Citations

Abstract Background: Clostridium ramosum ( C. ramosum ) is an anaerobic gram-positive bacillus of the human intestine and a rare cause of bacteremia. This retrospective cohort study evaluated clinical characteristics and outcomes of a multicenter cohort of adults with C. ramosum bacteremia. Methods: This multicenter retrospective cohort included adults (≥ 18 years) with true C. ramosum bacteremia at Mayo Clinic hospitals in Arizona, Florida, Minnesota, and Wisconsin from September 1, 2012, through December 31, 2025. Data were collected through search for C. ramosum in microbiological culture records. Clinical characteristics assessed included immune status, source of bacteremia, presence of sepsis, neutropenic fever, monomicrobial vs. polymicrobial bacteremia, antimicrobial resistance patterns, antimicrobial therapy, length of stay and 30-day all cause mortality. Exploratory odds ratios (ORs) with 95% confidence intervals (CIs) were reported. Results: Among 90 patients with a positive C. ramosum blood culture, 17 were classified as contaminants and 73 comprised the study cohort. Median age was 66.0 years (IQR, 56.0–75.0); 44 (60.3%) were male and 33 (45.2%) were immunocompromised (including 26 with active malignancy, while the remaining 7 were received biologic immunosuppression). The most common infection sources were gastrointestinal (32/73, 43.8%) and central line-related (8/73, 11%). At presentation, 50.7% of patients met criteria for sepsis and 15/73 (20.5%), were in septic shock. Of 73 isolates tested, 31/73 (44.3%) were clindamycin resistant and 9/73 (12.9%) tested intermediate. Anaerobic-active antimicrobial therapy was received by 53/73 (72.6%). Thirty-day mortality was 11/73 (15.1%). Mortality was 30.0% (6/20) with therapy without reliable anaerobic activity and 9.4% (5/53) with anaerobic-active antimicrobial therapy (OR, 4.02; 95% CI, 0.88–19.46; P = 0.060). The median hospital LOS was 8.0 days. Among 30-day survivors, anaerobic active antimicrobial therapy was associated with a shorter median LOS compared to therapy without reliable anaerobic activity (8.5 vs. 12.0 days). Immunocompromised patients had higher odds of monomicrobial C. ramosum bacteremia than immunocompetent patients (OR 3.16, 95% CI 1.19–8.39; p = 0.03). Patients with polymicrobial bacteremia had higher odds of sepsis (OR, 3.89; 95% CI, 1.43–10.55; P = 0.008) and septic shock (OR, 5.66; 95% CI, 1.17–27.36; P = 0.020). Patients with malignancy or neutropenia demonstrated significantly lower odds of presenting in septic shock (p = 0.018; p = 0.029 retrospectively). Microbiological clearance was achieved in 91.3% (42/46) of evaluable cases. Conclusions: This largest reported cohort defines the clinical and microbiological profile of C. ramosum bacteremia. Frequent clindamycin nonsusceptibility is clinically actionable. Several clinical associations found on univariable analysis should be further investigated in larger studies.

Background. The use of immune checkpoint inhibitors (ICIs) in kidney transplant recipients (KTR) for cancer treatment is limited by concerns of allograft rejection and uncertain oncologic efficacy. Methods. We conducted a single-center retrospective study of KTR with unresectable or metastatic malignancies treated between 2018 and 2025. The primary study cohort included 33 patients treated with ICI, whose outcomes were compared with 20 matched KTR treated with non-ICI systemic chemotherapy (SC). Results. KTR treated with ICI achieved an objective response rate of 36.4% (12/33) versus 30.0% (6/20) with SC, and a clinical benefit rate of 54.5% (18/33) versus 35.0% (7/20); neither difference was statistically significant (objective response rate P = 0.77; clinical benefit rate P = 0.27). Disease progression occurred in 81.8% of ICI-treated patients and 95.0% of SC-treated patients ( P = 0.23), and death because of cancer progression occurred in 63.6% and 75.0%, respectively ( P = 0.58). Median progression-free survival was 7.3 mo (95% confidence interval [CI], 4.3-10.8 mo) in the ICI group versus 4.1 mo (95% CI, 2.8-6.3 mo) in the SC group (log-rank P = 0.156). Median overall survival was 15.1 mo (95% CI, 7.6-37.3 mo) with ICI versus 8.7 mo (95% CI, 4.9-14.8 mo) with SC (log-rank P = 0.079). Posttreatment allograft rejection occurred in 12.1% of ICI-treated patients and 0.0% of SC-treated patients ( P = 0.29), with irreversible graft loss in 3.0%. Grade ≥2 immune-related adverse events occurred in 12.1% of ICI-treated patients, and no treatment-related deaths were observed. Conclusions. ICI therapy was associated with a trend toward longer overall survival when compared with SC and with a low rate of rejection and allograft loss.

