Implementation of Low Glycemic Index Diet Together with Cornstarch in Post-Gastric Bypass Hypoglycemia: Two Case Reports

Postprandial metabolomics analysis reveals disordered serotonin metabolism in post-bariatric hypoglycemia

BACKGROUNDBariatric surgery is a potent therapeutic approach for obesity and type 2 diabetes but can be complicated by post-bariatric hypoglycemia (PBH). PBH typically occurs 1-3 hours after meals, in association with exaggerated postprandial levels of incretins and insulin.METHODSTo identify mediators of disordered metabolism in PBH, we analyzed the plasma metabolome in the fasting state and 30 and 120 minutes after mixed meal in 3 groups: PBH (n = 13), asymptomatic post-Roux-en-Y gastric bypass (post-RYGB) (n = 10), and nonsurgical controls (n = 8).RESULTSIn the fasting state, multiple tricarboxylic acid cycle intermediates and the ketone β-hydroxybutyrate were increased by 30%-80% in PBH versus asymptomatic. Conversely, multiple amino acids (branched-chain amino acids, tryptophan) and polyunsaturated lipids were reduced by 20%-50% in PBH versus asymptomatic. Tryptophan-related metabolites, including kynurenate, xanthurenate, and serotonin, were reduced 2- to 10-fold in PBH in the fasting state. Postprandially, plasma serotonin was uniquely increased 1.9-fold in PBH versus asymptomatic post-RYGB. In mice, serotonin administration lowered glucose and increased plasma insulin and GLP-1. Moreover, serotonin-induced hypoglycemia in mice was blocked by the nonspecific serotonin receptor antagonist cyproheptadine and the specific serotonin receptor 2 antagonist ketanserin.CONCLUSIONTogether these data suggest that increased postprandial serotonin may contribute to the pathophysiology of PBH and provide a potential therapeutic target.FUNDINGNational Institutes of Health (NIH) grant R01-DK121995, NIH grant P30-DK036836 (Diabetes Research Center grant, Joslin Diabetes Center), and Fundação de Amparo à Pesquisa do Estado de São Paulo grant 2018/22111-2.

The Impact of Cholecystectomy in Patients with Post-Bariatric Surgery Hypoglycemia

BACKGROUND

Metabolic surgery is the foremost treatment for obesity and its associated medical conditions. Nonetheless, post-bariatric hypoglycemia (PBH) emerges as a prevalent complication. PBH pathophysiology implicates heightened insulin and glucagon-like peptide 1 (GLP-1) levels, with bile acids (BA) contributing to GLP-1 release. A plausible association exists between cholecystectomy and PBH, which is attributed to alterations in BA metabolism and ensuing hormonal responses. The objective of this retrospective cohort study was to evaluate the impact of cholecystectomy on PBH pharmacological treatment, diagnostic timelines and metabolic parameters.

MATERIALS AND METHODS

Patients diagnosed with PBH after bariatric surgery were evaluated based on their history of cholecystectomy. Demographic, anthropometric and clinical data were collected. Mixed meal tolerance tests (MMTT) results were compiled to assess metabolic responses.

RESULTS

Of the 131 patients with PBH included in the study, 29 had prior cholecystectomy. The time to PBH diagnosis was similar across groups. Patients with prior cholecystectomy required higher doses of acarbose (p = 0.046), compared to those without prior cholecystectomy. Additionally, MMTT revealed higher insulin (t = 60 min: p = 0.010 and t = 90 min: p = 0.034) and c-peptide levels (t = 60 min: p = 0.008) and greater glycemic variability in patients with prior cholecystectomy (p = 0.049), highlighting the impact of cholecystectomy on glucose metabolism.

CONCLUSION

Our study offers novel insights into PBH pharmacotherapy, indicating that PBH patients with a history of cholecystectomy require elevated doses of acarbose for symptom control than PBH patients without such surgical history. Furthermore, our findings underscore the pivotal role of hyperinsulinism in PBH aetiology, emphasizing the significance of the BA-GLP-1-insulin axis.

Society for Endocrinology guidelines for the diagnosis and management of post-bariatric hypoglycaemia

Post bariatric hypoglycaemia (PBH) is typically a post-prandial hypoglycaemia occurring about 2-4 hours after eating in people who have undergone bariatric surgery. PBH develops relatively late after surgery and often after discharge from post-surgical follow-up by bariatric teams, leading to variability in diagnosis and management in non-specialist centres.

