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Background: Preeclampsia (PE) is a hypertensive disorder of pregnancy defined by new-onset hypertension occurring after 20 weeks of pregnancy, with end organ damage. Pro-inflammatory changes are also observed in these patients. Although the clinical features of PE are resolved soon after delivery, affected patients face a higher risk and earlier onset of cardiovascular disease (CVD). It is unknown what leads to this persistent elevated risk, and long-term alterations of the maternal immune system could be involved. Study objective: Our goal was to address the immune alterations and functional changes in the first year postpartum in PE as compared to normotensive (NT) pregnancies. Hypothesis: We hypothesize that the maternal immune profile is altered in the postpartum period in PE vs NT patients, with a proinflammatory bias and altered function in PE patients. Brief Statement of Methods: We prospectively followed 31 women (PE=15, NT=16) and collected blood 24 hours, and 3, 6, and 12 months postpartum. Plasma and peripheral blood mononuclear cells (PBMC) were isolated and stored for analysis. Inflammatory mediators were quantified through multiplex assays, and PBMCs profile were defined through flow cytometry as well as following inflammatory stimuli to assess their functional changes through intracellular cytokine staining and expression of activation markers. Summary of Results: PE patients had elevated CD3+ T cell frequencies at 3 and 12 months postpartum compared to NT patients. Both groups showed reduced CD14+ monocytes across postpartum timepoints compared with 24 hours. PE was also associated with increased amounts of pro-inflammatory cytokines (such as IL1α, IL9, IFNγ), chemokines and growth factors at multiple timepoints throughout the first year postpartum; NT patients had decreased amounts of pro-inflammatory cytokines. Intracellular staining showed altered immune cell functions in PE, with decreased IL-6 production following polyI:C stimulation and decreased IL-10+ monocytes after LPS and polyI:C at 3 months postpartum. At 3 months, PE patients had increased markers of activation (i.e. CD69+) in both NK cells and T cells, the latter following PMA/Ionomycin stimulation. Statement of Conclusions: Pregnancy itself induces lasting immune changes persisting to 12 months postpartum, even in NT patients, whilst PE complicated pregnancies have sustained inflammation and altered immune function in the postpartum period. Overall, this work will provide essential insight into an understudied period that many women experience and help to identify long lasting immunological changes that could impact long term maternal health. Future work will explore the impact of this sustained inflammation on epigenetic modifications in immune cells. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Background: Cardiovascular-Kidney-Metabolic (CKM) syndrome entails pathophysiological interactions leading to multiorgan dysfunction and a high rate of cardiovascular morbidity and mortality, largely driven by the development of heart failure (HF). Mechanisms leading to HF in CKM syndrome are unknown. We created a model of CKM syndrome in swine and showed that cardiac abnormalities associate with cardiac microvascular (MV) rarefaction and decreased expression and availability of VEGF. Emerging research focuses on micro-RNAs (miRNAs) and their role in the pathophysiology of HF, but whether they play a role in the development of cardiac injury in CKM syndrome via VEGF modulation has not been investigated. We aimed to identify specific miRNAs that can target VEGF to test the hypothesis that their direct cardiac inhibition will rescue cardiac VEGF, improve angiogenic signaling, and cardiac hemodynamics in CKM syndrome. Methods: CKM (bilateral renal artery stenosis+high-cholesterol/high-carbohydrate feeding) and normal pigs (n=4 each, 2 males/2 females) were studied for 14 weeks. Unbiased micro-RNA sequencing identified 26 miRNAs differentially expressed in CKM pig hearts, of which only miR-452-5p can target VEGFA, which was confirmed by pulldown analysis and qPCR. In addition, CKM (n=4, 2 males/2 females) were treated after 6 weeks with a single intracoronary (IC) administration of a miR-452-5p inhibitor (antagomiR). Cardiac hemodynamics (echocardiography), MV architecture (3D micro-CT) and cardiac expression of VEGF and miR-452-5p (RT-qPCR) were quantified before IC miR-452-5p inhibition, and again at the end of the study (14 weeks). Results: Pigs with CKM