Decrease in Serum Protein Carbonyl Groups Concentration and Maintained Hyperhomocysteinemia in Patients Undergoing Bariatric Surgery

Investigation of homocysteine level after bariatric metabolic surgery, effect on vitamin B12 and folate levels

BACKGROUND

Obesity is a serious health problem with increasing incidence. worldwide and remains one of the most important causes of preventable deaths. We aimed to examine the relationship between Vitamin B12 and Folic acid, which have an important role for human life, and homocysteine is widely recognized for its association with the development of cardiovascular disease, although its role as an independent risk factor remains a topic of ongoing debate.

MATERIALS AND METHODS

We evaluated 126 patients who underwent bariatric metabolic surgery between September 2019-September 2020. In addition to demographic characteristics of the patients, weight, Vitamin B12, folate, HbA1c, cholesterol, triglyceride, ferritin, serum iron, albumin levels at preoperative, postoperative 1st month, 6th month, 12th month follow-ups were analyzed.

RESULTS

Patients with the desired biochemical parameters at the determined follow-up points were identified and two groups were formed as RYGB(n = 43) and SG(n = 7) patients. When biochemical parameters were analyzed between the groups, homocysteine, HbA1c, HDL Cholesterol, VLDL Cholesterol, Total Cholesterol, Triglycerides, Ferritin, Serum Iron levels showed a statistical difference (p < 0.001). Folate (p = 0.064) and albumin (p = 0.257) did not show a significant difference over time. The change in vitamin B12 (p = 0.409) over time was not significant in the SG group, whereas a significant difference was observed in the RYGB group (p < 0.001). When we established a marginal model to determine the factors affecting the change in homocysteine over time, vitamin B12 and folate values.

CONCLUSIONS

The relationship between Vitamin B12, folate and homocysteine is important in order to better understand the complications that develop in bariatric metabolic surgery patients, to prevent possible complications and to better manage the process.

Association Between Dietary Intake After Roux-en-Y Gastric Bypass Surgery and Antioxidant/inflammatory Status: A 6-Month Pilot Prospective Cohort Study

BACKGROUND/AIM

Adipose tissue can increase levels of inflammation and oxidative stress, which explains the relationship between obesity and many chronic diseases. Weight loss, changes in adipose tissue metabolism, and dietary nutrient intake changes following bariatric surgery could affect a number of oxidative- and inflammation-related factors. Therefore, this study aimed to assess the potential relationship between dietary intake and inflammatory/antioxidant markers in the 6 months following Roux-en-Y gastric bypass surgery (RYGB).

MATERIAL AND METHODS

This pilot prospective cohort study included 45 patients with severe obesity who underwent RYGB. The patients were assessed at three different time points: baseline, 3 months, and 6 months post-surgery. Throughout the study, dietary intake data, levels of total antioxidant capacity (TAC), NF-κB, and serum levels of certain micronutrients were measured three times. Dietary macro- and micronutrient intake data were obtained three times throughout the study using the 24-h food recall questionnaire.

RESULTS

The analysis of dietary indices in the present study found a significant positive correlation between the dietary intake of zinc, copper, MUFA, and serum TAC levels. It also revealed a significant inverse correlation between serum levels of NF-κB with vitamin E and PUFA intake. Additionally, there was a significant positive association between the amount of dietary carbohydrates and saturated fatty acids intake and the levels of NF-κB. Furthermore, within 3 to 6 months after the surgery, patients experienced an increase in serum levels of TAC, ferritin, vitamin D3, vitamin B12, and folate. However, there was a decrease in serum levels of NF-κB, zinc, and copper.

CONCLUSIONS

Weight loss and nutritional status may potentially impact oxidative stress and inflammation levels within 6 months following RYGB surgery. Further research is necessary to comprehensively investigate the different facets of this correlation and elucidate the precise underlying mechanism.

