Faculty Bibliography

INTRODUCTION/BACKGROUND:In city hospitals, subway-related traumatic amputations are a frequent pattern of injury, however there is a paucity of literature on this specific injury pattern. The purpose of this study was to describe the epidemiology of subway-related traumatic amputations, as well as compare them to non-subway traumatic amputations. PATIENTS AND METHODS/METHODS:Retrospective review was performed at a single Level-1 trauma center in a metropolitan area. All patients who sustained a traumatic lower-extremity amputation over a seven-year period were included. Demographics, injury, treatment-related information, and complications were collected. Subway and non-subway traumatic amputations were statistically compared. Cohorts were further subdivided into above-knee amputations (AKAs) and below-knee amputations (BKAs) for statistical comparison. RESULTS:Fifty-seven patients sustained 72 traumatic lower-extremity amputations, including 64 subway-related amputations. Fifteen patients with bilateral lower-extremity amputations all had subway-related injuries. Patients with subway-related injuries were more likely to have a history of alcohol use disorder (58.1 % vs. 0 %; P = 0.002), and experienced longer stays in the intensive care unit (ICU) (8.9 vs. 3.6 days; P = 0.006). Twenty-four amputations (33.3 %) were complicated by wound infection during the initial hospitalization, with wound cultures growing a variety of organisms, most frequently Enterococcus species and Enterobacter cloacae. When subway injuries were separated by AKAs and BKAs, patients with AKAs underwent more irrigation and debridement procedures on average (10.3 vs. 5.8; P = 0.006), had a higher rate of wound infections (58.8 % vs. 25.0 %; P = 0.018), and had longer hospital stays (50.4 vs. 32.2 days; P = 0.047). CONCLUSION/CONCLUSIONS:Subway-related amputations are associated with longer ICU stays and a history of alcohol use disorder compared to non-subway traumatic amputations. Approximately 1/3 of these patients are expected to develop a wound infection, with Enterococcus and Enterobacter species being the most commonly identified organisms. Further research into high-energy, traumatic amputations, including subway injuries, may help improve prognostication of patient outcomes, identify potential in-hospital complications, and proactively direct differences in care compared to the standard for non-subway-related amputations. LEVEL OF EVIDENCE/METHODS:Prognostic Level III.

BACKGROUND & AIMS/UNASSIGNED:Metabolic syndrome-associated steatotic liver disease (MASLD) and metabolic syndrome-associated steatohepatitis (MASH) have global prevalence rates exceeding 25% and 3-6%, respectively. The introduction of high-fructose corn syrup to the diet in the 1970s has been linked to metabolic and hepatic disturbances. Despite these associations, the potential for sex-dependent responses resulting from fructose-containing diets on MASLD/MASH has not been addressed. METHODS/UNASSIGNED:standard chow for 16 weeks (n = 40 mice). At sacrifice, plasma and liver were retrieved, the latter for single-nucleus RNA sequencing. Publicly available data sets of human male and female MASH liver were probed. RESULTS/UNASSIGNED:0.0001). Single-nucleus RNA sequencing revealed distinct sex-specific transcriptional profiles in hepatocytes and stellate cells responding to the FPC-NASH diet compared to the standard chow. In female mice, compared to males, pathways associated with lipid and metabolic processes in hepatocytes and cell-cell communication and adhesion in stellate cells were enriched. Metabolic flux analyses demonstrated reduced bile acid metabolism in female mice and human hepatocytes in FPC-NASH and MASH conditions, respectively, compared to their male counterparts. CONCLUSIONS/UNASSIGNED:Molecular profiling of hepatocytes and stellate cells in FPC-NASH diet-fed mice revealed significant sex differences mirrored in human MASH. The identification of intrinsic, within-sex, diet-dependent disparities underscores the critical need to include both male and female individuals in MAFLD/MASH studies and clinical trials. IMPACT AND IMPLICATIONS/UNASSIGNED:male patients with MASH. These results highlight potential mechanistic explanations and therapeutic targets for addressing sex differences and underscore the need to study both sexes in animal models and human MASH.

BACKGROUND/UNASSIGNED:Endovascular abdominal aortic aneurysm repair (EVAR) is a preferred surgery to prevent aneurysm sac enlargement and minimize the risk of life-threatening rupture in patients with AAA. Serious complications of type II endoleaks following EVAR can cause sac expansion and increase rupture risk. This study focused on evaluating clinical and blood characteristics in patients with type II endoleaks to refine our understanding of systemic fluctuations associated with unsuccessful EVAR. METHODS/UNASSIGNED:This retrospective study included 146 patients with AAA who underwent primary elective endovascular procedures (EVAR/fEVAR) between 2013 and 2021. Clinical characteristics, complete blood count (CBC) and imaging data were analyzed from patients who did and did not develop type II endoleaks. RESULTS/UNASSIGNED:Mean platelet volume (MPV) was significantly increased in patients who developed type II endoleaks after EVAR. Receiver operating characteristic analysis showed that MPV has a satisfactory discriminatory performance in distinguishing post-EVAR patients who developed type II endoleaks, yielding an area under the curve (AUC) value of 0.64. A risk stratification panel incorporating MPV, type II diabetes history, and administration of dual antiplatelet therapies yielded an AUC of 0.70 and predicted an endoleak-free survival rate with a hazard ratio of 2.94. A nomogram revealed that MPV had the highest scoring weight among all significant variables. CONCLUSION/UNASSIGNED:Patients with type II endoleaks following EVAR have elevated MPV indicative of different phenotypes of circulating platelets. MPV presents an attractive predictive criteria for assessing the occurrence of type II endoleaks in patients with AAA.

