Citations

Antiretroviral therapy has transformed treatment of HIV infection from a fatal disease into a chronic condition, yet opportunistic infections remain prevalent in patients with declining CD4 cell counts, requiring a pattern-based radiologic approach and vigilant clinical assessment to differentiate infections, malignancies, and immune reconstitution inflammatory syndrome.

BACKGROUND AND OBJECTIVES: Craniopharyngiomas are complex intracranial tumors that pose significant challenges in surgical management. We aimed to develop risk-stratified surgical outcome benchmarks for adult patients undergoing endoscopic craniopharyngioma resection by using the Registry of Adenomas of the Pituitary and Related Disorders database to facilitate comparisons across institutions and guide clinical decision-making. METHODS: A retrospective cohort of adult patients (18 years and older) with craniopharyngioma undergoing a first-time endoscopic transnasal surgery across 14 academic centers in the United States was analyzed using data collected from 2011 to 2024. Patients were stratified into low-risk and high-risk cohorts based on criteria including age, body mass index, selected tumor characteristics (size, infundibular relationship, intraventricular extension), and previous radiation. Surgical outcomes were analyzed, and benchmarking ranges were defined using the established methodology. RESULTS: The overall cohort included 318 patients with a mean age of 50 years. Upon benchmarking analysis (50th-75th percentile performance), low-risk patients (n = 136) had a median length of stay of 4.0 to 6.0 days, 90-day readmission rates of 15.5% to 22.2%, skilled nursing facility discharge rates of <1.0%, postoperative cerebrospinal fluid leak incidence of <1.0% to 14.3%, gross total resection rates of 50.0% to 60.8%, new postoperative arginine vasopressin deficiency rates of 33.3% to 50.0%, and tumor progression/recurrence rates of <1.0% to 18.3% over a median follow-up period of 27.0 (IQR 10.5-56.5) months. Benchmarking ranges were proposed for each outcome to facilitate cross-institutional comparisons. CONCLUSION: Establishing surgical outcome benchmarks for adult patients undergoing craniopharyngioma resection using data from the Registry of Adenomas of the Pituitary and Related Disorders provides a framework for assessing surgical performance and guiding clinical decision-making. Benchmark ranges can inform institutional quality improvement efforts, perioperative risk stratification, and patient counseling regarding expected postoperative outcomes.

Abstract Hyperpolarized [1-¹³C]pyruvate MRI provides real-time, radiation-free insight into myocardial pyruvate metabolism and mitochondrial oxidative capacity, yet its utility in patients with severe multivessel coronary artery disease before and after surgical revascularization remains unknown. Here we show, in the first prospective study applying this technique to three-vessel disease, that serial imaging is feasible and safe with no serious adverse events in 22 injections. Healthy myocardium displayed a bicarbonate-to-total hyperpolarized carbon product ratio of 0.66 ± 0.13, indicating that the majority of pyruvate undergoes oxidation. Patients exhibited significantly lower ratios in the inferolateral segment (P = 0.03) with reciprocal increases in lactate, and global ratios correlated with left ventricular ejection fraction (r = 0.695, P = 0.006). Post-revascularization changes were heterogeneous across individuals. These findings establish hyperpolarized 13C MRI as a powerful tool for noninvasive assessment of myocardial metabolism in multivessel coronary artery disease and support its potential for longitudinal therapeutic monitoring.

Chylous effusion is a complication most frequently seen in the iatrogenic setting secondary to thoracic surgery or other intervention. Management of this complication includes conservative measures, surgical exploration/ligation, and percutaneous thoracic duct embolization. This case presents a medically complex patient with persistent chylous effusions after thoracoscopic resection of a fluorodeoxyglucose (FDG) and Cu 64 DOTATATE-avid retrocrural lymph node. Initial conventional fluoroscopic lymphangiogram and thoracic duct embolization were unsuccessful. Subsequent magnetic resonance lymphangiography (MRL) more accurately localized the leak which was then marked with computed tomography-guided needle placement before conversion to fluoroscopically guided embolization. This case demonstrates the utility of MRL as a problem-solving tool for localizing hard-to-treat lymphatic leaks. MRL localized embolization is a safe and effective treatment for lymphatic leaks.

