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Rationale Human chromosomal anomalies, notably trisomies, induce several alterations in gene expression, leading to various disease phenotypes. Recent studies showed that dermal fibroblasts from patients with trisomy 13 (T13), T18 or T21 present features of increased senescence and oxidative stress. We recently demonstrated that T21 lungs present abnormalities prenatally. Senescence is a state of cell division arrest that plays an important role in organogenesis. However, little is known about cellular senescence in fetal human lung with T13, T18 and T21. We therefore sought to characterize cellular senescence in these lung tissues. Methods Fresh human fetal lung tissues with T13, T18 and T21 were collected along with euploid age and sex matched controls. RT-qPCR and immunofluorescence staining (IF) were performed to assess the expression of senescence markers as well as Senescence-Associated Secretory Phenotype (SASP) elements in the various lung compartments (epithelial and mesenchymal). In addition, fibroblasts were isolated and cultured from each sample to determine the extent of senescence on isolated mesenchyme by IF and RT-qPCR. Staining for oxidative stress detection and Reactive oxygen species were assessed by CellROX and MitoSOX. Results RT-qPCR analysis in T13 whole lung tissues demonstrated no significant differences in the expression of either senescence or SASP markers as compared to control ( P16/ P21/ TP53 and IL6/ IL1 β/ TGF β/ CXCL8 respectively; n=5). Interestingly however, IF staining in T13 tissues showed a significant increase of γ-H2AFX, a marker of senescence, in the mesenchyme (n=4) as well as significantly decreased P21 staining in both the epithelial and mesenchymal compartments. Additionally, isolated fibroblasts from T13 lungs expressed significantly more IL6 as compared to control (n=3), with IF staining demonstrating a significant increase of γ-H2AFX. T18 lungs displayed significantly increased expression of P16 as compared to control (n=6), whereas IF staining revealed an increase of γ-H2AFX in whole tissue (n=4). Fibroblasts isolated from T18 lungs revealed no significant difference in any markers (gene or protein). Lastly, T21 lungs showed a significant increase of CXCL8 expression as compared to control (n=6). IF staining of T21 lungs demonstrated an increase γ-H2AFX in both the epithelium and mesenchyme (n=8). However, isolated T21 lung fibroblasts displayed significantly increased expression of P16, P21, TP53, and CXCL8. Furthermore, IF staining of T21 lung fibroblasts displayed significantly more γ-H2AFX and P21 positive cells as compared to controls (n=5). Interestingly, only cells from T21 lungs presented a significant increase of CellROX and MitoSOX staining (n=5). Conclusion In this study we established that expression of both senescence and SASP markers differ depending on the trisomy. Our results suggest that cellular senescence is more pronounced in lungs from individuals with trisomy 21. These authors acknowledge funding from NIH/NHLBI R01HL141856 (to DAA); NIH/ Office Of The Director, National Institutes Of Health (OD) R01HL155104 (SD); NIH/NHLBI R21HL165411 (SD and DAA); CIRM training grant EDUC4-12837 (RB) and NIH/NICHD 2R24HD000836-52 (IG). 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.