Bariatric Surgery in Obesity: Metabolic Quality Analysis and Comparison of Surgical Options

Obesity is a constantly growing health problem which reduces quality of life and life expectancy. Bariatric surgery (BS) for obesity is considered when all other conservative treatment modalities have failed. Comparison of the multidisciplinary programs with BS regarding to the weight loss showed that substantial and durable weight reduction have been achieved only with bariatric surgical treatments. Although laparoscopic sleeve gastrectomy is the most popular BS, it has high long-term failure rates, and it is claimed that one of every three patients will undergo another bariatric procedure within a 10-year period. Although BS provides weight loss and improvement of metabolic comorbidities, in long-term follow-up, weight gain is observed in half of the patients, while decrease in bone mass and nutritional deficiencies occur in up to 90%. Moreover, despite significant weight loss, several psychological aspects of patients are worsened in comparison to preoperative levels. Nearly one-fifth of postoperative patients with "Loss-of-eating control" meet food addiction criteria. Therefore, the benefits of weight loss following bariatric procedures alone are still debated in terms of the proinflammatory and metabolic profile of obesity.

Changes in Total Homocysteine and Glutathione Levels After Laparoscopic Sleeve Gastrectomy in Children with Metabolic-Associated Fatty Liver Disease

PURPOSE

Paediatric obesity is a well-known risk factor for metabolic-associated fatty liver disease (MAFLD). The aim of this study was to evaluate the effects of laparoscopic sleeve gastrectomy (LSG) on the levels of total homocysteine (tHcy) and total glutathione (tGSH) plasma levels in children with MAFLD.

MATERIAL AND METHODS

Twenty-four children with severe obesity who underwent LSG were included in the study. The metabolic parameters, systemic inflammatory markers, one-carbon metabolism products, ultrasound and histological improvement were evaluated at baseline (T0M) and after 12 months from LSG (T12M).

RESULTS

The patients exhibited a significant amelioration of several metabolic parameters at T12M. A significant reduction of steatosis was observed at ultrasound (from 72.7% of moderate-severe grade to 0% severe steatosis), accompanied by a statistically significant improvement of ballooning, portal and lobular inflammation and fibrosis. A statistically significant decrease of tumour necrosis factor circulating levels was also observed (T0M median = 290.3, IQR = 281.0-317.0 pg/mL; T12M median = 260.4, IQR = 240.0-279.0 pg/mL; p < 0.0001). After 12 months from LSG, a significant increase of mean plasma levels of tHcy(T0M mean = 15.7 ± 4.1 μmol/L; T12M mean = 21.1 ± 9.3 μmol/L; p = 0.0146) was also observed. The increase of tHcy showed no causal link with the improvement of MAFLD-related inflammatory, metabolic and histological pattern.

CONCLUSION

LSG in children with obesity induces an improvement of MAFLD-related metabolic derangement and liver damage, but also a mild hyperhomocysteinemia that should be avoided to prevent cardiovascular risk.

Behaviour of carbonyl groups in several clinical conditions: Analysis of our survey

Protein carbonylation is a marker of oxidative protein damage, that is likely involved in the pathogenesis of several diseases. The aim of this study was to evaluate the protein carbonyl (PC) groups in different clinical conditions. It included different groups of subjects: 81 trained subjects; 23 subjects with mild essential hypertension; 31 middle-aged subjects with metabolic syndrome (MS); 106 subjects with MS not selected for age (subdivided into two subgroups, with and without diabetes mellitus); 91 obese adults subdivided in two subgroups (BMI 30-35 Kg/m2 and BMI > 35 kg/m2); 48 subjects with obstructive sleep apnea syndrome (OSAS) subdivided in accordance with the apnea/hypopnea index (AHI); 27 subjects with chronic kidney disease (CKD) on conservative therapy; 31 subjects with CKD on haemodialysis treatment; and 50 subjects with juvenile myocardial infarction. PC groups were reduced in trained subjects in comparison with sedentary controls, while no variation was observed in mild essential hypertension. PC groups were increased in MS subjects and in adult obese subjects. In MS subjects the PC groups were not influenced by the presence of diabetes mellitus and in adult obese subjects were not influenced by the obesity degree. In OSAS subjects only those with AHI > 30 showed an increase of PC groups. PC groups increased in CKD subjects undergoing conservative treatment and haemodialysis therapy. In dialyzed subjects, after a standard dialysis session, there was a marked increase in PC groups. In juvenile myocardial infarction PC groups were higher than in controls; there was no difference between STEMI and NSTEMI and their concentration was unaffected by the number of cardiovascular risk factors or stenosed coronary vessels.

