Low-grade persistent inflammation is a feature of diabetes-driven vascular complications, in particular activation of the Nod-like receptor family pyrin domain containing 3 (NLRP3) inflammasome to trigger the maturation and release of the inflammatory cytokine interleukin-1β (IL-1β). We investigated whether inhibiting the NLRP3 inflammasome, through the use of the specific small-molecule NLRP3 inhibitor MCC950, could reduce inflammation, improve vascular function, and protect against diabetes-associated atherosclerosis in the streptozotocin-induced diabetic apolipoprotein E-knockout mouse. Diabetes led to an approximately fourfold increase in atherosclerotic lesions throughout the aorta, which were significantly attenuated with MCC950 (P < 0.001). This reduction in lesions was associated with decreased monocyte–macrophage content, reduced necrotic core, attenuated inflammatory gene expression (IL-1β, tumor necrosis factor-α, intracellular adhesion molecule 1, and MCP-1; P < 0.05), and reduced oxidative stress, while maintaining fibrous cap thickness. Additionally, vascular function was improved in diabetic vessels of mice treated with MCC950 (P < 0.05). In a range of cell lines (murine bone marrow–derived macrophages, human monocytic THP-1 cells, phorbol 12-myristate 13-acetate–differentiated human macrophages, and aortic smooth muscle cells from humans with diabetes), MCC950 significantly reduced IL-1β and/or caspase-1 secretion and attenuated leukocyte–smooth muscle cell interactions under high glucose or lipopolysaccharide conditions. In summary, MCC950 reduces plaque development, promotes plaque stability, and improves vascular function, suggesting that targeting NLRP3-mediated inflammation is a novel therapeutic strategy to improve diabetes-associated vascular disease.

Activation of nucleotide-binding oligomerization domain-like receptor pyrin domain containing 3 (NLRP3) inflammasome has been reported in diabetic complications including diabetic kidney disease (DKD). However, it remains unknown if NLRP3 inhibition is renoprotective in a clinically relevant interventional approach with established DKD. We therefore examined the effect of the NLRP3-specific inhibitor MCC950 in streptozotocin-induced diabetic mice to measure the impact of NLRP3 inhibition on renal inflammation and associated pathology in DKD. We identified an adverse effect of MCC950 on renal pathology in diabetic animals. Indeed, MCC950-treated diabetic animals showed increased renal inflammation and macrophage infiltration in association with enhanced oxidative stress as well as increased mesangial expansion and glomerulosclerosis when compared with vehicle-treated diabetic animals. Inhibition of the inflammasome by MCC950 in diabetic mice led to renal up-regulation of markers of inflammation (Il1β, Il18 and Mcp1), fibrosis (Col1, Col4, Fn1, α-SMA, Ctgf and Tgfβ1) and oxidative stress (Nox2, Nox4 and nitrotyrosine). In addition, enhanced glomerular accumulation of pro-inflammatory CD68 positive cells and pro-oxidant factor nitrotyrosine was identified in the MCC950-treated diabetic compared with vehicle-treated diabetic animals. Collectively, in this interventional model of established DKD, NLRP3 inhibition with MCC950 did not show renoprotective effects in diabetic mice. On the contrary, diabetic mice treated with MCC950 exhibited adverse renal effects particularly enhanced renal inflammation and injury including mesangial expansion and glomerulosclerosis.

Diabetes is a chronic metabolic disorder associated with the accelerated development of macrovascular (atherosclerosis and coronary artery disease) and microvascular complications (nephropathy, retinopathy and neuropathy), which remain the principal cause of mortality and morbidity in this population. Current understanding of cellular and molecular pathways of diabetes‐driven vascular complications, as well as therapeutic interventions has arisen from studying disease pathogenesis in animal models. Diabetes‐associated vascular complications are multi‐faceted, involving the interaction between various cellular and molecular pathways. Thus, the choice of an appropriate animal model to study vascular pathogenesis is important in our quest to identify innovative and mechanism‐based targeted therapies to reduce the burden of diabetic complications. Herein, we provide up‐to‐date information on available mouse models of both Type 1 and Type 2 diabetic vascular complications as well as experimental analysis and research outputs. LINKED ARTICLES This article is part of a themed issue on Preclinical Models for Cardiovascular disease research (BJP 75th Anniversary). To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.5/issuetoc

