Advances in the etiology and management of hyperinsulinemic hypoglycemia after Roux-en-Y gastric bypass

Workup and Management of Recurrent Attacks of Post-bariatric Hypoglycemia in a Patient With Non-alcoholic Steatohepatitis

Bariatric surgery is an established treatment option for patients with non-alcoholic fatty liver disease (NAFLD) as well as non-alcoholic steatohepatitis (NASH) and is said to effectively reduce hepatic inflammation as well as steatosis in these patients. However, bariatric surgery is associated with multiple complications, including nutritional deficiencies, malnutrition, post-bariatric hypoglycemia (PBH), anastomotic leaks, and bowel strictures. This case report describes a rare but significant complication of post-bariatric surgery hypoglycemia in a patient with NASH, which started almost six months after Roux-en-Y gastric bypass (RYGB) surgery. This 55-year-old male patient presented with recurrent episodes of severe hypoglycemia, which, on further work-up, were found to be predominantly nocturnal as well as occurring two to three hours after meals. We report the successful treatment of the patient with an unconventional approach using nifedipine and acarbose. Our findings emphasize the importance of careful evaluation of patients who have undergone bariatric surgery, as this complication can occur as early as six months following the bariatric surgery as well as several years after the surgery. Our case report highlights the need for early recognition, relevant workup, and appropriate management of resistant hypoglycemic events using calcium channel blockers and acarbose, thus adding to the existing literature on this topic.

Beyond diabetes remission a step further: Post bariatric surgery hypoglycemia

Postbariatric hypoglycemia is a rare but increasingly recognized complication of bariatric surgery, with significant associated morbidity, and many patients often require multimodal treatment. A mixed meal challenge test is often helpful to diagnose this condition. This manuscript highlights the underlying mechanisms that lead to this condition and the novel emerging therapeutic targets that target these mechanisms.

An unusual presentation of post gastric bypass hypoglycemia with both postprandial and fasting hypoglycemia

There has been an increasing awareness of post gastric bypass hypoglycemia (PGBH). Histopathologic findings from such patients who underwent partial/total pancreatomy, however, can vary widely from minimal changes to classic nesidioblastosis, making the pathologic diagnosis challenging. PGBH typically presents as postprandial hypoglycemia, as opposed to insulinoma, which presents as fasting hypoglycemia. Herein, we describe an unusual case of a patient with PGBH who initially presented with postprandial hypoglycemia three years after surgery, but later developed fasting hyperinsulinemic hypoglycemia as the disease progressed. Our hypothesis for this phenomenon is that this disease is progressive, and later in its course, the insulin release becomes dissociated from food stimulation and is increased at baseline. Future studies are needed to investigate the prevalence as well as etiology of this progression from postprandial to fasting hypoglycemia. Learning points: •• There has been an increasing awareness of post gastric bypass hypoglycemia (PGBH). •• Histopathologically, PGBH can vary from minimal changes to nesidioblastosis. •• Although uncommon, patients with PGBH after Roux-en-Y gastric bypass may present with both postprandial and fasting hyperinsulinemic hypoglycemia as disease progresses. •• Our hypothesis for this phenomenon is that the insulin release becomes dissociated from food stimulation and is increased at baseline with disease progression.

Examples of dramatic failures and their effectiveness in modern surgical disciplines: can we learn from our mistakes?

Innovation can be variably defined, but when applied to healthcare is often considered to be the introduction of something new, whether an idea, method or device, into an unfilled void or needy environment. Despite the introduction of many positive surgical subspecialty altering concepts/devices however, epic failures are not uncommon. These failures can be dramatic in regards to both their human and economic costs. They can also be very public or more quiet in nature. As surgical leaders in our communities and advocates for patient safety and outcomes, it remains crucial that we meet new introductions in technology and patient care with a measured level of curiosity, skepticism and science-based conclusions. The aim of an expert committee was to identify the most dominant failures in technological innovation and/or dogmatic clinical beliefs within each major surgical subspecialty. In summary, this effort was pursued to highlight the past failures and remind surgeons to remain vigilant and appropriately skeptical with regard to the introduction of new innovations and clinical beliefs within our craft.

Evidence of unrestrained beta-cell proliferation and neogenesis in a patient with hyperinsulinemic hypoglycemia after gastric bypass surgery

Hyperinsulinemic hypoglycemia syndrome (HIHG) is a rare complication of roux-en-Y gastric bypass surgery. The pathology is associated with an excessive function of pancreatic beta-cells, and requires pancreas resection in patients that are recalcitrant to nutritional and pharmacological interventions. The exact prevalence is not clearly understood and the underlying mechanisms not yet fully characterized. We herein sought to perform histological and molecular examination of pancreatic sections obtained from a patient who developed HIHG as a complication of gastric bypass compared to 3 weight-matched controls. We studied markers of cellular replication and beta-cell differentiation by immunohistochemistry and immunofluorescence. HIHG after gastric bypass was characterized by a profound increase in beta-cell mass. Cellular proliferation was increased in islets and ducts compared to controls, suggesting unrestrained proliferation in HIHG. We also detected beta-cell differentiation markers in duct cells and occasional duct cells displaying both insulin and glucagon immunoreactivity. These histological observations suggest that beta-cell differentiation from ductal progenitor cells could also underly beta-cell mass expansion in HIHG. Altogether, our results can be construed to demonstrate that HIHG after gastric bypass is characterized by abnormal beta-cell mass expansion, resulting from both unrestrained beta-cell replication and neogenesis.

Bariatric Surgery for Obesity

In this review, the authors discuss the indications for and the published outcomes of commonly performed bariatric procedures, including weight loss, perioperative morbidity and mortality, late complications, as well as the impact of bariatric surgery on comorbidities, cardiovascular risk, and mortality. They also briefly discuss the mechanisms by which bariatric/metabolic surgery causes such significant weight loss and health gain.

Differences in Anthropometric and Metabolic Parameters Between Subjects with Hypoglycaemia and Subjects with Euglycaemia After an Oral Glucose Tolerance Test Six Months After Laparoscopic Sleeve Gastrectomy

BACKGROUND

Hypoglycaemia after an oral glucose tolerance test (OGTT) can occur in up to 33 % of subjects after laparoscopic sleeve gastrectomy (LSG). The underlying pathophysiology is not well understood. We aimed to compare the anthropometric and metabolic characteristics of subjects with post-OGTT hypoglycaemia (HYPO) to subjects with post-OGTT euglycaemia (EU) 6 months after LSG.

