Relief of gouty arthritis in rats by total saponins from Dioscorea nipponica Makino through suppression of neutrophil extracellular trap formation via the PI3K/AKT/mTOR axis

Gouty arthritis (GA) is an inflammatory disorder that is associated with elevated serum levels of uric acid. Total saponins from Dioscorea nipponica Makino (TSDN) are a natural component that ameliorates inflammation while also decreasing uric acid levels. The aim of the present study was to unravel the mechanism of TSDN in gouty rats in regard to regulation of the formation of neutrophil extracellular traps (NETs) via the PI3K/AKT/mTOR axis. A total of 40 Wistar rats were divided into 4 groups: normal, model, TSDN and rapamycin groups. Reverse-transcription-quantitative PCR (RT-qPCR) and western blot analysis were used to assess the mRNA and protein expression levels of the PI3K/AKT/mTOR axis. The formation of NETs was detected by immunohistochemical and immunofluorescent methods. ELISA was used to measure the levels of IL-1β and TNF-α. RT-qPCR and western blotting demonstrated that TSDN compromised the mRNA and protein expression levels of activated protein kinase (AMPK) and mTOR, as well as the mRNA expression levels of AKT and PTEN. Furthermore, it increased the protein expression levels of phosphorylated (p-) PI3K, p-AKT and p-AMPK. Immunohistochemical and immunofluorescent analyses revealed that TSDN decreased the protein expression levels of neutrophil elastase, proteinase 3, cathepsin G, lactoferrin and myeloperoxidase, as well as the number of citrullinated histone 3+ cells. TSDN also reduced the release of IL-1β and TNF-α. Overall, the anti-inflammatory action of TSDN in gouty rats may be realized by suppressing the formation of NETs by regulating the PI3K/AKT/mTOR axis.

Association between thiazolidinedione use and rheumatoid arthritis risk in patients with type II diabetes, a population-based, case-control study

AIM

A previous study revealed that PPARγ agonists have anti-inflammatory effects in rheumatoid arthritis (RA). Furthermore, some studies have shown that type 2 diabetes mellitus (T2DM) may elicit the development of RA. In this study, we aimed to investigate whether the use of thiazolidinediones (TZDs) is associated with a lower risk of developing RA in patients with T2DM.

METHODS

Based on the Taiwan National Health Insurance Research Database, we conducted a nationwide case-control study. The selected cases were patients with T2DM who were diagnosed with RA between 2000 and 2013. The controls were retrieved at a ratio of 1:4 by propensity score matching. Logistic regression was conducted to evaluate whether TZD use lowers the risk of RA in patients with T2DM. The dose-response effect was examined according to the total TZD dose, within 2 years before the index date (the first diagnosis date of RA), and TZD doses were divided into four groups by cumulative Defined Daily Dose (cDDD): <30, 31-90, 91-365, and >365 cDDDs.

RESULTS

A total of 3605 cases and 14 420 controls were included in this study. After adjusting for age, sex, baseline comorbidities, the results demonstrated that TZD use did not significantly reduce the risk of RA in patients with T2DM (adjusted OR = 0.91, 95% CI 0.81-1.02). In the subgroup analysis by total TZD exposure dose within 2 years, 91-365 cDDDs of TZD had a lower risk of RA development, aOR = 0.87 (95% CI 0.71-1.06) and >365 cDDDs of TZD, aOR = 0.85 (95% CI 0.73-1.01). In the trend test, P was <.05.

CONCLUSIONS

TZD use might reduce the risk of RA in patients with T2DM, but it was non-statistically significant. Further research is necessary to assess this association.

Rheumatoid Arthritis and CLOVES Syndrome: A Tricky Diagnosis

The PI3K/AKT/mTOR signaling pathway is significantly activated in rheumatoid arthritis. In addition, somatic activating mutations of the PI3K/AKT/mTOR pathway may result in PIK3CA-related overgrowth spectrum diseases, including CLOVES (Congenital Lipomatous Overgrowth, Vascular malformation, Epidermal nevi, Skeletal abnormalities/Scoliosis) syndrome. We describe the case of a young female patient, with anti-citrullinated peptide antibodies-positive rheumatoid arthritis, referred for persistent finger pain and stiffness. Examination revealed discrete macrodactyly involving two fingers, scoliosis, asymmetrical calves, venectasias, a shoulder nevus and triangular feet with a “sandal gap” between two toes. These mild dysmorphic features with early-onset and the history of surgeries for thoracic lipoma and venous malformation were strongly suggestive of CLOVES syndrome. Confirmatory mutation analysis was not performed, as blood or saliva testing is not contributive for tissue-specific localized effects in the PIK3CA-related overgrowth spectrum. Nevertheless, lack of detection of a PIK3CA mutation does not exclude the diagnosis in patients fulfilling clinical criteria. Due to the patient’s wish to plan a pregnancy, therapy consisted in sulfasalazine and hydroxychloroquine, along with orthotic correction of leg length discrepancy. Overgrowth syndromes and arthritis may share common pathways. Mild macrodactyly should be differentiated from dactylitis. Diagnosing patients with minimal dysmorphic features within the PI3K-related overgrowth spectrum may help design better care strategies, in the quest for personalized medicine.