PROMISE: effect of protein supplementation on fat-free mass preservation after bariatric surgery, a randomized double-blind placebo-controlled trial

INTRODUCTION

Protein malnutrition after bariatric surgery is a severe complication and leads to significant morbidity. Previous studies have shown that protein intake and physical activity are the most important factors in the preservation of fat-free mass during weight loss. Low protein intake is very common in patients undergoing bariatric surgery despite dietary counseling. Protein powder supplements might help patients to achieve the protein intake recommendations after bariatric surgery and could therefore contribute to preserve fat-free mass. This double-blind randomized placebo-controlled intervention study aims to assess the effect of a daily consumed clear protein powder shake during the first 6 months after bariatric surgery on fat-free mass loss in the first 12 months after laparoscopic Roux-en-Y gastric bypass (LRYGB).

METHODS AND ANALYSIS

Inclusion will take place at the outpatient clinic of the bariatric expertise center for obesity of the Maasstad Hospital. Patients will be randomly assigned to either the intervention or control group before surgery. The intervention group will receive a clear protein powder shake of 200 ml containing 20 g of whey protein dissolved in water which should be taken daily during the first 6 months after LRYGB on top of their normal postoperative diet. The control group will receive an isocaloric, clear, placebo shake containing maltodextrine. Postoperative rehabilitation and physiotherapeutical guidance will be standardized and similar in both groups. Also, both groups will receive the same dietary advice from specialized dieticians. The main study parameter is the percentage of fat-free mass loss 6 months after surgery, assessed by multi-frequency bioelectrical impedance analysis (MF-BIA).

ETHICS AND DISSEMINATION

The protocol, version 2 (February 20, 2022) has been approved by the Medical Research Ethics Committees United (MEC-U) (NL 80414.100.22). The results of this study will be submitted to peer-reviewed journals.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05570474. Registered on October 5, 2022.

T and B Cell Composition and Cytokine Producing Capacity Before and After Bariatric Surgery

Morbid obesity is associated with a chronic state of low-grade inflammation, which may lead to accelerated differentiation of T and B cells. These differentiated immune cells are strongly cytotoxic and have an increased pro-inflammatory cytokine producing capacity. Furthermore, the anti-inflammatory function of the T and B cells decreases. The aim of this study was to evaluate the effect of morbid obesity on the subset profile and cytokine producing capacity of T and B cells. Subsequently, we assessed whether bariatric surgery affected the subset profile and cytokine producing capacity of these cells. We determined the proportion of T and B cell subsets and their cytokine producing capacity in peripheral blood collected from 23 morbidly obese patients before and three months after bariatric surgery using flow-cytometry. We compared this with the results of 25 lean controls. Both CD4+ and CD8+ T cells showed a more differentiated subset profile in morbidly obese patients as compared to lean controls, which was not recovered three months after bariatric surgery. The B cell composition of morbidly obese patients after bariatric surgery adjusted towards the profile of lean controls. However, the IL-2 and IFN-γ producing capacity of CD8+ T cells and the IL-2, IFN-γ, TNF-α and IL-10 producing capacity of B cells was not restored three months after bariatric surgery. In conclusion, the data suggest that the immune system has the capacity to recover from the detrimental effects of morbid obesity within three months after bariatric surgery in terms of cell composition; however, this was not seen in terms of cytokine producing capacity. The full restoration of the immune system after bariatric surgery may thus take longer.

Resizing a large pouch after laparoscopic Roux-en-Y gastric bypass: comparing the effect of two techniques on weight loss

BACKGROUND

Insufficient weight loss or weight regain has many causes including a large gastric pouch. A large gastric pouch may be due to the surgical technique or can be patient related (dilation). Resizing the gastric pouch may lead to additional weight loss. Currently, there is no gold standard for the revisional surgical technique. Therefore this study was performed to determine which surgical technique for revisional bariatric surgery (BS) has superior outcomes in terms of weight loss: sleeve resection of the gastrojejunostomy and gastric pouch (SGP), or resection of the gastrojejunostomy with resizing of the pouch and creation of a new anastomosis (RGJ).