METHODS

Eighteen morbidly obese patients with normal glucose tolerance (NGT) were evaluated with an OGTT before and 6 months after LSG. Serum glucose and insulin were measured before and every 30 min after glucose ingestion up to 120'. The patients were categorized as HYPO or EU based on lowest glucose levels 90' to 120' post-OGTT 6 months after LSG (hypoglycaemia defined as glucose levels <60 mg/dl). OGTT derived indices of insulin secretion; insulin sensitivity and beta cell function were also evaluated.

RESULTS

Eight patients (44.4 %) were categorized as HYPO. Preoperatively, subjects with HYPO had lower BMI (p = 0.02) compared to that with EU. Postoperatively, subjects with HYPO had lower BMI (p = 0.01), lower weight (p = 0.01), and higher percentage of total weight loss (%TWL) (p = 0.03) compared to that with EU. The beta cell function index was higher in the HYPO group postoperatively compared to EU (p = 0.02)-especially during the latter portion of the OGTT. No difference was detected in insulin secretion and insulin sensitivity indices between the two groups preoperatively or postoperatively.

CONCLUSIONS

Subjects with NGT who developed HYPO 6 months after LSG are leaner, with higher TWL% and higher beta cell function at the latter portion of the OGTT compared to those with EU.

The treatment of hyperinsulinemic hypoglycaemia in adults: an update

BACKGROUND

Treatment of hyperinsulinemic hypoglycaemia (HH) is challenging due to the rarity of this condition and the difficulty of differential diagnosis. The aim of this article is to give an overview of the recent literature on the management of adult HH.

METHODS

A search for reviews, original articles, original case reports between 1995 and 2016 in PubMed using the following keywords: hyperinsulinemic hypoglycaemia, insulinoma, nesidioblastosis, gastric bypass, autoimmune hypoglycaemia, hyperinsulinism, treatment was performed.

RESULTS

One hundred and forty articles were selected and analysed focusing on the most recent treatments of HH.

CONCLUSIONS

New approaches to treatment of HH are available including mini-invasive surgical techniques and alternative local-regional ablative therapy for benign insulinoma and everolimus for malignant insulinoma. A correct differential diagnosis is of paramount importance to avoid unnecessary surgical operations and to implement the appropriate treatment mainly in the uncommon forms of HH, such as nesidioblastosis and autoimmune hypoglycaemia.

The Impact of Bariatric Surgery on Type 2 Diabetes Mellitus and the Management of Hypoglycemic Events

Recent studies discussed the benefit of bariatric surgery on obese patients diagnosed with type 2 diabetes mellitus (T2DM). Several factors play an essential role in predicting the impact of bariatric surgery on T2DM, such as ABCD score (age, BMI, C-peptide, and duration of the disease), HbA1c, and fasting blood glucose, incretins [glucagon-like peptide-1 (GLP-1) and gastric inhibitory peptide (GIP)]. DiaRem score known to include factors such as age, HbA1c, medication, and insulin usage used to predict the remission of T2DM, but it has some limitations. An extensive literature search was conducted on PubMed and Google Scholar using keywords such as gastric bypass, T2DM, bariatric surgery, GLP-1, GIP, and post bariatric hypoglycemia. Restrictive-malabsorptive procedures are most effective in treating T2DM patients based on changes induced in appetite through regulation of gastrointestinal hormones, with decreased hunger and increased satiation. We provide a review of bariatric surgery influence on T2DM and management of post-intervention hypoglycemic events. Post-bariatric surgery hypoglycemia is a serious complication especially when patients develop life-threatening neuroglycopenia with loss of consciousness and seizure. The avoidance of this adverse event may be achieved by strict dietary modification including a restriction on carbohydrates as well as foods with high glycemic index. Further research will provide more information on post-bariatric surgery hyperinsulinemic hypoglycemia pathophysiology and management.

Pancreatic Uptake by 18F-FDOPA PET/CT in Patients With Hypoglycemia After Gastric Bypass Surgery Compared With Controls With or Without Carbidopa Pretreatment

PURPOSE

The use of Fluorine-labeled dihydroxy-phenyl-alanine (F-FDOPA) PET/CT in patients with hypoglycemia suspected to be caused by pancreatic disease can be helpful to localize the source of excess insulin production. In this setting, carbidopa pretreatment is not recommended. However, quantitative comparisons of pancreatic tracer uptake in patients with or without carbidopa pretreatment and in diffuse pancreatic disease are lacking. Therefore, we aimed to describe and quantify pancreatic F-FDOPA uptake in patients without pancreatic disease with or without carbidopa pretreatment and in patients with hypoglycemia after gastric bypass surgery.

PATIENTS AND METHODS

This is a retrospective data analysis of F-FDOPA PET/CT scans performed at a university medical center in the period from 2009 to 2015. All scans were reconstructed and calculated based on the European Association of Nuclear Medicine/EANM Research Ltd guidelines. Of 358 patients without evidence of pancreatic disease or hypoglycemic disorders, 344 received carbidopa and 14 did not. Another 9 patients had post-gastric bypass hypoglycemia. The main outcome measurement was F-FDOPA SUVmax for pancreatic head, body, and tail regions.

RESULTS

Carbidopa pretreated patients had a lower median SUVmax (-1.15, -1.20, and -0.84 in pancreatic head, body, and tail [all P < 0.01]) than patients without carbidopa pretreatment. Patients with post-gastric bypass hypoglycemia scanned without carbidopa pretreatment had higher median SUVmax (+1.18, +1.39, and +1.63, all P < 0.03) compared with controls without pretreatment.

CONCLUSIONS

Patients with post-gastric bypass hypoglycemia have increased uptake in all pancreatic regions. Carbidopa pretreatment lowers pancreatic F-FDOPA uptake in the nonaffected pancreas and may therefore mask disease activity in post-gastric bypass hypoglycemia.

[Metabolic surgery or conservative measures as therapy of obese type 2 diabetics?]

