. , Barisoni, Laura , Alexander, Mariam P., Augustine, Joshua J. , Leibovich, Bradley C. , Thompson, R. Houston, Alexander, Mariam P. , Asghar, Muhammad S , Moustafa, Amr , Alexander, Mariam P , Leibovich, Bradley C , Rule, Andrew D , Denic, Aleksandar , Barisoni, Laura , Mullan, Aidan , Stegall, Mark D. , Augustine, Joshua , Rule, Andrew D.

Journal of the American Society of Nephrology | May 31, 2023 | Volume: 34 | Issue: 8 | Pages: 1421-1432

10.1681/asn.0000000000000171 | PMID 37254246 Get It

Significance Statement Nephrosclerosis (glomerulosclerosis, interstitial fibrosis, and tubular atrophy) is the defining pathology of both kidney aging and CKD. Optimal thresholds for nephrosclerosis that identify persons with a progressive disease are unknown. This study determined a young-age threshold (18–29 years) and age-based 95th percentile thresholds for nephrosclerosis on the basis of morphometry of kidney biopsy sections from normotensive living kidney donors. These thresholds were 7.1-fold to 36-fold higher in older (70 years or older) versus younger (aged 18–29 years) normotensive donors. Age-based thresholds, but not young-age threshold, were prognostic for determining risk of progressive CKD among patients who underwent a radical nephrectomy or a for-cause native kidney biopsy, suggesting that age-based thresholds are more useful than a single young-age threshold for identifying CKD on biopsy. Background Nephrosclerosis, defined by globally sclerotic glomeruli (GSG) and interstitial fibrosis and tubular atrophy (IFTA), is a pathology of both kidney aging and CKD. A comparison of risk of progressive CKD using aged-based thresholds for nephrosclerosis versus a single young-adult threshold is needed. Methods We conducted morphometric analyses of kidney biopsy images for %GSG, %IFTA, and IFTA foci density among 3020 living kidney donors, 1363 patients with kidney tumor, and 314 patients with native kidney disease. Using normotensive donors, we defined young-age thresholds (18–29 years) and age-based (roughly by decade) 95th percentile thresholds. We compared age-adjusted risk of progressive CKD (kidney failure or 40% decline in eGFR) between nephrosclerosis that was “normal compared with young,” “normal for age but abnormal compared with young,” and “abnormal for age” in patients with tumor and patients with kidney disease. Results The 95th percentiles in the youngest group (18–29 years) to the oldest group (70 years or older) ranged from 1.7% to 16% for %GSG, 0.18% to 6.5% for %IFTA, and 8.2 to 59.3 per cm 2 for IFTA foci density. Risk of progressive CKD did not differ between persons with nephrosclerosis “normal compared with young” versus “normal for age but abnormal compared with young.” Risk of progressive CKD was significantly higher with %GSG, %IFTA, or IFTA foci density that was abnormal versus normal for age in both cohorts. Conclusions Given that increased risk of progressive CKD occurs only when nephrosclerosis is abnormal for age, age-based thresholds for nephrosclerosis seem to be better than a single young-age threshold for identifying clinically relevant CKD.
Needs of persons living withALSat home and their family caregivers: A scoping review
Young, Heather M. , Kilaberia, Tina , Whitney, Robin L. , Link, Benjamin M. , Bell, Janice F. , Tonkikh, Orly , Famula, Jessica , Oskarsson, Björn , Oskarsson, Björn

Muscle & Nerve | May 30, 2023 | Volume: 68 | Issue: 3 | Pages: 240-249

10.1002/mus.27849 | PMID 37248728 Get It

AbstractIntroduction/AimsMost persons with amyotrophic lateral sclerosis (ALS) live at home with support of family caregivers, with escalating complexity of care over the trajectory of the disease requiring resources and support to mitigate negative physical, social, and emotional outcomes.MethodsThis scoping review identifies the home health/home care needs of persons with ALS and their caregivers as a basis for creating a home health medical standard. We used the PRISMA Extension for Scoping Reviews (PRISMA‐ScR) to examine studies describing home care needs published between 2011 and 2021.ResultsOur search yielded 481 articles, of which 44 were included with a total of 3592 (9–273) participants. Most studies used a cross‐sectional design and 20 (45%) were rated as high quality. We grouped the needs identified as emotional/psychological, assistive devices and technology, information and education, and human resources and professional services. Most studies demonstrated persistent unmet needs and that available interventions were helpful while needs generally were not met proactively, despite the predictable trajectory.DiscussionThis review describes biopsychosocial and equipment interventions over the trajectory of ALS with implications for anticipatory planning by clinicians, as well as policy for coverage of necessary services and supports. Interdisciplinary expert teams could develop consensus around needs across the trajectory and recommended services and supports. To make knowledge more accessible, encourage availability of services, and clarify the need for coverage of services, we aim to develop an expert consensus‐based ALS home health medical standard guidance document in collaboration with the American Association of Neuromuscular and Electrodiagnostic Medicine.
Measurement of Maximum Velocity of the Succinate Dehydrogenase Reaction in Isolated Cardiomyocytes
Jensen, Cole, Ruiz-Soto, Juan Pablo, Bhat, Sanjana Mahadev , Han, Young Soo , Mahadev Bhat, Sanjana , Jensen, Cole, Sieck, Gary C.