Nutritional Deficiencies, Bariatric Surgery, and Serum Homocysteine Level: Review of Current Literature

Obesity is currently one of the biggest global health problems. In the case of severe obesity, bariatric surgeries are considered to be the most important method of treatment. The 2 most commonly performed bariatric surgery procedures include Roux-en-Y gastric bypass and sleeve gastrectomy. However, these methods are not free from complications, and the most common ones (moderately long or long term) are micronutrient deficiencies. The deficiency of vitamins B6, B12, and folic acid as cofactors of the folate cycle contributes to the development of hyperhomocysteinemia. It seems that apart from nutritional factors, there are other aspects that have a significant influence on the concentration of homocysteine in blood, such as the type of conducted bariatric surgery, the post-surgical concentration of betaine and creatinine, and the clearance of methionine (i.e., the mutations of the gene that encodes the MTHFR reductase as well as other genes associated with the process of methylation, e.g., methionine synthase). Their presence might be one of the causes of the increased concentration of homocysteine after surgery despite the fact that patients take vitamin-mineral supplementation.

Plasma homocysteine after laparoscopic Roux-en-Y gastric bypass increases in the early postoperative phase but decreases in the long-term follow-up. A retrospective analysis

BACKGROUND

Homocysteine is an important independent risk factor for predicting cardiovascular disease (CVD). However, changes in the homocysteine levels after bariatric surgery remain controversial.

OBJECTIVES

Modeling differences in homocysteine after bariatric surgery.

SETTING

University Hospital, Austria.

METHODS

Seven hundred eight consecutive bariatric surgery patients (78% female, 22% male, mean body mass index 41 kg/m² preoperatively) underwent laparoscopic long-limb Roux-en-Y gastric bypass in a 6-year period and were retrospectively evaluated for changes in their preoperative homocysteine levels, at 3, 6, 9, 12, 18, 24, 36, 48, 60, and 72 months postoperatively. Furthermore, a postal and telephone screening for postoperative CVD with a follow-up of 71% was conducted.

RESULTS

Hyperhomocysteinemia was present in 11.8% preoperatively (normal range: <15 μmol/L). The median plasma homocysteine level was 10.4 preoperatively, 12.1 at 3, 11.2 at 6, 10.0 at 9, 9.8 at 12, 8.9 at 18, 8.7 at 24, 8.6 at 36, 9.1 at 48, 9.8 at 60, and 10.0 μmol/L at 72 months postoperatively. After subdividing the study population in morbidly obese (n = 509, body mass index 40-50 kg/m²) and super-obese (n = 199, body mass index >50 kg/m²) patients, the short-term increase into homocysteine levels remained. Overall, newly onset CVD risk was 4.2%. After subdividing the CVD risk into risk for myocardial infarction, stroke, and risk for deep vein thrombosis/pulmonary embolism the distribution was as follows: .2% myocardial infarction, .59% stroke, and 2.97% deep vein thrombosis/pulmonary embolism (median 36 [interquartile range 36-48] mo postoperatively).

CONCLUSION

Laparoscopic Roux-en-Y gastric bypass leads to increased homocysteine levels in the early postoperative period. However, there was no relationship between increased homocysteine levels and CVD event onset.

One Anastomosis Gastric Bypass Reconstitutes the Appropriate Profile of Serum Amino Acids in Patients with Morbid Obesity

Bariatric surgery leads to metabolic benefits in patients with obesity, but their mechanisms are not well understood. The appropriate composition of serum amino acids (AA) is important for sufficient supply of these components into various tissues and organs. Obesity leads to alterations in serum AA concentrations. The aim of this study was to examine the effect of one anastomosis gastric bypass (OAGB), a promising type of bariatric surgery, on serum AA concentrations, which were assayed by LC-MS in serum of 46 bariatric patients prior to and 6–9 months after OAGB, as well as in 30 lean control subjects. The results were analyzed by principle components analysis and metabolic pathway analysis. PCA analysis showed that OAGB led to normalization of serum AA concentrations of patients with obesity to a pattern similar to the control subjects, and the concentrations of essential AA remained decreased after OAGB. Changes of individual AA and their associated metabolic pathways were also presented. OAGB caused normalization of the AA profile, which may contribute to improvement of glucose homeostasis and reduction of cardiovascular risk. Considering decreased essential AA concentrations after OAGB, increased intake of high protein food should be recommended to the patients after this type of bariatric surgery.

