BMI-independent inverse relationship of plasma leptin levels with outcome in patients with acute pulmonary embolism

Circulating adipokine concentrations and the risk of venous thromboembolism: A Mendelian randomization and mediation analysis

Background: Previous observational studies have suggested that circulating adipokine concentrations are related to a greater risk of venous thromboembolism (VTE). However, it remained unclear whether these observations reflect causality.

Objective: This study aimed to investigate the causal relationship between circulating adipokine concentrations (including adiponectin, leptin, PAI-1, MCP-1, leptin receptor, and RETN) and the risk of VTE and its subtypes (DVT and PE) and to determine whether circulating adipokine concentrations are a mediator of venous thromboembolic events in obese patients.

Methods: We used Mendelian randomization (MR) analyses to determine the effects of the body mass index (BMI), adiponectin, leptin, PAI-1, MCP-1, leptin receptor, and RETN levels on VTE, DVT, and PE in a cohort of 11,288 VTE cases, 5,632 DVT cases, 5,130 PE cases, and 254,771 controls. We then assessed the proportion of the effect of obesity on VTE, DVT, and PE explained by circulating leptin levels.

Result: Genetically predicted higher BMI was related to increased VTE (OR = 1.45, p < 0.001), DVT (OR = 1.63, p < 0.001), and PE (OR = 1.37, p < 0.001) risk, and higher circulating leptin levels increase odds of VTE (OR = 1.96, q < 0.001), DVT (OR = 2.52, q < 0.001), and PE (OR = 2.26, q = 0.005). In addition, we found that the causal effect between elevated serum adiponectin and the decreased risk of VTE (OR = 0.85, p = 0.013, q = 0.053) and PE (OR = 0.81, p = 0.032, q = 0.083) and between MCP-1 and the reduced risk of VTE (OR = 0.88, p = 0.048, q = 0.143) is no longer significant after FDR adjustment. In MR mediation analysis, the mediation effect of circulating leptin levels in the causal pathway from BMI to PE was estimated to be 1.28 (0.95–1.71, p = 0.10), accounting for 39.14% of the total effect.

Conclusion: The circulating leptin level is a risk factor for VTE, DVT, and PE, but it might be a potential mediator of BMI on the risk of PE, and thus, interventions on the circulating leptin level in obesity might reduce the risk of PE. Adiponectin is a potential protective factor for both VTE and PE.

A targeted proteomics investigation of the obesity paradox in venous thromboembolism

The obesity paradox, the controversial finding that obesity promotes disease development but protects against sequelae in patients, has been observed in venous thromboembolism (VTE). The aim of this investigation was to identify a body mass-related proteomic signature in VTE patients and to evaluate whether this signature mediates the obesity paradox in VTE patients. Data from the Genotyping and Molecular Phenotyping in Venous ThromboEmbolism Project, a prospective cohort study of 693 VTE patients, were analyzed. A combined end point of recurrent VTE or all-cause death was used. Relative quantification of 444 proteins was performed using high-throughput targeted proteomics technology. Measurements were performed in samples collected during the acute VTE event and at 12-month follow-up. An 11-protein signature (CLEC4C, FABP4, FLT3LG, IL-17C, LEP, LYVE1, MASP1, ST2, THBS2, THBS4, TSLP) for body mass in VTE patients was identified. The signature did not significantly mediate the obesity paradox (change in hazard ratio [HR]: 0.04; likelihood ratio test of nested models = 7.7; P = .74), but its main constituent protein, leptin, was inversely associated with recurrent VTE or death (adjusted HR [95% confidence interval] per standard deviation increase: 0.66 [0.46-0.94]). This relationship was significantly (P = .007) modified by markers of leptin resistance (ie, high body mass index and high circulating matrix metalloproteinase-2 levels). Although the signature did not substantially explain the obesity paradox, leptin appears to be protective against disease recurrence and death in VTE patients. This protective effect was abrogated under conditions of leptin resistance and hence was unrelated to the obesity paradox.

Association of adipocytokines serum levels with left atrial thrombus formation in atrial fibrillation patients on oral anticoagulation (Alert) - A cross-sectional study

BACKGROUND AND AIMS

Oral anticoagulation is effective for stroke prevention in atrial fibrillation (AF). However, strokes may still occur in high-risk individuals. We conducted a prospective trial to assess the association between adipocytokine serum levels and surrogate parameters for thromboembolic events.