syndrome showed blunted diastolic relaxation, increased cardiac remodeling, and reduced subendocardial MV density and cardiac VEGF expression, accompanied by higher cardiac expression of miR-452-5p compared to normal pigs. Notably, most of these parameters were improved after in vivo IC miR-452-5p inhibition (single dose). Blood pressure was unchanged ( Table 1 ). Conclusions: Our study supports a role for VEGF in preserving cardiac MV integrity in CKM syndrome. Also, it identifies a targeted post-transcriptional regulation of VEGF via miR-452-5p and supports the feasibility and efficacy of its mechanistic modulation in vivo. The predictive power of our model conceptually supports the potential of a novel targeted intervention to protect the heart in CKM syndrome. [Table: see text] Support: NIH AG084154 (ARC), and DK129240 (AE) This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Rationale: Respiratory disease is a major cause of mortality in Down syndrome (DS; trisomy 21, T21). DS is considered a progeroid syndrome, with elevated cellular senescence (SEN) and oxidative stress. Because SEN shapes organogenesis, its dysregulation may impair lung morphogenesis. We previously found SEN/SASP (senescence-associated secretory phenotype) abnormalities in prenatal human T21 lungs. Here, we test whether these alterations persist and change after birth. Methods: We analyzed human lung single-nuclear RNA (snRNA-seq) datasets (prenatal and postnatal) to quantify epithelial and mesenchymal SEN/SASP signatures. Sex- and age-matched T21 and non-T21 prenatal and postnatal lungs were studied; fibroblasts were isolated as prenatal human lung fibroblasts (HFLF) and postnatal human lung fibroblasts (HLF). SEN/SASP were measured by RT-qPCR and immunofluorescence (IF) in tissue and HFLF/HLF. HFLF/HLF were assayed for SA-β-gal, oxidative stress (CellROX/MitoSOX), and Ca 2 + dynamics (Fura-2 AM). 48h treatments with tunicamycin (1µM, SEN inducer), 4-phenylbutyrate (4-PBA, 2 mM, ER Stress inhibitor), or pyrroloquinoline quinone (PQQ, 20 μM, antioxidant) were performed on T21 and non-T21 HFLF/HLF. Conditioned media (CM) were collected after 48h from untreated cultures and then applied to cells of the opposite genotype for 24, 48, and 72h. Results: Overall SEN profile was similar in epithelium and mesenchyme across ages, but pathway signatures differed. Epithelium shows an inflammatory SASP, while mesenchyme shows a less-inflammatory, remodeling/growth-factor SASP. These lineage patterns were more evident postnatally. Whole-tissue IF showed increased γ-H2AX and p21 in T21 vs non-T21 both prenatally and postnatally (p< 0.05). At baseline, T21 HFLF/HLF had higher CDKN1A, CDKN2A, TP53, CDKN2B, and SERPINE1 (p< 0.05; n=5–6), with increased γ-H2AX/p21 IF (p< 0.01; n=6), SA-β-gal (p< 0.05; n=5–6), and ER/mitochondrial stress (p< 0.05; n=5–6). Fura-2 AM showed greater Ca 2 + release in T21 HFLF/HLF at baseline and after acetylcholine (10 μM, p< 0.01; n=5). Mitochondrial-morphology genes (FIS1, DNM1L, MFN1) were elevated in T21 HFLF/HLF (p< 0.05; n=6). In T21 HFLF, 4-PBA and PQQ each reduced SA-β-gal (p< 0.01; n=6). In postnatal HLF, PQQ had the stronger effect (p< 0.05; n=5). T21 CM induced progressively greater SEN/SASP over 24/48/72h in non-T21 cells (p< 0.05; n=5-6), while non-T21 CM partially rescued T21-HLF phenotypes at 24h only (p< 0.05; n=5-6). Conclusion: These data indicate that lung senescence in T21 initiates in utero and intensifies after birth and reflects lineage-specific pathways. ER-stress-related mechanisms are more prominent prenatally, while mitochondrial/redox mechanisms are predominant postnatally. This evidence suggests age and lineage-dependent drivers of senescence that may help explain DS lung disease and highlight potential new mechanistic targets. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Our knowledge regarding baroreflex regulation of subpopulations of differently sized sympathetic action potentials (APs) remains incomplete. This study tested the hypothesis that baroreflex sigmoid morphology varies across AP subpopulations. In 12 healthy individuals (6 females; 32 ± 5 years), we measured diastolic blood pressure (DBP; brachial artery catheter) and muscle sympathetic APs (peroneal microneurography; continuous wavelet transform) during a modified Oxford protocol (100 μg nitroprusside bolus, 150 μg phenylephrine bolus). Baroreflex sigmoids (four-parameter logistic functions) modelled the relationship between DBP and sympathetic AP discharge probability for 10 normalized AP