AIM

to improve and standardise clinical practice in the diagnosis and management of PBH.

OBJECTIVES

(1) to undertake an up-to-date review of the current literature; (2) to formulate practical and evidence-based guidance with regards on the diagnosis and treatment of PBH; (3) to recommend future avenues for research in this condition.

METHOD

A scoping review was undertaken after an extensive literature search. A consensus on the guidance and confidence in the recommendations was reached by the steering group authors prior to review by key stakeholders.

OUTCOME

We make pragmatic recommendations for the practical diagnosis and management of PBH including criteria for diagnosis and recognition, as well as recommendations for research areas that should be explored.

Postbariatric surgery hypoglycemia: Nutritional, pharmacological and surgical perspectives

Post-bariatric hypoglycaemia (PBH) is a metabolic complication of bariatric surgery (BS), consisting of low post-prandial glucose levels in patients having undergone bariatric procedures. While BS is currently the most effective and relatively safe treatment for obesity and its complications, the development of PBH can significantly impact patients' quality of life and mental health. The diagnosis of PBH is still challenging, considering the lack of definitive and reliable diagnostic tools, and the fact that this condition is frequently asymptomatic. However, PBH's prevalence is alarming, involving up to 88% of the post-bariatric population, depending on the diagnostic tool, and this may be underestimated. Given the prevalence of obesity soaring, and an increasing number of bariatric procedures being performed, it is crucial that physicians are skilled to diagnose PBH and promptly treat patients suffering from it. While the milestone of managing this condition is nutritional therapy, growing evidence suggests that old and new pharmacological approaches may be adopted as adjunct therapies for managing this complex condition.

Post-Bariatric Hypoglycemia Is Associated with Endothelial Dysfunction and Increased Oxidative Stress

Post-bariatric hypoglycemia (PBH) is a potentially serious complication that may occur after bariatric surgery. Recurrent hypoglycemia may exert detrimental effects on vascular function. The aim of the present study was to evaluate endothelial function and oxygen reactive compounds in patients who experience PBH compared with controls. We performed a cross-sectional study on subjects with PBH (HYPO) and those without (NO-HYPO), detected by seven-day continuous glucose monitoring (CGM) performed at least twelve months after bariatric surgery. We enrolled 28 post-bariatric subjects (17.9% males, mean age 40.6 ± 10.7 years), with 18 in the HYPO group and 10 in the NO-HYPO group. In the two groups, we measured brachial artery flow-mediated dilation (FMD), oxidized low-density lipoproteins (oxLDL) and reactive oxygen metabolites (D-ROMs). The HYPO group had significantly lower FMD values than the NO-HYPO group (3.8% ± 3.0 vs. 10.5% ± 2.0, p < 0.001). A significant correlation was found between FMD and the time spent in hypoglycemia (rho = −0.648, p < 0.001), the number of hypoglycemic events (rho = −0.664, p < 0.001) and the mean glucose nadir (rho = 0.532, p = 0.004). The HYPO group showed significantly higher levels of D-ROMs (416.2 ± 88.7 UCARR vs. 305.5 ± 56.3 UCARR, p < 0.001) and oxLDLs (770.5 ± 49.7 µEq/L vs. 725.1 ± 51.6 µEq/L, p = 0.035) compared to the NO-HYPO group. In the multiple linear regression analysis, hypoglycemia independently predicted FMD values (β = −0.781, p < 0.001), D-ROMs (β = 0.548, p = 0.023) and oxLDL levels (β = 0.409, p = 0.031). PBH is associated with impaired endothelial function accompanied by increased oxidative stress.

Rate of post-bariatric hypoglycemia using continuous glucose monitoring: A meta-analysis of literature studies

AIMS

Hypoglycemia is a serious complication of bariatric surgery. The aim of the present meta-analysis was to evaluate the rate and the timing of post-bariatric hypoglycemia (PBH) with different bariatric procedures using reliable data from continuous glucose monitoring (CGM).

DATA SYNTHESIS

Studies were systematically searched in the Web of Science, Scopus and PubMed databases according to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. The prevalence of PBH was expressed as weighted mean prevalence (WMP) with pertinent 95% confidence intervals (95%CI). A total of 8 studies (16 datasets) enrolling 280 bariatric subjects were identified. The total WMP of PBH was 54.3% (95%CI: 44.5%-63.8%) while the WMP of nocturnal PBH was 16.4% (95%CI: 7.0%-34%). We found a comparable rate of PBH after Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) (OR 1.62, 95%CI: 0.71-3.7; P = 0.248); likewise, the percent time spent in hypoglycemia was similar with the two procedures (mean difference 5.3%, 95%CI: -1.4%-12.0%; P = 0.122); however, RYGB was characterized by a higher glycemic variability than SG. Regression models showed that the time elapsed from surgical intervention was positively associated with a higher rate of both total PBH (Z-value: 3.32, P < 0.001) and nocturnal PBH (Z-value: 2.15, P = 0.013).