Background: Chronic kidney disease (CKD), an independent risk factor for heart failure with preserved ejection fraction (HFpEF), is present in over 50% of CKD patients and accounts for over 50% of hospital admissions for HF. We showed in a novel swine model of CKD-HFpEF that cardiac abnormalities associate with upregulation of pro-inflammatory nuclear factor kappa B (NF-kB). NF-κB activation is controlled by its natural inhibitor IkBα, a protein encoded by the NFKBIA gene that prevents its nuclear translocation, but the exact mechanisms remain unknown. We hypothesize that micro-RNAs (miRNAs), small noncoding RNAs that regulate gene expression, downregulate cardiac NFKBIA and activates NF-κB contributing to cardiomyocyte injury in CKD-HFpEF. Methods: Unbiased cardiac miRNA-sequencing was performed in normal and CKD-HFpEF pigs (n=4/group, 2 males/2 females). Differentially expressed (fold change ≥2 and false discovery rate (FDR)≤0.05) miRNAs capable of targeting NFKBIA were identified using miRWalk 3.0 and Target Scan 8.0, further validated by qPCR. To study the impact of CKD-HFpEF on cardiac tissue, cardiomyocites (CM) were exposed for 48 hours to plasma from normal and CKD-HFpEF pigs (n=3 each) and cardiac injury (LDH release) evaluated, and selected miRNAs modulated (mimic, antagomiR). Results: All CKD-HFpEF pigs showed a significant reduction in renal hemodynamics and function compared to controls accompannied by left ventricular hypertrophy (LVH), abnormal diastolic relaxation and LV strain, and increased circulating ANP and BNP levels, underscoring successful developing of CKD-HFpEF.Unbiased miRNA-seq identified 402 miRNAs targeting NFKBIA, of which 13 were broadly conserved among vertebrates and only 4 expressed in pig’s cardiac tissue. Among them, only miR-532-3p was upregulated in myocardium of CKD-HFpEF pigs.Expression of miR-532-3p was also higher in CM exposed to CKD-LVDD plasma or miR-532-3p mimic, associated with down-regulation of NFKBIA and LDH release. Treatment with anti-miR-532-3p decreased miR-532-3p, increased NFKBIA expression, and reduced CM injury. Conclusions: These observations support a role of miR-532-3p in cardiac NF-kB activation in CKD-HFpEF. In turn, these proof-of-concept studies may assist to identify novel therapeutic targets and develop new interventions to protect the heart in CKD. NIH HL095638 (ARC), DK129240 (AE) 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.

Airway inflammation is the central driver behind the pathogenesis of respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), chronic bronchitis, and the very recent pandemic outbreak of COVID-19. Previous studies reported that proinflammatory cytokine TNFa plays a significant role in airway inflammation by inducing hyper-reactivity of airway smooth muscle (ASM) and airway remodeling. TNFa also increases ASM force generation and ATP hydrolysis that requires energy. The excess energy demand is met by an increase in the level of PGC1a protein, mitochondrial biogenesis and subsequently increased mitochondrial volume density. Based on these previous findings, we hypothesized that TNFa promotes CREB phosphorylation at a specific serine 133 residue (pCREBS133) thereby transcriptionally activating PGC1a expression leading to mitochondrial biogenesis and increased mitochondrial volume density. In the study, human ASM cells were dissociated from bronchiolar tissue samples collected during bronchiolar surgery from female and male donors (34 to 71 years of age) with no history of respiratory diseases or current smoking. The dissociated ASM cells were serum-deprived for 48 h before experimentation. The ASM cells from each donor were separated into two groups: 1) time-matched untreated controls, and 2) TNFa treated (20 ng/ml for 6 h). Expression of CREB, pCREBS133, PCG1a, VDAC (an indicator of mitochondrial volume), and downstream signaling molecules (NRFs, TFAM), which regulate transcription and replication of the mitochondrial genome, were determined by quantitative real-time PCR (qPCR) and/or Western blot analysis. The binding of pCREBS133 to the PGC1a promoter was confirmed by bioinformatics analysis and chromatin immunoprecipitation (ChIP) assay. Mitochondria within ASM cells were labeled using MitoTracker green and imaged by 3D confocal microscopy for the assessment of mitochondrial volume density. Mitochondrial biogenesis was quantified by mitochondrial DNA (mtDNA) copy number relative to nuclear DNA using qPCR. Results were analyzed by one-way analysis of variance (ANOVA). Human ASM cells treated with TNFa showed increased pCREBS133 phosphorylation without any significant change in total CREB. The ChIP assay using a CREB-specific antibody revealed that pCREBS133 binds to the promoter of PGC1a and TNFa treatment further increased the binding affinity. Consistent with these findings, TNFa treatment increased PCG1a expression in ASM cells, and subsequently activated its downstream signaling pathway revealed by increased expression of its target genes, NRF1, NRF2 and TFAM. TNFa-induced activation of the PCG1a signaling pathway in ASM cells resulted in increased mitochondrial biogenesis as indicated by increased mitochondrial DNA copy number and increased mitochondrial volume density. Supported by NIH grant HL157984 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.