clusters. For each AP cluster, baroreflex sigmoid morphology was quantified by max gain, threshold, centering, and saturation pressures, and operating and response ranges. One-way analyses of variance and Dunnett post-hoc tests were performed. Data are mean ± SD. At the centering pressure of the baroreflex sigmoid, max gain was greater for medium APs (e.g., Cluster 3: -5.6 ± 2.9%/mmHg) compared to small (e.g., Cluster 1: -1.4 ± 1.1%/mmHg; P < 0.01) and large APs (e.g., Cluster 9: -0.6 ± 0.4%/mmHg; P < 0.01). Discharge probability at the centering pressure was also greater for medium APs (e.g., Cluster 3: 61 ± 22%) compared to small (e.g., Cluster 1: 12 ± 10%; P < 0.01) and large APs (e.g., Cluster 9: 3 ± 3%; P < 0.01). There were no differences in the saturation pressure (i.e., DBP where any further reduction does not elicit an increase in AP discharge probability) between AP clusters (main effect P = 0.22). The threshold pressure (i.e., DBP where any further reductions elicit an increase in AP discharge probability) was greater for medium (e.g., Cluster 3: 78 ± 8mmHg) compared to large APs (e.g., Cluster 9: 74 ± 11mmHg; P = 0.03). The operating range (i.e., Threshold – Saturation DBP) was greater for medium (e.g., Cluster 3: 14 ± 3mmHg) compared to large APs (e.g., Cluster 9: 8 ± 5mmHg; P < 0.01). There were no differences in the threshold pressure or operating range of medium compared to small APs (both P ≥ 0.82). The response range (i.e., Saturation – Threshold discharge probability) was greater for medium (e.g., Cluster 3: 26 ± 13%) compared to small (e.g., Cluster 1: 5 ± 4%; P < 0.01) and large APs (e.g., Cluster 9: 1 ± 1%; P < 0.01). These data confirm prior work using linear modeling and spontaneous approaches to quantify sympathetic AP baroreflex gain and extend to demonstrate variation in the morphology of the baroreflex sigmoid. During large changes in blood pressures, we identify differences in broader features of baroreflex control (e.g., threshold pressure, operating range, and response range) between AP subpopulations that support strong baroreflex regulation over medium-sized APs. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

The motor unit consists of an individual motor neuron (MN) and the muscle fibers it innervates. In humans and rodents, muscle weakness in aging (sarcopenia) has focused on altered motor unit discharge properties and intrinsic skeletal muscle pathophysiology, with MNs relatively ignored. In the brainstem, the intrinsic and extrinsic tongue muscles are innervated by hypoglossal MNs. In the spinal cord, the hindlimb muscles are innervated by the lumbar motor enlargement. Both aerodigestive and locomotor behaviours are affected in old age. In Fischer 344 rats, age-related MN death is evident by 24 months, disproportionately affecting larger (likely fast fatiguable motor unit) MNs. Here, we evaluated hypoglossal and lumbar MN survival in female and male Sprague Dawley rats at young (6-months-old; n=12) and old (24-months-old; n=6) ages. Stereological assessment of hypoglossal MN numbers and surface areas were performed on 16 µm Nissl-stained brainstem and spinal cord cryosections. We observed a robust loss of ~20% of hypoglossal MNs and a modest ~15% reduction in their surface areas with age. In the larger size tertile of hypoglossal MNs, age-associated loss of MNs approached ~30%. Similarly, we observed an ~20% lumbar MN loss, with a striking ~25% reduction in somal surface area. In the larger size tertile of lumbar MNs, age-associated loss of MNs approached ~40%. These findings underscore a marked neurogenic component to age-related neuromotor dysfunction, with reliability of findings across rat strains. This MN death likely contribute to physiologically relevant aerodigestive and locomotor impairments in old age. This study was supported by R56 HL166204 (MJF), R01 AG086136 (MJF) and AG44615 (GCS) from the NIH. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Mitochondrial quality control is maintained by coordinated turnover mechanisms involving mitophagy (removal of damaged mitochondria) and mitochondrial biogenesis (generation of new mitochondria). Disruption of either one or both processes results in the accumulation of damaged mitochondria, oxidative stress and subsequently impaired cellular function. In human airway smooth muscle (hASM) cells, such impairment compromises sustained ATP production required for contractile responses. A key regulator of this balance is PARIS (ZNF746), a transcriptional repressor of PGC1α. Accumulated PARIS binds upstream to the promoter of PGC1α and interferes with the recruitment of transcriptional activators, resulting in decreased PGC1α transcription and reduced mitochondrial biogenesis. In addition, PARIS is implicated in the disruption of cellular antioxidant defense mechanisms due to its direct interaction with NRF2 transcriptional complex. Under basal conditions, PARIS levels are tightly regulated by post-translational modifications such as ubiquitination and phosphorylation. As a target of PINK1/pParkinS65 mediated mitophagy, pParkinS65 binds to PARIS, catalyzing its ubiquitination and proteasomal degradation, thereby alleviating its transcriptional repression of PGC1α and NRF2 and promoting mitochondrial biogenesis. Furthermore, evidence indicates that NRF2 transcriptionally regulates PINK1 expression during oxidative stress and amplifies mitophagy. Therefore, we hypothesize that mitochondrial turnover mechanisms can be regulated by targeting PARIS. In the present study, primary hASM cells were isolated from bronchiolar tissue of 6 patients with no history of chronic pulmonary disease or smoking. The hASM cells were phenotyped and separated into two treatment groups: 1) FCCP (1 µM, 6 h; positive control), a proton ionophore that induces mitochondrial depolarization (damage); 2) untreated control. We observed that FCCP induced extensive mitochondrial membrane depolarization, assessed by changes in mitochondrial membrane potential (Ψm) using TMRM (250 nM). Increased mitochondrial damage was observed with FCCP, measured by the extent of co-labeling of MitoTracker Red FM (200 nM) and CellLight Mitochondria-GFP. Mitochondrial turnover was also quantified by confocal imaging of hASM cells transfected with pMitoTimer, a fluorescent reporter protein in which fluorescence shifts over time from green (Excitation/Emission-488 nm/518 nm) to red (Excitation/Emission-543 nm/572 nm) when oxidized due to mitochondrial stress. Ratiometric analysis of pMitoTimer revealed significant shift from green to red fluorescence with FCCP and accumulation of pure red fluorescent puncta indicative of damaged mitochondria. FCCP increased PINK1 recruitment to mitochondria and increased pParkinS65 and ubiquitin (pUbS65) phosphorylation. Total PARIS accumulation decreased due to increased PARIS ubiquitination, as measured by immunoprecipitation. As a result, PGC1α and downstream NRF2 mRNA and protein expression, as well as mtDNA copy number were increased, indicative of increased mitochondrial biogenesis. Bioinformatics analysis and chromatin immunoprecipitation (ChIP) assay using an NRF2-specific antibody revealed that NRF2 binds to the promoter of PINK1, with FCCP further increasing the binding, thereby increasing PINK1 expression and enhancing mitophagy. Together, these findings identify the PARIS-NRF2 axis as a promising target to mitigate oxidative stress and maintain mitochondrial homeostasis in hASM cells. Supported by NIH grants HL157984 (GCS) and AG44615 (GCS) This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Background: Vascular endothelial dysfunction is a key antecedent to cardiovascular diseases (CVD) in older adults. Reduced nitric oxide (NO) bioavailability secondary to excess mitochondria-related reactive oxygen species (mitoROS) bioactivity are key mechanisms of endothelial dysfunction with aging. Cellular senescence is a state of largely irreversible cell cycle arrest that drives endothelial dysfunction. This occurs in part through secretion of bioactive factors into serum, collectively referred to as the circulating senescence-associated secretory phenotype (SASP), that promote excess mitoROS and reduce NO. We have shown fisetin improves endothelium-dependent dilation in old mice by reducing cellular senescence and mitoROS. Here, we sought to translate our preclinical findings to older adults. Hypotheses: We tested the primary hypothesis that intermittent fisetin treatment would improve endothelial function in older adults and that this would be mediated by reductions in mitoROS and associated with lower cell senescence. We also determined if fisetin altered the serum to improve endothelial cell (EC) NO and reduce whole-cell ROS and mitoROS ex vivo. Exploratory analyses assessed if fisetin changed circulating SASP factors. Methods: In a randomized, placebo-controlled, parallel-group design pilot trial, 41 older men and postmenopausal women were randomized to fisetin (2 mg/kg/day) (age: 71±1 yrs [mean±SEM], n=22 [13 W]) or placebo (age: 71±1 yrs, n=19 [12 W]) administered in an intermittent