After bariatric surgery there are some favourable effects on comorbidities of obesity as glucose and lipid metabolism besides weight loss. Therefore surgical measures targeting at improvement of such metabolic disorders especially diabetes type 2 has been called "metabolic surgery". The complexity of its underlying metabolic mechanisms is not yet clear, but restriction of energy and weight loss (maintenance) seem to be the cornerstones.Risks of these procedures which are drawn of the established methods of bariatric surgery are reported to be relatively low in qualified centers. Being an elective operation special focus has to be set on mortality and morbidity, numbers of therapeutic failure and redo-surgery. Multiple irreversible and not seldom severe, potentially life-threatening consequences of bariatric surgery require consequent interdisciplinary postsurgery care and therapy throughout the whole life, especially substitution therapy of deficiencies due to post-operative malassimilation, if necessary. Little is known about long term consequences of modified anatomy and function of digestive system caused by surgery, and there may be a delay of (many) years until manifestation of clinical problems.Obese diabetics (BMI ≥ 35 kg/m²) should primarily be treated conservatively in an "individualized" way. Metabolic surgery should not be considered earlier than failure of the conservative approach has to be stated (in this case as an "ultima ratio" in well defined trials). A broader use of metabolic surgery beyond this narrow frame is not yet supported by long-term evidence-based data showing its value and safety.

Evaluation, Medical Therapy, and Course of Adult Persistent Hyperinsulinemic Hypoglycemia After Roux-en-Y Gastric Bypass Surgery: A Case Series

OBJECTIVE

To describe the evaluation and treatment of hyperinsulinemic hypoglycemia in adults who had undergone gastric bypass surgery. A small number of patients who undergo Roux-en-Y bypass surgery develop postprandial hypoglycemia in the absence of dumping. In some cases, such patients have been treated with pancreatectomy.

METHODS

We report the demographics, diagnostic results, response to medical therapy, and subsequent course of 6 referral patients with post-Roux-en-Y gastric bypass hypoglycemia.

RESULTS

Characteristic clinical and metabolic parameters consistent with hyperinsulinemic hypoglycemia were identified. Parameters were similar for both spontaneous and glucose-challenge-induced hypoglycemia. In the context of exclusively postprandial symptoms, simultaneous glucose ≤55 mg/dL, insulin ≥17 μU/mL, C peptide ≥3.0 ng/mL, and insulin to glucose ratio >0.3 were associated with Roux-en-Y gastric bypass hyperinsulinemic hypoglycemia. Five of 6 patients improved on therapy consisting of dietary modification plus either calcium channel blockade, acarbose, or both. Two patients have remained on therapy for 12 to 15 months. The nonresponder was atypical and had had hypoglycemic events for several decades. Three treated patients were subsequently observed to have undergone partial or complete remission from hypoglycemic episodes after 2 to 37 months of therapy. None of the 6 have undergone pancreatectomy, and none have evidence of insulinoma. Invasive diagnostic procedures were of limited utility.

CONCLUSION

In a subset of patients with post-Roux-en-Y gastric bypass hyperinsulinemic hypoglycemia, medical management can be efficacious and an alternative to partial pancreatectomy. In some cases, the disorder remits spontaneously.

Nutritional and Protein Deficiencies in the Short Term following Both Gastric Bypass and Gastric Banding

BACKGROUND

The number of morbidly obese patients undergoing bariatric surgery (BS) has increased dramatically in recent years. Therefore, monitoring food intake and its consequences in terms of nutritional status is necessary to prevent nutritional deficiencies. The aim of this study was to analyze the effect of food restriction on nutritional parameters in the short-term (≤3 months) period after BS in morbid obesity.

METHOD

In a prospective study, we followed 22 obese women who underwent Roux-en-Y gastric bypass (GBP) or adjustable gastric banding (AGB) at baseline (T0) and 1 (T1) and 3 (T3) months after surgery. We evaluated food intake, nutrient adequacy and serum concentrations of vitamins and minerals known to be at risk for deficiency following BS.

RESULTS

Before surgery, we observed suboptimal food intakes, leading to a risk of micronutrient deficiencies. Serum analysis confirmed nutritional deficiencies for iron and thiamine for 27 and 23% of the patients, respectively. The drastic energy and food reduction seen in the short term led to very low probabilities of adequacy for nutrients equivalent across both surgeries. Serum analysis demonstrated a continuous decrease in prealbumin during the follow-up, indicating mild protein depletion in 21 and 57% of GBP patients and 50 and 63% of AGB patients, respectively, at T1 and T3. Regarding vitamins and minerals, systematic supplementation after GBP prevented most nutritional deficiencies. By contrast, AGB patients, for whom there is no systematic supplementation, developed such deficiencies.

CONCLUSIONS

Our results suggest that cautious monitoring of protein intake after BS is mandatory. Furthermore, AGB patients might also benefit from systematic multivitamin and mineral supplementation at least in the short term.

Post-Gastric Bypass Hypoglycemia

Obesity is a major public health problem worldwide. Obesity-related illnesses, such as coronary heart disease, type 2 diabetes, hypertension, dyslipidemia, stroke, sleep apnea, and several forms of cancer (endometrial, breast, and colon), contribute to a significant number of deaths in the USA. Bariatric surgery, including the Roux-en-Y gastric bypass (RYGB) procedure, has demonstrated significant improvements in obesity and obesity-related co-morbidities and is becoming more popular as the number of obese individuals rises. Despite the reported benefits of bariatric surgery, there are potential complications that physicians need to be aware of as the number of patients undergoing these procedures continues to increase. One challenging and potentially life-threatening complication that to date is not well understood is post-RYGB surgery hypoglycemia (PGBH). In this review, we will present the definition, historical perspective, diagnostic approach, currently available treatment options, and anecdotal assessment and treatment algorithm for this disorder.

Hyperinsulinemic Hypoglycemia after Bariatric Surgery: Diagnosis and Management Experience from a Spanish Multicenter Registry

BACKGROUND

Severe postprandial hypoglycemia after bariatric surgery is a rare but invalidating complication. Our aim was to describe the different tests performed for its diagnosis and their outcomes as well as the response to the prescribed pharmacological and surgical treatments.

METHODS

Multicenter, retrospective systematic review of cases with recurrent severe postprandial hypoglycemia.

RESULTS

Over 11 years of follow-up, 22 patients were identified. The test most used to provoke hypoglycemia was the oral glucose load test followed by the mixed meal test which was the least standardized test. With pharmacological treatment, 3 patients were symptom-free (with octreotide) and in 12 patients hypoglycemic episodes were attenuated. Seven patients had persistent hypoglycemic episodes and underwent surgery. Partial pancreatectomy was performed in 3 patients who had positive selective arterial calcium stimulation, and nesidioblastosis was confirmed in 2 patients. Reconversion to normal anatomy was performed in 3 patients, and 1 patient underwent a resection of the 'candy cane' roux limb, with resolution of hypoglycemia in all cases.