METHODS

All patients who underwent revisional BS for insufficient weight loss or weight regain as a result of an enlarged pouch after LRYGB from April 2014 to June 2018 in our hospitals were included in this observational cohort study. Outcomes were measured in percentage total weight loss (%TWL).

RESULTS

A total of 37 patients who underwent SGP and 21 patients who underwent RGJ as revisional BS were included in this study. The median body mass index before revisional BS was 37.6 kg/m² versus 35.7 kg/m² (SGP vs RGJ, respectively, P = 0.115). There was no significant difference in %TWL between the two cohorts 1 and 2 years after revisional BS, respectively; SGP 14.5% vs RGJ 11.0%, P = 0.885 and SGP 12.3% vs RGJ 10.8%, P = 0.604. Comparing %TWL based on weight at LRYGB, there was also no significant difference two years after revisional BS (SGP 22.0% vs RGJ 22.2%, P = 0.885). The average use of surgical disposables for the SGP technique were lower compared to the RGJ technique.

CONCLUSIONS

Resizing a large pouch leads to additional weight loss. Both techniques have comparable outcomes in terms of weight loss. However, based on average surgical costs, the SGP technique may be preferable.

P936 Early signs of cardiac dysfunction in obesity patients, results of the CARDIOBESE study

Introduction

Obesity is becoming a global epidemic. Current knowledge on early signs of cardiac dysfunction in obesity patients is insufficient. The onset of heart failure in obesity patients cannot be fully explained by the presence of traditional cardiovascular risk factors.

Purpose

To detect early signs of cardiac dysfunction in obesity patients without known cardiovascular disease.

Methods

The CARDIOBESE-study is a cross-sectional multicentre study of 100 obesity patients scheduled for bariatric surgery (body mass index (BMI) ≥35 kg/m2) without known cardiovascular disease, and 50 age-matched and gender-matched non-obese controls (BMI ≤30 kg/m2). Speckle tracking echocardiography, biomarkers and Holter monitoring were used to identify parameters that are able to show cardiac dysfunction at a very early stage in obesity patients.

Results

Obesity patients had impaired left ventricular ejection fraction, global longitudinal strain (GLS) and diastolic function parameters (e.g. septal e" velocity, lateral e" velocity, E/e’ and E/A-ratio) as compared to the non-obese controls (Table). C-reactive protein (CRP) and heart rate were increased, whereas heart rate variability (Standard deviation of NN intervals, SDNN) was decreased. Obesity patients were subdivided in patients with impaired (< -17%, n = 56) or normal GLS (n = 36). Comparison between these patients revealed no differences regarding BMI, prevalence of traditional cardiovascular risk factors or CRP value. Nevertheless, patients with abnormal GLS had a higher waist circumference and lower SDNN.

Conclusion

There is a high prevalence of subclinical cardiac dysfunction as measured by GLS in obesity patients (56%), which appears to be related to abdominal fat and decreased heart rate variability and not to BMI, traditional cardiovascular risk factors or CRP.

Non-obese controls (n = 50) Obesity patients (n = 100) p-value Obesity patients with normal GLS (n = 36) Obesity patients with impaired GLS (n = 56) p-value Age (years) 49.2 ± 9.5 47.9 ± 7.6 0.36 47.6 ± 7.1 48.3 ± 7.6 0.68 BMI (kg/m2) 24.9 ± 3.2 42.9 ± 4.1 <0.001 42.7 ± 4.2 42.7 ± 4.1 0.98 Waist circumference (cm) 81.1 ± 10.4 133.1 ± 12.3 <0.001 128.2 ± 11.5 135.2 ± 10.5 0.006 E/A- ratio 1.19 ± 0.26 1.01 ± 0.3 <0.001 1.08 ± 0.2 0.96 ± 0.27 0.048 Septel e" velocity 10.3 ± 9.8 8.1 ± 1.8 0.03 8.2 ± 1.9 7.8 ± 1.7 0.24 E/e" 8.5 ± 2.1 8.9 ± 2.5 0.32 9.5 ± 2.4 8.7 ± 2.5 0.14 CRP (mg/L) 1.9 ± 2.9 8.8 ± 8.8 <0.001 8.5 ± 7.3 9.3 ± 10.1 0.67 SDNN 160.2 ± 35.4 109.4 ± 46.0 <0.001 130.4 ± 48.3 98.9 ± 41.2 0.001 Table: Selection of parameters. Values are means ± SD. SDNN= Standard deviation of NN intervals (heart rate variability)

