Clinical Study Of Sleeve Gastrectomy In Obese Patients And The Effects On B Lymphocytes

Objectives:Sleeve gastrectomy（SG）is an effective way to treat obesity and related diseases.In this study,we observed the clinical efficacy and safety of SG.Obesity has been proven to be under a status of low-grade,chronic inflammation,which contributes to insulin resistance（IR）and type 2 diabetes mellitus（T2DM）.Moreover,it has been reported that B lymphocytes played an important role in obesity-induced inflammation.In order to regulate B lymphocytes functions and improve obesity and metabolic diseases,we studied the effects of SG on B lymphocyte subsets and functions in the peripheral blood of obese patients,and explored the potential mechanisms.Methods:In part II,82 obese subjects were recruited from the Second Xiangya Hospital of Central South University.All of these obese patients accepted SG and finished follow–up at 1,2,6 and 12 months after surgery.We collected the clinical and biochemical data at each visit time.Eighty-four subjects were recruited in part III,included healthy controls（n=42）and obese participants（n=42）.Obese participants all accepted SG,and returned for following-up at 1,2,6 and 12 months after surgery.Moreover,the healthy controls in part III were detected the same indicators at baseline.We evaluated the frequencies of circulating B lymphocyte subsets,including na?ve B cell（CD19⁺Ig D⁺CD27^-）,memory B cell（CD19⁺CD27⁺）,DN B cell（CD19⁺Ig D^-CD27^-）and Breg(CD19⁺CD27⁺CD24^high)by flow cytometry.B lymphocytes for RNA sequencing and quantitative real-time PCR performing were isolated from obese patients before and 2 months after SG.Glucose uptake capacity was detected by flow cytometry.Isolated CD19⁺B lymphocytes in peripheral blood of obese patients were treated with or without 2-Deoxy-D-glucose（2-DG）（1m M）for 3 days,after that,B lymphocyte subsets were measured by flow cytometry.Serum Ig G,Ig M,and Ig A were detected by FAME-STAR automatic immune-enzymatic analytic system.Results:（1）Compared with baseline,obese patients showed great decreases in body mass index（BMI）,waist,hip,diastolic blood pressure（DBP）,fasting C–peptide（FCP）and glycosylated hemoglobin（Hb A₁c）at12 months after SG（P<0.05）.After SG,the fast blood glucose（FBS）level was not decreased in obese patients without type 2 diabetes mellitus（T2DM）.For lipid metabolism,the triglyceride（TG）level decreased to 1.2±0.1 mmol/L in obese patients with T2DM（P<0.001）,and the high-density lipoprotein cholesterol-C（HDL-C）level increased significantly in both groups,while the total cholesterol（TC）level in the group without T2DM increased significantly.There was no sexual difference in the clinical efficacy of SG.（2）Compared with the baseline,the serum albumin levels increased significantly at 1–12 months after surgery（P<0.001）,and the hypoalbuminemia rate decreased from 8.5%to 0%throughout the study（P=0.063）.Anemia was present in 7.3%of all patients before surgery,and its prevalence increased to 11.0%at 12 months post-operation（P=0.109）.The anemia rate of females was higher than that of males（21.4 vs 2.3%,P=0.036）.No significant changes were found in vitamin B12 deficiency throughout the study（0 vs 3.8%,P=1.0）.The increases in the folate deficiency were only discovered in the female group（3.7 vs 20%,P=0.031）and normal glucose tolerance（NGT）group after SG（27.3 vs 47.1%,P=0.031）.A decrease in the ferritin levels and an increase in iron deficiency at 12 months post-surgery were found among all patients.The bone mineral density（BMD）of the femoral neck,lumbar spine,and total hip significantly decreased from baseline to 12 months after SG;however,no significant differences were found in the prevalence of osteopenia and osteoporosis in patients after surgery.（3）At baseline,compared with healthy controls,the frequencies of na?ve B and DN B cells increased,while Breg and memory B cells decreased in obese participants（P<0.05）.At baseline,serum Ig M levels in obese group were lower compared with healthy controls（1.1±0.1 vs1.5±0.1g/L,P=0.01）,while the levels of Ig A and Ig G showed no differences between the two groups.Compared with the baseline,the frequencies of na?ve B and DN B cells consistently declined after surgery in obese patients（75.5±1.2 vs 64.9±2.3%,P<0.001;8.0±0.4 vs 6.8±0.2%,P=0.017,respectively）.Moreover,the frequencies of Breg and memory B cells were increased at 12 months after surgery in obese patients（14.1±1.1 vs 21.2±1.8%,P<0.001;16.5±1.2 vs 28.3±2.4%,P<0.001;respectively）.Serum Ig G and Ig M levels were increased in obese patients at 1 year after surgery（P=0.008,P=0.046）.Increased interleukin-10gene expression,while declined glucose uptake capacity and hexokinase 2gene expression of B cells in obese patients were observed at 2 months after surgery（P<0.05）.At baseline,compared with B cells in obese patients treated without 2-DG,B cells treated with 2-DG showed decreased proportion of naive B cells（64.9±5.0 vs 55.6±5.3%,P<0.001）,and increased proportions of memory B cells（24.2±3.4 vs 27.2±3.2%,P=0.04）,DN B cells（10.9±1.9 vs 17.2±2.6%,P<0.001）and Breg cells（9.2±2.1 vs 13.8±2.5%,P<0.001）.Conclusions:（1）Based on 12 months of follow-up,SG shows no sexual difference in the clinical efficacy and has a modest effect on nutritional deficiencies,which suggests that SG is an effective and comparably safe procedure for Chinese patients considering nutritional deficiencies.（2）SG may regulate the peripheral blood B cell subsets imbalance and dysfunction by affecting the glucose metabolism of B cells in obese patients.