CONCLUSIONS

There is high heterogeneity in the evaluation and treatment options for postoperative hypoglycemia. In patients that do not respond to pharmacological treatment, reconstruction of gastrojejunal continuity may be the safest and most successful procedure.

Bariatric and metabolic surgery: current trends and what's to follow

PURPOSE OF REVIEW

Obesity is a global epidemic and bariatric surgery remains an underperformed modality for its treatment. Even though the dangers of obesity are well understood, surgical intervention is underestimated. The purpose of this review is to discuss emerging trends in bariatric surgery.

RECENT FINDINGS

Studies suggest that different operations have different effects on both obesity and its comorbidities. Combining the concepts of malabsorption and restriction, we are looking toward more advanced and efficient treatment options. Less-invasive techniques such as endoscopic devices are under investigation and their results remain to be determined.

SUMMARY

A paradigm shift is occurring and both obesity and diabetes will be increasingly treated with surgical and endoscopic procedures. Bariatric care is a growing field for surgeons and therapeutic endoscopists with many future opportunities for improvement.

Recognition and management of hyperinsulinemic hypoglycemia after bariatric surgery

Hyperinsulinemic hypoglycemia with neuroglycopenia is an increasingly recognized complication of Roux-en-Y gastric bypass (RYGB) due to the changes in gut hormonal milieu. Physicians should be aware of this complication to ensure timely and effective treatment of post-RYGB patients, who present to them with hypoglycemic symptoms. Possible causes of hypoglycemia in these patients include late dumping syndrome, nesidioblastosis and rarely insulinoma. Systematic evaluation including history, biochemical analysis, and diagnostic testing might help in distinguishing among these diagnoses. Continuous glucose monitoring is also a valuable tool, revealing the episodes in the natural environment and can also be used to monitor treatment success. Treatment should begin with strict low carbohydrate diet, followed by medication therapy. Therapy with diazoxide, acarbose, calcium channel blockers and octreotide have been proven to be beneficial, but the response apparently is highly variable. When other treatment options fail, surgical options can be considered.

Effect of carbohydrate restriction in patients with hyperinsulinemic hypoglycemia after Roux-en-Y gastric bypass

BACKGROUND

Hyperinsulinemic hypoglycemia is a rare complication of Roux-en-Y gastric bypass (RYGB) surgery. Meals with a high carbohydrate (carb) content and high glycemic index (GI) may provoke these hypoglycemic attacks. The aim of this study is to assess the effects of reducing meal carb content and GI on glycemic responses in patients with post-RYGB hypoglycemia.

METHODS

Fourteen patients with post-RYGB hypoglycemia underwent two meal tests: a mixed meal test (MMT) with a carb content of 30 g and a meal test with the low GI supplement, Glucerna SR 1.5® (Glucerna meal test (GMT)). Plasma glucose and serum insulin levels were measured for a period of 6 h.

RESULTS

Peak glucose levels were reached at T 30 during GMT and at T 60 during MMT, and they were 1.5 ± 0.3 mmol/L lower during GMT than during MMT (7.5 ± 0.4 vs 9.0 ± 0.4 mmol/L, P < 0.005). GMT induced the most rapid rise in plasma insulin: at T 30 plasma, insulin was 30.7 ± 8.5 mU/L higher during GMT than during MMT (P < 0.005). None of the carb-restricted meals induced post-prandial hypoglycemia.

CONCLUSION

A 30-g carb-restricted meal may help to prevent post-prandial hypoglycemia in patients with post-RYGB hypoglycemia. The use of a liquid, low GI, supplement offers no additional advantage.

Post-Gastric Bypass Hyperinsulinemic Hypoglycemia: Fructose is a Carbohydrate Which Can Be Safely Consumed

CONTEXT

Postprandial hypoglycemia after gastric bypass surgery is a serious problem. Available treatments are often ineffective.

OBJECTIVE

The objective was to test the hypotheses that injection of rapid-acting insulin before a high-carbohydrate meal or replacement of other carbohydrates with fructose in the meal would prevent hypoglycemia.

DESIGN

This was a randomized, crossover trial comparing a high-carbohydrate meal with premeal saline injection (control), a high-carbohydrate meal with premeal insulin injection, and a high-fructose meal with total carbohydrate content similar to the control meal.

SETTING

The setting was an academic medical center.

PATIENTS

Ten patients with post-gastric bypass hyperinsulinemic hypoglycemia participated.

INTERVENTIONS

Interventions included lispro insulin injected before test meals and replacement of other carbohydrates with fructose in test meals.

MAIN OUTCOME MEASURE

The main outcome measure was plasma glucose < 60 mg/dL after test meals.

RESULTS

After the control meal, mean peak glucose and insulin were 173 ± 47 mg/dL and 134 ± 55 mU/L, respectively; mean glucose nadir was 44 ± 15 mg/dL; and eight of 10 subjects demonstrated glucose < 60 mg/dL. Five subjects demonstrated a glucose nadir < 40 mg/dL. There were no significant differences in the corresponding values after premeal insulin treatment, except that the mean glucose nadir of 34 ± 10 mg/dL was lower (P < .05). After the fructose meal, mean peak postprandial glucose and insulin were 117 ± 20 mg/dL and 45 ± 31 mU/L, respectively (both P < .001 for comparison with control), mean glucose nadir was 67 ± 10 mg/dL (P < .001), and two of 10 subjects demonstrated glucose < 60 mg/dL (P < .05).

CONCLUSIONS

People with post-gastric bypass hypoglycemia can consume a meal sweetened with fructose with little risk of hypoglycemia. Treatment with rapid-acting insulin before a carbohydrate-containing meal did not prevent hypoglycemia.

Hypoglycemia in everyday life after gastric bypass and duodenal switch

DESIGN

Gastric bypass (GBP) and duodenal switch (DS) in morbid obesity are accompanied by marked metabolic improvements, particularly in glucose control. In recent years, episodes of severe late postprandial hypoglycemia have been increasingly described in GBP patients; data in DS patients are scarce. We recruited three groups of subjects; 15 GBP, 15 DS, and 15 non-operated overweight controls to examine to what extent hypoglycemia occurs in daily life.