Glucocorticoids (GCs) are the most prescribed anti-inflammatory and immunosuppressive drugs. However, their use is often limited by substantial side effects, such as GC-induced osteoporosis (GIO) with the underlying mechanisms still not fully understood. In this study, we identify Tau as a low-affinity binding receptor for GCs that plays a crucial role in GIO. Tau deficiency largely abolished bone loss induced by high-dose dexamethasone, a synthetic GC, in both inflammatory arthritis and GIO models. Furthermore, TRx0237, a Tau inhibitor identified from an FDA-approved drug library, effectively prevented GIO. Notably, combinatorial administration of TRx0237 and dexamethasone completely overcame the osteoporosis adverse effect of dexamethasone in treating inflammatory arthritis. These findings present Tau as a previously unrecognized GC receptor with low affinity, and provide potential strategies to mitigate a spectrum of GC-related adverse effects, particularly osteoporosis.

Desmosomes are adhesive cell contacts abundant in tissues exposed to mechanical strain, such as the stratified and simple epithelia of the epidermis and mucous membranes, as well as the myocardium. Besides their role in mechanical cell cohesion, desmosomes also modulate pathways important for tissue differentiation, wound healing and immune responses. Dysfunctional desmosomes, resulting from pathogenic variants in genes encoding desmosomal components, autoantibodies targeting desmosomal adhesion molecules or inflammation, cause the life-threatening diseases arrhythmogenic cardiomyopathy and pemphigus and contribute to the pathogenesis of inflammatory bowel diseases. The Alpine Desmosome Disease Meeting 2024 (ADDM 2024), held in Grainau, Germany in October 2024, connected international researchers from basic sciences with clinical experts from dermatology, cardiology, gastroenterology and surgery. The participants discussed recent advances, identified hot topics in desmosome biology and disease and provided new concepts for pathogenesis and treatment approaches.

The human high-affinity sodium-dicarboxylate cotransporter (NaDC3) imports various substrates into the cell as tricarboxylate acid cycle intermediates, lipid biosynthesis precursors and signaling molecules. Understanding the cellular signaling process and developing inhibitors require knowledge of the structural basis of the dicarboxylate specificity and inhibition mechanism of NaDC3. To this end, we determined the cryo-electron microscopy structures of NaDC3 in various dimers, revealing the protomer in three conformations: outward-open C_o, outward-occluded C_oo and inward-open C_i. A dicarboxylate is first bound and recognized in C_o and how the substrate interacts with NaDC3 in C_oo likely helps to further determine the substrate specificity. A phenylalanine from the scaffold domain interacts with the bound dicarboxylate in the C_oo state and modulates the kinetic barrier to the transport domain movement. Structural comparison of an inhibitor-bound structure of NaDC3 to that of the sodium-dependent citrate transporter suggests ways for making an inhibitor that is specific for NaDC3.

BACKGROUND/UNASSIGNED:Cholesterol efflux capacity (CEC) of HDL (high-density lipoprotein) is inversely associated with incident cardiovascular events, independent of HDL cholesterol. Obesity is characterized by low HDL cholesterol and impaired HDL function, such as CEC. Bariatric surgery, including Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), broadly leads to improved cardiovascular outcomes, but impacts on risk factors differ by procedure, with greater improvements in weight loss, blood pressure, and glycemic control after RYGB, but greater improvements in HDL cholesterol and CEC levels after SG. This study sought to determine effects of RYGB and SG on HDL protein and lipid cargo and investigate associations with CEC changes. METHODS/UNASSIGNED:We prospectively studied nondiabetic, premenopausal Hispanic women with severe obesity not using lipid medications undergoing RYGB (n=31) or SG (n=36). Anthropometric measurements and blood sampling were obtained before and at 6 and 12 months after surgery. HDL was isolated from plasma, and quantitative proteomic and lipidomic assessments were performed with LC-MS/MS (liquid chromatography with tandem mass spectrometry). CEC was assessed ex vivo using apoB-depleted serum. RESULTS/UNASSIGNED:Participants experienced similar, significant weight loss over 12 months following bariatric surgery (38.0±10.4 kg) regardless of the procedure. Relative quantities of 47 proteins (34 increased, 13 decreased) and 150 lipids (71 increased, 79 decreased) carried on HDL were significantly altered following either surgical procedure. Proteins with similar aggregate response patterns were clustered into 15 groups (5 increased, 5 decreased, 5 minimal change) and lipids with similar aggregate responses into 25 groups (7 increased, 11 decreased, 7 minimal change). Network mediation analyses suggested that changes in 4 protein and 2 lipid clusters mediated changes in ABCA1 (ATP-binding cassette transporter A1) CEC and that 1 lipid cluster mediated changes in non-ABCA1 CEC. The protein and lipid clusters that mediated changes in CEC were distinct between SG and RYGB. CONCLUSIONS/UNASSIGNED:Bariatric surgery produces substantial changes in HDL lipid and protein cargo, and specific changes may mediate changes in HDL function in CEC. Further study of these mechanisms may lead to improved interventions to reduce cardiovascular risk in patients with obesity.