Abstract Introduction: Surveillance biopsies after kidney transplantation provide an opportunity to assess early renal disease processes, including diabetic nephropathy, before clinical manifestation. This study aimed to identify proteomic alterations in renal allografts at 5 years post-transplant (5yrPT) and their associations with histologic features in diabetic/obese (DM/OB) versus non-diabetic/non-obese (nDM/nOB) recipients. Methods: We studied protocol biopsies from 17 DM/OB and 14 nDM/nOB kidney transplant recipients at Mayo Clinic (2000–2012). Laser capture microdissection followed by mass spectrometry was used for proteomic profiling. Histologic assessment included Banff and Tervaert scoring and morphometric analysis. Statistical comparisons were performed using ANOVA with Tukey post-hoc testing. Results: DM/OB recipients demonstrated greater histologic and metabolic injury at 5yrPT. Proteomic analysis identified 101 glomerular and 86 non-glomerular proteins differentially expressed between groups. Significant alterations were observed in proteins associated with mitochondrial dysfunction, including VDAC1 (fold change [FC] 2.6, p = 0.03), NDUFB9 (FC 0.15, p = 0.009), and NDUFA9 (FC 1.72, p = 0.01). Extracellular matrix remodeling proteins COL6A1, COL6A2, and COL6A3 were upregulated (FC 1.6–1.8, p < 0.05). Immune and inflammatory markers C9 (FC 1.6, p < 0.03) and TGFBI (FC 1.7, p < 0.001), as well as oxidative stress–related CLU, were increased. GGACT showed the greatest decrease (FC 0.30, p < 0.001), implicating altered energy metabolism. Conclusion: Distinct proteomic signatures at 5yrPT in DM/OB recipients highlight early mitochondrial, metabolic, immune, and extracellular matrix pathways involved in diabetic kidney disease. These changes precede clinical disease and identify candidate biomarkers and therapeutic targets to improve graft longevity.

Background: Overlap between diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS) is associated with significantly higher mortality than either condition alone. While hypertonic (trans locational) hyponatremia is common in hyperglycemic crises, clinically significant hypernatremia in mixed DKA/HHS presents with certain treatment challenges due to rapid osmotic shifts during insulin therapy. Case presentations: A 40-year-old woman with non-significant past medical history presented with vomiting, polyuria, polydipsia, and confusion for two days. Laboratory evaluation revealed serum glucose 1280 mg/dL, arterial pH 7.214, bicarbonate 13.1 mmol/L, anion gap 24, β-hydroxybutyrate 6.0 mmol/L, corrected sodium 152 mmol/L (measured sodium 133 mmol/L), and calculated effective osmolality 337 mOsm/kg. Initial treatment with isotonic saline and intravenous insulin led to improvement in hyperglycemia but worsening corrected hypernatremia to 160 mmol/L after 3 liters of normal saline. Free water deficit was calculated at 6.3 L. Fluid therapy was transitioned to hypotonic solutions with titration to limit sodium correction to ≤10 mmol/L per 24 hours. Sodium levels gradually normalized with resolution of ketoacidosis, and improvement in mental status without significant neurologic complications. Conclusion: In mixed DKA/HHS, early assessment of corrected sodium and effective osmolality is critical. Insulin-mediated intracellular water shifts may unmask or worsen hypernatremia. Prompt reassessment of corrected sodium and individualized fluid management is needed to avoid treatment-related exacerbation of hypertonicity.