METHODS

Continuous glucose monitoring (CGM) was used during 3 days of normal activity. The glycemic variability was measured by mean amplitude of glycemic excursion and continuous overall net glycemic action. Fasting blood samples were drawn, and the patients kept a food and symptom log throughout the study.

RESULTS

The GBP group displayed highly variable CGM curves, and 2.9% of their time was spent in hypoglycemia (<3.3  mmol/l, or 60  mg/dl). The DS group had twice as much time in hypoglycemia (5.9%) and displayed CGM curves with little variation as well as lower HbA1c levels (29.3 vs 35.9 mmol/mol, P<0.05). Out of a total of 72 hypoglycemic episodes registered over the 3-day period, 70 (97%) occurred in the postprandial state and only about one-fifth of the hypoglycemic episodes in the GBP and DS groups were accompanied by symptoms. No hypoglycemias were seen in controls during the 3-day period.

CONCLUSION

Both types of bariatric surgery induce marked, but different, changes in glucose balance accompanied by frequent, but mainly unnoticed, hypoglycemic episodes. The impact and mechanism of hypoglycemic unawareness after weight-reduction surgery deserves to be clarified.

Surgery in the treatment of type 2 diabetes mellitus

Background and Aims:

The prevalence of diabetes is increasing worldwide, and most of the cases are type 2 diabetes mellitus. The relationship between type 2 diabetes mellitus and obesity is well established, and surgical treatment is widely used for obese patients with type 2 diabetes mellitus. The aim was to present current knowledge about the possible mechanisms responsible for glucose control after surgical procedures and to review the surgical treatment results.

Material and Methods:

Medical literature was searched for the articles presenting the impact of surgical treatment on glycemic control, long-term results, and possible mechanisms of action among obese individuals with type 2 diabetes mellitus.

Results:

Remission of type 2 diabetes mellitus after bariatric surgery depends on the definition of the remission used. Complete remission rate after surgery with the new criteria is lower than was considered before. Randomized controlled studies demonstrate that surgery is superior to best medical treatment for the patients with type 2 diabetes mellitus. The recurrence of type 2 diabetes mellitus after bariatric surgery is observed in up to 40% of cases with ≥5 years of follow-up. Despite the recurrence of type 2 diabetes mellitus in this group, better glycemic control and lower risk of macrovascular complications are present. Incretin effects on glycemic control after bariatric surgery are well described, but the role of other possible mechanisms (bile acids, microbiota, intestinal gluconeogenesis) in humans is unclear.

Conclusion:

Surgery is an effective treatment of type 2 diabetes mellitus in obese patients. The most optimal surgical procedure for the treatment of obese patients with type 2 diabetes mellitus is still to be established. More research is needed to explore the mechanisms of glycemic control after bariatric surgery.

Endocrine and metabolic complications after bariatric surgery

Bariatric surgery is the most effective therapeutic option for obese patients; however, it carries substantial risks, including procedure-related complications, malabsorption, and hormonal disturbance. Recent years have seen an increase in the bariatric surgeries performed utilizing either an independent or a combination of restrictive and malabsorptive procedures. We review some complications of bariatric procedures more specifically, hypoglycemia and osteoporosis, the recommended preoperative assessment and then regular follow up, and the therapeutic options. Surgeon, internist, and the patient must be aware of the multiple risks of this kind of surgery and the needed assessment and follow up.

Interdisciplinary European guidelines on metabolic and bariatric surgery

In 2012, an expert panel composed of presidents of each of the societies, the European Chapter of the International Federation for the Surgery of Obesity (IFSO-EC), and of the European Association for the Study of Obesity (EASO), as well as of the chair of EASO Obesity Management Task Force (EASO OMTF) and other key representatives from IFSO-EC and EASO, devoted the joint Medico-Surgical Workshop of both institutions to the topic of metabolic surgery in advance of the 2013 European Congress on Obesity held in Liverpool. This meeting was prompted by the extraordinary advancement made in the field of metabolic and bariatric surgery during the past decade. It was agreed to revise and update the 2008 Interdisciplinary European Guidelines on Surgery of Severe Obesity produced by focusing in particular on the evidence gathered in relation to the effects on diabetes and the changes in the recommendations of patient eligibility criteria. The expert panel allowed the coverage of key disciplines in the comprehensive management of obesity and obesity-associated diseases, aimed specifically at updating the clinical guidelines to reflect current knowledge, expertise and evidence-based data on metabolic and bariatric surgery.

Approach to the patient with spontaneous hypoglycemia

Hypoglycemia is common in daily clinical practice and often occurs during the treatment of diabetes mellitus. However, a small minority of hypoglycemia encountered in clinical practice is spontaneous and thus not induced by glycemic lowering agents. These spontaneous hypoglycemic events confront the clinician with a diagnostic enigma. Although the trained clinician can recognize the autonomic and neuroglycopenic symptoms of hypoglycemia even in a patient not on insulin, it remains challenging to decipher the etiology of a spontaneous hypoglycemic event. A logical and stepwise approach to the spontaneous hypoglycemic event allows for a conclusive diagnosis. This diagnostic process consists of adequately diagnosing hypoglycemia by fulfilling Whipple's triad, stratifying patients according to their clinical status and analyzing a full hypoglycemic blood panel. A complete hypoglycemic blood panel should include the analysis of glucose, insulin, C-peptide, pro-insulin, insulin antibodies and the presence of oral hypoglycemic agents. For patients with episodes of hypoglycemia induced by excessive endogenous insulin, additional imaging is often required to detect the presence of an underlying insulinoma. By diagnosing the underlying cause of the spontaneous hypoglycemia, the physician also diagnosis the mechanism by which the hypoglycemic event occurs. Allowing for a problem orientated therapeutic approach.

METHODOLOGY

The present review is based upon a comprehensive PubMed search between 1985 and 2013. This uses search terms of spontaneous hypoglycemia, insulinoma, nesidioblastosis, insulin auto-immunity, noninsulinoma pancreatogenous hypoglycemia syndrome, hormone deficiency, pro-IGF II, and pro-insulin growth factor II, and cross reference searching of pivotal articles in the subject.