manner (2, 3-day dosing periods separated by 14 days). Outcomes were measured at baseline and 1-3 weeks after the final dose. Endothelial function was assessed as brachial artery flow-mediated dilation (FMDBA). The change in FMDBA with an acute supratherapeutic dose (160mg) of the mitochondrial antioxidant MitoQ was used to assess mitoROS-related inhibition of endothelial function. Gene expression of cellular senescence markers Cdkn1a (encodes p21) and Lmnb1 (encodes Lamin B1) were assessed in peripheral blood mononuclear cells (PBMCs) by Q-PCR. Human aortic ECs (HAECs) in culture were exposed to 10% participant serum for 2 hrs; acetylcholine (ACh)-stimulated NO production (DAR-4M-AM) and basal whole-cell ROS (CellROX) and mitoROS (MitoBright Deep Red) bioactivity were assessed via immunofluorescence. Luminex analyses (Biotechne) measured circulating levels of SASP factors in serum. Results: FMDBA was improved by 41% with fisetin (pre: 3.9±0.4%, post: 5.5±0.5%, P< 0.0001), but unchanged with placebo (pre: 4.4±0.5%, post: 4.5±0.4%) (group x time interaction effect: P< 0.01). Similar efficacy was observed in men and women. Acute MitoQ enhanced FMDBA at baseline and after placebo (all P< 0.05) but led to no further improvements in FMDBA after fisetin treatment. Consistent with lower cell senescence, expression of Cdkn1a was reduced (P< 0.05) by 12% and expression of Lmnb1 increased (P=0.06) by 16% in PBMCs collected after fisetin but not placebo. Compared with pre-intervention, serum collected after fisetin, but not placebo, increased HAEC ACh-stimulated NO by 6% (P< 0.01) and lowered whole-cell and mitoROS bioactivity by ~10% (both P< 0.05). Protein levels of CXCL12 in serum were 5% lower (P< 0.05) after fisetin compared with pre-intervention and after placebo. Traditional cardiometabolic risk factors were unchanged. Conclusions: Intermittent fisetin treatment improves vascular endothelial function in older adults in part by suppressing mitoROS. These effects are linked to reduced cell senescence and select changes to the circulating SASP. Funding: AHA 23CDA1056582; NIH F31AG087709; NIH/NCATS CTSA UL1TR002535; Life Extension® provided fisetin (BioFisetin) and placebo. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Accurate assessment of arterial wall mechanics is essential for detecting vascular pathologies. The technique described herein incorporates a commercially available ultrasound system and applanation tonometry to noninvasively evaluate the local mechanical properties of the common carotid artery (CCA). Pressure waveforms were acquired using a tonometer combined with ultrasound-based diameter of the CCA. The signals were temporally aligned, converted to physical units using brachial systolic and diastolic pressure, and interpolated over uniform strain increments. Hoop stress was estimated using thick-wall assumptions, and hoop strain was derived from mid-wall circumferential stretch. Incremental elastic modulus was computed from local linear fits to the stress–strain data, and the area of the resulting hysteresis loop was used as a surrogate for viscoelastic energy loss, quantified by the energy dissipation ratio (EDR). The method was applied to healthy subjects (HS) and those with cardiovascular risk or confirmed atherosclerosis. In HS, pressure–strain elastic modulus (Ep) ranged from 50–55 kPa and EDR from 2%–6%, while non-healthy subjects showed higher EDR values (10%–20%), reflecting increased arterial viscoelasticity. Results revealed nonlinear pressure–diameter relationships with clear hysteresis, reflecting viscoelastic effects. The technique offers potential as a diagnostic tool for evaluating early, localized vascular alterations.

Abstract The lateral and medial meniscus play vital roles in load distribution across the knee joint and in the prevention of knee osteoarthritis. As such, every effort should be made to save and repair the meniscus when possible, as partial and total meniscectomies have been shown to impair the meniscus’ ability to effectively dissipate shock. Recently, an algorithm—coined the “ABCs of meniscal repair”—has emerged as a blueprint for optimizing the success of a meniscal repair. The “ABCs of meniscal repair” refer to anatomic reduction, biologic augmentation, and circumferential compression across the meniscus tear, respectively. In this technique, we describe a modified use of the arthroscopic skid that allows for access to difficult‐to‐reach peripheral meniscal tears while simultaneously aiding in the anatomic reduction of the tear.