Inhibition of monoacylglycerol lipase reduces nicotine withdrawal

Background and Purpose

Abrupt discontinuation of nicotine, the main psychoactive component in tobacco, induces a withdrawal syndrome in nicotine-dependent animals, consisting of somatic and affective signs, avoidance of which contributes to drug maintenance. While blockade of fatty acid amide hydrolase, the primary catabolic enzyme of the endocannabinoid arachidonoylethanolamine (anandamide), exacerbates withdrawal responses in nicotine-dependent mice, the role of monoacylglycerol lipase (MAGL), the main hydrolytic enzyme of a second endocannabinoid 2-arachidonylglycerol (2-AG), in nicotine withdrawal remains unexplored.

Experimental Approach

To evaluate the role of MAGL enzyme inhibition in nicotine withdrawal, we initially performed a genetic correlation approach using the BXD recombinant inbred mouse panel. We then assessed nicotine withdrawal intensity in the mouse after treatment with the selective MAGL inhibitor, JZL184, and after genetic deletion of the enzyme. Lastly, we assessed the association between genotypes and smoking withdrawal phenotypes in two human data sets.

Key Results

BXD mice displayed significant positive correlations between basal MAGL mRNA expression and nicotine withdrawal responses, consistent with the idea that increased 2-AG brain levels may attenuate withdrawal responses. Strikingly, the MAGL inhibitor, JZL184, dose-dependently reduced somatic and aversive withdrawal signs, which was blocked by rimonabant, indicating a CB₁ receptor-dependent mechanism. MAGL-knockout mice also showed attenuated nicotine withdrawal. Lastly, genetic analyses in humans revealed associations of the MAGL gene with smoking withdrawal in humans.

Conclusions and Implications

Overall, our findings suggest that MAGL inhibition maybe a promising target for treatment of nicotine dependence.     

Indications and diagnostic outcome of antineutrophil cytoplasmic antibody testing in hospital medicine: a pattern of over-screening

Clinical Rheumatology - Antineutrophil cytoplasmic antibodies (ANCA) serology can aid in the diagnosis and classification of ANCA-associated vasculitides (AAV). However, it is often ordered in...     

G20210A mutation in the prothrombin gene and the risk of recurrent venous thromboembolism

OBJECTIVES: The study was done to determine whether the G20210A mutation in the prothrombin gene increases the risk of recurrent venous thromboembolism (VTE), both alone and in combination with factor V Leiden. BACKGROUND: Several inherited defects of coagulation are associated with increased risk of first VTE, including a recently identified G20210A mutation in the prothrombin gene. However, whether the presence of this mutation confers an increased risk of recurrent venous thromboembolism is controversial. METHODS: A total of 218 men with incident venous thromboembolism were genotyped for the prothrombin mutation and for factor V Leiden and were followed prospectively for recurrent VTE over a follow-up period of 7.3 years. RESULTS: A total of 29 men (13.3%) suffered recurrent VTE. Five of the 14 carriers of the prothrombin mutation developed recurrent VTE (35.7%; incidence rate = 8.70 per 100 person-years), while 24 of 204 individuals who did not carry the prothrombin mutation developed recurrent VTE (11.8%; incidence rate = 1.76 per 100 person-years). Thus, presence of the G20210A mutation was associated with an approximate fivefold increased risk for recurrent VTE (crude relative risk [RR] 4.93; 95% confidence interval [CI] 1.9-12.9; p = 0.001; age-, smoking-, and body mass index-adjusted RR 5.28; 95% CI 2.0-14.0; p = 0.001). In these data, recurrence rates were similar among those with an isolated mutation in the prothrombin gene (18.2%) as compared to those with an isolated factor V Leiden mutation (19.2%). However, all three study participants who carried both mutations (100%) suffered a recurrent event during follow-up. CONCLUSIONS: In a prospective evaluation of 218 men, the presence ofprothrombin mutation was associated with a significantly increased risk of recurrent VTE, particularly among those who co-inherited factor V Leiden.     

Systemic sclerosis and interstitial lung disease: a pilot study using pulse intravenous methylprednisolone and cyclophosphamide to assess the effect on high resolution computed tomography scan and lung function

OBJECTIVE: To document the effectiveness, including the longterm effect, of a course of intravenous (IV) pulses of methylprednisolone (MP) and cyclophosphamide (CYC) in patients with scleroderma (SSc) who had evidence of lung inflammation on high resolution computer tomographic (HRCT) scan of the chest. METHODS: Fourteen consecutive patients with SSc and lung involvement were treated with 6 pulses of IV MP (10 mg/kg) and IV CYC (15 mg/kg) given at 3-4 weekly intervals. HRCT scans and lung function tests were performed at baseline and after the 6th pulse. Further lung function tests were repeated at 12 months and annually thereafter. RESULTS: Modified Rodnan skin scores improved significantly by 35% from a median baseline score of 17 (IQR 14-26.5) to a posttreatment score of 13 (IQR 10.5-18.5; p = 0.0058). HRCT scan scores improved significantly (p = 0.04). Twelve of 13 patients experienced either improvement or stabilization of the HRCT score. Median DLCO and lung volumes remained stable during the first 12 months. After a median followup of 26 months (IQR 19-43), 67% of patients experienced deterioration in DLCO. Median deterioration was 23% (IQR 44-0.6), with the median rate of deterioration of the predicted value of the DLCO/month being 0.87% (IQR 1.24-0.02). The treatment was safe and well tolerated. CONCLUSION: This IV regimen stabilized lung disease in patients with SSc. When treatment was stopped, or reduced in intensity, a deterioration in lung function occurred in the majority of patients. Rate of deterioration of DLCO may be a useful marker for determining the intensity of treatment. These findings have implications for treating lung disease and designing clinical trials in patients with SSc.     

Renal cryoablation – a practical guide for interventional radiologists

Renal cryoablation is a treatment option for early stage renal cell carcinomas with excellent oncological outcomes and low morbidity. This review outlines the technique of renal cryoablation and provides a guide for interventional radiologists on setting up an integrated service within a renal cancer network multidisciplinary setting. Patient selection and preparation, together with the technical aspects which ensure optimal oncological outcomes and avoid collateral damage to adjacent organs are highlighted.