Advances in cancer treatment by chemotherapy, radiation, and personalized targeted therapy have significantly improved cancer survivorship. Life extension from chemotherapy is arguably the most accessible non-surgical treatment strategy, but it is accompanied by neurotoxic sequelae that are detrimental to cognitive function in survivors. Using the platinum-based drug cisplatin to model chemotherapy induced cognitive impairments (CICI; also called chemobrain) in mice, we recently identified that elevated hippocampal adenosine A 2A receptor (A 2A R) levels are causally associated with CICI. Although neuroinflammation is a major pathological mechanism underlying CICI, it remains unclear whether A 2A R mediates cisplatin-induced neuroinflammation. To address this knowledge gap, we demonstrate for the first time that cisplatin increases microglial process extension and branching complexity, consistent with a primed, hyper-surveillant morphological phenotype. Remarkably, caffeine, a non-specific A 2A R antagonist and known cognitive enhancer, attenuated the primed microglial morphology caused by cisplatin. Furthermore, we show that caffeine mitigates cisplatin-induced body-weight loss, accelerates physical recovery, and protects against motor dysfunction. We also show that caffeine confers protection against cisplatin potentiated impairments in hippocampal dendritic spine density, neurogenesis, and confers modest memory benefits. Collectively, these results suggest that A 2A R-mediated microglial priming is associated with cognitive dysfunction in chemobrain and A 2A R inhibition by caffeine may represent a strategy to ameliorate the physical and cognitive impairments caused by cisplatin.

Abstract The impact of microglia antigen presentation on CNS infiltrating CD8 T cells responses during neurotropic virus infection has been difficult to define. Using Theiler’s murine encephalomyelitis virus (TMEV) infection of neurons as a model system, our laboratory has previously determined that H-2D b restricted, but not H-2K b restricted CD8 T cells are required for viral clearance, demonstrating the role of discrete MHC class I alleles. To determine the extent microglia antigen presentation impacts brain-infiltrating CD8 T cells, our laboratory generated novel single MHC class I conditional knockout mice in which H-2K b or H-2D b can be specifically deactivated in TMEM119+ microglia with tamoxifen administration. During TMEV infection, conditional knockout of H-2K b in microglia reduced antigen-specific CD8 T cell proliferation in the brain. Meanwhile, mice with deletion of D b in microglia had reduced levels of perforin in antigen-specific CD8 T cells. Furthermore, microglia specific deletion of H-2D b reduced CD8 T cell numbers in the brain and preserved blood-brain barrier (BBB) integrity. Microglial D b restricted antigen presentation was also essential for the reactivation of CD8 tissue resident memory (TRM) cells and BBB integrity during memory recall responses. These findings further our understanding of how brain infiltrating antiviral CD8 T cell responses are impacted by microglia, as well as define how this cellular interaction contributes to BBB disruption during neuroinflammation. These findings also have high significance to our understanding of how microglia impact CD8 TRM cell populations that reside in the brain long after virus infection is cleared. Graphical abstract

Rationale: Pulmonary hypertension (PH) is a fatal disease characterized by a sustained elevated pulmonary vascular resistance that results in right heart failure. Despite therapeutic advances, no treatment provides disease progression reversion, resulting in poor long-term survival. Identifying new therapeutic targets for PH therefore requires a deeper understanding of its mechanisms. A defining feature of PH is pulmonary vascular remodeling, a result from excessive proliferation, migration, and apoptosis resistance of pulmonary artery smooth muscle cells (PASMC). SNAI1, a transcription factor regulating cell proliferation and differentiation during development and disease, has recently been implicated in endothelial dysfunction and endothelial-to-mesenchymal transition in PH. However, its role within PASMC remains unknown. Here, we