Citations

Calcific aortic valve disease (CAVD) is a highly active process, and upregulation of osteogenic signaling is thought to be a major driver to initiation and progression of disease. While previous reports by our group and others demonstrated dysregulation of antioxidants and pro-oxidants in calcified aortic valves, it remains unclear if loss of antioxidant is a causal event driving valvular calcification and dysfunction. We hypothesized that MnSOD deficiency—an essential mitochondrial antioxidant—would result in accelerated reductions of cusp separation distance, increased osteogenic signaling, and augmented calcium deposition in a hypercholesterolemic mouse model of CAVD. We used ldlr -/- / ApoB 100/100 (LA) mice that were either wild-type (LA-MnSOD +/+ ) or MnSOD-deficient (LA-MnSOD +/- ), fed a Western Diet for 3 or 6 months. We used qRT-PCR and immunohistochemistry to measure changes in pro-osteogenic signaling, histopathological analyses of calcium burden (Alizarin Red), and echocardiography to assess aortic valve function. BMP2—a pro-osteogenic marker—increased over time with Western diet feeding, though MnSOD-deficiency did not exacerbate these increases. mRNA levels of pro-osteogenic markers (Runx2, Msx2) were also unchanged with either time on diet or with experimental reduction of MnSOD. Surprisingly, protein levels of late- stage osteoblast marker, osterix, were modestly decreased at the three month time point in in LA-MnSOD +/- mice compared to age-matched wild-type littermates. Consistent with our hypothesis, however, loss of mitochondrial antioxidant capacity substantially increased osterix protein levels and calcium burden at the 6 month time point compared to age-matched wild-type littermates. Functionally, loss of mitochondrial antioxidant capacity did not alter aortic valve cusp separation distance at both 3 and 6 month time points. Collectively, these data suggest that loss of MnSOD does not alter disease initiation but instead augments osteogenic signaling and valvular calcification in established aortic valve disease. Future studies aimed at targeting mitochondrial oxidative stress could elucidate novel strategies to slow progression of established CAVD.

Activation of soluble guanylate cyclase (sGC), a key downstream target of nitric oxide (NO) signaling, is reduced in valve tissue from patients with fibrocalcific aortic valve stenosis (FCAVS). We hypothesized that restoring NO signaling pathway using Ataciguat (ATA)—an activator of oxidized sGC—would slow progression of aortic valve calcification. To determine whether Ataciguat attenuates bone morphogenetic protein (BMP2) signaling in vitro, we treated mouse aortic valve interstitial cells with exogenous BMP2(200ng/ml) with or without ATA(10nm), and demonstrated that ATA significantly reduced canonical BMP2 signaling by more than 50% (p< 0.01). To determine whether Ataciguat slows progression of FCAVS in vivo , ldlr -/- /apoB 100/100 mice were assigned to one of two groups:1) 9 months of western diet feeding (WD), or 2) 6 months of WD followed by 3 months of WD + ATA (5mg/kg ATA). In this model, Ataciguat attenuated BMP signaling in aortic valve tissue (p < 0.05), reduced aortic valve calcification (p < 0.05), and prevented progression of aortic valve dysfunction (p < 0.05). Finally, to determine whether ATA slows progression of calcification in humans, we treated patients with mild-to-moderate FCAVS with placebo or ATA (200 mg/day) for 6 months. In this Phase II clinical trial, ATA significantly slowed progression of aortic valve calcification (computed tomography imaging; p = 0.05) and also tended to slow progressive reductions in aortic valve area and valvular stenosis. Collectively, we believe this is the first study to demonstrate the pre-clinical and clinical utility of pharmacologically stimulating sGC to attenuate osteogenic signaling and slow progression of aortic valve disease in mice and humans, and creates a unique opportunity for larger trials focused on the effectiveness of this strategy to delay or prevent surgery in FCAVS.

