Loss of Antigen Presentation in Adipose Tissue Macrophages or in Adipocytes, but Not Both, Improves Glucose Metabolism.

Macrophages, B cells, and adipocytes are among the adipose tissue (AT) APCs that differentiate and activate naive CD4+ T cells. Mice with adipocyte loss of MHC class II (MHC II) are more insulin sensitive. Because macrophages are professional APCs, mice with genetic myeloid MHC II depletion (myeloid MHC II knockout [mMHCII-/-]) were created and metabolically characterized. FITC+ glucan-coated particles (glucan-encapsulated small interfering RNA [siRNA] particles [GeRPs]) were also used to target MHC II knockout specifically in AT macrophages (ATMs). Mice with total body mMHCII-/- were generated by crossing LyzMCre with H2Ab1 floxed mice. For specific ATM depletion of H2Ab1, GeRPs containing H2Ab1 siRNA were administered to high-fat diet-fed C57BL/6 mice. Unexpectedly, mMHCII-/- mice had loss of both macrophage and adipocyte H2Ab1, one of only two Ag-presenting arms; thus, neither cell could present Ag and activate CD4+ T cells. This inability led to a reduction in AT immunosuppressive regulatory T cells, increased AT CD8+ T cells, and no improvement in systemic metabolism. Thus, with combined systemic myeloid and adipocyte MHC II loss, the impact of ATM-specific alterations in APC activity could not be delineated. Therefore, GeRPs containing H2Ab1 siRNA were administered to specifically reduce ATM H2Ab1 which, in contrast, revealed improved glucose tolerance. In conclusion, loss of either ATM or adipocyte APC function, but not both, improves systemic glucose metabolism because of maintenance of AT regulatory T cells.

Class III obesity rather than metabolic syndrome impacts clinical outcomes of acute pancreatitis: A propensity score weighted analysis.

OBJECTIVES: The incidence rates of acute pancreatitis (AP) and the prevalence of class III obesity, and metabolic syndrome (MetS) are increasing in the US. Since class III obesity was associated with adverse clinical outcomes of AP, we sought to understand if the presence of metabolic comorbidities collectively recognized, as MetS were associated with worse clinical outcomes and increased health-care utilization. METHODS: The Nationwide Readmissions Database (NRD) (2010-2014) was reviewed to identify all adult subjects with a principal discharge diagnosis of AP. Inpatient mortality, severe AP (SAP), and 30-day readmissions were the primary outcomes analyzed. Propensity score weighted analyses were used to compare AP subjects with and without MetS and were further stratified by class III obesity status. RESULTS: MetS was associated with 12.91% (139,165/1,078,183) of all admissions with AP. Propensity score weighted analyses showed that MetS was associated with an increased proportion of SAP (OR 1.21, 95% CI 1.17, 1.25), but decreased mortality (OR 0.62, 95% CI 0.54, 0.70) and 30-day readmissions (OR 0.86, 95% CI 0.83, 0.89). Propensity score weighted analyses also revealed that class III obesity was independently associated with increased mortality in AP subjects with (OR 1.92, 95% CI 1.41, 2.61) and without MetS (OR 1.55, 95% CI 1.26, 1.92), and increased SAP in subjects with and without MetS. CONCLUSIONS: Class III obesity appears to be the primary factor associated with adverse clinical outcomes in subjects with MetS admitted with AP. This has significant implications for patient management and future research targeting AP.

EUS-guided confocal laser endomicroscopy: prediction of dysplasia in intraductal papillary mucinous neoplasms (with video).