Impact of Ileal Transposition Surgical Intervention on Antioxidant Status Measured in Liver Tissue of Obese Zucker Rats (Crl:ZUC-Leprfa)

Background

The main factor characteristic for low-grade systemic inflammation typical for obesity is oxidative stress (OS). Reactive oxygen species (ROS) production is higher and more increased in time in the obese patients than in lean subjects.

Aims

To assess the effect of ileal transposition (IT) and sham types of bariatric procedures on the antioxidative systems in the liver tissue of Zucker rats (Crl:ZUC Lepr^fa).

Method

21 animals were divided into the experimental groups: control group (n = 7), sham group (n = 7), and IT group (n = 7). Sham and IT animals underwent selected surgery. The concentration of total antioxidant capacity (TAC), total antioxidant status (TOS), and activity of glutathione reductase (glutathione-disulfide reductase, GR, GSR), catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST), and total superoxide dismutase activity (SOD) were assessed in liver tissue 3 months after surgery.

Results

IT procedure significantly increased TAC when compared to sham and the control group. Animals after IT showed higher levels of TOS when compared to sham procedure. The total amount of TOS was similar in IT and control groups. GPx activity was increased in the groups submitted to the sham and IT surgery in relation to control. GR and CAT activities were significantly higher after IT in comparison to control and sham procedures. Total SOD and MnSOD were significantly higher in sham-operated animals in comparison to IT intervention and control groups.

Conclusions

IT procedure had a positive impact on the diminishing of oxidative stress measured by TAC and TOS markers. The dynamic, adaptive, and protective mechanisms of enzymatic antioxidant systems were observed after the IT but not sham procedure. Nevertheless, 3 months after surgery, the midterm effect of bariatric surgery was observed, which might not fully balance the antioxidative response.

Beneficial changes on plasma apolipoproteins A and B, high density lipoproteins and oxidized low density lipoproteins in obese women after bariatric surgery: comparison between gastric bypass and sleeve gastrectomy

Background

The beneficial effects in lipid profiles after obesity surgery might be associated with the decrease in cardiovascular risk. However, direct comparison between different surgical techniques has not been extensively performed.

Methods

In the present study we compare 20 obese women submitted to laparoscopic Roux en Y gastric bypass (RYGB) with 20 women submitted to sleeve gastrectomy (SG). Twenty control women matched for age and baseline cardiovascular risk were also included. Both patients and controls were followed up for 1 year after surgery or conventional treatment with diet and exercise, respectively. Lipid profiles were measured at baseline, 6 and 12 months later. Carotid intima-media thickness was measured by ultrasonography at baseline and at the end of the study.

Results

Women submitted to bariatric surgery showed a decrease in total cholesterol, triglycerides, oxidized-LDL and ApoB, and an increase in HDL and ApoA concentrations that occurred regardless of the surgical procedure. LDL concentrations, however, decreased only after RYGB whereas Lp(a) showed no changes. We did not observe any correlation between the changes in serum lipid concentrations and those in carotid intima-media thickness.

Conclusions

Sleeve gastrectomy and gastric bypass induce a similar beneficial effect on serum lipids in women with high cardiovascular risk 1 year after surgery.

Potential Application of 1H NMR for Routine Serum Lipidome Analysis -Evaluation of Effects of Bariatric Surgery

Routine laboratory lipid assays include simple measurements of total cholesterol, triacylglycerols and HDL. However, lipids are a large group of compounds involved in many metabolic pathways, and their alterations may have serious health consequences. In this study, we used 1H NMR to analyze lipids extracted from sera of 16 obese patients prior to and after bariatric surgeries. We observed a post-surgery decrease in serum concentrations of lipids from various groups. The hereby presented findings imply that 1H NMR is suitable for rapid, simple and non-invasive detection of lipids from 30 structural groups, among them triacylglycerols, phosphatidylcholine, phosphatidylethanolamine, sphingomyelin, total phospholipids, total, free and esterified cholesterol, total and unsaturated fatty acids. NMR-based analysis of serum lipids may contribute to a substantial increase in the number of routinely determined markers from this group; therefore, it may find application in clinical assessment of obese subjects prior to and after bariatric surgeries, as well as in the examination of patients with other metabolic diseases.

