Caspase cleavage of gasdermin E causes neuronal pyroptosis in HIV-associated neurocognitive disorder.

Despite effective antiretroviral therapies, 20-30% of persons with treated HIV infection develop a neurodegenerative syndrome termed HIV-associated neurocognitive disorder (HAND). HAND is driven by HIV expression coupled with inflammation in the brain but the mechanisms underlying neuronal damage and death are uncertain. The inflammasome-pyroptosis axis coordinates an inflammatory type of regulated lytic cell death that is underpinned by the caspase-activated pore-forming gasdermin proteins. The mechanisms driving neuronal pyroptosis were investigated herein in models of HAND, using multi-platform molecular and morphological approaches that included brain tissues from persons with HAND and simian immunodeficiency virus (SIV)-infected non-human primates as well as cultured human neurons. Neurons in the frontal cortices from persons with HAND showed increased cleaved gasdermin E (GSDME), which was associated with ß-III tubulin degradation and increased HIV levels. Exposure of cultured human neurons to the HIV-encoded viral protein R (Vpr) elicited time-dependent cleavage of GSDME and Ninjurin-1 (NINJ1) induction with associated cell lysis that was inhibited by siRNA suppression of both proteins. Upstream of GSDME cleavage, Vpr exposure resulted in activation of caspases-1 and 3. Pretreatment of Vpr-exposed neurons with the caspase-1 inhibitor, VX-765, reduced cleavage of both caspase-3 and GSDME, resulting in diminished cell death. To validate these findings, we examined frontal cortical tissues from SIV-infected macaques, disclosing increased expression of GSDME and NINJ1 in cortical neurons, which was co-localized with caspase-3 detection in animals with neurological disease. Thus, HIV infection of the brain triggers the convergent activation of caspases-1 and -3, which results in GSDME-mediated neuronal pyroptosis in persons with HAND. These findings demonstrate a novel mechanism by which a viral infection causes pyroptotic death in neurons while also offering new diagnostic and therapeutic strategies for HAND and other neurodegenerative disorders.

Medicaid Expansion Is Associated With Increases in Medicaid-Funded Total Joint Arthroplasty.

BACKGROUND: Existing literature presents competing views concerning the impact of Medicaid expansion on total joint arthroplasty (TJA) utilizations. While some reports demonstrate that expansion does not increase Medicaid acceptance by surgeons, others show increases in Medicaid-funded TJA via limited analyses. We conducted a nationwide, multi-insurance, econometric study to determine if Medicaid-funded and all-funding-source total hip arthroplasty (THA) or total knee arthroplasty (TKA) utilizations increased following expansion. METHODS: This study examined 999,015 THA and 2,099,975 TKA from 2010 to 2017 using a commercially available national payer database. Difference-in-differences analyses, econometric regression methods used to assess the impact of policy change, were used to examine the impact of Medicaid expansion on TJA utilizations, and event analyses were used to confirm the parallel trends assumption, which helps to ensure that the estimated effect is not a result of existing differences in trends between treatment and nontreatment groups. RESULTS: Event analyses confirmed parallel trends in the pre-expansion period. Difference-in-differences analyses found a persistent increase in Medicaid-funded THA (40.4%, P = .001, confidence interval [CI]: 12.7, 62.1%), but not THA from all funding sources (4.6%, P = .128, CI: -1.3, 10.8%). Medicaid-funded TKA (35.8%, P < .001, CI: 17.4, 68.0%) increased, but not TKA from all funding sources (3.4%, P = .321, CI: -3.1, 10.1%). CONCLUSION: While the number of Medicaid-funded TJAs increased, expansion had no significant effect when examining all funding sources. This suggests that Medicaid expansion primarily affected source of TJA funding, not overall volume. Further research is needed to examine state-specific predictors of response to Medicaid expansion.

The Effect of Surgical Approach on the Outcomes of Same-Day Discharge Outpatient Total Hip Arthroplasty at a Single Ambulatory Surgery Center.

BACKGROUND: Primary total hip arthroplasty (THA) is increasingly being performed in the outpatient setting. However, there is little known regarding the differences in same-day discharge (SDD) rates and complications of operative approach in same-day total hip arthroplasty in the ambulatory surgery center (ASC) setting. METHODS: A retrospective chart review was performed between July 2019 and October 2021 for all patients who underwent primary THA in a single freestanding ASC. Successful SDDs, surgical approaches, lengths of surgery, estimated blood losses (EBL), complications, and readmission events were recorded for each patient. Complications were compared using Pearson Chi-Squares, while EBL and surgery lengths were compared with 1-way analysis of variances (ANOVA) (alpha = 0.5). There were 17 total complications in 326 total hip arthroplasties (5.2%), including direct admissions to the emergency department, 30-day and 90-day readmissions, wound complications, instability, infection, and revision surgery. Among all complications, there were 5 direct admissions, making the successful SDD rate 98.5%. RESULTS: Complications and direct admissions were not associated with approach. The 30-day readmission rates were associated with approach, with no readmissions in the direct anterior approach (DAA) or the antero-lateral approach (AL) cohorts and 3 (4.3%) in the posterior approach (PA) cohort. CONCLUSIONS: In the ASC setting, patients undergoing THA regardless of approach showed no difference in successful SDDs or complications aside from 30-day readmissions. Same-day THA can be safely performed in the DAA, AL, and PA to the hip.

