Senescence-associated ß-galactosidase in subcutaneous adipose tissue associates with altered glycaemic status and truncal fat in severe obesity.

AIM/HYPOTHESIS: Altered adipose tissue secretory profile contributes to insulin resistance and type 2 diabetes in obesity. Preclinical studies have identified senescent cells as a cellular source of proinflammatory factors in adipose tissue of obese mice. In humans, potential links with obesity comorbidities are poorly defined. Here, we investigated adipose tissue senescent status and relationships with metabolic complications in human obesity. METHODS: The study includes a prospective cohort of 227 individuals with severe obesity. A photometric method was used to quantify senescence-associated ß-galactosidase (SA-ß-gal) activity in paired subcutaneous and omental adipose tissue biopsies obtained during gastric surgery. Gene and secretory profiling was performed in adipose tissue biopsies and in human primary pre-adipocytes in the presence or absence of senolytic drugs targeting senescent cells. Participants were phenotyped for anthropometric and bioclinical variables, metabolic complications and gastric surgery-induced improvement to address relationships with adipose tissue SA-ß-gal. RESULTS: SA-ß-gal activity was sevenfold higher in subcutaneous than in omental adipose tissue and not associated with BMI or chronological age. Several factors, including insulin-like growth factor binding protein 3 (IGFBP3), plasminogen activator inhibitor 1 (PAI1), C-C motif chemokine ligand 2 (CCL2) and IL-6, were upregulated in subcutaneous adipose tissue in relation with SA-ß-gal (p for linear trend across tertiles <0.05) and in pre-adipocytes cultured with inflammatory macrophage conditioned media. Senolytic treatment reduced SA-ß-gal staining and normalised these alterations. In the whole population, subcutaneous adipose tissue SA-ß-gal activity was positively associated with serum leptin, markers of insulin resistance and increased trunk fat mass. Metabolic complications, including type 2 diabetes and dyslipidaemia, were more prevalent in patients with high levels of SA-ß-gal, but improved with bariatric surgery whatever the initial adipose tissue senescent status. CONCLUSIONS/INTERPRETATION: This study highlights a phenotype of senescence in adipose tissue of severely obese individuals, which characterises prominently subcutaneous fat depots. Subcutaneous adipose tissue senescence is significantly linked to altered glucose metabolism and body fat distribution. Elimination of senescent cells through senolytic treatment could alleviate metabolic complications in severely obese people. Graphical abstract.

"If I knew I could get that every hour instead of alcohol, I would take the cannabis": need and feasibility of cannabis substitution implementation in Canadian managed alcohol programs.

BACKGROUND: While there is robust evidence for strategies to reduce harms of illicit drug use, less attention has been paid to alcohol harm reduction for people experiencing severe alcohol use disorder (AUD), homelessness, and street-based illicit drinking. Managed Alcohol Programs (MAPs) provide safer and regulated sources of alcohol and other supports within a harm reduction framework. To reduce the impacts of heavy long-term alcohol use among MAP participants, cannabis substitution has been identified as a potential therapeutic tool. METHODS: To determine the feasibility of cannabis substitution, we conducted a pre-implementation mixed-methods study utilizing structured surveys and open-ended interviews. Data were collected from MAP organizational leaders (n = 7), program participants (n = 19), staff and managers (n = 17) across 6 MAPs in Canada. We used the Consolidated Framework for Implementation Research (CFIR) to inform and organize our analysis. RESULTS: Five themes describing feasibility of CSP implementation in MAPs were identified. The first theme describes the characteristics of potential CSP participants. Among MAP participants, 63% (n = 12) were already substituting cannabis for alcohol, most often on a weekly basis (n = 8, 42.1%), for alcohol cravings (n = 15, 78.9%,) and withdrawal (n = 10, 52.6%). Most MAP participants expressed willingness to participate in a CSP (n = 16, 84.2%). The second theme describes the characteristics of a feasible and preferred CSP model according to participants and staff. Participants preferred staff administration of dry, smoked cannabis, followed by edibles and capsules with replacement of some doses of alcohol through a partial substitution model. Themes three and four highlight organizational and contextual factors related to feasibility of implementing CSPs. MAP participants requested peer, social, and counselling supports. Staff requested education resources and enhanced clinical staffing. Critically, program staff and leaders identified that sustainable funding and inexpensive, legal, and reliable sourcing of cannabis are needed to support CSP implementation. CONCLUSION: Cannabis substitution was considered feasible by all three groups and in some MAPs residents are already using cannabis. Partial substitution of cannabis for doses of alcohol was preferred. All three groups identified a need for additional supports for implementation including peer support, staff education, and counselling. Sourcing and funding cannabis were identified as primary challenges to successful CSP implementation in MAPs.