CONCLUSIONS

PBH, both post-prandial and nocturnal, is more prevalent than currently believed. The rate of PBH increases at increasing time from surgery and is comparable after RYGB and SG with a higher glucose variability after RYGB.

A case of severe acidosis in a 12-month-old: Succinyl-CoA:3-ketoacid-CoA transferase deficiency with OXCT1 gene mutations

Succinyl-CoA:3-ketoacid CoA transferase (SCOT) deficiency is a rare autosomal recessive disorder that results in severe ketoacidosis due to a defect in ketone utilization. We describe a case of a 12-month-old infant presenting with severe metabolic acidosis, ketosis, and hyperammonemia, a combination of symptoms suggestive of an inborn error of metabolism. Genetic testing found our patient had a homozygous variant in the OXCT1 gene, c.1543A>G (p.Met515Val). This was the first identified case of SCOT deficiency at our institution. We share our acute management strategies for initial stabilization in the intensive care unit, as well as our approach to preventing morning ketosis after discharge using uncooked cornstarch.

Glycemic Patterns Are Distinct in Post-Bariatric Hypoglycemia After Gastric Bypass (PBH-RYGB)

CONTEXT

Severe hypoglycemia with neuroglycopenia, termed post-bariatric hypoglycemia (PBH). typically occurs postprandially, but it is also reported after activity or mid-nocturnally.

OBJECTIVE

To quantify glycemia, glycemic variability, and magnitude/duration of low sensor glucose (SG) values in patients with PBH after Roux-en-Y gastric bypass (PBH-RYGB).

METHODS

This retrospective analysis of data from an academic medical center included individuals with PBH-RYGB (n = 40), reactive hypoglycemia without gastrointestinal surgery (Non-Surg Hypo, n = 20), prediabetes (Pre-DM, n = 14), newly diagnosed T2D (n = 5), and healthy controls (HC, n = 38). Masked continuous glucose monitoring (Dexcom G4) was used to assess patterns over 24 hours, daytime (6 am-midnight) and nighttime (midnight-6 am). Prespecified measures included mean and median SG, variability, and percent time at thresholds of sensor glucose.

RESULTS

Mean and median SG were similar for PBH-RYGB and HC (mean: 99.8 ± 18.6 vs 96.9 ± 10.2 mg/dL; median: 93.0 ± 14.8 vs 94.5 ± 7.4 mg/dL). PBH-RYGB had a higher coefficient of variation (27.3 ± 6.8 vs 17.9 ± 2.4%, P < 0.0001) and range (154.5 ± 50.4 vs 112.0 ± 26.7 mg/dL, P < 0.0001). Nadir was lowest in PBH-RYGB (42.5 ± 3.7 vs HC 49.0 ± 11.9 mg/dL, P = 0.0046), with >2-fold greater time with SG < 70 mg/dL vs HC (7.7 ± 8.4 vs 3.2 ± 4.1%, P = 0.0013); these differences were greater at night (12.6 ± 16.9 vs 1.0 ± 1.5%, P < 0.0001). Non-Surg Hypo also had 4-fold greater time with SG < 70 at night vs HC (SG < 70: 4.0 ± 5.9% vs 1.0 ± 1.5%), but glycemic variability was not increased.

CONCLUSION

Patients with PBH-RYGB experience higher glycemic variability and frequency of SG < 70 compared to HC, especially at night. These data suggest that additional pathophysiologic mechanisms beyond prandial changes contribute to PBH.