Chronic Anticoagulation in Patients Who Have Atrial Fibrillation Undergoing Outpatient Total Knee Arthroplasty: A Retrospective Matched Cohort Study.

BACKGROUND: Patients who have atrial fibrillation frequently require long-term anticoagulation with warfarin or a direct-acting oral anticoagulant (DOAC), such as apixaban or rivaroxaban, to avoid vascular complications. However, the impact of anticoagulant use on postoperative complications following total knee arthroplasty (TKA) in an outpatient setting has not been thoroughly elucidated. The purpose of this study was to examine the impact of anticoagulant use on early postoperative complications among atrial fibrillation patients undergoing outpatient TKA. METHODS: An insurance claims database was queried to identify all patients who underwent outpatient TKA between January 2010 and April 2022. There were two cohorts of patients, with associated 1:1 matched controls, who had atrial fibrillation and filled a prescription of either warfarin (N = 4,396) or DOAC (N = 5,383) for at least 30 days. The mean age was 70 years (range, 51 to 84 years) and 47.9% were women in the warfarin cohort, while the mean age was 70 years and 49.2% were women in the DOAC cohort. Postoperative 30-day medical and 90-day surgical complications were subsequently compared. RESULTS: Patients on warfarin had a higher incidence of pulmonary embolism (1.1 versus 0.2%, P < 0.001) and a lower incidence of TKA revision (0.1 versus 0.4%, P = 0.003) than matched controls. Similarly, patients on DOACs exhibited a higher incidence of pneumonia (1.4 versus 0.6%, P < 0.001) and myocardial infarction (3.2 versus 1.5%, P < 0.001) and a lower incidence of wound dehiscence (0.1 versus 0.5%, P < 0.001), joint infection (0.4 versus 0.9%, P = 0.002), and TKA revision (0.1 versus 0.4%, P = 0.002) than matched controls. CONCLUSIONS: Atrial fibrillation patients on long-term anticoagulants undergoing outpatient TKA experience higher rates of medical complications and lower rates of surgical complications than matched controls. Thus, patients on long-term anticoagulants may be considered for outpatient TKA, but should be counseled appropriately on associated medical risks.

Changes in mammographic density and risk of breast cancer among a diverse cohort of women undergoing mammography screening.

PURPOSE: Mammographic density (MD) is a strong breast cancer risk factor. MD may change over time, with potential implications for breast cancer risk. Few studies have assessed associations between MD change and breast cancer in racially diverse populations. We investigated the relationships between MD and MD change over time and breast cancer risk in a large, diverse screening cohort. MATERIALS AND METHODS: We retrospectively analyzed data from 8462 women who underwent ≥ 2 screening mammograms from Sept. 2010 to Jan. 2015 (N = 20,766 exams); 185 breast cancers were diagnosed 1-7 years after screening. Breast percent density (PD) and dense area (DA) were estimated from raw digital mammograms (Hologic Inc.) using LIBRA (v1.0.4). For each MD measure, we modeled breast density change between two sequential visits as a function of demographic and risk covariates. We used Cox regression to examine whether varying degrees of breast density change were associated with breast cancer risk, accounting for multiple exams per woman. RESULTS: PD at any screen was significantly associated with breast cancer risk (hazard ratio (HR) for PD = 1.03 (95% CI [1.01, 1.05], p < 0.0005), but neither change in breast density nor more extreme than expected changes in breast density were associated with breast cancer risk. We found no evidence of differences in density change or breast cancer risk due to density change by race. Results using DA were essentially identical. CONCLUSIONS: Using a large racially diverse cohort, we found no evidence of association between short-term change in MD and risk of breast cancer, suggesting that short-term MD change is not a strong predictor for risk.

Distinctive Roles of Furin and TMPRSS2 in SARS-CoV-2 Infectivity.

