Lymphangioleiomyomatosis Presenting as Recurrent Pneumothorax.

Lymphangioleiomyomatosis (LAM) is a disorder that causes cystic disease in the lungs. This condition is associated with renal angiomyolipomas and commonly occurs in individuals with tuberous sclerosis. Despite its frequent association with tuberous sclerosis, LAM is a rare condition and is often underdiagnosed. An identification of the array of signs for LAM is necessary to start the patient on appropriate long-term guideline-directed medical therapy. A 24-year-old female patient with a past medical history of tuberous sclerosis, gestational hypertension, stable renal angiomyolipoma, and recent pneumothorax presented to our emergency department complaining of four weeks of productive cough. On presentation, she was found to have stable vital signs, and on examination, she had absent breath sounds in the right basilar and anterior mid-lung field compared to the left. Subsequent imaging confirmed a recurrence of pneumothorax from her visit three months prior to her current presentation as well as progressive cystic lung disease and an unchanged angiomyolipoma, suggestive of LAM. We present this article with the hope of raising the index of suspicion for LAM in the setting of the particular signs and symptoms and to encourage prompt stabilization of the patient and initiation of guideline-directed medical therapy and strict follow-up to provide the greatest possible improvement in the patient's quality of life.

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."

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.

Clusterin Impairs Hepatic Insulin Sensitivity and Adipocyte Clusterin Associates With Cardiometabolic Risk.

OBJECTIVE: Components of the adipose tissue (AT) extracellular matrix (ECM) are recently discovered contributors to obesity-related cardiometabolic disease. We identified increased adipocyte expression of ECM-related clusterin (apolipoprotein J) in obese versus lean women by microarray. Our objective was to determine 1) whether subcutaneous AT adipocyte (SAd) clusterin and serum clusterin are associated with insulin resistance (IR) and known markers of cardiometabolic risk and 2) how clusterin may contribute to increased risk. RESEARCH DESIGN AND METHODS: We validated increased clusterin expression in adipocytes from a separate group of 18 lean and 54 obese individuals. The relationship of clusterin gene expression and plasma clusterin with IR, cardiovascular biomarkers, and risk of cardiovascular disease (CVD) was then determined. Further investigations in human cultured cells and in aged LDLR-/- mice prone to development of obesity-associated complications were performed. RESULTS: SAd clusterin correlated with IR, multiple CVD biomarkers, and CVD risk, independent of traditional risk factors. Circulating human clusterin exhibited similar associations. In human adipocytes, palmitate enhanced clusterin secretion, and in human hepatocytes, clusterin attenuated insulin signaling and APOA1 expression and stimulated hepatic gluconeogenesis. LRP2 (megalin), a clusterin receptor, highly expressed in liver, mediated these effects, which were inhibited by LRP2 siRNA. In response to Western diet feeding, an increase in adipocyte clusterin expression was associated with a progressive increase in liver fat, steatohepatitis, and fibrosis in aged LDLR-/- mice. CONCLUSIONS: Adipocyte-derived clusterin is a novel ECM-related protein linking cardiometabolic disease and obesity through its actions in the liver.