BACKGROUND AND AIMS: Previous studies have validated EUS-guided needle-based confocal laser endomicroscopy (nCLE) diagnosis of intraductal papillary mucinous neoplasms (IPMNs). We sought to derive EUS-guided nCLE criteria for differentiating IPMNs with high-grade dysplasia/adenocarcinoma (HGD-Ca) from those with low/intermediate-grade dysplasia (LGD). METHODS: We performed a post hoc analysis of consecutive IPMNs with a definitive diagnosis from a prospective study evaluating EUS-guided nCLE in the diagnosis of pancreatic cysts. Three internal endosonographers reviewed all nCLE videos for the patients and identified potential discriminatory EUS-guided nCLE variables to differentiate HGD-Ca from LGD IPMNs (phase 1). Next, an interobserver agreement (IOA) analysis of variables from phase 1 was performed among 6 blinded external nCLE experts (phase 2). Last, 7 blinded nCLE-naïve observers underwent training and quantified variables with the highest IOA from phase 2 using dedicated software (phase 3). RESULTS: Among 26 IPMNs (HGD-Ca in 16), the reference standard was surgical histopathology in 24 and cytology confirmation of metastatic liver lesions in 2 patients. EUS-guided nCLE characteristics of increased papillary epithelial "width" and "darkness" were the most sensitive variables (90%; 95% confidence interval [CI], 84%-94% and 91%; 95% CI, 85%-95%, respectively) and accurate (85%; 95% CI, 78%-90% and 84%; 95% CI, 77%-89%, respectively) with substantial (κ = 0.61; 95% CI, 0.51-0.71) and moderate (κ = 0.55; 95% CI, 0.45-0.65) IOAs for detecting HGD-Ca, respectively (phase 2). Logistic regression models were fit for the outcome of HGD-Ca as predictor variables (phase 3). For papillary width (cut-off ≥50 µm), the sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) for detection of HGD-Ca were 87.5% (95% CI, 62%-99%), 100% (95% CI, 69%-100%), and 0.95, respectively. For papillary darkness (cut-off ≤90 pixel intensity), the sensitivity, specificity, and AUC for detection of HGD-Ca were 87.5% (95% CI, 62%-99%), 100% (95% CI, 69%-100%), and 0.90, respectively. CONCLUSIONS: In this derivation study, quantification of papillary epithelial width and darkness identified HGD-Ca in IPMNs with high accuracy. These quantifiable variables can be used in multicenter studies for risk stratification of IPMNs. (Clinical trial registration number: NCT02516488.).

Endoscopic diagnosis of pancreatic cysts.

PURPOSE OF REVIEW: Pancreatic cystic lesions (PCLs) are increasingly identified on abdominal imaging. Given the malignant potential of certain cyst subtypes and the poor survival rates of pancreatic cancer, accurate diagnosis and appropriate management of these cysts are critical. RECENT FINDINGS: Advances in endoscopic ultrasound (EUS)-guided diagnostics have increased the accuracy of differentiating PCLs. These include cyst fluid molecular analysis, EUS-guided needle-based confocal laser endomicroscopy, and EUS-guided through the needle microforceps biopsy. This review encapsulates recent advances in the endoscopic management of PCLs with a specific focus on EUS-guided diagnosis. SUMMARY: It is important to accurately diagnose pancreatic cystic lesions with malignant potential where the definitive management is surgical resection. Misdiagnosis can result in inadvertent surgery of an otherwise benign lesion or malignant progression of a precancerous cyst. Moreover, pancreatic surgery is associated with significant morbidity and mortality. Recent advances in EUS-guided tissue acquisition, imaging, and molecular biomarkers have resulted in improved diagnostic accuracy of pancreatic cystic lesions. Future studies need to define efficient and accurate diagnostic algorithms for improved management of pancreatic cysts.

The effect of histopathologic analysis and tissue cultures on inpatient management of cellulitis: a randomized control trial.

BACKGROUND: In the absence of a gold-standard diagnostic modality for cellulitis, sterile inflammatory disorders may be misdiagnosed as cellulitis. OBJECTIVE: To determine the utility of skin biopsy and tissue culture for the diagnosis and management of patients admitted with a diagnosis of presumed cellulitis. DESIGN: Pilot single-blind parallel group randomized controlled clinical trial in 56 patients with a primary diagnosis of presumed cellulitis. In the intervention group only, skin biopsy and tissue culture results were made available to the primary care team to guide diagnosis and management. Length of hospital stay and antibiotic use were evaluated as outcome measures. RESULTS: Length of stay showed the greatest opportunity for further study as a primary outcome (intervention: 4, IQR (2-6) vs. control: 5 IQR (3-8) days; p = 0.124). LIMITATIONS: The COVID-19 pandemic placed limitations on participant enrollment and study duration; in addition, data was collected from a single medical center. CONCLUSION: This study demonstrates that length of stay and anti-pseudomonal antibiotic de-escalation are endpoints that may be influenced by biopsy and tissue culture results in presumed cellulitis patients; these outcomes warrant further study.

Obesity-associated microbiomes instigate visceral adipose tissue inflammation by recruitment of distinct neutrophils.