aimed to define the contribution of SNAI1 in PASMC to the pathogenesis of PH. Methods: Normal human PASMC were exposed to normoxia (21% O 2 ) or hypoxia (3% O 2 ) for 72 hours. PASMC were also isolated from patients with or without PH. Cell proliferation and migration were assessed by EdU incorporation and wound scratch assays respectively. Mice were exposed to hypoxia (10% O 2 ) or Sugen5416/hypoxia (10% O 2 plus Sugen5416 20mg/kg, i.p., weekly) for 6 weeks. PH phenotype was characterized by right heart catheterization, right ventricle (RV) hypertrophy by Fulton index and pulmonary artery (PA) remodeling by H&E staining of lung tissues. Pharmacological blocker GN-25 was used to inhibit SNAI1 in vitro and in vivo. Results: SNAI1 expression was markedly increased in hypoxic PASMC and in PASMC from patients with PH. Hypoxia also upregulated HIF-1alpha, Vimentin, p-AKT, PCNA at the protein level in PASMC. EdU incorporation and migration rates were significantly higher in hypoxic cells as well as in PASMC isolated from PH patients compared with controls. In vitro, GN-25 (100 nM) abolished hypoxia-induced PASMC proliferation and migration. Right ventricular systolic pressure (RVSP), a surrogate measurement of PA systolic pressure, estimated mean PAP (mPAP), and RV contractility (RV-±dP/dtmax) were significantly increased in both PH models compared with controls. Additionally, Sugen5416/hypoxia-treated mice exhibited higher RVSP, mPAP and RV-±dP/dtmax compared to hypoxia-treated animals. The Fulton index (weight of RV vs. left ventricle and septum), was increased in both PH groups indicating development of RV hypertrophy in PH compared to control. PH mice lost body weight by 5-10%. Additionally, when Fulton index was normalized by body weight, RV hypertrophy was significantly higher in Sugen5416/hypoxia-treated mice compared with hypoxic animals. Lung tissues from PH mice exhibit PA hypertrophy (media remodeling) with some PA partially or completely occluded. Additionally, we detected protein upregulation of Snai1 and Vimentin in lung tissues of PH mice in both groups. Treatment of PH mice with GN-25 (20 mg/kg, daily, for the last 3 weeks under PH stimuli) in reversal experiments attenuated PH phenotype in both animal models by decreasing hemodynamic parameters, right ventricle hypertrophy and pulmonary vascular remodeling. Conclusions: Our findings identify a key role for SMC SNAI1 in the pathogenesis of lung vascular remodeling during hypoxia-induced PH. Inhibition of SNAI1 in PASMC may constitute a new therapeutic strategy for the treatment of PH. 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: Hypoxia challenges the regulation of arterial oxygenation (SaO 2 ), eliciting a compensatory increase in ventilation ([Formula: see text]E) to preserve blood-gas homeostasis. However, the ability to maintain blood-gas homeostasis during hypoxic exercise may differ between sexes due to differences in chemoreflex drive and the mechanical capacity to augment ventilation. The purpose of this study was to evaluate sex differences in ventilatory and blood-gas responses to progressive hypoxia during moderate walking exercise. Specifically, we asked whether females would be more susceptible to hypoxemia. We hypothesized that females would exhibit a smaller ventilatory response and a less steep ventilatory CO 2 -response (Δ[Formula: see text]E/ΔPaCO 2 ) compared with males, resulting in a greater reduction in SaO 2 during progressive hypoxia. Methods: Twenty-six physically active adults (15M: age 35.3±9.4; [Formula: see text]O 2 max 54.3±15.5 mL/kg/min, 11F: age 36.2±9.0; [Formula: see text]O 2 max 44.6±5.2 mL/kg/min) were studies during two visits. Visit 1: we determined the participants’ maximal oxygen uptake ([Formula: see text]O 2 max) during an incremental treadmill test. Visit 2: participants walked at ~50% of their [Formula: see text]O 2 max while we reduced the fraction of inspired oxygen (FiO 2 ) progressively every 5 minutes (0.21, 0.19, 0.17, 0.15, 0.13, 0.12, 0.11). Arterial blood samples were collected from a brachial artery catheter during the final 30 seconds of each stage; cardiometabolic and ventilatory data were averaged over the final minute of each stage. The test ended when peripheral oxygen