Uncooked cornstarch for the prevention of hypoglycemic events

Hypoglycemia is a pathological condition characterized by a low plasma glucose concentration associated with typical autonomic and/or neuroglycopenic symptoms, and resolution of these symptoms with carbohydrate consumption. Hypoglycemia is quite common in clinical practice, particularly in insulin-treated patients with diabetes and in other inherited or acquired conditions involving the regulation of glucose metabolism. Beyond symptoms that might strongly affect the quality of life, hypoglycemia can lead to short- and long-term detrimental consequences for health. Hypoglycemia can be prevented by appropriate changes in dietary habits or by relevant modifications of the drug treatment. Several dietary approaches based on the intake of various carbohydrate foods have been tested for hypoglycemia prevention; among them uncooked cornstarch (UCS) has demonstrated a great efficacy. In this narrative review, we have summarized the current evidence on the UCS usefulness in some conditions characterized by high hypoglycemic risk, focusing on some inherited diseases -i.e. glycogen storage diseases and other rare disorders - and acquired conditions such as type 1 diabetes, postprandial hypoglycemia consequent to esophageal-gastric or bariatric surgery, and insulin autoimmune syndrome. We also considered the possible role of UCS during endurance exercise performance. Lastly, we have discussed the dose requirement, the side effects, the limitations of UCS use, and the plausible mechanisms by which UCS could prevent hypoglycemia.

Patient involvement to inform the design of a clinical trial in postbariatric hypoglycaemia

Background

Bariatric surgery may lead to symptomatic postprandial hypoglycaemia as a major side effect without established therapy so far. We aimed to develop an evidence-based study design of a clinical trial that tests treatment options and can provide useful patient-relevant evidence.

Methods

We searched systematically for guidance of core outcome sets to determine the most relevant types of outcomes and duration of such a trial. Our search comprised literature databases, a database of core outcome sets and self-help organizations. We then developed a simple online questionnaire based on interviews with German-speaking patients with postprandial hypoglycaemia after bariatric surgery. We recruited participants by reaching out to all German speaking endocrinologists in Switzerland and large Swiss bariatric centres. We asked for preferences regarding outcome types and acceptable duration of being included in a corresponding clinical trial.

Results

The literature search did not identify evidence-based guidance for informing our study design. Experience of clinical and research routine as well as patient interviews helped in identifying potential outcomes and the design of an online questionnaire. Therein, a total of 29 persons started the questionnaire and 22 answered questions related to the primary outcome. Of these, 17 (77.3%) deemed quality of life more relevant as primary outcome than the rate of hypoglycaemic episodes. A trial length of four weeks or longer was regarded as acceptable for 19 of 21 respondents to this question (91.4%) and of six months or longer for 12 respondents (56%).

Conclusions

In situations with no other guidance, a simple questionnaire may help to inform trial design decisions. This study identifies a patient preference for “quality of life” as a primary outcome and supports the evidence-based conception of a patient-centred clinical trial in postbariatric hypoglycaemia.

Supplementary Information

Supplementary information accompanies this paper at 10.1186/s12874-020-01171-z.

Continuous glucose monitoring in subjects undergoing bariatric surgery: Diurnal and nocturnal glycemic patterns

BACKGROUND AND AIMS

Although the use of Continuous Glucose Monitoring (CGM) is rapidly extending, little evidence is currently available on daily glycemic excursions after different bariatric procedures. We assessed glycemic patterns after sleeve gastrectomy (SG) and roux-en-Y gastric bypass (RYGB) using CGM.

METHODS AND RESULTS

Cross-sectional study in subjects who had undergone RYGB (n = 22) or SG (n = 29) since at least 1 year, without pre-surgery or in current diabetes (T2DM) remission. All subjects underwent 7 day-CGM (Dexcom G4 PLATINUM), which provides glucose variability (GV), number and time spent in hypoglycemia, hypoglycemia patterns (postprandial, nocturnal or mixed). All indexes of GV were higher after RYGB than after SG (p < 0.001). Twenty-eight (55%) subjects experienced hypoglycemia. The number of events was higher after RYGB than SG (p = 0.017) while it did not differ in subjects with or without pre-surgery T2DM (p = 0.129). Overall, 9 (32%) subjects presented hypoglycemia exclusively during the postprandial period, 8 (29%) an exclusively nocturnal pattern and 11 (39%) a mixed pattern. The nocturnal pattern was more frequent after SG than RYGB (53.8% vs 6.7%, p = 0.036) while no difference was observed in subjects with or without pre-surgery T2DM (p = 0.697). Hypoglycemia symptoms were more frequent in subjects with postprandial than in those with nocturnal pattern (77.8% vs 12.5%, p = 0.015).

CONCLUSIONS

RYGB is characterized by a greater GV and a higher number of hypoglycemia events mostly post-prandial and symptomatic, while SG is associated with nocturnal and often asymptomatic hypoglycemia. These findings suggest that post-bariatric hypoglycemia is a more complex, not exclusively, postprandial phenomenon.