Neutrophils are increasingly implicated in chronic inflammation and metabolic disorders. Here, we show that visceral adipose tissue (VAT) from individuals with obesity contains more neutrophils than in those without obesity and is associated with a distinct bacterial community. Exploring the mechanism, we gavaged microbiome-depleted mice with stool from patients with and without obesity during high-fat or normal diet administration. Only mice receiving high-fat diet and stool from subjects with obesity show enrichment of VAT neutrophils, suggesting donor microbiome and recipient diet determine VAT neutrophilia. A rise in pro-inflammatory CD4+ Th1 cells and a drop in immunoregulatory T cells in VAT only follows if there is a transient spike in neutrophils. Human VAT neutrophils exhibit a distinct gene expression pattern that is found in different human tissues, including tumors. VAT neutrophils and bacteria may be a novel therapeutic target for treating inflammatory-driven complications of obesity, including insulin resistance and colon cancer.

Necrosis of the Ear Following Skin Cancer Resection.

We report 2 patients who underwent Mohs micrographic surgery (MMS) and operative closure on the ear. Both cases were complicated by necrosis resulting in the formation of auricular defects. These cases highlight the importance of the auricular vasculature and the associated watershed regions during operative planning for MMS as well as the complications that can arise with vascular compromise. This case report also provides a review of the auricular vasculature with special attention to these vulnerable watershed regions.

Adipocytes, Innate Immunity and Obesity: A Mini-Review.

The role of adipose tissue (AT) inflammation in obesity and its multiple related-complications is a rapidly expanding area of scientific interest. Within the last 30 years, the role of the adipocyte as an endocrine and immunologic cell has been progressively established. Like the macrophage, the adipocyte is capable of linking the innate and adaptive immune system through the secretion of adipokines and cytokines; exosome release of lipids, hormones, and microRNAs; and contact interaction with other immune cells. Key innate immune cells in AT include adipocytes, macrophages, neutrophils, and innate lymphoid cells type 2 (ILC2s). The role of the innate immune system in promoting adipose tissue inflammation in obesity will be highlighted in this review. T cells and B cells also play important roles in contributing to AT inflammation and are discussed in this series in the chapter on adaptive immunity.

Characterization of inflammatory changes in the breast cancer associated adipose tissue and comparison to the unaffected contralateral breast.

BACKGROUND: Adipose tissue has emerged as an important window into cancer pathophysiology, revealing potential targets for novel therapeutic interventions. The goal of this study was to compare the breast adipose tissue (BrAT) immune milieu surrounding breast carcinoma and contralateral unaffected breast tissue obtained from the same patient. MATERIALS AND METHODS: Patients undergoing bilateral mastectomy for unilateral breast cancer were enrolled for bilateral BrAT collection at the time of operation. After BrAT was processed, adipocyte and stromal vascular fraction (SVF) gene expression was quantified by PCR. SVF cells were also processed for flow cytometric immune cell characterization. RESULTS: Twelve patients underwent bilateral mastectomy for unilateral ductal carcinoma. BrAT adipocyte CXCL2 gene expression trended higher in the tumor-affected breast as compared to the unaffected breast. Macrophage MCP-1 and PPARγ gene expression also tended to be higher in the tumor-affected breasts. T cell gene expression of FOXP3 (p = 0.0370) were significantly greater in tumor-affected breasts than unaffected breasts. Affected BrAT contained higher numbers of Th2 CD4+ cells (p = 0.0165) and eosinophils (p = 0.0095) while trending towards increased macrophage and lower Th1 CD4+ cells infiltration than tumor-affected BrAT. CONCLUSION: This preliminary study aimed to identify the immunologic environment present within BrAT and is the first to directly compare this in individual patients' tumor-associated and unaffected BrAT. These findings suggest that cancer-affected BrAT had increased levels of T cell specific FOXP3 and higher levels of anti-inflammatory/regulatory cells compared to the contralateral BrAT.

Hospital outcomes and early readmission for the most common gastrointestinal and liver diseases in the United States: Implications for healthcare delivery.