The spike protein (S) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) directs infection of the lungs and other tissues following its binding to the angiotensin-converting enzyme 2 (ACE2) receptor. For effective infection, the S protein is cleaved at two sites: S1/S2 and S2'. The "priming" of the surface S protein at S1/S2 (PRRAR685↓) [the underlined basic amino acids refer to critical residues needed for the furin recognition] by furin has been shown to be important for SARS-CoV-2 infectivity in cells and small-animal models. In this study, for the first time we unambiguously identified by proteomics the fusion activation site S2' as KPSKR815↓ (the underlined basic amino acids refer to critical residues needed for the furin recognition) and demonstrated that this cleavage was strongly enhanced by ACE2 engagement with the S protein. Novel pharmacological furin inhibitors (BOS inhibitors) effectively blocked endogenous S protein processing at both sites in HeLa cells, and SARS-CoV-2 infection of lung-derived Calu-3 cells was completely prevented by combined inhibitors of furin (BOS) and type II transmembrane serine protease 2 (TMPRSS2) (camostat). Quantitative analyses of cell-to-cell fusion and S protein processing revealed that ACE2 shedding by TMPRSS2 was required for TMPRSS2-mediated enhancement of fusion in the absence of S1/S2 priming. We further demonstrated that the collectrin dimerization domain of ACE2 was essential for the effect of TMPRSS2 on cell-to-cell fusion. Overall, our results indicate that furin and TMPRSS2 act synergistically in viral entry and infectivity, supporting the combination of furin and TMPRSS2 inhibitors as potent antivirals against SARS-CoV-2. IMPORTANCE SARS-CoV-2, the etiological agent of COVID-19, has so far resulted in >6.1 million deaths worldwide. The spike protein (S) of the virus directs infection of the lungs and other tissues by binding the angiotensin-converting enzyme 2 (ACE2) receptor. For effective infection, the S protein is cleaved at two sites: S1/S2 and S2'. Cleavage at S1/S2 induces a conformational change favoring the S protein recognition by ACE2. The S2' cleavage is critical for triggering membrane fusion and virus entry into host cells. Our study highlights the complex dynamics of interaction between the S protein, ACE2, and the host proteases furin and TMPRSS2 during SARS-CoV-2 entry and suggests that the combination of a nontoxic furin inhibitor with a TMPRSS2 inhibitor significantly reduces viral entry in lung cells, as evidenced by an average synergistic ∼95% reduction of viral infection. This represents a powerful novel antiviral approach to reduce viral spread in individuals infected by SARS-CoV-2 or future related coronaviruses.

RALDH Activity Induced by Bacterial/Fungal Pathogens in CD16+ Monocyte-Derived Dendritic Cells Boosts HIV Infection and Outgrowth in CD4+ T Cells.

HIV reservoirs persist in gut-homing CD4+ T cells of people living with HIV and receiving antiretroviral therapy, but the antigenic specificity of such reservoirs remains poorly documented. The imprinting for gut homing is mediated by retinoic acid (RA), a vitamin A-derived metabolite produced by dendritic cells (DCs) exhibiting RA-synthesizing (RALDH) activity. RALDH activity in DCs can be induced by TLR2 ligands, such as bacterial peptidoglycans and fungal zymosan. Thus, we hypothesized that bacterial/fungal pathogens triggering RALDH activity in DCs fuel HIV reservoir establishment/outgrowth in pathogen-reactive CD4+ T cells. Our results demonstrate that DCs derived from intermediate/nonclassical CD16+ compared with classical CD16- monocytes exhibited superior RALDH activity and higher capacity to transmit HIV infection to autologous Staphylococcus aureus-reactive T cells. Exposure of total monocyte-derived DCs (MDDCs) to S. aureus lysates as well as TLR2 (zymosan and heat-killed preparation of Listeria monocytogenes) and TLR4 (LPS) agonists but not CMV lysates resulted in a robust upregulation of RALDH activity. MDDCs loaded with S. aureus or zymosan induced the proliferation of T cells with a CCR5+integrin ß7+CCR6+ phenotype and efficiently transmitted HIV infection to these T cells via RALDH/RA-dependent mechanisms. Finally, S. aureus- and zymosan-reactive CD4+ T cells of antiretroviral therapy-treated people living with HIV carried replication-competent integrated HIV-DNA, as demonstrated by an MDDC-based viral outgrowth assay. Together, these results support a model in which bacterial/fungal pathogens in the gut promote RALDH activity in MDDCs, especially in CD16+ MDDCs, and subsequently imprint CD4+ T cells with gut-homing potential and HIV permissiveness. Thus, nonviral pathogens play key roles in fueling HIV reservoir establishment/outgrowth via RALDH/RA-dependent mechanisms that may be therapeutically targeted.

Risk of Dislocation and Revision Following Primary Total Hip Arthroplasty in Patients With Prior Lumbar Fusion With Spinopelvic Fixation.