Sirtuin-6 (SIRT6) is a protein deacetylase that functions in several pathways related to aging, as complete loss of SIRT6 in mice elicits multiple age-associated phenotypes and premature death. While increasing age is a major risk factor for development of calcific aortic valve disease (CAVD), it is unclear whether loss of SIRT6 accelerates aortic valve calcification. Here, we report the role of SIRT6 in a subset of aortic valve interstitial cell progenitors (neural crest-derived VICs) by crossing mice carrying Cre recombinase under the control of a PAX3 promoter with mice harboring a SIRT6 gene that can be conditionally inactivated (SIRT6 FL/+ ). We hypothesized that tissue-specific reductions of SIRT6 would increase calcification, increase pro-osteogenic signaling, and impair aortic valve function. We examined mice of the genotypes Cre-/SIRT6 FL/+ or Cre+/ SIRT6 FL/+ at two different time points: young (3 months) and old (14-24 months). First, we used qRT-PCR to demonstrate that SIRT6 was effectively reduced in the aortic valve from PAX3-cre/SIRT6 FL/FL mice. Although reductions in SIRT6 did not change aortic valve calcium (Alizarin Red) in young mice, reducing SIRT6 increased valvular calcium levels in old mice compared to their WT littermates. Interestingly, protein levels of osterix were substantially increased in young, SIRT6-deficient mice compared to WT littermates but were paradoxically decreased in old SIRT6-deficient mice. Regardless of age, histopathological, or molecular changes, we did not observe detectable changes in cusp separation distance at any time point. Collectively, these data suggest that, contrary to our hypothesis, depletion of SIRT6 in neural crest cells—which are key progenitors of valve interstitial cells—is not sufficient to impair aortic valve function. Importantly, this finding suggests that age-associated reductions in SIRT6 may be a permissive context for development of CAVD but relies heavily on the presence of additional risk factors.

ABSTRACTBackground and AimsNerve conduction studies (NCS) are integral to diagnosing chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), but their role in predicting treatment outcomes remains underexplored. This study evaluates NCS changes at first follow‐up (first NCS changes) as predictors of treatment success in CIDP, focusing on their correlation with clinical outcomes over time.MethodsNewly diagnosed CIDP patients meeting the 2021 EAN/PNS criteria were retrospectively evaluated. Baseline and first follow‐up NCS parameters were compared with clinical outcomes, assessed by the Neuropathy Impairment Score (NIS) and Inflammatory Neuropathy Cause and Treatment (INCAT) disability score. All patients received first‐line immunotherapy (intravenous immunoglobulin, corticosteroids, or plasma exchange).ResultsOf 39 treated patients, 26 (66.7%) were responders based on improving NIS trends, while 13 (33.3%) were nonresponders. Responders showed significant improvements at the first follow‐up in fibular compound muscle action potential (CMAP) amplitude, ulnar CMAP amplitude, summated CMAP amplitudes, and fibular motor conduction velocity. Changes in fibular CMAP amplitude consistently correlated with NIS (R = −0.8 to −0.6, p ≤ 0.004) and INCAT disability score improvements (R = −0.6 to −0.3, p ≤ 0.032) across all follow‐up intervals up to 60 months. Ulnar and summated CMAP amplitude changes also correlated with clinical outcomes, though their associations were less sustained than those of fibular CMAP amplitude.InterpretationThe first change in fibular CMAP amplitude is a reliable biomarker for predicting CIDP treatment response, with ulnar and summated CMAP amplitudes as alternatives when the fibular response is absent. Our findings highlight the utility of first NCS changes in monitoring and predicting treatment outcomes in CIDP.