The discovery of long non-coding RNAs (lncRNAs) has provided a new perspective on the centrality of RNA in gene regulation and genome organization. Here, we screened for lncRNAs with putative functions in the host response to single-stranded RNA respiratory viruses. We identify CARINH as a conserved cis-acting lncRNA up-regulated in three respiratory diseases to control the expression of its antisense gene IRF1, a key transcriptional regulator of the antiviral response. CARINH and IRF1 are coordinately increased in the circulation of patients infected with human metapneumovirus, influenza A virus, or SARS-CoV-2, and in macrophages in response to viral infection or TLR3 agonist treatment. Targeted depletion of CARINH or its mouse ortholog Carinh in macrophages reduces the expression of IRF1/Irf1 and their associated target gene networks, increasing susceptibility to viral infection. Accordingly, CRISPR-mediated deletion of Carinh in mice reduces antiviral immunity, increasing viral burden upon sublethal challenge with influenza A virus. Together, these findings identify a conserved role of lncRNA CARINH in coordinating interferon-stimulated genes and antiviral immune responses.

BACKGROUND:Lipoprotein(a) [Lp(a)] is a driver of residual cardiovascular risk. Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) decrease Lp(a) with significant heterogeneity in response. We investigated contributors to the heterogeneous response. METHODS:CHOlesterol Reduction and Residual Risk in Diabetes (CHORD) was a prospective study examining lipid lowering in participants with a low-density lipoprotein cholesterol (LDL-C) >100 mg/dL with and without diabetes (DM) on lipid lowering therapy (LLT) for 30-days with evolocumab 140 mg every 14 days combined with either atorvastatin 80 mg or ezetimibe 10 mg daily. Lp(a) level was measured by immunoturbidometry, and the apolipoprotein (a) [apo(a)] isoform size was measured by denaturing agarose gel electrophoresis and western blotting. We examined the change in Lp(a) levels from baseline to 30 days. RESULTS:Among 150 participants (mean age 50 years, 58% female, 50% non-White, 17% Hispanic, 50% DM), median (interquartile range) Lp(a) was 27.5 (8-75) mg/dL at baseline and 23 (3-68) mg/dL at 30 days, leading to a 10% (0-36) median reduction (P < 0.001). Among 73 (49%) participants with Lp(a) ≥30 mg/dL at baseline, there was a 15% (3-25) median reduction in Lp(a) (P < 0.001). While baseline Lp(a) level was not correlated with change in Lp(a) (r = 0.04, P = 0.59), apo(a) size directly correlated with Lp(a) reduction (P < 0.001). After adjustment for age, sex, race/ethnicity, DM, and type of LLT, apo(a) size remained positively associated with a reduction in Lp(a) (Beta 0.95, 95% confidence interval, 0.93-0.97, P < 0.001). CONCLUSION/CONCLUSIONS:Our data demonstrate variation in Lp(a) reduction with potent LLT. Change in Lp(a) was strongly associated with apo(a) isoform size.

Human endogenous retroviruses (HERVs) occupy a large portion of the human genome. Most HERVs are transcriptionally silent, but they can be reactivated during pathological states such as viral infection and certain cancers. The HERV-K HML-2 clade includes elements that recently integrated have in the human germ line and often contain intact open reading frames that possibly support peptide and protein expression. Understanding HERV-K-host interactions and their potential as biomarkers is problematic due to the high similarity among different elements. Previously, we described a long-read single molecule real-time sequencing (PacBio) strategy to analyze HERV-K RNA expression profiles in different cell types. However, identifying HERV-K HML-2 proteins accurately is difficult without robust and reliable methods and reagents. Here we present a new approach to characterize the HML-2 elements that (a) are being translated and (b) produce enough protein to be detected and identified by mass spectrometry. Our data reveal that RNA expression profiling alone cannot accurately predict which HML-2 elements are responsible for protein production, as we observe several differences between the highest expressed RNAs and the elements that are the predominant source of HERV-K HML-2 protein synthesis. These studies represent an important advance toward untangling the complexity of HERV-K-host interactions.