Potential contribution of the gut microbiota to hypoglycemia after gastric bypass surgery

Obesity has become a global health problem. Lifestyle modification and medical treatment only appear to yield short-term weight loss. Roux-en-Y gastric bypass (RYGB) is the most popular bariatric procedure, and it sustains weight reduction and results in the remission of obesity-associated comorbidities for obese individuals. However, patients who undergo this surgery may develop hypoglycemia. To date, the diagnosis is challenging and the prevalence of post-RYGB hypoglycemia (PRH) is unclear. RYGB alters the anatomy of the upper gastrointestinal tract and has a combined effect of caloric intake restriction and nutrient malabsorption. Nevertheless, the physiologic changes after RYGB are complex. Although hyperinsulinemia, incretin effects, dysfunction of β-cells and α-cells, and some other factors have been widely investigated and are reported to be possible mediators of PRH, the pathogenesis is still not completely understood. In light of the important role of the gut microbiome in metabolism, we hypothesized that the gut microbiome might also be a critical link between RYGB and hypoglycemia. In this review, we mainly highlight the current possible factors predisposing individuals to PRH, particularly related to the gut microbiota, which may yield significant insights into the intestinal regulation of glucose metabolic homeostasis and provide novel clues to improve the treatment of type 2 diabetes mellitus.

Nesidioblastosis and Insulinoma: A Rare Coexistence and a Therapeutic Challenge

Background: Nesidioblastosis and insulinoma are disorders of the endocrine pancreas causing endogenous hyperinsulinemic hypoglycemia. Their coexistence is very unusual and treatment represents a still unresolved dilemma. Case Description: The patient was a 43-year-old Caucasian woman, with a 2-year history of repeated severe hypoglycemic events. The diagnostic work-up was strongly suggestive of insulinoma and the patient was submitted to surgical treatment carried out laparoscopically under robotic assistance. However, surgical exploration and intraoperative ultrasonography failed to detect a pancreatic tumor. Resection was therefore carried out based on the results of selective intra-arterial calcium stimulation test, following a step-up approach, eventually leading to a pancreatoduodenectomy at the splenic artery. The histopathology examination and the immunohistochemical staining were consistent with adult-onset nesidioblastosis. After surgery, the patient continued to experience hypoglycemia with futile response to medical treatments (octreotide, calcium antagonists, diazoxide, and prednisone). Following multidisciplinary evaluation and critical review of a repeat abdominal computed tomography scan, a small nodular lesion was identified in the tail of the pancreas. The nodule was enucleated laparoscopically and the pathological examination revealed an insulinoma. In spite of the insulinoma resection, glycemic values were only partially restored, with residual nocturnal hypoglycemia. Administration of uncooked cornstarch (1.25 g/kg body weight) at bedtime was associated with significant improvement of interstitial glucose levels (p < 0.0001) and reduction of nocturnal hypoglycemia episodes (p = 0.0002). Conclusions: This report describes a rare coexistence of adult-onset nesidioblastosis and insulinoma, suggesting the existence of a wide and continuous spectrum of proliferative β-cell changes. Moreover, we propose that uncooked cornstarch may offer an additional approach to alleviate the hypoglycemic episodes when surgery is impracticable/unaccepted.

Hypoglycemia After Upper Gastrointestinal Surgery: Clinical Approach to Assessment, Diagnosis, and Treatment

CONTEXT

Post-bariatric hypoglycemia (PBH) is an increasingly encountered complication of upper gastrointestinal surgery; the prevalence of this condition is anticipated to rise given yearly increases in bariatric surgical procedures. While PBH is incompletely understood, there is a growing body of research describing the associated factors, mechanisms, and treatment approaches for this condition.

EVIDENCE ACQUISITION

Data are integrated and summarized from studies of individuals affected by PBH and hypoglycemia following upper gastrointestinal surgery obtained from PubMed searches (1990-2020).

EVIDENCE SYNTHESIS

Information addressing etiology, incidence/prevalence, clinical characteristics, assessment, and treatment were reviewed and synthesized for the practicing physician. Literature reports were supplemented by clinical experience as indicated, when published data were not available.

CONCLUSION

PBH can be life-altering and severe for a subset of individuals. Given the chronic nature of this condition, and sequelae of both acute and recurrent episodes, increasing provider awareness of both the condition and associated risk factors is critical for assessment, prompt diagnosis, treatment, and preoperative identification of individuals at risk.