Gastric per-oral endoscopic myotomy (G-POEM) for the treatment of gastric sleeve stenosis: a feasibility and safety study.

BACKGROUND: Traditional endoscopic treatments have limited success in gastric sleeve stenosis (GSS). Gastric peroral endoscopic myotomy (G-POEM) could conceivably obliterate the twist/angulation that causes GSS through a tunneled stricturotomy. We report early outcomes of G-POEM for GSS treatment. METHODS: We retrospectively reviewed all patients with GSS treated with G-POEM at our center. The primary end point was clinical success, defined as symptom improvement with resumption of adequate oral intake, without requiring further intervention. RESULTS: 13 patients (mean age 43 ±â€Š10.9 years; 12 female) underwent G-POEM for predominantly helical (11/13, 85 %) GSS. Three (23 %) had concurrent sleeve leak and 10 (77 %) had prior GSS treatment. Two intraoperative complications occurred, with no deviation to the procedure; no major complications occurred. At median follow-up of 175 (interquartile range [IQR] 119-260) days, clinical success was achieved in 10 patients (77 %). Median Gastroparesis Cardinal Symptom Index score in responders decreased from 2.06 (IQR 1.5-2.8) to 0.39 (IQR 0.2-0.5). Three patients (23 %) required surgical revision. CONCLUSIONS: G-POEM was feasible and safe, and may provide an alternative option for those averse to undergoing surgical revision for treatment of GSS.

Providing complex GI surgical care with minimally invasive approaches: a survey of the practice patterns of Fellowship Council alumni.

INTRODUCTION: The Fellowship Council (FC) oversees 172 non-ACGME surgical fellowships offering 211 fellowship positions per year. These training programs cover multiple specialties including Advanced gastrointestinal (GI), Advanced GI/MIS, Bariatric, Hepatopancreaticobiliary (HPB), Flexible Endoscopy, Colorectal, and Thoracic Surgery. Although some data have been published detailing the practice environments (i.e., urban vs. rural) and yearly total case volumes of FC alumni, there is a lack of granular data regarding the practice patterns of FC graduates. The aim of this study was to gather detailed data on the specific case types performed and surgical approaches employed by recent FC alumni. METHODS: A 21-item survey covering 64 data points was emailed to 835 FC alumni who completed their fellowship between 2013 and 2017. Email addresses were obtained from FC program directors and FC archives. RESULTS: We received 327 responses (39% response rate). HPB, Advanced Colorectal, and Advanced Thoracic alumni appear to establish practices focused on their respective fields. Graduates from Advanced GI, Adv GI/MIS, and Bariatric programs appear to build practices with a mix of several complex GI case types including bariatrics, colorectal, foregut, HPB, and hernia cases. CONCLUSIONS: This is the first large data set to provide granular information on the practice patterns of FC alumni. FC trained surgeons perform impressive volumes of complex procedures, and minimally invasive approaches are extremely prevalent in these practices. Further, many graduates carve out practices with large footprints in robotics and endoscopy.

Obesity is associated with copper elevation in serum and tissues.

Copper misbalance has been linked to fat accumulation in animals and experimental systems; however, information about copper homeostasis in human obesity is limited. In this study, the copper status of obese individuals was evaluated by measuring their levels of copper and cuproproteins in serum, adipose and hepatic tissues. The analysis of serum trace elements showed significant positive and element-specific correlation between copper and BMI after controlling for gender, age, and ethnicity. Serum copper also positively correlated with leptin, insulin, and the leptin/BMI ratio. When compared to lean controls, obese patients had elevated circulating cuproproteins, such as semucarbazide-sensitive amine oxidase (SSAO) and ceruloplasmin, and higher SSAO activity and copper levels in visceral fat. Although hepatic steatosis reduces copper levels in the liver, obese patients with no or mild steatosis have higher copper content in the liver compared to lean controls. In conclusion, obese patients evaluated in this study had altered copper status. Strong positive correlations of copper levels with BMI and leptin suggest that copper and/or cuproproteins may be functionally linked to fat accumulation.

