Resistance exercise promotes the resolution and recanalization of deep venous thrombosis in a mouse model via SIRT1 upregulation

Nomogram-based prediction of the prognosis in patients with free floating venous thrombus after closed traumatic fracture

BACKGROUND

Free-floating venous thrombosis (FFVT), a distinct subtype of deep vein thrombosis (DVT), is associated with pulmonary thromboembolism (PTE) and carries a high mortality risk.

OBJECTIVE

This study aimed to develop a nomogram to predict the prognosis of FFVT in patients with closed traumatic fractures.

MATERIALS AND METHODS

A retrospective analysis of clinical and ultrasound data from 326 patients with FFVT post-closed traumatic fractures was conducted. Patients were divided into training (n = 240, January 2019-June 2023) and validation (n = 86, June 2023-June 2024) sets. Prognostic risk factors were identified using LASSO and multivariable logistic regression. A nomogram was constructed using R Studio, and its predictive accuracy was validated via calibration curves, receiver operating characteristic (ROC) analysis, and external validation.

RESULTS

Independent risk factors for FFVT progression to closed thrombus included D-dimer levels, FFVT location, collateral blood flow volume around the thrombus, and thrombus margins (P < 0.05). The model demonstrated high discriminative ability, with a C-index of 0.945. ROC analysis revealed areas under the curve (AUC) of 0.949 (training set) and 0.924 (validation set). Calibration curves confirmed strong agreement between predicted and observed outcomes.

CONCLUSION

The nomogram provides an accurate prognostic tool for FFVT in patients with closed traumatic fractures, aiding clinical decision-making to improve patient outcomes.

CLINICAL TRIAL NUMBER

Not applicable.

Venous thrombosis and obesity: from clinical needs to therapeutic challenges

Weight bias and stigma have limited the awareness of the systemic consequences related to obesity. As the narrative evolves, obesity is emerging as a driver and enhancer of many pathological conditions. Among these, the risk of venous thromboembolism (VTE) is a critical concern linked to obesity, ranking as the third most common cardiovascular condition. Obesity is recognized as a multifactorial risk factor for VTE, influenced by genetic, demographic, behavioral, and socio-economic conditions. Despite established links, the exact incidence of obesity related VTE in the general population remains largely unknown. The complexity of distinguishing between provoked and unprovoked VTE, coupled with gaps in obesity definition and assessment still complicates a tailored risk assessment of VTE risk. Obesity reactivity, hypercoagulability, and endothelial dysfunction are driven by the so-called 'adiposopathy'. This state of chronic inflammation and metabolic disturbance amplifies thrombin generation and alters endothelial function, promoting a pro-thrombotic environment. Additionally, the inflammation-induced clot formation-also referred to as 'immunothrombosis' further exacerbates VTE risk in people living with obesity. Furthermore, current evidence highlights significant gaps in the management of obesity related VTE, particularly concerning prophylaxis and treatment efficacy of anticoagulants in people living with obesity. This review underscores the need for tailored therapeutic approaches and well-designed clinical trials to address the unique challenges posed by obesity in VTE prevention and management. Advanced research and innovative strategies are imperative to improve outcomes and reduce the burden of VTE in people living with obesity.

Effect of muscle strength on deep vein thrombosis: A Mendelian randomization study

Deep vein thrombosis (DVT) is a serious condition characterized by blood clots in deep veins, posing a significant public health burden. Muscle strength has been implicated as a potential risk factor for DVT due to its influence on venous return. This study aims to investigate the causal association between muscle strength and DVT using a Mendelian randomization (MR) approach, leveraging genetic variants as instrumental variables (IVs). We conducted a 2-sample MR analysis using genome-wide association study (GWAS) data for hand-grip strength and DVT. IVs were selected based on their significant associations with muscle strength and DVT, as well as their linkage disequilibrium patterns. We employed statistical methods including inverse-variance weighting (IVW), MR-Egger, and weighted median to address pleiotropy bias. Sensitivity analyses were conducted to evaluate the robustness of the results. A total of 21 and 14 independent IVs were identified for hand grip strength (EWGSOP) and hand grip strength (FNIH), respectively. IVW analysis revealed a consistent causal and negative association between both definitions of hand grip strength and DVT (EWGSOP: OR = 0.702, 95% CI: 0.511-0.964, P = .029; FNIH: OR = 0.715, 95% CI: 0.570-0.898, P = .004). No directional pleiotropy was detected in MR-Egger and MR-PRESSO analyses for either definition (EWGSOP: MR-Egger Intercept P = .516; MR-PRESSO global test P = .162; FNIH: MR-Egger Intercept P = .569; MR-PRESSO global test P = .371).Sensitivity analyses demonstrated the stability of the causal effect estimates, with little influence from individual IVs. The MR analysis provided evidence of a causal association between muscle strength and DVT risk, suggesting that increasing muscle strength may have a protective effect. These findings have implications for preventive strategies and the promotion of resistance exercises and muscle-strengthening activities. Further research and validation of these results could inform clinical guidelines and interventions for DVT prevention.

SIRT1 and thrombosis

Thrombosis is a major cause of morbidity and mortality worldwide, with a complex and multifactorial pathogenesis. Recent studies have shown that SIRT1, a member of the sirtuin family of NAD + -dependent deacetylases, plays a crucial role in regulating thrombosis, modulating key pathways including endothelial activation, platelet aggregation, and coagulation. Furthermore, SIRT1 displays anti-inflammatory activity both in vitro, in vivo and in clinical studies, particularly via the reduction of oxidative stress. On these bases, several studies have investigated the therapeutic potential of targeting SIRT1 for the prevention of thrombosis. This review provides a comprehensive and critical overview of the main preclinical and clinical studies and of the current understanding of the role of SIRT1 in thrombosis.

Protective Role of Endothelial SIRT1 in Deep Vein Thrombosis and Hypoxia-induced Endothelial Dysfunction Mediated by NF-κB Deacetylation

Venous hypoxia is considered as the major pathogenetic mechanism linking blood flow stagnancy with deep vein thrombosis (DVT). Our previous study showed that activating SIRT1 may attenuate inferior vena cava (IVC) stenosis-induced DVT in rats. This study was aimed to investigate the role of endothelial SIRT1 in DVT and hypoxia-induced endothelial dysfunction as well as the underlying mechanism. Protein profiling of IVCs and blood plasma of DVT rats induced by IVC stenosis was analysed by 4D Label free proteomics analysis. To verify the independent role of SIRT1 in DVT and oxygen-glucose deprivation (OGD)-induced endothelial dysfunction, SIRT1 specific activator SRT1720 and SIRT1 knockdown in both local IVCs and endothelial cells were employed. Moreover, the role of the NF-κB were investigated using NF-κB inhibitor caffeic acid phenethyl ester (CAPE). SRT1720 significantly inhibited thrombus burden, leukocytes infiltration, protein expressions of cell adhesion molecules and chemokines, as well as acetylation level of NF-κB/p65 in wild DVT rats, while these protective effects of SRT1720 were abolished in rats with SIRT1 knockdown in local IVCs. In vitro, SRT1720 protected endothelial cells against OGD-induced dysfunction characterized with enhanced adhesion of monocytes as well as the protein expressions of cell adhesion molecules and chemokines, whereas these protective effects of SRT1720 were vanished by SIRT1 stable knockdown. Furthermore, CAPE attenuated endothelial cell dysfunction and abolished these effects of SIRT1 knockdown. Collectively, these data suggested that endothelial SIRT1 plays an independent role in ameliorating hypoxia-induced endothelial dysfunction and thrombotic inflammation in DVT, and this effect is mediated by NF-κB deacetylation.