Intensive cholesterol-lowering treatment reduces synovial inflammation during early collagenase-induced osteoarthritis, but not pathology at end-stage disease in female dyslipidemic E3L.CETP mice.

INTRODUCTION: The association between metabolic syndrome (MetS) and osteoarthritis (OA) development has become increasingly recognized. In this context, the exact role of cholesterol and cholesterol-lowering therapies in OA development has remained elusive. Recently, we did not observe beneficial effects of intensive cholesterol-lowering treatments on spontaneous OA development in E3L.CETP mice. We postulated that in the presence of local inflammation caused by a joint lesion, cholesterol-lowering therapies may ameliorate OA pathology. MATERIALS AND METHODS: Female ApoE3∗Leiden.CETP mice were fed a cholesterol-supplemented Western type diet. After 3 weeks, half of the mice received intensive cholesterol-lowering treatment consisting of atorvastatin and the anti-PCSK9 antibody alirocumab. Three weeks after the start of the treatment, OA was induced via intra-articular injections of collagenase. Serum levels of cholesterol and triglycerides were monitored throughout the study. Knee joints were analyzed for synovial inflammation, cartilage degeneration, subchondral bone sclerosis and ectopic bone formation using histology. Inflammatory cytokines were determined in serum and synovial washouts. RESULTS: Cholesterol-lowering treatment strongly reduced serum cholesterol and triglyceride levels. Mice receiving cholesterol-lowering treatment showed a significant reduction in synovial inflammation (P = 0.008, WTD: 95% CI: 1.4- 2.3; WTD + AA: 95% CI: 0.8- 1.5) and synovial lining thickness (WTD: 95% CI: 3.0-4.6, WTD + AA: 95% CI: 2.1-3.2) during early-stage collagenase-induced OA. Serum levels of S100A8/A9, MCP-1 and KC were significantly reduced after cholesterol-lowering treatment (P = 0.0005, 95% CI: -46.0 to -12.0; P = 2.8 × 10-10, 95% CI: -398.3 to -152.1; P = 2.1 × 10-9, -66.8 to -30.4, respectively). However, this reduction did not reduce OA pathology, determined by ectopic bone formation, subchondral bone sclerosis and cartilage damage at end-stage disease. CONCLUSION: This study shows that intensive cholesterol-lowering treatment reduces joint inflammation after induction of collagenase-induced OA, but this did not reduce end stage pathology in female mice.

IL-1ß inhibition combined with cholesterol-lowering therapies decreases synovial lining thickness and spontaneous cartilage degeneration in a humanized dyslipidemia mouse model.

INTRODUCTION: Both systemic inflammation and dyslipidemia contribute to osteoarthritis (OA) development and have been suggested as a possible link between metabolic disease and OA development. Recently, the CANTOS trial showed a reduction in knee and hip replacements after inhibition of IL-1ß in patients with a history of cardiovascular disease and high inflammatory risk. In this light, we investigated whether inhibition of IL-1ß combined with cholesterol-lowering therapies can reduce OA development in dyslipidemic APOE∗3Leiden mice under pro-inflammatory dietary conditions. MATERIALS AND METHODS: Female ApoE3∗Leiden mice were fed a cholesterol-supplemented Western-Type diet (WTD) for 38 weeks. After 14 weeks, cholesterol-lowering and anti-inflammatory treatments were started. Treatments included atorvastatin alone or with an anti-IL1ß antibody, and atorvastatin combined with proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitor alirocumab without or with the anti-IL1ß antibody. Knee joints were analyzed for cartilage degradation, synovial inflammation and ectopic bone formation using histology at end point. RESULTS: Cholesterol-lowering treatment successfully decreased systemic inflammation in dyslipidemic mice, which was not further affected by inhibition of IL-1ß. Synovial thickening and cartilage degeneration were significantly decreased in mice that received cholesterol-lowering treatment combined with inhibition of IL-1ß (P < 0.01, P < 0.05, respectively) compared to mice fed a WTD alone. Ectopic bone formation was comparable between all groups. CONCLUSION: These results indicate that inhibition of IL-1ß combined with cholesterol-lowering therapy diminishes synovial thickening and cartilage degeneration in mice and may imply that this combination therapy could be beneficial in patients with metabolic inflammation.

A single dose of anti-IL-1ß antibodies prevents Western diet-induced immune activation during early stage collagenase-induced osteoarthritis, but does not ameliorate end-stage pathology.