Secured Lumen-Apposing Fully Covered Metallic Stents for Stenoses in Post-Bariatric Surgery Patients.

New approaches for refractory stenosis in post-bariatric surgical patients include fully covered lumen-apposing metallic stents (LAMS); however, stent migration continues to be a problem. Endoscopic suture placement to LAMS can reduce the migration. Aiming to assess the feasibility and safety of the procedure, we evaluated nine consecutive patients with inability to tolerate a solid diet due to a benign gastrointestinal stricture recalcitrant to previous attempts at endoscopic therapy. All patients were symptom-free starting from 1-week follow-up. Median stent dwell time was nearly 3 months. During the removal procedures, three incidental foreign bodies were found and removed. No stent migration was observed in any patients. Suturing LAMS is a feasible technique allowing for prolonged stent dwell times; however, it requires a high level of expertise plus additional procedure time.

Cytokine, Chemokine, and Cytokine Receptor Changes Are Associated With Metabolic Improvements After Bariatric Surgery.

Context: Altered cytokine levels and chronic low-grade inflammation contribute to metabolic dysfunction in obesity. The extent of cytokine changes and their impact on metabolic improvements after bariatric surgery have not been fully explored. Objective: To compare 76 circulating cytokines, chemokines, and secreted cytokine receptors in subjects with obesity and lean subjects and determine how these cytokines are altered by bariatric surgery. Design, Setting, and Participants: A total of 37 patients with obesity and 37 lean patients in a cross-sectional study at an academic medical center. We also investigated cytokine changes in 25 patients with obesity after bariatric surgery. Intervention: Bariatric surgery (Roux-en-Y gastric bypass and vertical sleeve gastrectomy). Main Outcome Measures: Quantification of 76 circulating cytokines, chemokines, and secreted cytokine receptors. Results: A total of 13 cytokines were significantly higher, and 4 lower, in patients with obesity relative to lean controls. Soluble vascular endothelial growth factor receptor 2 (sVEGFR2), soluble TNF receptor (sTNFR) 1, and sTNFR2 were positively correlated, and soluble receptor for advanced glycation end-products was inversely correlated, with weight and body mass index. sTNFR2 was positively correlated with fasting glucose, homeostatic model assessment of insulin resistance, and hemoglobin A1c. After bariatric surgery, adiponectin increased, and leptin decreased. Elevated sVEGFR2 levels in patients with obesity were decreased (P = 0.01), whereas reduced chemokine (C-X-C motif) ligand (CXCL) 12 levels in patients with obesity increased (P = 0.03) after surgery. Patients with higher soluble interleukin receptor (sIL) 1R2 and sIL-6R levels before surgery had greater weight loss after surgery (P < 0.05). Conclusions: We demonstrate that chemokine (C-C motif) ligand (CCL) 14, sVEGFR2, and platelet-derived growth factor BB are elevated in obesity, and CXCL12, CCL11, and CCL27 are lower in obesity. We found clinically concordant directionality between lean and patients with obesity and before vs after surgery for six cytokines, suggesting that bariatric surgery shifted the cytokine profiles of patients with obesity toward that of lean controls.

The Role of Laboratory Testing in Differentiating Type 1 Diabetes from Type 2 Diabetes in Patients Undergoing Bariatric Surgery.