This report presents the outcomes of a systematic review (SR) identifying the mechanisms and chemicals involved in the pathogenesis of Parkinson's disease (PD) and childhood leukaemia (CL). This work serves as a basis for defining and mapping the causal linkages between a molecular initiating event (MIE) and a final adverse outcome (AO) that are relevant for the development of a prototype adverse outcome pathway (AOP) for assessing risk factors for PD and CL. Search for literature from 1990 to present was conducted using Web of Science, PubMed and TOXNET, and relevant references were selected using established inclusion/exclusion criteria and ranked using a set of quality control factors.For PD, 7,384 individual references were identified to be relevant for PD pathogenesis and chemicals associated with PD. Dopaminergic neurodegeneration in the substantia nigra leading to locomotor deficits was identified as the AO in PD. Other identified key events in PD pathogenesis include mitochondrial dysfunction, cellular accumulation of alpha-synuclein and oxidative stress. 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, rotenone and paraquat are some chemicals identified to be associated with PD pathogenesis.For CL, 1,988 individual references were identified to be relevant for CL pathogenesis and chemicals associated with CL. Chromosomal translocation, genetic damage/mutation and hyperdiploidy are considered as driving forces of CL. Except for infant leukaemia, CL pathogenesis requires a 'two-hit' model with an initiating event occurring in utero followed by a secondary hit potentially occurring after birth. Potential MIEs leading to these driving mechanisms include aberrant DNA topoisomerase II activity and erroneous DNA repair. Epigenetics appears to also play an influential role in CL pathogenesis. Benzene, bioflavonoids and organophosphates are some chemicals identified to be implicated in CL pathogenesis.The challenges of developing AOPs for these two diseases and the data gaps identified from the outcomes of this SR are also elaborated in this report. The present document has been produced and adopted by the bodies identified above as authors. This task has been carried out exclusively by the authors in the context of a contract between the European Food Safety Authority and the authors, awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the authors. KEY WORDSSystematic Review, Parkinson Disease, Childhood Leukaemia, Pathogenesis, Chemicals, Pesticides, Adverse Outcome Pathway SUMMARYThe aim of this project was to perform a systematic review (SR) to collect relevant publications related to the mechanisms involved in the pathogenesis of Parkinson's disease (PD)...

Epidemiologic data suggest that the prevalence of hypertension in patients with diabetes mellitus is ∼1.5–2.0 times greater than in matched non-diabetic patients. This co-existent disease burden exacerbates cardiac and vascular injury, leading to structural and functional changes to the myocardium, impaired cardiac function and heart failure. Oxidative stress and persistent low-grade inflammation underlie both conditions, and are identified as major contributors to pathological cardiac remodelling. There is an urgent need for effective therapies that specifically target oxidative stress and inflammation to protect against cardiac remodelling. Animal models are a valuable tool for testing emerging therapeutics, however, there is a notable lack of appropriate animal models of co-morbid diabetes and hypertension. In this study, we describe a novel preclinical mouse model combining diabetes and hypertension to investigate cardiac and vascular pathology of co-morbid disease. Type 1 diabetes was induced in spontaneously hypertensive, 8-week old, male Schlager (BPH/2) mice via 5 consecutive, daily injections of streptozotocin (55 mg/kg in citrate buffer; i.p.). Non-diabetic mice received citrate buffer only. After 10 weeks of diabetes induction, cardiac function was assessed by echocardiography prior to post-mortem evaluation of cardiomyocyte hypertrophy, interstitial fibrosis and inflammation by histology, RT-PCR and flow cytometry. We focussed on the oxidative and inflammatory stress pathways that contribute to cardiovascular remodelling. In particular, we demonstrate that markers of inflammation (monocyte chemoattractant protein; MCP-1), oxidative stress (urinary 8-isoprostanes) and fibrosis (connective tissue growth factor; CTGF) are significantly increased, whilst diastolic dysfunction, as indicated by prolonged isovolumic relaxation time (IVRT), is elevated in this diabetic and hypertensive mouse model. In summary, this pre-clinical mouse model provides researchers with a tool to test therapeutic strategies unique to co-morbid diabetes and hypertension, thereby facilitating the emergence of novel therapeutics to combat the cardiovascular consequences of these debilitating co-morbidities.