Background: Multiple asthma phenotypes are driven by pathobiological heterogeneity. Almost 25% of asthma patients do not respond well to current treatments like inhaled corticosteroids, urging researchers and clinicians to propose novel treatment targets and strategies. Orphan type C G-protein coupled receptor GPRC5B is one such novel target abundantly expressed in various tissues, but there are no known ligands for GPRC5B. Previously, we demonstrated that orphan type C G-protein coupled receptor GPRC5B is increasingly expressed in human asthmatic airways and plays a crucial role in regulating intracellular calcium ([Ca2+]i) in human airway smooth muscle (ASM) cells. However, the role of GPRC5B activation on airway contraction is not identified yet. Our objective for this study is to design and synthesize a novel ligand for GPRC5B and determine the effect of GPRC5B activation on [Ca2+]i responses in ASM cells and airway contractility in ex vivo murine airways. Methods: ZincPharmer was used for pharmacophore search. After energy minimization, the top hit compound was synthesized using a standard amide coupling reaction, purified by flash chromatography, and characterized by NMR spectroscopy. Human ASM cells loaded with Fura-2 AM were imaged for [Ca2+]i responses. Silencer select siRNA was used for transient silencing of GPRC5B in ASM cells. Myosin light chain (MLC) phosphorylation was measured using immunoblot analysis. Precision-cut lung slices (PCLS) (~200 μm thickness) of wild-type C57BL6 mice were used for contractile studies. Results: Based on molecular docking data, the top compound N-(5-chloro-2-hydroxybenzyl)-2-((tetrahydro-2H-pyran-4-yl)oxy) acetamide (L1) was synthesized. Concentration-dependent [Ca2+]i responses were observed on human ASM cells stimulated with L1 (1 nM - 1 μM) that were comparable to the known contractile agonist histamine (10 μM). L1-induced [Ca2+]i response was significantly reduced in GPRC5B knockdown ASM cells. GPRC5B knockdown in ASM cells was verified by Western analysis. Further, L1 exposure increased the MLC phosphorylation (Thr18/Ser19) in human ASM cells compared to vehicle. Acute exposure of L1 (1 μM) increased airway contractility of PCLS (~17%-25%) compared to vehicle exposure. Conclusion: These findings suggest that GPRC5B activation modulates intracellular calcium and airway contractility in human ASM cells and murine PCLS. Thus, GPRC5B could potentially be considered for a novel therapeutic regimen to tackle asthma. This work was partly supported by NIH grants R01-HL146705 (Venkatachalem), R01-HL088029 (Prakash), and R01-HL142061 (Pabelick, Prakash). 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.

Anoctamins (ANO) are activated by intracellular Ca2+ and function as phospholipid scramblases and/or Cl- channels. ANO4 is mutated in miniature schnauzers with calcium oxalate stones (CaOx), and ANO4 protein in urinary extracellular vesicles is decreased in human CaOx stone formers. In Drosophila Malpighian tubules (MT), subdued (ANO4-homolog) functions as Ca2+-activated Cl- channel, scramblase, and plays a role in host defense against gram-negative bacteria. Increasing evidence shows the participation of bacteria in urinary stone formation in humans. We used a Drosophila avatar to investigate whether subdued changes CaOx crystallization and if crystallization increases with bacterial infection.Uro:Gal4 flies were crossed with UAS:subdued-RNAi flies to knockdown (KD) subdued in MT principal cells (PC) or with w1118 flies to generate normal controls (WT). F1 generation underwent CaOx crystallization in association or not with uropathogenic E. coli (UPEC) infection. In vivo, flies were fed on diet supplemented with 20mM sodium Ox (NaOx) + UPEC:eGFP for 4 days. For ex vivo assays, dissected MTs were submerged in solution containing 10mM NaOx+ UPEC:eGFP for 90 minutes. subdued-KD in PC reduced subdued mRNA by 56% in MT. Neither crystal number nor size were changed by subdued-KD after prolonged NaOx feeding. However, when UPEC is introduced with the NaOx diet, subdued-KD flies exhibited a large bacterial presence in MT lumen and produced enlarged CaOx crystals compared to WT flies. Similar augmented presence of UPEC in subdued-KD MTs was observed during ex vivo assays. Short-term exposure to NaOx+UPEC resulted in increased number of crystals in subdued-KD MTs compared to WT MTs, but no difference was observed in crystal size.Fly cell atlas ( flycellatlas.org ) revealed that subdued is also found in MT stellate cells (SC; water and Cl- secretion). C724:Gal4>UAS:subdued-RNAi flies were used to assess the effect of subdued-KD in SC. This s ubdued-KD slightly increased bacterial infection but did change CaOx crystallization in MTs after 4 days of NaOx+UPEC feeding.The presence of subdued in PC limits CaOx crystals formation and aggregation through reducing bacterial invasion in the MT lumen. These Drosophila results suggest a role for ANO4 in bacterial-related human and dog kidney stone formation. Future experiments will determine whether other functional aspects of subdued affect CaOx crystallization. U54-DK100227, R01-DK092408, FAPESP (2022/01226-1), Mayo Foundation. 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.