BACKGROUND: It may be difficult to distinguish between adults with type 1 diabetes and type 2 diabetes by clinical assessment. In patients undergoing bariatric surgery, it is critical to correctly classify diabetes subtype to prevent adverse perioperative outcomes including diabetic ketoacidosis. This study aimed to determine whether testing for C-peptide and islet cell antibodies during preoperative evaluation for bariatric surgery could improve the classification of type 1 versus type 2 diabetes compared to clinical assessment alone. METHODS: This is a retrospective analysis of the Improving Diabetes through Lifestyle and Surgery trial, which randomized patients with clinically diagnosed type 2 diabetes and BMI 30-40 kg/m2 to medical weight loss or bariatric surgery; one participant was discovered to have type 1 diabetes after experiencing postoperative diabetic ketoacidosis. Using blood samples collected prior to study interventions, we measured islet cell antibodies and fasting/meal-stimulated C-peptide in all participants. RESULTS: The participant with type 1 diabetes was similar to the 11 participants with type 2 diabetes in age at diagnosis, adiposity, and glycemic control but had the lowest C-peptide levels. Among insulin-treated participants, fasting and stimulated C-peptide correlated strongly with the C-peptide area-under-the-curve on mixed meal tolerance testing (R = 0.86 and 0.88, respectively). Three participants, including the one with type 1 diabetes, were islet cell antibody positive. CONCLUSIONS: Clinical characteristics did not correctly identify type 1 diabetes in this study. Preoperative C-peptide testing may improve diabetes classification in patients undergoing bariatric surgery; further research is needed to define the optimal C-peptide thresholds.

Inversion Technique for the Removal of Partially Covered Self-Expandable Metallic Stents.

BACKGROUND AND AIMS: Partially covered self-expandable metallic stents (PCSEMS), although an effective treatment for anastomotic/staple line leaks and strictures, can be difficult to remove. This study examines the effectiveness of the inversion technique for the removal of PCSEMS in the treatment of leaks and strictures that occurred post-sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB). METHODS: Consecutive patients who underwent PCSEMS removal for a leak and/or stricture post-SG or RYGB between July 2013 and December 2016 at the Johns Hopkins Medical Institutions were reviewed. All PCSEMS removals were first attempted via the inversion technique, which involves grasping the distal end of the stent and inverting it through itself. RESULTS: Fourteen patients (four males) underwent PCSEMS removal via the inversion technique for an anastomotic/staple line leak (50%), stricture (29%) or both (21%) post-SG (79%) or RYGB (21%). Technical success (successful removal of the stent) was achieved in one endoscopic session for 13 of the 14 PCSEMS (93%). One PCSEMS required the use of the stent-in-stent technique for removal. The median dwell time was 47 days (range 5-72). A distal partial occlusion developed in five patients (35%) due to tissue overgrowth and one PCSEMS (7%) migrated, necessitating premature removal. Eight patients (57%) experienced clinical success at follow-up, and six patients (43%) required subsequent treatment due to persistence or recurrence of the pathology. CONCLUSIONS: The inversion technique is a safe, effective, and efficient method of removing PCSEMS placed to correct anastomotic/staple line leaks and strictures post-SG and RYGB.

CTRP7 deletion attenuates obesity-linked glucose intolerance, adipose tissue inflammation, and hepatic stress.

Chronic low-grade inflammation and cellular stress are important contributors to obesity-linked metabolic dysfunction. Here, we uncover an immune-metabolic role for C1q/TNF-related protein 7 (CTRP7), a secretory protein of the C1q family with previously unknown function. In obese humans, circulating CTRP7 levels were markedly elevated and positively correlated with body mass index, glucose, insulin, insulin resistance index, hemoglobin A1c, and triglyceride levels. Expression of CTRP7 in liver was also significantly upregulated in obese humans and positively correlated with gluconeogenic genes. In mice, Ctrp7 expression was differentially modulated in various tissues by fasting and refeeding and by diet-induced obesity. A genetic loss-of-function mouse model was used to determine the requirement of CTRP7 for metabolic homeostasis. When fed a control low-fat diet, male or female mice lacking CTRP7 were indistinguishable from wild-type littermates. In obese male mice consuming a high-fat diet, however, CTRP7 deficiency attenuated insulin resistance and enhanced glucose tolerance, effects that were independent of body weight, metabolic rate, and physical activity level. Improved glucose metabolism in CTRP7-deficient mice was associated with reduced adipose tissue inflammation, as well as decreased liver fibrosis and cellular oxidative and endoplasmic reticulum stress. These results provide a link between elevated CTRP7 levels and impaired glucose metabolism, frequently associated with obesity. Inhibiting CTRP7 action may confer beneficial metabolic outcomes in the setting of obesity and diabetes.