Physiology | May 29, 2023 | Volume: 38 | Issue: S1 | Pages: No page available

10.1152/physiol.2023.38.s1.5733899 Get It

Succinate dehydrogenase (SDH) is a key enzyme in the tricarboxylic acid (TCA) cycle, as well as Complex II of the electron transport chain (ETC). In the SDH reaction, succinate is oxidized to fumarate in the TCA cycle, producing FADH2 contributing to the proton gradient that drives the reduction of ubiquinone to ubiquinol in the ETC. Thus, measurement of the maximum velocity of the SDH reaction (SDHmax) provides insight into both TCA cycle and ETC contributions to the maximum respiratory capacity of mitochondria. The goal of the present study was to use a quantitative histochemical technique, which we previously developed in skeletal muscle fibers, to quantify the SDHmax in permeabilized (45 μg/mL saponin) cardiomyocytes isolated from male Sprague-Dawley rats. In the SDH reaction, the oxidation of succinate (80 mM succinate; determined to be the maximum substrate concentration) to fumarate is coupled to the reduction of nitroblue tetrazolium (NBT; 1.5 mM) to its diformazan (NBTdfz) using 1-methoxyphenazine methosulphate (mPMS; 1 mM) as an exogenous electron carrier and azide (0.75 mM) to inhibit Complex IV. The progressive accumulation of NBTdfz as the reaction proceeds is measured by repeated densitometric (at 570 nm, the peak absorbance wavelength for NBTdfz) measurements. The optical density (OD) measurements are converted to mM fumarate using the Beer-Lambert-Bouger equation based on pathlength for light absorbance and the molar extinction coefficient for NBTdfz. Importantly, the pathlength for light absorbance must be controlled. In cross-sections of skeletal muscle fibers, pathlength was controlled by cryosectioning at 6 μm. In the present study, pathlength was controlled by optical sectioning using a confocal microscope. The isolated cardiomyocytes were imaged in 3D using a Nikon Eclipse A1 laser scanning confocal system with a ×40x/1.3 NA oil-immersion lens with an optical slice set at 0.5 μm. Changes in OD within a series of 10 optical slices were measured every 15 s over a 5 min period and expressed as mM fumarate/min using the Beer-Lambert-Bouger equation. We found that the SDH reaction was linear across 5 min, and that the change in OD was consistent throughout all 10 optical slices within a cardiomyocyte, suggesting that NBTdfz accumulates in the cytoplasm. Our results confirm that this assay of SDHmax is reproducible in cardiomyocytes and offers a single cell alternative to high-resolution respirometry. The ability to measure SDHmax in single cells is in contrast to respirometry, which only measures the average O2 consumption of aggregates of cells (isolated or in tissue). Thus, a direct measurement of SDHmax can provide valuable physiological insight into variation in mitochondrial function across a population of cardiomyocytes, e.g., as might occur with ischemic injury. Supported by the Mayo Clinic This is the full abstract presented at the American Physiology Summit 2023 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.
Paired Indoor and Outdoor Nitrogen Dioxide Associated With Childhood Asthma Outcomes in a Mixed Rural-Urban Setting: A Feasibility Study
Wi, Chung‐Il , Gent, Janneane F., Bublitz, Joshua T., Ryu, Euijung , Sorrentino, Keli, Plano, Julie, McKay, Lisa A. , Porcher, Julie C., Wheeler, Philip H., DeWan, Andrew T. , Sheares, Beverley J. , Leaderer, Brian P., Juhn, Young J. , King, Katherine S. , Porcher, Julie, Chiarella, Sergio E , DeWan, Andrew T , Wi, Chung-Ii , Chiarella, Sergio E. , Pollitt, Krystal J. Godri

Journal of Primary Care & Community Health | May 27, 2023 | Volume: 14 | Issue: No issue available | Pages: No page available

10.1177/21501319231173813 | PMID 37243352 Get It

Introduction: Nitrogen dioxide (NO 2 ) is known to be a trigger for asthma exacerbation. However, little is known about the role of seasonal variation in indoor and outdoor NO 2 levels in childhood asthma in a mixed rural-urban setting of North America. Methods: This prospective cohort study, as a feasibility study, included 62 families with children (5-17 years) that had diagnosed persistent asthma residing in Olmsted County, Minnesota. Indoor and outdoor NO 2 concentrations were measured using passive air samples over 2 weeks in winter and 2 weeks in summer. We assessed seasonal variation in NO 2 levels in urban and rural residential areas and the association with asthma control status collected from participants’ asthma diaries during the study period. Results: Outdoor NO 2 levels were lower (median: 2.4 parts per billion (ppb) in summer, 3.9 ppb in winter) than the Environmental Protection Agency (EPA) annual standard (53 ppb). In winter, a higher level of outdoor NO 2 was significantly associated with urban residential living area ( P = .014) and lower socioeconomic status (SES) ( P = .027). For both seasons, indoor NO 2 was significantly higher ( P < .05) in rural versus urban areas and in homes with gas versus electric stoves ( P < .05). Asthma control status was not associated with level of indoor or outdoor NO 2 in this cohort. Conclusions: NO 2 levels were low in this mixed rural-urban community and not associated with asthma control status in this small feasibility study. Further research with a larger sample size is warranted for defining a lower threshold of NO 2 concentration with health effect on asthma in mixed rural-urban settings.