Obesity, bariatric surgery and oxidative stress

Introduction:

Obesity refers to the accumulation of fatty tissues and it favors the occurrence of oxidative stress. Alternatives that can contribute to body weight reduction have been investigated in order to reduce the production of reactive oxygen species responsible for tissue damage. The aim of the current study was to assess whether the oxidant and antioxidant markers of obese women before and after bariatric surgery were able to reduce oxidative damage.

Method:

We have assessed 16 morbidly obese women five days before and 180 days after the surgery. The control group comprised 16 non-obese women. Levels of thiobarbituric acid-reactive substances, carbonylated proteins, reduced glutathione and ascorbic acid were assessed in the patients' plasma.

Results:

Levels of lipid peroxidation and protein carbonylation in the pre-surgical obese women were higher than those of the controls and post-surgical obese women. Levels of reduced glutathione in the pre-surgical obese women were high compared to the controls, and declined after surgery. Levels of ascorbic acid fell in the pre--surgical obese women compared to the control and post-surgical obese women.

Conclusion:

Body weight influences the production of reactive oxygen species. Bariatric surgery, combined with weight loss and vitamin supplementation, reduces cellular oxidation, thus reducing tissue damage.

Does Bariatric Surgery Improve Obesity Associated Comorbid Conditions

Obesity is a constantly growing health problem which reduces quality of life and life expectancy. Bariatric surgery for obesity is taken into account when all other conservative treatment modalities have failed. Comparison of the multidisciplinary programs with bariatric surgery regarding to weight loss showed that substantial and durable weight reduction have been achieved only with bariatric surgical treatments. However, the benefits of weight loss following bariatric procedures are still debated regarding the pro-inflammatory and metabolic profile of obesity.

Alterations of specific lipid groups in serum of obese humans: a review

Obesity is a major contributor to the dysfunction of liver, cardiac, pulmonary, endocrine and reproductive system, as well as a component of metabolic syndrome. Although development of obesity-related disorders is associated with lipid abnormalities, most previous studies dealing with the problem in question were limited to routinely determined parameters, such as serum concentrations of triacylglycerols, total cholesterol, low-density and high-density lipoprotein cholesterol. Many authors postulated to extend the scope of analysed lipid compounds and to study obesity-related alterations in other, previously non-examined groups of lipids. Comprehensive quantitative, structural and functional analysis of specific lipid groups may result in identification of new obesity-related alterations. The review summarizes available evidence of obesity-related alterations in various groups of lipids and their impact on health status of obese subjects. Further, the role of diet and endogenous lipid synthesis in the development of serum lipid alterations is discussed, along with potential application of various lipid compounds as risk markers for obesity-related comorbidities.

Bariatric surgery in morbidly obese patients improves the atherogenic qualitative properties of the plasma lipoproteins

OBJECTIVE

The purpose of this study was to evaluate the effect of weight loss induced in morbidly obese subjects by Roux-en-Y gastric bypass bariatric surgery on the atherogenic features of their plasma lipoproteins.

METHODS

Twenty-one morbidly obese subjects undergoing bariatric surgery were followed up for up to 1 year after surgery. Plasma and lipoproteins were assayed for chemical composition and lipoprotein-associated phospholipase A2 (Lp-PLA2) activity. Lipoprotein size was assessed by non-denaturing polyacrylamide gradient gel electrophoresis, and oxidised LDL by ELISA. Liver samples were assayed for mRNA abundance of oxidative markers.

RESULTS

Lipid profile analysis revealed a reduction in the plasma concentrations of cholesterol and triglycerides, which were mainly associated with a significant reduction in the plasma concentration of circulating apoB-containing lipoproteins rather than with changes in their relative chemical composition. All patients displayed a pattern A phenotype of LDL subfractions and a relative increase in the antiatherogenic plasma HDL-2 subfraction (>2-fold; P < 0.001). The switch towards predominantly larger HDL particles was due to an increase in their relative cholesteryl ester content. Excess weight loss also led to a significant decrease in the plasma concentration of oxidised LDL (∼-25%; P < 0.01) and in the total Lp-PLA2 activity. Interestingly, the decrease in plasma Lp-PLA2 was mainly attributed to a decrease in the apoB-containing lipoprotein-bound Lp-PLA2.