Gastric mucus is a complex hydrogel that protects the epithelial surface of the stomach from gastric acid and prevents invasion of pathogens such as Helicobacter pylori. The viscoelastic properties of the mucus layer are considered essential for barrier function. However, since native human gastric mucus is not readily accessible, the majority of previous studies were performed with animal mucus or with purified gastric mucin that lacks functionally important mucus components. Moreover, commonly used purification protocols may damage mucin structure and impact gel-forming capacity. Therefore, the objective of this study was to engineer sterile human gastric mucus in vitro to study interactions between mucus and H. pylori bacteria. We hypothesize that our bioengineered mucus layer is both structurally and functionally relevant and applicable to in vivo gastric mucus. Based on previous studies with organoid-derived monolayers, we developed and optimized a protocol to produce mucus in 2D air-liquid-interface (ALI) cultures derived from human gastric organoids. The structure of the mucus was analyzed using cryo-scanning electron microscopy, and viscoelastic properties were quantified using particle tracking microrheology. Live imaging and particle tracking also were used to quantify the motility of H. pylori in the bioengineered mucus. 2D monolayers of human gastric organoids cultured at an ALI on transwell inserts consistently produced milliliter quantities of sterile human gastric mucus. This bioengineered mucus could be easily harvested and did not require purification or processing. Mucus production by the ALI cultures was maintained for over one month, demonstrating the robustness of our culture system. Electron microscopy confirmed that the bioengineered mucus had a characteristic honeycomb structure with pore sizes of 10.8 ± 3.4 microns, consistent with previous studies on porcine and canine gastric mucus. Particle tracking microrheology confirmed the viscous behavior of the collected mucus. Compared to liquid media, the bioengineered mucus also caused a significant decrease in H. pylori swimming speed, with 42.8 ± 0.2 microns/second in brucella broth and 10.9 ± 0.1 microns/second in mucus (P ≤ 0.001). We here leveraged the ability of gastric organoids cultured as monolayers at an ALI to secrete sterile mucus to produce native human gastric mucus for in vitro studies. Using this system, we showed that the mucus inhibited bacterial motility, limiting bacterial invasion into the mucus layer. Our observations support previous hypotheses on gastric mucus function and demonstrate the potential of organoid-derived mucus for mechanistic studies of gastric mucus layer physiology. NIH R01GM131408-01, NIH UL1 TR002319 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.

Increased cognitive hyperarousal is a proposed mechanism associated with clinical poor sleep including insomnia. An objective marker of nocturnal hyperarousal is high frequency electroencephalography during sleep, including increased beta frequency during stage two (N2) sleep. Acute and chronic poor sleep quality are associated with autonomic dysfunction, but little is known regarding the relationship between nocturnal beta frequency intrusion and nocturnal autonomic function. The purpose of this study was to explore the association between beta spectral power during stage two (N2) sleep and nocturnal heart rate variability (HRV) in healthy female and male adults. We hypothesized that heightened beta spectral power during N2 sleep would be associated with reduced nocturnal HRV. Twenty-four participants (12 males, 12 females; age, 25 ± 1 years; BMI 27 ± 1 kg/m2) underwent an 8-hour overnight sleep opportunity with continuous polysomnography and 5-lead electrocardiogram monitoring. Periods of 5 – 10 minutes of stable N2 sleep absent of cortical arousals, respiratory events, and limb movement-associated arousals were identified (one per cycle) for analysis. Periods from the first two cycles of N2 sleep from the full night were selected for analysis. Beta spectral power from the central and frontal regions and nocturnal HRV data were analyzed and averaged across each hemisphere. Time-domain HRV was quantified as the root mean squared of successive differences (RMSSD) and proportion of R-R intervals (RRI) varying by greater than 50 ms (pNN50). An inverse correlation was observed between central beta power and RRI (R= -0.473, p=0.019), pNN50 (R= -0.450, p=0.028), and RMSSD (R= -0.406, p=0.049). This was paralleled by a similar relationship between frontal beta and RRI (R= -0.487, p=0.016) and pNN50 (R= -0.423, p=0.039). Our results indicate a negative association between N2 beta power and nocturnal HRV measures. These findings suggest that nocturnal hyperarousal may be associated with poor cardiac autonomic function and has implications for individuals with insomnia in whom cognitive hyperarousal is frequently reported. Support is provided by the National Institutes of Health (AA-024892, U54GM115371; P20GM103474, 2TL1 TR002318). 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.