Vitamin D status and supplementation before and after bariatric surgery: a comprehensive literature review.

BACKGROUND: Bariatric surgery is the most effective long-term weight loss method. The most common procedures are Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG). Bariatric patients are at high risk of vitamin D deficiency (VDD) and insufficiency (VDI), which are associated with skeletal and nonskeletal ailments. There is no consensus regarding the optimal treatment for VDD/VDI in bariatric patients. OBJECTIVES: To critically examine the literature on vitamin D status (serum 25[OH]D concentrations) pre- and postbariatric surgery as well as supplementation regimens currently used. METHODS: We searched PubMed, Embase, and Cochrane from inception to May 2015 for articles relating to vitamin D, RYGB, and VSG. Of 208 citations retrieved, 30 were included. RESULTS: Preoperative VDD (<20 ng/mL) ranged from 13% to 90%, while VDI (<30 ng/mL) was found in up to 98%. Prevalence remained similar postoperatively and was highest after RYGB. Most studies found dosages<800 IU daily insufficient postbariatric surgery. Other studies examined the effectiveness of dosages between 1000 and 5000 IU daily, reaching similar conclusions. Several studies suggested using 50,000 IU weekly plus a daily dose. No studies reported optimization. CONCLUSIONS: It is widely accepted that serum 25(OH)D concentrations above 30 ng/mL are optimal; however, current postbariatric vitamin D supplementation fails to raise 25(OH)D above that level universally. This review highlights both the great need and the lack of consensus on the optimal supplementation regimen (dosage and frequency) for pre- and postbariatric patients. Future studies should investigate multiple regimens and attempt to identify methods for personalizing these regimens if found necessary.

C1q/TNF-Related Protein-9 (CTRP9) Levels Are Associated With Obesity and Decrease Following Weight Loss Surgery.

CONTEXT: C1q/TNF-related protein-9 (CTRP9) is a novel adipokine that has beneficial metabolic and cardiovascular effects in various animal models. Alterations in circulating CTRP9 have also been observed in patients with cardiovascular disease and diabetes, but little is known about the impact of obesity and bariatric surgery on CTRP9 concentrations. OBJECTIVE: The aim of this study was to compare CTRP9 levels in obese and lean subjects and to determine whether circulating CTRP9 levels in morbidly obese patients are altered by bariatric surgery. DESIGN, SETTING, AND PARTICIPANTS: Fifty-nine obese bariatric surgical patients and 62 lean controls were recruited to participate in a cross-sectional study at an academic medical center. The obese patients were further invited to participate in a cohort study, and 21 returned for analysis at 3 and 6 months postsurgery. INTERVENTION: Bariatric surgery (Roux-en-Y gastric bypass and vertical sleeve gastrectomy) was the intervention for this study. MAIN OUTCOME MEASURES: Fasting serum was obtained from all subjects on entry to the study and was analyzed in the core laboratory for hemoglobin A1c, glucose, aspartate aminotransferase, alanine aminotransferase, total cholesterol, high- and low-density lipoprotein cholesterol, and triglycerides; CTRP9, insulin, adiponectin, and leptin were measured by ELISA. Serum from the patients in the cohort study was also analyzed at 3 and 6 months. RESULTS: Serum CTRP9 was significantly higher in the obese group compared to the lean group. CTRP9 was associated with obesity, even after controlling for age, gender, and ethnicity. Following bariatric surgery, there was a significant decrease in weight at 3 and 6 months postprocedure, accompanied by decreases in CTRP9, hemoglobin A1c and leptin, and an increase in serum adiponectin. CONCLUSIONS: CTRP9 levels are elevated in obesity and significantly decrease following weight loss surgery. Our data suggest that CTRP9 may play a compensatory role in obesity, similar to that of insulin, and is down-regulated following weight loss surgery.

Treatment for Vitamin D Deficiency Prior to Bariatric Surgery: a Prospective Cohort Study.