CONCLUSION

Our data indicate that the weight loss induced by bariatric surgery ameliorates the atherogenicity of plasma lipoproteins by reducing the apoB-containing Lp-PLA2 activity and oxidised LDL, as well as increasing the HDL-2 subfraction.

Oxidative stress and protein carbonylation in adipose tissue - implications for insulin resistance and diabetes mellitus

While historically considered simply as a depot for excess energy, white adipose tissue is a dynamically active endocrine organ capable of responding to a variety of efferent stimuli resulting in the synthesis and secretion of peptides, proteins and metabolites that serve as signal transducers to the peripheral and central circulation. Such regulation controls a variety of physiological processes including energy expenditure, food intake, reproductive capacity and responsiveness to insulin. Indeed, the accumulation of inflammatory cells in white adipose tissue is considered to be causative in the development of insulin resistance and eventually type 2 diabetes mellitus. A large body of evidence suggests that oxidative stress in adipose tissue not only correlates with insulin resistance but is also causative in its development. Moreover, using the available plasma oxidative stress biomarkers, many clinical studies have shown the presence of systemic oxidative stress in obese insulin resistant subjects, and its decrease after the successful treatment of obesity. In this review we emphasize the role of protein carbonylation in dysfunctional obese white adipose tissue and its metabolic implications. We focus on glutathione S-transferase A4 as the key enzyme for trans-4-hydroxy-2-nonenal and trans-4-oxo-2-nonenal removal from the cell, thus preventing protein carbonylation. This article is part of a Special Issue entitled: Posttranslational Protein modifications in biology and Medicine.

Serum cystatin C in relation to fat mass loss after bariatric surgery

Serum cystatin C concentration, generally accepted as renal function marker, is associated with cardiovascular risk and metabolic syndrome. Recent studies indicate that cystatin C increases in human obesity and that adipose tissue contributes to enhanced serum cystatin C concentration in obese subjects. The aim of the study was to assess whether a reduction in body and fat mass after bariatric surgery has any impact on serum cystatin C concentrations.

MATERIAL AND METHODS

Serum from 27 obese patients were tested before and 6 months after bariatric surgery. Twenty healthy subjects with normal body weight served as controls. Serum cystatin C concentrations were assayed by ELISA.

RESULTS

Serum cystatin C concentrations were significantly higher in obese patients compared with non-obese subjects. Decrease of body and fat mass after bariatric surgery resulted in improvement of several parameters associated with cardiovascular risk and metabolic syndrome, like serum lipids, blood pressure and insulin sensitivity. Surprisingly the mean postoperative serum cystatin C concentration was not significantly different from that before surgery. Serum creatinine and GFR also remained unchanged.

CONCLUSION

The results presented here suggest that serum cystatin C concentration is not tightly associated with body and fat mass loss in obese patients after bariatric surgery.

Decreased serum betaine concentrations in patients after bariatric surgery

Bariatric surgery significantly reduces the risk of cardiovascular diseases but has no effects on hyperhomocysteinemia, the risk factor for atherogenesis. We hypothesize that the decrease in serum betaine (involved in homocysteine metabolism) concentrations, after bariatric surgery, impairs conversion of homocysteine to methionine, leading to hyperhomocysteinemia. If this is true, it may be desirable to supply patients after bariatric surgery with betaine. Serum betaine and homocysteine concentrations were measured by liquid chromatography/mass spectrometry, in 16 obese patients, before and 6 months after bariatric surgery. Ten healthy individuals with normal body mass index served as controls. Serum betaine concentrations decreased to the values lower than in controls after bariatric surgery, whereas serum homocysteine concentrations remained elevated. In patients supplemented with B(12) and folate, no effect of bariatric surgery on serum concentrations of vitamins involved in homocysteine metabolism was observed. These results suggest that betaine deficit could be responsible for maintenance of hyperhomocysteinemia after bariatric surgery. We postulate that supplementation with betaine could be of therapeutic value for the treatment of hyperhomocysteinemia after bariatric surgery.