The diaphragm muscle is important in both sustaining ventilation and performing higher-force behaviors necessary for maintaining airway patency. Ventilatory behaviors (i.e., eupnea and response to hypoxia-hypercapnia) require only ~20% of maximal force generation, whereas coughing requires forces ~60% of maximal. Existing techniques to measure the full range of forces generated by respiratory muscles are limited by their invasiveness (e.g., balloon manometry for transdiaphragmatic pressure (Pdi) measurements), requirements for training, supervision and subjectivity (e.g., maximal inspiratory and expiratory pressures). Ultrasound-based shear-wave elastography (SWE) assesses muscle stiffness and has shown promising results in being used as a surrogate for Pdi to evaluate diaphragm muscle force. Previous literature has demonstrated a correlation between diaphragm SWE and Pdi at lower force behaviors and the goal of the present study was to evaluate the efficacy of SWE-based measurements of the diaphragm in correlating with Pdi measurements across the range of forces generated by the diaphragm. In this pilot study, we recruited 6 male and 5 female healthy volunteers. Subjects were positioned in a seated position with their torso unsupported. Pdi was measured during graded inspiratory threshold loading trials using a POWERbreathe Plus commercial inspiratory loading device, as well as during maximal inspiratory pressure (MIP). Simultaneously, SWE was performed at the zone of apposition in the right anterior axillary line, and diaphragm Young’s modulus and shear wave speed were subsequently measured. The average Pdi during MIP testing was 149 ± 66 cm H2O. Pdi during inspiratory loading at a low resistance was 39 ± 14 cm H2O and at a high resistance was 78 ± 29 cm H2O. Subjects were able to generate an average Pdi range of 39 ± 19 cm H2O across the graded resistance levels, and the average percent of MIP obtained was 54 ± 13%. Average Young’s modulus as measured with SWE during inspiratory loading at a low resistance was 46 ± 19 kPa and at a high resistance was 104 ± 19 kPa. From low to high resistance, Pdi, Young’s modulus, and shear wave speed increased by an average of 100%, 126%, and 59%, respectively. Taken together, SWE is a promising method of non-invasive assessment of diaphragm muscle forces across a range of voluntary behaviors. Support from NIH grant R21 DA055848 and 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.