saturation (SpO 2 ) fell below 70%. Because 0.13 FiO 2 was the lowest stage completed by all participants, Δ responses were calculated from 0.21 to 0.13 FiO 2 . Independent t-tests compared Δ responses between sexes; data are mean±SD, significance was set at p < 0.05. Results: There was no significant difference in ΔSaO 2 between sexes across hypoxia (M: −22.0±3.7%; F: −22.8±5.5%; p = 0.89). Males had higher arterial oxygen content (CaO 2 ) than females across all stages (M: 20.6±1.2 to 16.0±1.4 mL O 2 ·dL -1 ; F: 18.5±1.1 to 13.8±2.0 mL O 2 ·dL -1 ), but the ΔCaO 2 during hypoxia was not significantly different between sexes (M: −4.6±0.7; F: −4.7±1.4 mL O 2 ·dL -1 ; p = 0.86). Similarly, there was no significant difference in the change in arterial CO 2 (ΔPaCO 2 ) between sexes (M: −5.8±1.5 mmHg; F: −6.5±3.6 mmHg, p = 0.51). In contrast, males exhibited a significantly greater increase in ventilation (Δ[Formula: see text]E: +13.9±4.2 L·min -1 ) than females (+8.6±2.7 L·min -1 ; p = 0.003). Consequently, the ventilatory CO 2 -response (Δ[Formula: see text]E/ΔPaCO 2 ) was steeper in males (−2.46±0.66 L·min -1 ·mmHg -1 ) compared with females (−1.57±0.68 L·min -1 ·mmHg -1 ; p = 0.004). However, when Δ[Formula: see text]E was expressed relative to maximal ventilatory capacity (%[Formula: see text]Emax), there was no sex difference (M: 8.8±2.6% vs F: 8.3±2.8%; p = 0.68). Conclusion: Females were not more susceptible to hypoxemia than males; both sexes showed comparable reductions in SaO 2 during moderate exercise in progressive hypoxia. Reductions in PaCO 2 were also similar, indicating comparable ventilatory drive. Although males exhibited a larger absolute increase in [Formula: see text]E and a steeper ventilatory CO 2 -response, this difference disappeared when Δ[Formula: see text]E was expressed relative to %[Formula: see text]Emax. These findings indicate that apparent sex differences in ventilation during hypoxia largely reflect differences in ventilatory capacity rather than true differences in oxygenation or ventilatory drive. Taken together, these findings challenge the assumption that females are inherently more susceptible to hypoxemia or have a lower ventilatory drive than males during moderate hypoxic exercise. Funding: NIH T32 DK007352, UL1 TR002377 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: During hypoxic exercise, oxygen transport becomes increasingly challenged as oxygen availability decreases. As the inspired oxygen fraction (FiO 2 ) decreases, peripheral oxygen saturation (SpO 2 ) gradually declines, then drops rapidly upon reaching the steepest point of the sigmoidal shaped, oxyhemoglobin dissociation curve. This reduction in FiO 2 creates a distinct SpO 2 “breakpoint,” which likely represents the threshold at which compensatory mechanisms, such as increases in ventilation and cardiac output, can no longer maintain arterial oxygenation. Several physiological factors may modulate this breakpoint, including hemoglobin concentration, blood volume, and ventilatory capacity. This study aimed to determine the SpO 2 breakpoint during steady-state, submaximal, hypoxic exercise and examine whether factors like sex, age, and fitness level influence the SpO 2 breakpoint. We hypothesized that SpO 2 breakpoints would differ by sex, age, and fitness level, with earlier breakpoints visible in females, older adults, and those with higher aerobic fitness. Methods: Twenty-six physically active adults (15M: age 35±9 yrs, [Formula: see text]O 2 max 54.3±15.5 mL/kg/min, 11F: age 38±10 yrs, [Formula: see text]O 2 max 44.6±5.2 mL/kg/min) participated in a two-day study. Day one: participants performed a treadmill [Formula: see text]O 2 max test. Day two: participants walked at a steady state of ~50% of their [Formula: see text]O 2 max, for 40 minutes, while FiO 2 was progressively reduced every 5 minutes in a stepwise fashion (0.25, 0.21, 0.19, 0.17, 0.15, 0.13, 0.12, 0.11). The test was terminated when SpO 2 dropped below 70%. SpO 2 was measured continuously using a clinical-grade oximeter. Analysis was performed in RStudio by first determining each participant’s individual SpO 2 vs time breakpoint. Male and Female breakpoints were compared to assess sex-based differences. To evaluate whether