Reduction of 8-iso-prostaglandin F2α in the first week after Roux-en-Y gastric bypass surgery

Obesity is associated with increased markers of oxidative stress. We examined whether oxidative stress is reduced within the first week after Roux-en-Y gastric bypass (RYGB) surgery and could be related to changes in adipose tissue depots. The reactive oxygen species (ROS) marker 8-iso-prostaglandin F2α (8-iso-PGF2α) and activity of antioxidant glutathione peroxidases (GPX) in plasma were compared before and ~1 week after RYGB. The effects of RYGB on subcutaneous adipose tissue and interstitial fluid 8-iso-PGF2α levels and subcutaneous adipose tissue expression of GPX-3 were also assessed. Levels of 8-iso-PGF2α in subcutaneous and visceral adipose tissue were determined. Plasma 8-iso-PGF2α levels decreased (122 ± 75 to 56 ± 15 pg/ml, P = 0.001) and GPX activity increased (84 ± 18 to 108 ± 25 nmol/min/ml, P = 0.003) in the first week post-RYGB. RYGB also resulted in reductions of 8-iso-PGF2α in subcutaneous adipose tissue (1,742 ± 931 to 1,132 ± 420 pg/g fat, P = 0.046) and interstitial fluid (348 ± 118 to 221 ± 83 pg/ml, P = 0.046) that were comparable to plasma (26-33%, P = 0.74). Adipose GPX-3 expression was increased (6.7 ± 4.7-fold, P = 0.004) in the first postoperative week. The improvements in oxidative stress occurred with minimal weight loss (2.4 ± 3.4%, P = 0.031) and elevations in plasma interleukin-6 (18.0 ± 46.8 to 28.0 ± 58.9 pg/ml, P = 0.004). Subcutaneous and visceral adipose tissues express comparable 8-iso-PGF2α levels (1,204 ± 470 and 1,331 ± 264 pg/g fat, respectively; P = 0.34). These data suggest that RYGB affects adipose tissue leading to the restoration of adipose redox balance within the first postoperative week and that plasma 8-iso-PGF2α is primarily derived from subcutaneous adipose tissue.

Effect of bariatric surgery on sulphur amino acids and glutamate

Plasma total cysteine (tCys) concentrations are associated with BMI. To study the relationship between tCys and BMI, we monitored the changes in serum concentrations of tCys and metabolically related compounds in sixty obese patients (BMI 50–60 kg/m2) from before to 1 year after either gastric bypass surgery (mean 30 % weight loss) or duodenal switch surgery (mean 41 % weight loss). A total of fifty-eight healthy persons (BMI 17–31 kg/m2) served as controls. Before surgery, obese patients had modestly (approximately 17 %) higher mean serum tCys, and markedly (>2-fold) higher glutamate concentrations, than controls (P ≤ 0·001 for both). Serial examinations after surgery revealed that gastric bypass patients had no change in tCys concentrations (P = 0·22), while duodenal switch patients showed a modest (approximately 12 %) but significant decrease in tCys (P < 0·001). Total homocysteine concentrations increased in duodenal switch patients but not in gastric bypass patients. Independent of surgery type, serum concentrations of methionine and cystathionine decreased (P < 0·05 for both), while serum glutathione and taurine remained stable. Glutamate concentrations declined, as did γ-glutamyltransferase activity (P < 0·001 for both). These results show that despite 30 % weight loss, and decreases in methionine, cystathionine and glutamate, there was no significant change in serum tCys in patients after gastric bypass surgery. The decrease in tCys in patients undergoing duodenal switch could be related to malabsorption. The present findings do not suggest that BMI is a causal determinant of plasma tCys.

Determinants of hyperhomocysteinemia after gastric bypass surgery in obese subjects

BACKGROUND

Effectiveness of gastric bypass (GBP) on reduction of vascular risk factors is well established, but GBP induces nutritional deficits that could reduce the cardiovascular benefit of weight loss. Particularly, hyperhomocysteinemia, now clearly identified as a vascular risk factor, has been described after GBP. The aim of this study was to clarify the factors associated with increased homocysteine concentration after GBP.

METHODS

Homocysteine concentration and multiple nutritional parameters were measured in 213 consecutive subjects. One hundred and eight subjects were studied before surgery (control (CT)), 115 one to 6 years after GBP, and 41 both before and 6 months after GBP.