Insulin-like growth factor 1 predicts post-load hypoglycemia following bariatric surgery: a prospective cohort study

Postprandial hypoglycemia is a complication following gastric bypass surgery, which frequently remains undetected. Severe hypoglycemic episodes, however, put patients at risk, e.g., for syncope. A major cause of hypoglycemia following gastric bypass is hyperinsulinemic nesidioblastosis. Since pancreatic islets in nesidioblastosis overexpress insulin-like growth factor 1 (IGF-1) receptor α and administration of recombinant IGF-1 provokes hypoglycemia, our main objective was to investigate the occurrence of post-load hypoglycemia one year after bariatric surgery and its relation to pre- and post-operative IGF-1 serum concentrations. We evaluated metabolic parameters including 2 h 75 g oral glucose tolerance test (OGTT) and measured IGF-1 serum concentration in thirty-six non-diabetic patients (29 f/7 m), aged 41.3±2.0 y with a median (IQR) BMI of 30.9 kg/m2 (27.5-34.3 kg/m2), who underwent elective bariatric surgery (predominantly gastric bypass, 83%) at our hospital. Post-load hypoglycemia as defined by a 2 h glucose concentration <60 mg/dl was detected in 50% of patients. Serum insulin and C-peptide concentration during the OGTT and HOMA-IR (homeostatic model assessment-insulin resistance) were similar in hypoglycemic and euglycemic patients. Strikingly, pre- and post-operative serum IGF-1 concentrations were significantly higher in hypoglycemic patients (p = 0.012 and p = 0.007 respectively). IGF-1 serum concentration before surgery negatively correlated with 2 h glucose concentration during the OGTT (rho = -0.58, p = 0.0003). Finally, IGF-1 serum concentrations before and after surgery significantly predicted post-load hypoglycemia with odds ratios of 1.28 (95%CI:1.03-1.55, p = 0.029) and 1.18 (95%CI:1.03-1.33, p = 0.015), respectively, for each 10 ng/ml increment. IGF-1 serum concentration could be a valuable biomarker to identify patients at risk for hypoglycemia following bariatric surgery independently of a diagnostic OGTT. Thus, IGF-1 testing could help to prevent a significant complication of gastric bypass surgery.

Postprandial hyperinsulinemic hypoglycemia after gastric bypass surgical treatment

An association between post-Roux-en-Y gastric bypass (RYGB) hypoglycemia and nesidioblastosis was reported in 2005 and may cause serious neuroglycopenic symptoms. Most patients with postprandial hypoglycemia after RYGB respond to nutritional and medical treatment. A subset of patients, however, may not respond adequately and surgery may be considered. This review describes the current experience with surgical intervention for severe post-RYGB hypoglycemia. PubMed and MEDLINE searches were made for reports describing clinical outcome after such surgery. Fourteen papers including 75 patients were identified. Different surgical interventions were applied including gastric tube placement, reversal of the bypass with and without concomitant sleeve resection, gastric pouch restriction, and pancreatic resection and reresection. Pancreatic resection was performed in 51 (68%) patients, 17 (23%) had RYGB reversal and eleven (15%) had gastric pouch restriction alone. Eight (11%) patients received 2 or more consecutive procedures for hypoglycemia and combined interventions were made in several patients. Resolution of the symptoms occurred in 34/51 (67%) patients after pancreatic resection, 13/17 (76%) after reversal, and 9/11 (82%) after pouch restriction. Mean follow up, however, was short for most series and the methods applied for evaluation of hypoglycemia varied. Weight regain, diabetes and recurrent symptoms were late complications. The optimal therapy for hypoglycemia after RYGB is not defined. Long-term evaluations and knowledge about the physiology of post-RYGB hypoglycemia, may enable therapy with improved control of the glucose excursions.

GLP1 analogs as treatment of postprandial hypoglycemia following gastric bypass surgery: a potential new indication?

OBJECTIVE

The number of morbidly obese subjects submitted to bariatric surgery is rising worldwide. In a fraction of patients undergoing gastric bypass (GBP), episodes with late postprandial hypoglycemia (PPHG) develop 1-3 years after surgery. The pathogenesis of this phenomenon is not fully understood; meal-induced rapid and exaggerated increases of circulating incretins and insulin appear to be at least partially responsible. Current treatments include low-carbohydrate diets, inhibition of glucose intestinal uptake, reduction of insulin secretion with calcium channel blockers, somatostatin analogs, or diazoxide, a KATP channel opener. Even partial pancreatectomy has been advocated. In type 2 diabetes, GLP1 analogs have a well-documented effect of stabilizing glucose levels without causing hypoglycemia.

DESIGN

We explored GLP1 analogs as open treatment in five consecutive GBP cases seeking medical attention because of late postprandial hypoglycemic symptoms.

RESULTS

Glucose measured in connection with the episodes in four of the cases had been 2.7, 2.5, 1.8, and 1.6 mmol/l respectively. The patients consistently described that the analogs eliminated their symptoms, which relapsed in four of the five patients when treatment was reduced/discontinued. The drug effect was further documented in one case by repeated 24-h continuous glucose measurements.

CONCLUSION

These open, uncontrolled observations suggest that GLP1 analogs might provide a new treatment option in patients with problems of late PPHG.

The ductal origin of structural and functional heterogeneity between pancreatic islets

Islets form in the pancreas after the first endocrine cells have arisen as either single cells or small cell clusters in the epithelial cords. These cords constitute the developing pancreas in one of its earliest recognizable stages. Islet formation begins at the time the cords transform into a branching ductal system, continues while the ductal system expands, and finally stops before the exocrine tissue of ducts and acini reaches its final expansion. Thus, islets continuously arise from founder cells located in the branching and ramifying ducts. Islets arising from proximal duct cells locate between the exocrine lobules, develop strong autonomic and sensory innervations, and pass their blood to efferent veins (insulo-venous efferent system). Islets arising from cells of more distal ducts locate within the exocrine lobules, respond to nerve impulses ending at neighbouring blood vessels, and pass their blood to the surrounding acini (insulo-acinar portal system). Consequently, the section of the ductal system from which an islet arises determines to a large extent its future neighbouring tissue, architecture, properties, and functions. We note that islets interlobular in position are frequently found in rodents (rats and mice), whereas intralobularly-located, peripheral duct islets prevail in humans and cattle. Also, we expound on bovine foetal Laguesse islets as a prominent foetal type of type 1 interlobular neuro-insular complexes, similar to neuro-insular associations frequently found in rodents. Finally, we consider the probable physiological and pathophysiological implications of the different islet positions within and between species.