Background. Pancreas transplantation (PT), historically limited to patients with type 1 diabetes (T1D), is currently performed successfully in selected patients with type 2 diabetes (T2D). However, contemporary practice patterns and eligibility criteria for PT in T2D remain incompletely characterized. Methods. The International Pancreas and Islet Transplant Association Pancreas Transplant Interest Group developed an electronic survey to assess center-level approaches to patient phenotyping, candidacy, and peri- and posttransplant management for PT in patients with T2D. The survey was distributed to international transplant professionals during an International Pancreas and Islet Transplant Association Pre-Congress meeting on June 15, 2025. Results. Thirty-seven participants completed the survey. Most respondents’ programs offer PT for T2D only when a kidney transplant is also indicated. Fewer respondents’ programs also offer PT alone (10%), evaluate T2D candidates on a case-by-case basis (3%), or do not offer PT to patients with T2D (10%). Total daily insulin requirement and body mass index (BMI) were the most selected factors in determining eligibility. Considerable variability existed in metabolic thresholds: 62% of programs reported no C-peptide cutoff, whereas nearly half required a BMI of <30 kg/m 2 for C-peptide-positive candidates. Respondents frequently recommend weight-optimization strategies, including lifestyle modification, glucagon-like peptide-1 receptor agonists, and bariatric surgery for candidates exceeding acceptable BMI thresholds. Surgical technique, induction, and maintenance immunosuppression and early posttransplant glycemic management were largely uniform between T2D and T1D recipients. Conclusions. International practice reflects broad but heterogeneous adoption of PT for T2D, with most participants restricting its use to candidates requiring kidney transplantation and emphasizing integrated clinical phenotyping approaches.

Abstract Exposure to asbestos is the primary cause of mesothelioma, however the processes underpinning its initiation and evolutionary trajectory remain elusive. To address this knowledge gap, we conducted whole exome sequencing and phylogenetic analysis of 277 mesotheliomas. Using multidimensional Dirichlet process clustering we inferred phylogenies, uncovering mutation order dominated by early 13q,1p, 8p, 6q and 22q somatic copy number alterations. Mesotheliomas exhibit a spectrum of genomic intra-tumor heterogeneity spanning linear (L) to highly branched (B) tree topologies, quantifiable by the Weighted Shannon Entropy (WSE). Somatic copy number alterations emerge earlier than single nucleotide variants (SNVs), and at a much faster relative rate in L-mesotheliomas. BAP1 is the only positively selected driver in L-mesotheliomas, whereas, B-mesotheliomas harbor multiple positively selected drivers and an aggressive phenotype, including a bias of loss of RPL5, and MTAP deletion linked to breakpoint enriched with long interspersed nuclear elements. L-trees had lower WSE, but greater T-cell inflammation and tertiary lymphoid structures, despite having a lower neoantigen burden. WSE is higher in larger volume, immunologically cold mesotheliomas, and is associated with shorter survival. In summary, progressive genomic heterogeneity is a defining feature of more aggressive mesothelioma yet illuminates opportunities for precision therapeutic intervention.

Abstract Introduction Transthoracic echocardiography (TTE) identifies a hypercontractile phenotype (HP) in chronic coronary syndromes (CCS), characterized by elevated resting left ventricular (LV) elastance (force = systolic blood pressure/end-systolic volume). To evaluate the prognostic significance and functional correlates of HP. Methods In a prospective multicentre study, 10 677 patients with CCS underwent resting TTE to assess LV ejection fraction (EF), stroke volume, and force by quantitative volumetric echocardiography. All patients were followed for the endpoint of all-cause mortality. In a subset of 5834 patients, stress echocardiography (exercise or dobutamine) was performed for LV contractile reserve and heart rate reserve. Results Patients were stratified into Force quintiles (Q1–Q5). Patients with hypercontractile phenotype exhibited lower stroke volume at rest (Q5 = 34.8 ± 12.3 vs Q1–Q4 = 57.4 ± 19.1 mL; P &lt; .01) and higher EF at rest (Q5 = 64.8 ± 6.9% vs Q1–Q4 = 58.1 ± 8.7%, P &lt; .01). During a median follow-up of 24 months (interquartile range = 12–40 months), 509 deaths occurred. The exposure-adjusted death rate was lowest in Q3 (3.53–4.51 mmHg/mL; 1.03 per 100 person/years) and higher in Q1 (≤2.62 mmHg/mL, 2.88), Q2 (2.63–3.52 mmHg/mL, 1.86), Q4 (4.52–6.11 mmHg/mL, 1.56), and Q5 (HP, &gt;6.11 mmHg/mL; 1.88; P &lt; .0001 vs Q1 and Q3). Multivariable analysis identified HP (Q5; HR 1.531 vs Q3, 95% CI 1.116–2.099; P = .006) and EF (HR 0.963, 95% CI 0.953–0.972; P &lt; .0001) as independent predictors of death. During exercise or dobutamine stress, HP showed reduced LV contractile reserve (ΔEF: Q5 = 4.3 ± 9.4% vs Q1–Q4 = 7.0 ± 9.3%; P &lt; .001) and blunted heart rate reserve (Q5 = 1.77 ± 0.33 vs Q1–Q4 = 1.85 ± 0.39; P &lt; .01). All patients with force-based LV contractile reserve &gt;4.1 (present in 185, 3.2% of the population) survived. Conclusion Patients with CCS with HP assessed by resting TTE demonstrate higher mortality and multilayered functional impairment, including reduced LV contractile and chronotropic reserves. Hypercontractile phenotype improved the prediction of mortality by EF. A ‘stronger’ heart is, in fact, functionally and prognostically weaker.

