Baseline interleukin1beta expression in peripheral blood monocytes predicts the extent of weight loss and nonalcoholic fatty liver improvement in obese subjects with prediabetes or type 2 diabetes

Background

Non-alcoholic fatty liver disease (NAFLD) represents a hallmark of metabolic syndrome. Interleukin-1β (IL-1β), a well-studied cytokine involved in obesity-related systemic inflammation as well as in the pathogenesis of type 2 diabetes (T2D), promotes hepatic steatosis by stimulating triglycerides and cholesterol accumulation in primary liver hepatocytes and lipid droplets formation. The most compelling evidence for a major role for IL-1β in metabolic imbalance and inflammation comes from the recent Canakinumab Anti-inflammatory Thrombosis Outcome (CANTOs)trial, where inhibition of IL-1β pathway was associated with a reduction of cardiovascular events in high-risk patients.

Purpose

The present study was designed to determine: i)whether an equal degree of weight loss by liraglutide or lifestyle changes has a different impact on NAFLD extent and IL-1β expression in peripheral blood mononuclear cells from obese subjects with prediabetes or early T2D; ii)whether baseline IL-1β levels may predict the extent of weight loss and related metabolic changes.

Methods

Thirty-two metformin-treated obese subjects with prediabetes [impaired fasting glucose (IFG) or impaired glucose tolerance (IGT) or both (n=16)] or newly diagnosed T2D (n=16), were randomized to the glucagon-like peptide receptor agonist (GLP-RA) liraglutide (1.8 mg/d) or lifestyle counselling until achieving a modest and comparable weight loss (−7% of initial body weight). Visceral (VAT) and adipose tissue distribution were assessed by magnetic resonance. Gene expression of IL-1β in peripheral blood mononuclear cells was assessed by real time PCR.

Results

At baseline, IL-1β positively correlated to body mass index (BMI) (rho=0.421, p=0.016), fasting plasma glucose (rho=0.415, p=0.018), HbA1c (rho=0.349, p=0.050), VAT (rho=0.388, p=0.028), NAFLD (rho=0.454, p=0.009), platelet count (rho=0.510, p=0.003), chemerin (rho=0.455, p=0.009) and interleukin-1 receptor agonist (IL1-RA) (rho=0.519, p=0.002). After achievement of the weight loss target in the two groups, a comparable reduction of IL-1 β (p<0.001 lifestyle changes; p=0.029 liraglutide treatment) was observed in both arms, in parallel with a comparable improvement in glycaemic control, C-reactive protein (CRP),BMI and NAFLD. Furthermore, basal levels of IL-1β correlated directly with delta BMI (p=0.015) and delta NAFLD (p=0.002) (Figure 1).

Conclusion

In obese patients with initial impairment of glucose metabolism, IL-β-driven inflammation correlates with glycaemic control, adipose tissue distribution and platelet count. Successful weight loss, achieved with either lifestyle changes or an incretin-based therapy, is associated with a significant reduction of both IL-1β levels and NAFLD degree. Of interest, basal levels of IL-1β predicts the extent of weight loss and NAFLD improvement, regardless of the intervention. Our results may set the stage for ad-hoc studies investigating the usefulness of baseline IL-1β a levels as a drug-response biomarker.

Figure 1

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): This study was supported by a grant from the Italian Ministry of University and Research (PRIN no. 2010JS3PMZ to F.S.).

Circulating CD40 ligand, Dickkopf-1 and P-selectin in HIV-infected patients

OBJECTIVES

The aim of this study was to evaluate the circulating levels of CD40 ligand (CD40 L), Dickkopf-1 (DKK-1) and P-selectin, their relationships and their contributions to cardiovascular risk in subjects with HIV infection.

METHODS

The study population included 80 HIV-infected patients, 14 (17.5%) of whom had diabetes mellitus (DM) and 32 (40.0%) of whom had arterial hypertension (AH). The HIV-infected patients were compared with a control group with similar demographic and clinical features. CD40L, DKK-1 and P-selectin levels were measured using an enzyme-linked immunosorbent assay.