INTRODUCTION: The recent US Food and Drug Administration approval of resmetirom for treating metabolic dysfunction-associated steatohepatitis in patients necessitates patient selection for significant fibrosis or higher (≥F2). No existing vibration-controlled transient elastography (VCTE) algorithm targets ≥F2. METHODS: The mAchine Learning ADvanceD fibrosis and rIsk metabolic dysfunction-associated steatohepatitis Novel predictor (ALADDIN) study addressed this gap by introducing a machine-learning-based web calculator that estimates the likelihood of significant fibrosis using routine laboratory parameters with and without VCTE. Our study included a training set of 827 patients, a testing set of 504 patients with biopsy-confirmed metabolic dysfunction-associated steatotic liver disease from 6 centers, and an external validation set of 1,299 patients from 9 centers. Five algorithms were compared using area under the curve (AUC) in the test set: ElasticNet, random forest, gradient boosting machines, XGBoost, and neural networks. The top 3 (random forest, gradient boosting machines, and XGBoost) formed an ensemble model. RESULTS: In the external validation set, the ALADDIN-F2-VCTE model, using routine laboratory parameters with VCTE (AUC 0.791, 95% confidence interval [CI]: 0.764–0.819), outperformed VCTE alone (0.745, 95% CI 0.717–0.772, P < 0.0001), FibroScan-aspartate aminotransferase (0.710, 0.679–0.748, P < 0.0001), and Agile-3 model (0.740, 0.710–0.770, P < 0.0001) regarding the AUC, decision curve analysis, and calibration. The ALADDIN-F2-Lab model, using routine laboratory parameters without VCTE, achieved an AUC of 0.706 (95% CI: 0.668–0.749) and outperformed Fibrosis-4, steatosis-associated fibrosis estimator, and LiverRisk scores. DISCUSSION: Along with the steatosis-associated fibrosis estimator model developed to target significant fibrosis or higher, ALADDIN-F2-VCTE (https://aihepatology.shinyapps.io/ALADDIN1) uniquely supports a refined noninvasive approach to patient selection for resmetirom without the need for liver biopsy. In addition, ALADDIN-F2-Lab (https://aihepatology.shinyapps.io/ALADDIN2) offers an effective alternative when VCTE is unavailable.

Abstract Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder marked by progressive motor neuron degeneration in the primary motor cortex (PMC) and spinal cord. Aging is a key factor in ALS onset and progression, with evidence suggesting that biological aging—a process involving cellular decline— far outpaces chronological aging in ALS. This promotes senescent cell accumulation—marked by irreversible cell-cycle arrest, impaired apoptosis, and chronic inflammation—disrupting tissue homeostasis and impairing neuronal support functions. Thus, targeting senescence presents a novel therapeutic strategy for ALS. Here, we investigated the senolytic combination Dasatinib and Quercetin (D&Q) in TDP-43 Q331K ALS mice. D&Q improved neuromuscular function and reduced plasma neurofilament light chain, a biomarker of axonal damage. The most pronounced improvement was the improved cortical excitability, accompanied by reductions in senescence and TDP-43 in the PMC. These findings highlight the potential of senolytics to mitigate ALS-related dysfunction, supporting their viability as a therapeutic strategy. *Jose A. Viteriab, Nathan R. Kerrab, and Charles D. Brennana are co-first authors.

Abstract Human immune system (HIS) mice constructed in various ways are widely used for investigations of human immune responses to pathogens, transplants and immunotherapies. In HIS mice that generate T cells de novo from hematopoietic progenitors, T cell-dependent multisystem autoimmune disease occurs, most rapidly when the human T cells develop in the native NOD.Cg- Prkdcscid Il2rgtm1Wjl (NSG) mouse thymus, where negative selection is abnormal. Disease develops very late when human T cells develop in human fetal thymus grafts, where robust negative selection is observed. We demonstrate here that PD-1+CD4+ peripheral (Tph) helper-like and follicular (Tfh) helper-like T cells developing in HIS mice can induce autoimmune disease. Tfh- like cells were more prominent in HIS mice with a mouse thymus, in which the highest levels of IgG were detected in plasma, compared to those with a human thymus. While circulating IgG and IgM antibodies were autoreactive to multiple mouse antigens, in vivo depletion of B cells and antibodies did not delay the development of autoimmune disease. Conversely, adoptive transfer of enriched Tfh- or Tph-like cells induced disease and autoimmunity-associated B cell phenotypes in recipient mice containing autologous human APCs without T cells. Tfh/Tph cells from mice with a human thymus expanded and induced disease more rapidly than those originating in a murine thymus, implicating HLA-restricted T cell-APC interactions in this process. Since Tfh, Tph, autoantibodies and lymphopenia-induced proliferation (LIP) have all been implicated in various forms of human autoimmune disease, the observations here provide a platform for the further dissection of human autoimmune disease mechanisms and therapies.