Background: Patients with respiratory manifestations of acute COVID-19 infection have enlarged luminal areas of central conducting airways demonstrated on computed tomography imaging and abnormal pulmonary function. In some cases, COVID-19 symptoms may persist for more than 4 weeks, referred to as long COVID, and the effect on airway luminal area remains unknown. Herein, we report airway luminal cross-sections areas among a long COVID group, compared to individuals with an acute COVID-19. We aim to investigate if large conducting airways sizes are different between acute COVID-19 and long COVID patients. Methods: A cohort of 181 people with long COVID were screened, of which 20 people (9 men, 11 women; 55.9 ± 14.1 years) were included in analyses. Twenty age, height, and sex matched patients with an acute (< 4 weeks of persistent symptoms from diagnosis) COVID-19 infection (55.7 ± 15.2 years) served as a comparison group. We used a three-dimensional reconstruction of computed tomography imaging to measure luminal areas of the trachea, right and left main bronchi, bronchus intermediate, right and left upper lobe, and left lower lobe bronchi at proximal, middle, and distal cross-sectional points in both groups. Airway luminal area was taken as the average of the three points. We compared average lumen area of long COVID patients with acute COVID-19 individuals, using an independent samples t-test. Results: We found no significant difference comparing measurements of the following airway luminal cross-sectional areas: trachea (277.7 ± 100.4 vs. 268.0 ± 70.5 mm2 p=0.73), right main bronchus (191.0 ± 66.1 vs. 190.1 ± 49.0 mm2, p=0.96), bronchus intermediate (112.3 ± 33.4 vs. 109.3 ± 27.9 mm2, p=0.76), right upper lobe bronchus (74.4 ± 21.0 vs. 73.7 ± 25.5 mm2, p=0.92), left main bronchus (129.1 ± 50.1 vs. 136.9 ± 38.0 mm2, p=0.58), left lower lobe bronchus (57.8 ± 18.2 vs. 59.0 ± 13.4 mm2, p=0.82), and left upper lobe bronchus (80.1 ± 19.5 vs. 77.9 ± 22.9 mm2, p=0.75) in the long COVID and acute COVID-19 groups respectively. Conclusion: In patients with long COVID, compared to those with an acute COVID-19 infection, we did not see differences in central airway luminal areas. Further analysis of a larger cohort is needed to determine whether enlarged airway luminal areas, associated with acute COVID-19, persist in long COVID. This research will expand knowledge on functional consequences for patients with long COVID. Funding: F32HL154320 to JWS; 5R35HL139854 to MJJ. 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.

Background: Interstitial lung disease (ILD) encompasses several pulmonary disorders associated with scarring and fibrosis of pulmonary tissue. People with idiopathic pulmonary fibrosis, a subset of ILD, have greater central airway luminal area compared to age- and sex-matched healthy controls when evaluated using microcomputed tomography, a process examining the luminal area of ex-vivo lung tissue. In this study we aimed to confirm these findings using a different method of airway assessment, three-dimensional (3D) reconstruction of computed tomography (CT) scans. Moreover, in health, males have larger central airways than height-matched females, but it remains unknown if there are sex differences in airway area among people with ILD. We hypothesized that sex differences observed in healthy people would persist among people with ILD. Methods: A cohort of 399 patients with lung CT scans were screened, of which 19 people (7 females) with ILD were included in analyses after exclusions. People with ILD were matched based on sex, age, and height to 19 healthy controls. We assessed cross-sectional luminal area at the midpoint of seven conducting airways (trachea, left and right main bronchus, intermediate bronchus, left and right upper lobe, and left lower lobe). Results from pulmonary function tests were also abstracted, as available. To examine sex differences, we compared airway luminal area, normalized to participant height, between males and females with ILD. Sex differences were analyzed using a univariate ANOVA test. Results: People with ILD had a preserved ratio of forced expiratory volume in the first second to forced vital capacity (101 ±12%predicted) and decreased diffusing capacity for carbon monoxide (55 ±23%predicted). People with ILD had airways that were between 19.6%-45.0% larger than controls (p<0.05). Composite physiologic index, a marker of ILD severity, was not different between sexes (p=0.07). Males with ILD had significantly larger, luminal areas than females in two central airways - right main bronchus (1.46±0.41 vs. 1.07±0.22 mm2/cm, p=0.04) and left upper lobe (0.54±0.10 vs. 0.43±0.08 mm2/cm, p=0.02). However, luminal area of other central airways, including: trachea (2.15±0.57 vs. 1.65±0.32 mm2/cm, p=0.051), bronchus intermediate (0.77±0.23 vs. 0.61±0.13 mm2/cm, p=0.12), right upper lobe (0.47±0.15 vs. 0.40±0.06 mm2/cm, p=0.26), left main bronchus (0.93±0.33 vs. 0.69±0.16 mm2/cm, p=0.09), and left lower lobe (0.41±0.13 vs. 0.40±0.08 mm2 /cm, p=0.79) were not different between sexes in people with ILD. Conclusion: Sex differences observed in healthy people are potentially preserved in ILD, but a more robust sample is required to fully elucidate these findings. Illuminating any sex differences in ILD pathophysiology may provide knowledge to treat and improve clinical outcomes in ILD. Funding: National Heart, Lung, and Blood Institute (F32HL154320 to JWS; 5R35HL139854 to MJJ). 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.