Can Bariatric Surgery be Considered Standard Therapy to Treat Type 2 Diabetes?

With the rapid increase in obesity there has been a pronounced increase in obesity-related metabolic disorders including type 2 diabetes, cardiovascular disease, dyslipidaemia and hypertension. Bariatric surgery is a highly effective treatment for achieving long-term weight loss and is increasingly recognised to have benefits in diabetes treatment and cause improvement in other metabolic factors. Recent small randomised trials reported better glycaemic control after surgical intervention compared to pharmacological therapy. Physiological studies suggest a surgery-specific, weight-independent effect on glucose homeostasis. Long-term efficacy is to be proven. Consensus on definition of diabetes and diabetes remission must be achieved. Larger multicentre, randomised trials need to be done to clarify the place of metabolic surgery in diabetes treatment algorithms.

Outcomes of revisional procedures for insufficient weight loss or weight regain after Roux-en-Y gastric bypass

BACKGROUND

The Roux-en-Y gastric bypass (RYGB) performed laparoscopically (LRYGB) is the most frequently performed bariatric procedure in Belgium. However, late results in terms of weight loss or weight regain are inconsistent and may warrant a second procedure. This retrospective study analyzes the laparoscopic options for revisional surgery after LRYGB.

METHODS

Between January 1, 2001 and December 31, 2009, 70 patients underwent a new laparoscopic procedure for poor weight loss or weight regain after LRYGB. The revisional procedure was performed a median of 2.6 years after the initial bypass operation. Fifty-eight patients were available for follow-up (82.9 %); 19 underwent distalization; and 39 a new restrictive procedure.

RESULTS

The mean mass index (BMI) before the revisional procedure was 39.1 + 11.3 kg/m(2) (30.8-51.8), down from 42.7 + 19.7 kg/m(2) (33.0-56.6) initially, which corresponded to a percentage of excess weight loss (EWL) of 12.4 + 9.3 % (-1.0-29.1). After the corrective procedure, with a follow-up of approximately 4 years, mean BMI was 29.6 + 12.4 kg/m(2) (18.0-45.5), for a significant additional percentage of EWL of 53.7 + 9.8 % (2.0-65.8). The overall complication rate was 20.7 %, and the reoperation rate was 7.3 %. The overall leak rate was 12.1 %. Patients suffering from leaks could consistently be treated conservatively or by stent placement. Two patients needed reconversion after distal bypass. The satisfaction index was good in just over 50 % of the patients.

CONCLUSION

Revisional laparoscopic surgery after RYGB performed for weight issues provides good additional weight loss but carries significant morbidity. Leaks can usually be handled non-surgically. Patient satisfaction is only fair.

Clinical practice guidelines for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient--2013 update: cosponsored by American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery

The development of these updated guidelines was commissioned by the AACE, TOS, and ASMBS Board of Directors and adheres to the AACE 2010 protocol for standardized production of clinical practice guidelines (CPG). Each recommendation was re-evaluated and updated based on the evidence and subjective factors per protocol. Examples of expanded topics in this update include: the roles of sleeve gastrectomy, bariatric surgery in patients with type-2 diabetes, bariatric surgery for patients with mild obesity, copper deficiency, informed consent, and behavioral issues. There are 74 recommendations (of which 56 are revised and 2 are new) in this 2013 update, compared with 164 original recommendations in 2008. There are 403 citations, of which 33 (8.2%) are EL 1, 131 (32.5%) are EL 2, 170 (42.2%) are EL 3, and 69 (17.1%) are EL 4. There is a relatively high proportion (40.4%) of strong (EL 1 and 2) studies, compared with only 16.5% in the 2008 AACE-TOS-ASMBS CPG. These updated guidelines reflect recent additions to the evidence base. Bariatric surgery remains a safe and effective intervention for select patients with obesity. A team approach to perioperative care is mandatory with special attention to nutritional and metabolic issues.

Clinical practice guidelines for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient--2013 update: cosponsored by American Association of Clinical Endocrinologists, the Obesity Society, and American Society for Metabolic & Bariatric Surgery

The development of these updated guidelines was commissioned by the AACE, TOS, and ASMBS Board of Directors and adheres to the AACE 2010 protocol for standardized production of clinical practice guidelines (CPG). Each recommendation was re-evaluated and updated based on the evidence and subjective factors per protocol. Examples of expanded topics in this update include: the roles of sleeve gastrectomy, bariatric surgery in patients with type-2 diabetes, bariatric surgery for patients with mild obesity, copper deficiency, informed consent, and behavioral issues. There are 74 recommendations (of which 56 are revised and 2 are new) in this 2013 update, compared with 164 original recommendations in 2008. There are 403 citations, of which 33 (8.2%) are EL 1, 131 (32.5%) are EL 2, 170 (42.2%) are EL 3, and 69 (17.1%) are EL 4. There is a relatively high proportion (40.4%) of strong (EL 1 and 2) studies, compared with only 16.5% in the 2008 AACE-TOS-ASMBS CPG. These updated guidelines reflect recent additions to the evidence base. Bariatric surgery remains a safe and effective intervention for select patients with obesity. A team approach to perioperative care is mandatory with special attention to nutritional and metabolic issues.

Dual origin, development, and fate of bovine pancreatic islets

Endocrine cells are evident at an early stage in bovine pancreatic development when the pancreas still consists of primitive epithelial cords. At this stage, the endocrine cells are interspersed between the precursor cells destined to form the ductulo-acinar trees of later exocrine lobules. We here demonstrate that, in bovine fetuses of crown rump length ≥ 11 cm, the endocrine cells become increasingly segregated from the developing exocrine pancreas by assembly into two units that differ in histogenesis, architecture, and fate. Small numbers of 'perilobular giant islets' are distinguishable from larger numbers of 'intralobular small islets'. The two types of islets arise in parallel from the ends of the ductal tree. Aside from differences in number, location, and size, the giant and small islets differ in cellular composition (predominantly insulin-synthesising cells vs. mixtures of endocrine cells), morphology (epithelial trabeculae with gyriform and rosette-like appearance vs. compact circular arrangements of endocrine cells), and in their relationships to intrapancreatic ganglia and nerves. A further difference becomes apparent during the antenatal period; while the 'interlobular small islets' persist in the pancreata of calves and adult cattle, the perilobular giant islets are subject to regression, characterised by involution of the parenchyma, extensive haemorrhage, leukocyte infiltration (myeloid and T-cells) and progressive fibrotic replacement. In conclusion, epithelial precursor cells of the ductolo-acinar tree may give rise to populations of pancreatic islets with different histomorphology, cellular composition and fates. This should be taken into account when using these cells for the generation of pancreatic islets for transplantation therapy.