Effects of bariatric surgery on telomere length and T-cell aging

BACKGROUND

Obesity adversely affects health and is associated with subclinical systemic inflammation and features of accelerated aging, including the T-cell immune system. The presence of metabolic syndrome (MetS) may accelerate, while bariatric surgery might reverse these phenomena. To examine the effects of MetS and bariatric surgery on T-cell aging, we measured relative telomere length (RTL) and T-cell differentiation status in obese patients before and after bariatric surgery.

METHODS

WHO II/III classified obese patients scheduled for bariatric surgery were included: 41 without MetS and 67 with MetS. RTL and T-cell differentiation status were measured in circulating CD4⁺ and CD8⁺ T cells via flow cytometry. T-cell characteristics were compared between patients with and without MetS prior to and at 3, 6, and 12 months after surgery considering effects of age, cytomegalovirus-serostatus, and weight loss.

RESULTS

Thymic output, represented by numbers of CD31-expressing naive T cells, showed an age-related decline in patients with MetS. MetS significantly enhanced CD8⁺ T-cell differentiation. Patients with MetS had significant lower CD4⁺ RTL than patients without MetS. Within the first 6 months after bariatric surgery, RTL increased in CD4⁺ T cells after which it decreased at month 12. A decline in both thymic output and more differentiated T cells was seen following bariatric surgery, more pronounced in the MetS group and showing an association with percentage of body weight loss.

CONCLUSIONS

In obese patients, MetS results in attrition of RTL and accelerated T-cell differentiation. Bariatric surgery temporarily reverses these effects. These data suggest that MetS is a risk factor for accelerated aging of T cells and that MetS should be a more prominent factor in the decision making for eligibility for bariatric surgery.

Tranexamic acid therapy for postoperative bleeding after bariatric surgery

BACKGROUND

Tranexamic acid reduces blood loss associated with various surgical procedures. Postoperative bleeding caused by dissection or bleeding of the enteric staple lines is a well-known complication following bariatric surgery. Reoperation in order to restore hemostasis is frequently necessary (up to 2.5% in literature). The effect of conservative therapy using tranexamic acid for postoperative hemorrhage after bariatric surgery is still very much a novel technique. The aim is to present our results (reoperation rate and thrombo-embolic complication rate) of tranexamic acid therapy for postoperative bleeding after bariatric surgery in comparison to those in existing literature.

METHODS

We retrospectively reviewed 1388 patients who underwent bariatric surgery (laparoscopic gastric bypass or laparoscopic gastric sleeve). Use of tranexamic acid, reoperation rate, transfusion rate and rate of thrombo-embolic complications were reviewed.

RESULTS

Forty-five of 1388 (3.2%) total patients experienced significant hemorrhage after bariatric surgery. Tranexamic acid was administered in 44 of these patients. A failure of the treatment with tranexamic acid was observed in four patients. The incidence of reoperation was 0.4% for the entire population. No thrombo-embolic complications were registered for patients receiving tranexamic acid.

CONCLUSION

These findings suggest that the administration of tranexamic acid appears to be safe in reducing the reoperation rate for bleeding after bariatric surgery.

Ethnicity influences weight loss 1 year after bariatric surgery: a study in Turkish, Moroccan, South Asian, African and ethnic Dutch patients

Several studies conducted in the USA have demonstrated that the effectiveness of bariatric surgery differs between patients from African and European origin. However, little is known on differences in outcomes after bariatric surgery between individuals from other ethnic backgrounds. In this retrospective study, we found that, in terms of weight loss, gastric bypass surgery is less effective in African, South Asian, Turkish and Moroccan patients than in their ethnic Dutch counterparts. Our results underscore that ethnic differences in the effectiveness of bariatric surgery are not limited to those between patients of African and European origin, but extend to other minority groups as well. Therefore, it is important that prospective studies both determine ethnic differences in weight loss-related improvement of co-morbidities and elucidate the exact reasons for these ethnic disparities.