RESULTS

The HIV-infected patients showed higher levels of all the cardiovascular disease (CVD) markers. Both serum CD40L and DKK-1 were significantly higher in HIV-infected patients than in the HIV-negative controls (P < 0.001), while soluble P-selectin showed no significant between-group difference (P = 0.133), reflecting the role of HIV infection in CVD. In the HIV-infected group, patients with DM showed lower levels of CD40L and DKK-1 in comparison with the nondiabetic patients and patients with AH (P < 0.05, with Bonferroni correction). In contrast, patients with AH showed higher levels of CD40L and DKK-1 in comparison to patients without DM or AH (P < 0.05, with Bonferroni correction). Patients with AH showed higher levels of CD40L and DKK-1 than patients with DM (P < 0.05, with Bonferroni correction).

CONCLUSIONS

In this study, we found that HIV-infected patients displayed significantly higher circulating levels of both CD40L and DKK-1, which were linearly and directly correlated, when compared to HIV-negative patients. The presence of diabetes was associated with lower levels of both CD40L and DKK-1, whereas the presence of hypertension was associated with higher levels of CD40L.

The recovery of platelet cyclooxygenase activity explains interindividual variability in responsiveness to low-dose aspirin in patients with and without diabetes

BACKGROUND

Interindividual variability in response to aspirin has been popularized as 'resistance'. We hypothesized that faster recovery of platelet cyclooxygenase-1 activity may explain incomplete thromboxane (TX) inhibition during the 24-h dosing interval.

OBJECTIVE

To characterize the kinetics and determinants of platelet cyclooxygenase-1 recovery in aspirin-treated diabetic and non-diabetic patients.

PATIENTS/METHODS

One hundred type 2 diabetic and 73 non-diabetic patients on chronic aspirin 100 mg daily were studied. Serum TXB(2) was measured every 3 h, between 12 and 24 h after a witnessed aspirin intake, to characterize the kinetics of platelet cyclooxygenase-1 recovery. Patients with the fastest TXB(2) recovery were randomized to aspirin 100 mg once daily, 200 mg once daily or 100 mg twice daily, for 28 days and TXB(2) recovery was reassessed.

RESULTS AND CONCLUSIONS

Platelet TXB(2) production was profoundly suppressed at 12 h in both groups. Serum TXB(2) recovered linearly, with a large interindividual variability in slope. Diabetic patients in the third tertile of recovery slopes (≥ 0.10 ng mL(-1) h(-1) ) showed significantly higher mean platelet volume and body mass index, and younger age. Higher body weight was the only independent predictor of a faster recovery in non-diabetics. Aspirin 100 mg twice daily completely reversed the abnormal TXB(2) recovery in both groups. Interindividual variability in the recovery of platelet cyclooxygenase activity during the dosing interval may limit the duration of the antiplatelet effect of low-dose aspirin in patients with and without diabetes. Inadequate thromboxane inhibition can be easily measured and corrected by a twice daily regimen.

Platelet activation in obesity and metabolic syndrome

Obesity is associated with increased cardiovascular disease. Metabolic syndrome (MS) identifies substantial additional cardiovascular risk beyond the individual risk factors, and is a powerful predictor of cardiovascular events even regardless of body mass index, thus suggesting a common downstream pathway conferring increased cardiovascular risk. Platelet hyper-reactivity/activation plays a central role to accelerate atherothrombosis and is the result of the interaction among the features clustering in obesity and MS: insulin resistance, inflammation, oxidative stress, endothelial dysfunction. Interestingly, the same pathogenic events largely account for the less-than-expected response to antiplatelet agents, namely low-dose aspirin. The proposed explanations for this phenomenon, besides underdosing of drug and/or reduced bioavailability, subsequent to excess of adipose tissue, include enhanced platelet turnover, leading to unacetylated COX-1 and COX-2 in newly formed platelets as a source of aspirin-escaping thromboxane formation; extraplatelet sources of thromboxane, driven by inflammatory triggers; and enhanced lipid peroxidation, activating platelets with a mechanism bypassing COX-1 acetylation or limiting COX-isozyme acetylation by aspirin. This review will address the complex interactions between platelets and the pathogenic events occurring in obesity and MS, trying to translate this body of mechanistic information into a clinically relevant read-out, in order to establish novel strategies in the prevention/treatment of atherothrombosis.