Long-term results of laparoscopic Roux-en-Y Gastric bypass: evaluation after 9 years

This retrospective study aimed to evaluate the long-term results of the laparoscopic Roux-en-Y gastric bypass (LRYGB) procedure performed at our department of bariatric surgery. The 126 consecutive patients treated by LRYGB between January 1, 2001 and December 31, 2002 were analyzed in August 2011. Seventy-seven patients (61.1 %), including 18 who had had previous bariatric surgery, were available for evaluation after 9.4 ± 0.6 years (range, 8.7-10.9 years). Eight patients (10.4 %) suffered from type 2 diabetes mellitus (DMII) at the time of surgery. Initial body mass index (BMI) was 40.3 ± 7.5 kg/m(2) (range, 24.5-66.1 kg/m(2)). There was no postoperative mortality, but two patients died of causes unrelated to the surgery. Some 9 % of the patients suffered from internal herniation, despite the closure of potential hernia sites. With time, the patients had the tendency to experience weight regain: percentage of excess BMI lost was 56.2 ± 29.3 % (range, -78.8 to 117.9 %), down from a maximum of 88.0 ± 29.6 % (range, -19.7 to 197.1 %), that had been obtained after a median of 2.0 years (range, 1-8 years). LRYGB was effective for diabetes control in 85.7 % of the affected patients, but, surprisingly, 27.9 % developed new-onset diabetes. The weight regain in this latter patient group was statistically not different from the nondiabetic group. Conversely, four patients required hospitalization for hypoglycemic syndrome. Two patients underwent reversal of their bypass for problems linked to glucose metabolism (one hypoglycemia, one DMII). Patient quality of life was fair. The patient satisfaction remained good in 76 % of the cases.

Clinical practice guidelines for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient--2013 update: cosponsored by American Association of Clinical Endocrinologists, the Obesity Society, and American Society for Metabolic & Bariatric Surgery

The development of these updated guidelines was commissioned by the AACE, TOS, and ASMBS Board of Directors and adheres to the AACE 2010 protocol for standardized production of clinical practice guidelines (CPG). Each recommendation was re-evaluated and updated based on the evidence and subjective factors per protocol. Examples of expanded topics in this update include: the roles of sleeve gastrectomy, bariatric surgery in patients with type-2 diabetes, bariatric surgery for patients with mild obesity, copper deficiency, informed consent, and behavioral issues. There are 74 recommendations (of which 56 are revised and 2 are new) in this 2013 update, compared with 164 original recommendations in 2008. There are 403 citations, of which 33 (8.2%) are EL 1, 131 (32.5%) are EL 2, 170 (42.2%) are EL 3, and 69 (17.1%) are EL 4. There is a relatively high proportion (40.4%) of strong (EL 1 and 2) studies, compared with only 16.5% in the 2008 AACE-TOS-ASMBS CPG. These updated guidelines reflect recent additions to the evidence base. Bariatric surgery remains a safe and effective intervention for select patients with obesity. A team approach to perioperative care is mandatory with special attention to nutritional and metabolic issues.

Interdisciplinary European Guidelines on metabolic and bariatric surgery

In 2012, an outstanding expert panel derived from IFSO-EC (International Federation for the Surgery of Obesity-European Chapter) and EASO (European Association for the Study of Obesity), composed by key representatives of both Societies including past and present presidents together with EASO's OMTF (Obesity Management Task Force) chair, agreed to devote the joint Medico-Surgical Workshop of both institutions to the topic of metabolic surgery as a pre-satellite of the 2013 European Congress on Obesity (ECO) to be held in Liverpool given the extraordinarily advancement made specifically in this field during the past years. It was further agreed to revise and update the 2008 Interdisciplinary European Guidelines on Surgery of Severe Obesity produced in cooperation of both Societies by focusing in particular on the evidence gathered in relation to the effects on diabetes during this lustrum and the subsequent changes that have taken place in patient eligibility criteria. The expert panel composition allowed the coverage of key disciplines in the comprehensive management of obesity and obesity-associated diseases, aimed specifically at updating the clinical guidelines to reflect current knowledge, expertise and evidence-based data on metabolic and bariatric surgery.

Functional imaging in hyperinsulinemic hypoglycemia after gastric bypass surgery for morbid obesity

CONTEXT

Hyperinsulinemic hypoglycemia after Roux-en-Y gastric bypass (RYGB) has been increasingly reported. It is induced by β-cell hyperplasia often referred to as nesidioblastosis. Positron emission tomography (PET) with [11C]-5-hydroxytryptophan ((11)C-HTP) and 6-[18F]fluoro-3,4-dihydroxy-l-phenylalanine ((18)F-DOPA) has been successfully applied to image neuroendocrine tumors. No data are available of the usefulness of these functional imaging techniques in post-RYGB in this new endocrine disorder, neither for diagnostic purposes nor for follow-up.

OBJECTIVE

We present a patient with post-RYGB hypoglycemia who underwent (11)C-HTP and (18)F-DOPA PET scintigraphy for diagnostic purposes and to evaluate the effect of additional laparoscopic adjustable banding of the pouch as a surgical therapy for this disorder.

PATIENT

We describe a woman with biochemically confirmed post-RYGB hypoglycemia who showed diffuse uptake of the (11)C-HTP and (18)F-DOPA tracers in the entire pancreas. After failure of dietary and medical treatment options, she underwent a laparoscopic adjustable banding for pouch dilatation. Subjective improvement was noted, which coincided with decreased uptake of (18)F-DOPA and (11)C-HTP in the head of the pancreas.

CONCLUSIONS

Functional imaging by (18)F-DOPA- and (11)C-HTP-PET can accurately visualize diffuse endocrine pancreatic activity in post-gastric bypass hyperinsulinemic hypoglycemia. Both (11)C-HTP- and (18)F-DOPA-PET imaging appear to have a similar diagnostic performance in the presented case, and uptake of both tracers potentially relates to disease activity after surgical intervention.