Abstract Endothelial-to-mesenchymal transition (EndMT) is a biological process through which lung vascular endothelial cells (ECs) transdifferentiate into mesenchymal-like cells. EndMT has recently been implicated in the development and progression of pulmonary vascular remodeling in pulmonary hypertension (PH); however, its underlying regulatory mechanisms remain incompletely understood. MicroRNAs (miRNAs) are key post-transcriptional regulators of EC gene expression and cellular responses to various stimuli. Notably, microRNA-153 (miR-153) has been shown to directly target SNAI1 to modulate epithelial-to-mesenchymal transition (EMT), a process closely related to EndMT and extensively studied in cancer. Whether miR-153 also participates in EndMT regulation, however, remains unknown. In this study, we demonstrate that 72-hour hypoxic exposure induces SNAI1-mediated EndMT in human lung vascular ECs. Hypoxia also increased cell proliferation and disrupted intercellular junctions, leading to enhanced endothelial permeability. Reduced miR-153 expression was observed in both hypoxia- and TGF-β1-induced EndMT, as well as in ECs isolated from PH patients exhibiting an EndMT phenotype. Similar to hypoxia, TGF-β1 promoted EC permeability. Loss of miR-153 enhanced SNAI1-mediated EndMT, endothelial survival, and permeability under normoxic conditions, whereas miR-153 overexpression attenuated EndMT induced by hypoxia or TGF-β1. However, miR-153 restoration did not completely restore endothelial barrier integrity disrupted by these stimuli. In vitro findings were validated in experimental PH model. In conclusion, miR-153 serves as a critical regulator of EndMT, maintaining endothelial identity and barrier function. Therapeutic delivery of miR-153 may therefore represent a novel strategy to inhibit EndMT and attenuate pulmonary vascular remodeling in PH.

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 Pancreatic ductal adenocarcinoma (PDAC), the most common malignant type of pancreatic cancer, is characterized by a dense desmoplastic stroma, low neoantigen burden, and a highly immunosuppressive tumor microenvironment (TME). Methods We present a novel strategy harnessing acute transplant rejection mechanisms by employing a recombinant oncolytic rVMG vector engineered to express murine alloantigens H-2Kb (rVMG-H-2Kb) or H-2Kk (rVMG-H-2Kk), thereby inducing tumor-specific antigenic mismatch responses. Results In vitro, rVMG-H-2Kb and rVMG-H-2Kk exhibited strong replication and cytolytic activity while inducing cell surface expression of both H-2Kk and endogenous H-2Kb, in addition to upregulation of antigen presentation genes (β2-microglobulin, Tap1, and Tapbp). In two immunocompetent PDAC models, intratumoral and systemic delivery of rVMG-H-2Kb and rVMG-H-2Kk delayed tumor progression, with rVMG-H-2Kk conferring a survival advantage. Multiplex immunohistochemistry and immunophenotyping revealed substantial TME remodeling, marked by increased effector T-cell infiltration, regulatory T-cell depletion, and reduced fibrosis. Spatial transcriptomics further showed compartment-specific immune activation and epithelial metabolic reprogramming, corroborating with enhanced tumor immunogenicity. Despite these effects, rVMG-H-2Kk also induced compensatory immunosuppressive pathways, including upregulation of antiviral response genes and immune checkpoint receptors such as programmed death-ligand-2. Importantly, combination therapy with rVMG-H-2Kk and murine checkpoint blockade (anti-programmed cell death protein-1 and anti-cytotoxic T-lymphocyte-associated protein 4) drastically improved survival compared to checkpoint blockade alone. Strikingly, surviving mice resisted tumor rechallenge, indicating the establishment of durable antitumor memory. Conclusion These findings establish rVMG-mediated alloantigen delivery as a novel immunotherapeutic platform capable of converting immune-cold tumors into immune-hot, sensitizing tumors to immune checkpoint inhibitors, and establishing durable antitumor immunity in PDAC.