METHODS AND RESULTS

In this cross-sectional multicenter trial, we enrolled 189 patients with AF who were on oral anticoagulation. The primary endpoint was defined as either the presence of spontaneous echo contrast (SEC), a left atrial appendage (LAA), or a left atrial (LA) thrombus on transesophageal echocardiography. We investigated the association of adipocytokine serum levels with the combined endpoint using logistic regression analysis. Forty-eight individuals (25%) were assigned to group 1 (G1) due to the occurrence of at least one of the components of the combined endpoint (41 [21.7%] SEC, 3 [1.6%] LA thrombus, 13 [6.9%] LAA thrombus), whereas the remaining patients formed group 2 (G2). The BMI, logarithmized (log_e) leptin (G1: 2.0 ± 1.3 μg/ml, G2: 2.0 ± 1.1 μg/ml, p = 0.746) and visfatin serum levels (G1: 3.4 ± 0.3 ng/ml, G2: 3.4 ± 0.5 ng/ml, p = 0.900) did not significantly differ between the groups. Conversely, logarithmized adiponectin (G1: 3.3 ± 0.6 ng/ml, G2: 3.1 ± 0.7 ng/ml, p = 0.036) and resistin levels (G1: 1.8 ± 0.5 ng/ml, G2: 1.6 ± 0.5 ng/ml, p = 0.009) were higher in patients with the primary endpoint. Multivariate logistic regression analysis using a score that combined the individual adiponectin and resistin values in each patient corroborated this association.

CONCLUSIONS

Our results suggest that adiponectin and resistin may act as potential biomarkers to identify individuals with AF who are at high thromboembolic risk.

Elevated leptin and decreased adiponectin independently predict the post-thrombotic syndrome in obese and non-obese patients

Post-thrombotic syndrome (PTS) is a common complication of deep vein thrombosis (DVT). Little is known about the involvement of adipokines in the pathogenesis of DVT. We evaluated whether adipokines can predict PTS. In a prospective cohort study, 320 DVT patients aged 70 years or less were enrolled. Serum adiponectin, leptin and resistin levels were measured three months since the index first-ever DVT. After 2 years’ follow-up PTS was diagnosed in 83 of 309 available patients (26.9%) who had 13.9% lower adiponectin and 16% higher leptin levels compared with the remainder (both p < 0.0001). No PTS-associated differences in C-reactive protein, fibrinogen, D-dimer, plasminogen activator inhibitor-1 and resistin were observed. The multivariable logistic regression adjusted for age, sex, obesity and tissue plasminogen activator (tPa) showed that lower adiponectin (odds ratio [OR], 0.42; 95% confidence interval [CI], 0.31–0.56) and higher leptin levels (OR, 1.49; 95% CI, 1.31–1.69) are independent predictors for PTS. Obesity-stratified logistic regression analysis confirmed that lower adiponectin (OR, 0.49; 95% CI, 0.38–0.64) and higher leptin (OR, 1.41; 95% Cl, 1.25–1.58) levels predicted PTS. Our findings showed that lower adiponectin and higher leptin measured 3 months after DVT, regardless of obesity, can independently predict PTS, which suggests novel links between adipokines and thrombosis.

High preoperative serum leptin level is an independent risk factor for deep vein thrombosis after total knee arthroplasty in osteoarthritis patients: A prospective and cross-sectional study

It suggests that a high leptin level may increase the risk of venous thromboembolism (VTE) in animal studies. However, clinical studies in this field are still largely unexplored. Our objective was to evaluate the relationship between the preoperative serum leptin levels and postoperative VTE incidence in osteoarthritis (OA) patients who underwent total knee arthroplasty (TKA) at our institute.We conducted a prospective and cross-sectional study in these OA patients from March 2014 to March 2016. Preoperative leptin levels were analyzed by Luminex assays. VTE was assessed preoperatively and on postoperative day 5 and 7. The potential risk factors for VTE were also documented.We enrolled 203 OA patients. No PE was detected and DVT was diagnosed in 34 patients postoperatively. There were significant differences between the median leptin levels in DVT group and non-DVT group [25.13 ng/mL (interquartile range, 14.51-44.31) vs 18.71 ng/mL (8.26-28.99), P = .007]. The relative risk of DVT significantly increased with natural logarithm (ln) leptin (per SD increase) (OR 2.37, 95% confidence interval (95% CI), 1.29-4.33, P = .005). Multivariate analyses adjusted for potential confounders showed ln leptin (per SD increase) was significantly associated with the relative risk of DVT (OR 2.17, 95% CI, 1.01-4.64, P = .046). When patients were subdivided into tertiles according to their leptin values, the OR for DVT increased with increasing tertiles of serum leptin (OR 1.03, 95% CI, 1.01-1.06, P for trend = .023).In the present study, our results indicate that a high preoperative leptin level may be an independent risk factor for postoperative DVT.