RESULTS

Homocysteine concentration did not differ before and after GBP (9.1 ± 3.2 vs 8.6 ± 3.4 μmol/l), but 94% of subjects had been supplemented with a multivitamin preparation after surgery. The nutritional parameters best correlated with homocysteine concentration both before and after GBP were folate and creatinine concentrations (p < 0.0001). In contrast, vitamin B12 and metabolic parameters (including glucose, insulin, lipids and C-reactive protein) were not associated with homocysteine concentration. After GBP, homocysteine concentration was significantly lower in subjects taking a multivitamin supplementation containing a high dose of folate than those who did not (7.7 ± 2.8 vs 10.1 ± 3.9 μmol/l, p < 0.0001).

CONCLUSIONS

The main determinants of homocysteine concentration identified in this study are folate and serum creatinine. Multivitamin supplementation with a high dose of folate prevents hyperhomocysteinemia after GBP.

Oxidant/antioxidant status in obese children compared to pediatric patients with type 1 diabetes mellitus

BACKGROUND

Type 1 diabetes (T1D) mellitus and obesity are recognized risk factors for cardiovascular disease (CVD). A common mechanism underlying an increased risk for endothelial dysfunction in these two metabolic diseases is oxidative stress.

OBJECTIVE

To evaluate and compare the oxidant/antioxidant defense systems in children affected with T1D or obesity in order to determine the importance of oxidative stress before the emergence of complications.

SUBJECTS

Children with T1D (n = 20) or obesity (n = 22), without comorbidities, and age- and sex-matched controls (n = 16).

METHODS

We assessed lipid peroxidation by circulating levels of lipoperoxides and malondialdehyde, as well as protein oxidation by the concentration of plasma carbonyl groups. The endogenous antioxidative defense system was evaluated by the red cell glutathione peroxidase and reduced glutathione. The serum levels of alpha-tocopherol and beta-carotene were determined to assess exogenous antioxidants.

RESULTS

Lipid peroxidation was significantly higher in both T1D and obese children when compared with control children. However, T1D patients showed a more elevated level, because their malondialdehyde values were significantly increased with respect to obese children. Protein oxidation was present in both groups of children and did not differ between them. With respect to obese children, the glutathione peroxidase activity and exogenous antioxidants were decreased in T1D patients.

CONCLUSION

Oxidative stress is present in both children with T1D and obesity, although it is more pronounced in the former. Obese children may suffer an additional oxidative stress in the case of developing impaired glucose metabolism.

Increased serum nitric oxide concentration after bariatric surgery--a potential mechanism for cardiovascular benefit

BACKGROUND

It is believed that endothelial dysfunction associated with obesity contributes to reduced vascular production of nitric oxide (NO). Weight reduction after bariatric surgery is known to decrease the risk of cardiovascular disease. The purpose of this study was to determine whether bariatric surgery leads to improvement of metabolic markers of endothelial function: serum NO and its precursor (arginine) concentrations in obese patients.

METHODS

Serum NO and L-arginine concentrations were measured in 25 morbidly obese patients directly before and 6 months after bariatric surgery. Moreover, selected parameters that may be involved in development of endothelial dysfunction were also studied. Control group consisted of ten healthy individuals with normal body weight.

RESULTS

Six months after bariatric surgery, serum NO concentration was approximately 40% higher than before surgery. Surprisingly, serum NO concentration in nonobese controls was essentially similar to obese patients before surgery. In contrast, serum L-arginine concentration was higher in obese patients than in controls and decreased significantly after surgery. The body weight, blood pressure, triacylglycerols, LDL/HDL-cholesterol ratio, insulin, homeostasis model assessment score (HOMA-index), C-reactive protein, and white blood cell count were higher in obese patients as compared with controls and decreased significantly after surgery.

CONCLUSIONS

Our results indicate that improvement of insulin resistance, lipidemia, and blood pressure as well as reduction of systemic inflammation after bariatric surgery were associated with the increase of serum NO concentration. We propose that the increase in serum NO concentration contribute to diverse beneficial effects of weight loss after bariatric surgery especially in the context of risk of atherosclerosis.