BACKGROUND: Gastrointestinal (GI) and liver diseases contribute to substantial inpatient morbidity, mortality, and healthcare resource utilization. Finding ways to reduce the economic burden of healthcare costs and the impact of these diseases is of crucial importance. Thirty-day readmission rates and related hospital outcomes can serve as objective measures to assess the impact of and provide further insights into the most common GI ailments. AIM: To identify the thirty-day readmission rates with related predictors and outcomes of hospitalization of the most common GI and liver diseases in the United States. METHODS: A cross-sectional analysis of the 2012 National Inpatient Sample was performed to identify the 13 most common GI diseases. The 2013 Nationwide Readmission Database was then queried with specific International Classification of Diseases, Ninth Revision, Clinical Modification codes. Primary outcomes were mortality (index admission, calendar-year), hospitalization costs, and thirty-day readmission and secondary outcomes were predictors of thirty-day readmission. RESULTS: For the year 2013, the thirteen most common GI diseases contributed to 2.4 million index hospitalizations accounting for about $25 billion. The thirty-day readmission rates were highest for chronic liver disease (25.4%), Clostridium difficile (C. difficile) infection (23.6%), functional/motility disorders (18.5%), inflammatory bowel disease (16.3%), and GI bleeding (15.5%). The highest index and subsequent calendar-year hospitalization mortality rates were chronic liver disease (6.1% and 12.6%), C. difficile infection (2.3% and 6.1%), and GI bleeding (2.2% and 5.0%), respectively. Thirty-day readmission correlated with any subsequent admission mortality (r = 0.798, P = 0.001). Medicare/Medicaid insurances, ≥ 3 Elixhauser comorbidities, and length of stay > 3 d were significantly associated with thirty-day readmission for all the thirteen GI diseases. CONCLUSION: Preventable and non-chronic GI disease contributed to a significant economic and health burden comparable to chronic GI conditions, providing a window of opportunity for improving healthcare delivery in reducing its burden.

Obesogenic Memory Maintains Adipose Tissue Inflammation and Insulin Resistance.

BACKGROUND: Obesity is characterized by visceral adipose tissue (AT) inflammation. Immunosuppressive regulatory T cells (Tregs), phagocytic M2-like macrophages, and innate lymphoid cells type 2 (ILC2) control lean AT inflammation to maintain systemic insulin sensitivity, while the loss of these cells in obesity leads to AT inflammation and insulin resistance (IR). OBJECTIVE: The objective of this study was to determine if weight loss following obesity would correct AT inflammation and systemic metabolism. RESULTS: After six months of high fat diet (HFD) in male C57/Bl6 mice, flow analyses of epidydimal AT stromal vascular fraction (SVF) revealed depleted Tregs by 50%, doubling of CD8+ T cells, tripling of pro-inflammatory M1-like macrophages, and an 80% drop in ILC2 cells associated with changes in pro-inflammatory adipocyte and macrophage gene expression. Despite normalization of body weight, fat, and adipocyte size, mice ingesting 3 months of high-fat diet (HFD) followed by 3 months of chow-diet remained more insulin resistant and glucose intolerant than chow-fed animals. Adipocytes, AT Tregs, CD8+ T cells, ILC2 cells, and M1-like macrophages all failed to normalize with weight loss. CONCLUSIONS: Persistent AT inflammation contributes to the maintenance of IR despite body weight and fat normalization in previously obese mice. These findings highlight the importance of obesity prevention to avoid the consequences of "obesogenic memory."

Human Visceral Adipose Tissue Macrophages Are Not Adequately Defined by Standard Methods of Characterization.

Obesity is associated with a state of chronic low-grade inflammation both systemically and within specific tissues, including adipose tissue (AT). In murine models of obesity, there is a shift in the inflammatory profile of the AT immune cells, with an accumulation of proinflammatory M1 macrophages that surround the expanding adipocyte. However, much less is known about the immune cell composition and how to best define AT macrophages in humans. Objective. The goals of the current study were to determine the contribution of macrophages to the stromal vascular fraction (SVF) in lean versus obese human visceral AT (VAT); examine the expression of common M1, M2, and pan macrophage markers; and determine the association of specific macrophage types with known biomarkers of obesity-related cardiometabolic disease. Research Design and Methods. VAT biopsies were obtained from obese (n = 50) and lean (n = 8) patients during elective surgery. Adipocytes and SVF were isolated, and the SVF was subjected to flow cytometry analyses. Results. Our results indicate that VAT macrophages are increased in obesity and associate with biomarkers of CVD but that many macrophages do not fall into currently defined M1/M2 classification system based on CD206 receptor expression levels. Conclusions. VAT macrophages are increased in obese subjects, but the current markers used to define macrophage populations are inadequate to distinguish differences in human obesity. Further studies are needed to delineate the function of AT macrophages in the maintenance and progression of human AT inflammation in obesity.