Leptin, pre-existing vascular disease, and increased arteriovenous fistula maturation failure in dialysis patients

BACKGROUND

The adipocytokine leptin is an independent cardiovascular risk factor and exerts proatherogenic effect. Pre-existing vascular disease is an important cause of arteriovenous fistula (AVF) maturation failure. We explored the association between serum leptin, pre-existing vascular disease, and AVF maturation failure in incident hemodialysis patients.

METHODS

Vein samples from 62 patients were collected at the time of AVF creation. Pre-existing vascular disease was evaluated with histologic changes and immunohistochemical characteristics of cellular phenotypes in intima. AVF maturation failure was defined as an AVF that could not be used successfully by the third month after its creation.

RESULTS

The prevalence of body mass index ≥30 kg/m² was 17%, and AVF maturation failure occurred in 28 (45%) patients. Patients within the highest leptin tertile showed significantly higher maturation failure rate, independent of age, gender, diabetes, and body mass index. On histologic examination, significant differences in intimal hyperplasia (13.3 ± 4.5 vs 18.2 ± 5.2 vs 30.3 ± 14.3 μm) and medial thickening (76.8 ± 23.7 vs 103.9 ± 33.6 vs 109.3 ± 36.5 μm) were observed across leptin tertiles. Similarly, medial fibrosis was most severe in the highest tertile. According to the immunohistochemical staining, most intimal cells were α-smooth muscle actin-positive, vimentin-positive, desmin-negative myofibroblasts. However, in the lowest tertile, desmin-positive contractile smooth muscle cells were also frequently observed, suggesting relatively slow phenotypic changes in this group. Furthermore, as leptin tertiles increased, the expression of leptin receptor in the luminal border of intima was significantly decreased.

CONCLUSIONS

Obesity-related higher fistula maturation failure rate may be partly mediated by higher leptin level-associated pre-existing vascular diseases in end-stage renal disease patients. Decreased expression of leptin receptor may be related to this association.

Synthesis and biological evaluation of novel urea- and guanidine-based derivatives for the treatment of obesity-related hepatic steatosis

Leptin, the product of the obese gene, is an adipocyte-secreted protein hormone playing a key role in the progression of obesity and hepatic steatosis. In this study, 28 novel (thio)urea and guanidine-based analogues have been synthesized and N-(1-(4-(3-(2-chloroethyl)ureido)benzyl)piperidin-4-yl)-3-(trifluoromethyl) benzamide (7i) was found to be a potent regulator of leptin expression in 3T3-L1 adipocytes. Treatment with 7i at a dose of 50 mg/kg/day for 35 days reduced the body weight and liver weight of diet-induced obesity mice by 13.5% and 18.4%, respectively, while also improving the serum levels of triglyceride, total cholesterol, leptin, adiponectin, LDL-c, HDL-c. Hematoxylin-eosin (H&E) and Oil Red O staining also confirmed that 7i ameliorated fat deposition in liver tissue and restricted the size of adipocytes in obesity-related fatty liver disease.

Acute portal vein thrombosis precipitated by indomethacin in a HCV-positive elderly patient

Background

An increased risk of venous thromboembolism has been reported in patients treated with non-steroidal anti-inflammatory drugs (NSAIDs). We describe a case of acute portal vein thrombosis (PVT) in a hepatitis C virus (HCV)-positive elderly patient following administration of indomethacin.

Case presentation

A 79-year-old HCV-positive man was hospitalized for severe abdominal pain, nausea and vomiting, 15 days after starting indomethacin for back pain. Clinical signs and imaging evaluations disclosed a picture of PVT. Indomethacin was discontinued, and the patient was started on fondaparinux and antithrombin. He was discharged 15 days later due to improvement of his clinical conditions. Thirty days later, a follow-up ultrasound did not show appreciable signs of PVT. The time elapsing between the start of analgesic therapy and PVT onset suggests a role of indomethacin as the triggering agent. Indomethacin could have precipitated PVT by a combination of at least two detrimental mechanisms: 1) direct action on liver vascular endothelium by inhibition of prostacyclin biosynthesis; 2) damage to the intestinal mucosa, followed by inflammatory and pro-coagulant activation of portal endothelium upon exposure to bacterial endotoxins.

Conclusions

This case can be of interest to physicians, who should exert caution when prescribing NSAIDs for inflammatory pain in patients with background inflammatory dysfunctions of the portal vein endothelium.