SpO 2 breakpoint timing differed by age or fitness level, participants were then divided into tertiles for each variable. Age tertiles were derived from the sample distribution of chronological age, and fitness tertiles were defined using [Formula: see text]O 2 max (L/min). Mean breakpoint times were compared between the highest and lowest tertiles for both age and fitness. Mean SpO 2 breakpoints were compared between groups using independent sample t-tests. Significance was set to p< 0.05. Results: The overall mean breakpoint occurred at an SpO 2 of 90.7±2.8% during the 0.17 FiO 2 stage. No significant sex differences were observed in breakpoint SpO 2 and timing (M: SpO 2 = 90.7±2.7%, time = 18.6 min; F: SpO 2 = 90.7±3.0%, time = 17.7 min; p = 0.961). Age did not significantly influence breakpoint (younger tertile [21-30 yrs] SpO 2 = 91.0±2.4%, time = 18.4 min; older tertile [41-60 yrs] SpO 2 = 91.1±2.4%, time = 17.2 min, p = 0.953). Additionally, fitness level showed no significant difference on breakpoint (low fitness [1.91-3.01 L/min]: SpO 2 = 90.3±3.1%, time = 17.8 min; high fitness [4.38-5.25 L/min]: SpO 2 = 90.4±2.9%, time = 19.2 min; p = 0.992). Conclusion: During a hypoxic, steady state walking exercise, at ~50% [Formula: see text]O 2 max, we observed no difference in the peripheral oxygen saturation breakpoint, across sex, age, and fitness level. This may suggest that moderate exercise in hypoxia does not sufficiently challenge the cardiopulmonary system for individual variations in oxygen transport to influence the breakpoint. These findings imply that the SpO 2 breakpoint, during hypoxic exercise, may represent a physiological marker of the upper limit for maintaining oxygen saturation in healthy adults. Applying this protocol to identify SpO 2 breakpoints may offer insights for improving pharmacological interventions and our understanding of clinical populations with impaired oxygen transport. 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.

We previously showed that the Drosophila Malpighian tubule (MT) can model the formation of calcium oxalate (CaOx) kidney stones. Two epithelial cell types, stellate cells (SC) and principal cells (PC) comprise MTs, with each transporting different solutes from the hemolymph to MT lumen. Prestin, Neat and Ndae1 contribute to transepithelial ox2-, HCO 3 - transport and fluid secretion. Neat (2HCO 3 - /ox2- exchange) and NDAE1 (Na + ,2HCO 3 - /Cl - exchange) functionally combine to takeup hemolymph ox2-, can also facilitate HCO 3 - uptake. Prestin then secretes ox2- via Cl - / ox2-exchange to create luminal MT CaOx crystals, but it can also exchange Cl - /HCO 3 - . This study examines transepithelial ion secretion by Prestin (Slc26a6, apical), Neat (Slc26a1-like, basal) and Ndae1 (Slc4a8-like, basal). We use a functionally similar, simple genetic model (Drosophila Malpighian tubules, MT) to measure renal CaOx crystallization (NaOx feeding), membrane transport (pHi, fluorescent pH sensors) and fluid secretion (Ramsey assay) to: (1) compare cell-specific gene knockdown (KD) vs gene knockout, (2) quantify CaOx crystallization and intracellular pH (pHi) regulation by CO 2 /HCO 3 - , and (3) humanize these transporters by replacing them with human homologs. We hypothesize that humanizing individual transporters will restore MT physiology. Candidate transporter genes are tested for transepithelial ox2-and HCO 3 - secretion with gene-specific knockdown or knockout, using CRIMIC (CRISPR-Mediated Integration Cassette) alleles, in MTs due to comparable function to mammalian nephrons. Neat and NDAE1 work together to take-up hemolymph ox2- or HCO 3 - then Prestin secretes ox2- or HCO 3 - into the MT lumen. Prestin, Neat or NDAE1 knockdowns in principal cells decrease CaOx crystals. NDAE1 but not Neat knockdown in SC increases CaOx crystals like AQP (Drip, Prip)-knockdowns while either KD enhance HCO 3 - transport. Ndae1-SC-KD reduces fluid secretion like AQP-KD. Each CRIMIC allele must be physiologically compared to PC/SC-KDs because Ndae1-KO but not Neat-KO mirrors PC rather than SC function. Ndae1-SC-KD shows that HCO 3 - and Cl - secretion cause fluid secretion. Human homolog replacements are on-going. 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.