The Integrase Inhibitors Dolutegravir and Raltegravir Exert Proadipogenic and Profibrotic Effects and Induce Insulin Resistance in Human/Simian Adipose Tissue and Human Adipocytes.

BACKGROUND: Although some integrase strand transfer inhibitors (INSTIs) promote peripheral and central adipose tissue/weight gain in people with human immunodeficiency virus (PHIV), the underlying mechanism has not been identified. Here, we used human and simian models to assess the impact of INSTIs on adipose tissue phenotype and function. METHODS: Adipocyte size and fibrosis were determined in biopsies of subcutaneous and visceral adipose tissue (SCAT and VAT, respectively) from 14 noninfected macaques and 19 PHIV treated or not treated with an INSTI. Fibrosis, adipogenesis, oxidative stress, mitochondrial function, and insulin sensitivity were assessed in human proliferating or adipocyte-differentiated adipose stem cells after long-term exposure to dolutegravir or raltegravir. RESULTS: We observed elevated fibrosis, adipocyte size, and adipogenic marker expression in SCAT and VAT from INSTI-treated noninfected macaques. Adiponectin expression was low in SCAT. Accordingly, SCAT and VAT samples from INSTI-exposed patients displayed higher levels of fibrosis than those from nonexposed patients. In vitro, dolutegravir and, to a lesser extent, raltegravir were associated with greater extracellular matrix production and lipid accumulation in adipose stem cells and/or adipocytes as observed in vivo. Despite the INSTIs' proadipogenic and prolipogenic effects, these drugs promoted oxidative stress, mitochondrial dysfunction, and insulin resistance. CONCLUSIONS: Dolutegravir and raltegravir can directly impact adipocytes and adipose tissue. These INSTIs induced adipogenesis, lipogenesis, oxidative stress, fibrosis, and insulin resistance. The present study is the first to shed light on the fat modifications observed in INSTI-treated PHIV.

Knee and hip intra-articular adipose tissues (IAATs) compared with autologous subcutaneous adipose tissue: a specific phenotype for a central player in osteoarthritis.

OBJECTIVES: Compared with subcutaneous adipose tissue (SCAT), infrapatellar fat pad (IFP), the main knee intra-articular adipose tissue (IAAT), has an inflammatory phenotype in patients with osteoarthritis (OA). We phenotyped suprapatellar fat pad (SPFP) and hip acetabular fat pad (AFP), two other IAATs, to determinate the unique signature of IAATs compared with SCAT. METHODS: IFP, SPFP, AFP and autologous SCAT were obtained from patients with OA during total knee (n=38) or hip replacement (n=5). Fibrosis and adipocyte area were analysed by histology and vascularisation, leucocyte and mast cell infiltration were analysed by immunohistochemistry for von Willebrand factor, leucocytes and tryptase, respectively. Secretion of interleukin (IL)-6, IL-8 and prostaglandin E2 (PGE2) was assessed by ELISA. The mRNA expression of adipocyte-associated genes (ATGL, LPL, PPAR-γ, FABP4 and CD36) and developmental genes (SFRP2, HoxC9 and EN1) was determined. The inflammatory response of isolated fibroblast-like synoviocytes (FLS) to autologous IFP and SPFP conditioned media was examined. RESULTS: Fibrosis, vascularisation and leucocyte and mast cell infiltration were greater in IAATs than SCAT, and levels of IL-6, IL-8 and PGE2 were greater in all IAATs than SCAT. IFP and SPFP induced a similar inflammatory response to FLS. Adipocyte area was smaller in IAATs than SCAT. Adipocyte-associated and developmental genes showed a similar gene expression pattern in all IAATs, different from SCAT. CONCLUSIONS: IFP but also SPFP and AFP (gathered under the term 'IAAT') may play a deleterious role in OA by affecting joint homeostasis because of their inflammatory phenotype and their close interaction with synovium in the same functional unit.