BACKGROUND: The effect of spinopelvic fixation in addition to lumbar spinal fusion (LSF) on dislocation/instability and revision in patients undergoing primary total hip arthroplasty (THA) has not been reported previously. METHODS: The PearlDiver Research Program was used to identify patients aged 30 and above undergoing primary THA who received (1) THA only, (2) THA with prior single-level LSF, (3) THA with prior 2-5 level LSF, or (4) THA with prior LSF with spinopelvic fixation. The incidence of THA revision and dislocation/instability was compared through logistic regression and Chi-squared analysis. All regressions were controlled for age, gender, and Elixhauser Comorbidity Index (ECI). RESULTS: Between 2010 and 2018, 465,558 patients without history of LSF undergoing THA were examined and compared to 180 THA patients with prior spinopelvic fixation, 5,299 with prior single-level LSF, and 1,465 with prior 2-5 level LSF. At 2 years, 7.8% of THA patients with prior spinopelvic fixation, 4.7% of THA patients with prior 2-5 level LSF, 4.2% of THA patients with prior single-level LSF, and 2.2% of THA patients undergoing only THA had a dislocation event or instability (P < .0001). After controlling for length of fusion, pelvic fixation itself was associated with higher independent risk of revision (at 2 years: 2-5 level LSF + spinopelvic fixation: aHR = 3.15, 95% CI 1.77-5.61, P < .0001 vs 2-5 level LSF with no spinopelvic fixation: aOR = 1.39, 95% CI 1.10-1.76, P < .0001). CONCLUSION: At 2 years, spinopelvic fixation in THA patients were associated with a greater than 3.5-fold increase in hip dislocation risk compared to those without LSF, and an over 2-fold increase in THA revision risk compared to those with LSF without spinopelvic fixation. LEVEL OF EVIDENCE: III.

Underweight Patients are at Increased Risk for Complications following Total Hip Arthroplasty.

BACKGROUND: Given the prevalence of obesity in the United States, much of the adult reconstruction literature focuses on the effects of obesity and morbid obesity. However, there is little published data on the effect of being underweight on postoperative outcomes. This study aimed to examine the risk of low body mass index (BMI) on complications after total hip arthroplasty (THA). METHODS: A large national database was queried between 2010 and 2020 to identify patients who had THAs. Using International Classification of Disease codes, patients were grouped into the following BMI categories: morbid obesity (BMI>40), obesity (BMI 30 to 40), normal BMI (BMI 20 to 30), and underweight (BMI<20). There were 58,151 patients identified, including 2,484 (4.27%) underweight patients, 34,710 (59.69%) obese patients, and 20,957 (36.04%) morbidly obese patients. Control groups were created for each study group, matching for age, sex, and a comorbidity index. Complications that occurred within 1 year postoperatively were isolated. Subanalyses were performed to compare complications between underweight and obese patients. Statistical analyses were performed using Pearson Chi-squares. RESULTS: Compared to their matched control group, underweight patients showed increased odds of THA revision (Odds Ratio (OR) = 1.32, P = .04), sepsis (OR = 1.51, P = .01), and periprosthetic fractures (OR = 1.63, P = .01). When directly comparing underweight and obese patients (BMI 30 and above), underweight patients had higher odds of aseptic loosening (OR = 1.62, P = .03), sepsis (OR = 1.34, P = .03), dislocation (OR = 1.84, P < .001), and periprosthetic fracture (OR = 1.46, P = .01). CONCLUSION: Morbidly obese patients experience the highest odds of complications, although underweight patients also had elevated odds for several complications. Underweight patients are an under-recognized and understudied high risk arthroplasty cohort and further research is needed.

Preoperative meningioma embolization reduces perioperative blood loss: a multi-center retrospective matched case-control study.

BACKGROUND AND PURPOSE: The utility of preoperative embolization remains controversial within the literature. Here, we evaluate whether preoperative meningioma embolization is effective in reducing intraoperative blood loss, safe to perform, and cost-effective when compared with surgical resection without preoperative embolization. METHODS: Twenty-nine patients with meningiomas were matched by tumor size and location to 29 control patients with meningiomas at another institution where preoperative embolization was not practiced. The variables evaluated were pre- and post-operative hemoglobin and hematocrit levels as a measure of operative blood loss and postoperative morbidity. The additional cost of undergoing angiography and embolization was calculated from hospital charges obtained from the billing department. RESULTS: The mean decrease in perioperative hemoglobin and hematocrit was 0.9 and 2.7, respectively, in the embolization group and 2.8 and 10.0, respectively, in the control group for a significant decrease in operative blood loss as measured by change in hematocrit and hemoglobin levels after surgery. There was no significant difference in operative blood loss when subdividing patients based on tumor location. There were no angiogram-related complications. Twenty-two of 29 patients (76%) underwent embolization of a feeding artery, whereas 7 patients underwent only a diagnostic angiogram. The mean additional charge per patient in the embolization group was $88,767. CONCLUSIONS: Preoperative embolization was safe and effective in reducing the overall perioperative blood loss in patients undergoing meningioma resection, as measured by the change in postoperative hemoglobin and hematocrit levels. However, the cost of embolization was significant.