OBJECTIVE: Metabolic dysfunction can cause IL-1ß mediated activation of the innate immune system, which could have important implications for the therapeutic efficacy of IL-1ß neutralizing drugs as treatment for OA in the context of metabolic syndrome (MetS). In the present study, we investigated whether early treatment with a single dose of IL-1ß blocking antibodies could prevent Western diet (WD) induced changes to systemic monocyte populations and their cytokine secretion profile and herewith modulate collagenase induced osteoarthritis (CiOA) pathology. METHODS: CiOA was induced in female C57Bl/6 mice fed either a standard diet (SD) or WD and treated with a single dose of either polyclonal anti-IL-1ß antibodies or control. Monocyte subsets and granulocytes in bone marrow and blood were analyzed with flow cytometry, and cytokine expression by bone marrow cells was analyzed using qPCR. Synovial cellularity, cartilage damage and osteophyte formation were assessed on histology. RESULTS: WD feeding of C57Bl/6 mice led to increased serum levels of low-density lipoprotein (LDL) and innate immune activation in the form of an increased number of Ly6Chigh cells in bone marrow and blood and increased cytokine expression of IL-6 and TNF-α by bone marrow cells. The increase in monocyte number and activity was ameliorated by anti-IL-1ß treatment. However, anti-IL-1ß treatment did not significantly affect synovial lining thickness, cartilage damage and ectopic bone formation during WD feeding. CONCLUSIONS: Single-dose systemic anti-IL-1ß treatment prevented WD-induced innate immune activation during early stage CiOA in C57Bl/6 mice, but did not ameliorate joint pathology.

Novel high-intensive cholesterol-lowering therapies do not ameliorate knee OA development in humanized dyslipidemic mice.

OBJECTIVE: High systemic cholesterol levels have been associated with osteoarthritis (OA) development. Therefore, cholesterol lowering by statins has been suggested as a potential treatment for OA. We investigated whether therapeutic high-intensive cholesterol-lowering attenuated OA development in dyslipidemic APOE∗3Leiden.CETP mice. METHODS: Female mice (n = 13-16 per group) were fed a Western-type diet (WTD) for 38 weeks. After 13 weeks, mice were divided into a baseline group and five groups receiving WTD alone or with treatment: atorvastatin alone, combined with PCSK9 inhibitor alirocumab and/or ANGPTL3 inhibitor evinacumab. Knee joints were analysed for cartilage degradation, synovial inflammation and ectopic bone formation using histology. Aggrecanase activity in articular cartilage and synovial S100A8 expression were determined as markers of cartilage degradation/regeneration and inflammation. RESULTS: Cartilage degradation and active repair were significantly increased in WTD-fed mice, but cholesterol-lowering strategies did not ameliorate cartilage destruction. This was supported by comparable aggrecanase activity and S100A8 expression in all treatment groups. Ectopic bone formation was comparable between groups and independent of cholesterol levels. CONCLUSIONS: Intensive therapeutic cholesterol lowering per se did not attenuate progression of cartilage degradation in dyslipidemic APOE∗3Leiden.CETP mice, with minor joint inflammation. We propose that inflammation is a key feature in the disease and therapeutic cholesterol-lowering strategies may still be promising for OA patients presenting both dyslipidemia and inflammation.

Elevated microRNA-181c and microRNA-30d levels in the enlarged amygdala of the valproic acid rat model of autism.

Autism spectrum disorders are severe neurodevelopmental disorders, marked by impairments in reciprocal social interaction, delays in early language and communication, and the presence of restrictive, repetitive and stereotyped behaviors. Accumulating evidence suggests that dysfunction of the amygdala may be partially responsible for the impairment of social behavior that is a hallmark feature of ASD. Our studies suggest that a valproic acid (VPA) rat model of ASD exhibits an enlargement of the amygdala as compared to controls rats, similar to that observed in adolescent ASD individuals. Since recent research suggests that altered neuronal development and morphology, as seen in ASD, may result from a common post-transcriptional process that is under tight regulation by microRNAs (miRs), we examined genome-wide transcriptomics expression in the amygdala of rats prenatally exposed to VPA, and detected elevated miR-181c and miR-30d expression levels as well as dysregulated expression of their cognate mRNA targets encoding proteins involved in neuronal system development. Furthermore, selective suppression of miR-181c function attenuates neurite outgrowth and branching, and results in reduced synaptic density in primary amygdalar neurons in vitro. Collectively, these results implicate the small non-coding miR-181c in neuronal morphology, and provide a framework of understanding how dysregulation of a neurodevelopmentally relevant miR in the amygdala may contribute to the pathophysiology of ASD.