SIV Infection and the HIV Proteins Tat and Nef Induce Senescence in Adipose Tissue and Human Adipose Stem Cells, Resulting in Adipocyte Dysfunction.

BACKGROUND: Aging is characterized by adipose tissue senescence, inflammation, and fibrosis, with trunk fat accumulation. Aging HIV-infected patients have a higher risk of trunk fat accumulation than uninfected individuals-suggesting that viral infection has a role in adipose tissue aging. We previously demonstrated that HIV/SIV infection and the Tat and Nef viral proteins were responsible for adipose tissue fibrosis and impaired adipogenesis. We hypothesized that SIV/HIV infection and viral proteins could induce adipose tissue senescence and thus lead to adipocyte dysfunctions. METHODS: Features of tissue senescence were evaluated in subcutaneous and visceral adipose tissues of SIV-infected macaques and in human adipose stem cells (ASCs) exposed to Tat or Nef for up to 30 days. RESULTS: p16 expression and p53 activation were higher in adipose tissue of SIV-infected macaques than in control macaques, indicating adipose tissue senescence. Tat and Nef induced higher senescence in ASCs, characterized by higher levels of senescence-associated beta-galactosidase activity, p16 expression, and p53 activation vs. control cells. Treatment with Tat and Nef also induced oxidative stress and mitochondrial dysfunction. Prevention of oxidative stress (using N-acetyl-cysteine) reduced senescence in ASCs. Adipocytes having differentiated from Nef-treated ASCs displayed alterations in adipogenesis with lower levels of triglyceride accumulation and adipocyte marker expression and secretion, and insulin resistance. CONCLUSION: HIV/SIV promotes adipose tissue senescence, which in turn may alter adipocyte function and contribute to insulin resistance.

Contribution of adipocyte precursors in the phenotypic specificity of intra-articular adipose tissues in knee osteoarthritis patients.

BACKGROUND: Intra-articular adipose tissues (IAATs) are involved in osteoarthritis (OA) pathophysiology. We hypothesize that mesenchymal cells residing in IAATs may account for the specific inflammatory and metabolic patterns in OA patients. METHODS: Adipocyte precursors (preadipocytes and dedifferentiated fat cells (DFATc)) from IAATs (infrapatellar and suprapatellar fat pads) and autologous subcutaneous adipose tissues (SCATs) were isolated from knee OA patients. The ability of these precursors to differentiate into adipocytes was assessed by oil red O staining after 14 days of culture in adipogenic medium. The gene expression of adipocyte-related transcription factors (C/EBP-α and PPAR-γ) and development-related factors (EN1 and SFRP2) were analyzed. The inflammatory pattern was assessed by RT-qPCR and ELISA (interleukin 6 (IL-6), IL-8, Cox2, and prostaglandin E2 (PGE2)) after a 24-h stimulation by IL-1ß (1 ng/mL) and by conditioned medium from OA synovium. RESULTS: IAAT preadipocytes displayed a significantly higher ability to differentiate into adipocytes and expressed significantly more C/EBP-α mRNA than SCAT preadipocytes. IAAT preadipocytes expressed significantly less EN-1 and SFRP2 mRNA than SCAT preadipocytes. Unstimulated IAAT preadipocytes displayed a less inflammatory pattern (IL-6, IL-8, and Cox2/PGE2) than SCAT preadipocytes. In contrast, the response of IAAT preadipocytes to an inflammatory stimulus (IL-1ß and conditioned media of OA synovium) was exacerbated compared to that of SCAT preadipocytes. Similar results were obtained with DFATc. CONCLUSION: IAAT adipocyte precursors from OA patients have a specific phenotype, which may account for the unique phenotype of OA IAATs. The exacerbated response of IAAT preadipocytes to inflammatory stimulation may contribute to OA pathophysiology.