BACKGROUND: Since obesity increases vitamin D deficiency (VDD) risk, bariatric surgery candidates are high-risk. Previously, we documented 71.4% VDD at our center. OBJECTIVES: To investigate diagnosis and treatment for VDD in our bariatric candidates. METHODS: 25(OH)D, if pending, and supplementation (form, dosing, frequency) were prospectively documented in 265 candidates. RESULTS: Candidates were 83.0% female, 48.9% white, age 43 ± 13 years and BMI 46.3 ± 10.5 kg/m(2). 25(OH)D was available for 18.5%: 35.7% VDD 39.3% insufficiency. VDD history did not differ by demographics or procedure, as with those tested versus not. CONCLUSION: VDD testing was lower than clinically-indicated. Of those tested, 35.7% were deficient and 39.3% insufficient. We previously reported higher rates: 71.4% deficiency, 92.9% insufficiency. Thus, many candidates are untested but high-risk.

Endoscopic Management of Bariatric Surgery Complications.

Obesity is a global epidemic that has significant impact on morbidity, mortality, and rising health care costs. In morbidly obese patients with body mass index >40 kg/m2, bariatric surgery is a grade A recommendation and is associated with up to 40% reduction in premature death. Increasingly, endoscopy is seen as a safer and more cost-effective approach to the management of weight loss surgery complications including gastrointestinal bleeding, development of anastomotic ulcers, staple-line leaks and fistulas, strictures, weight regain, bezoars, choledocholithiasis, and gastric band erosion and slippage. Many endoscopic interventions currently rely on a combination of specialized equipment, such as stents, suture systems, clips, and balloon dilators to successfully treat these issues. This article will present common postoperative complications in bariatric surgery, discuss the latest evidence for their endoscopic management, and offer future directions in the endoluminal therapy of obese patients.

Malnutrition in Bariatric Surgery Candidates: Multiple Micronutrient Deficiencies Prior to Surgery.

BACKGROUND: Over 78 million American adults have obesity. Bariatric surgery is the leading means of durable weight loss. Nutritional deficiencies are commonly treated post-operatively but are often undiagnosed pre-operatively. Malnutrition is correlated with adverse surgical outcomes. OBJECTIVES: The aim of this study is to assess pre-operative nutritional status in our bariatric surgery candidates in a cross-sectional study. METHODS: We recruited 58 bariatric candidates approved to undergo the Roux-en Y gastric bypass. Nutritional status was determined for vitamins A, B12, D, E-α, and E-ß/γ as well as thiamine, folate, and iron. We used clinical as well as frank deficiency cut-offs based on the Institute of Medicine and the World Health Organization guidelines. RESULTS: This cohort was largely female (77.6%) and white (63.8%). Median age was 42.2 years. Median body mass index (BMI) was 46.3 kg/m(2). Multiple comorbidities (MCM) were present in 41.4%, 54.0% hypertension, 42.0% diabetic, 34.0% sleep apnea. Men had more comorbidities, 69.2 % with MCM. Folate and iron saturation varied significantly by sex. Vitamins A, D, E-α, and thiamine significantly varied by race. Vitamin D negatively correlated with BMI (p = 0.003) and age (p = 0.030). Vitamin A negatively correlated with age (p = 0.001) and number of comorbidities (p = 0.003). These pre-operative bariatric candidates had significant malnutrition, particularly in vitamin D (92.9%) and iron (36.2 to 56.9 %). Multiple micronutrient deficiency (MMND) was more common in blacks (50.0 versus 39.7% overall). Number of comorbidities did not correlate with MMND. CONCLUSIONS: Malnutrition in one or multiple micronutrients is pervasive in this pre-operative bariatric cohort. The effect of pre-operative supplementation, especially vitamin D and iron, should be explored.

Early hospital readmission after bariatric surgery.

BACKGROUND: With the rise in bariatric procedures being performed nationwide and the growing focus on quality and outcome measures, reducing early hospital readmission (EHR) rates has garnered great clinical interest. The aim of this study was to identify the incidence, reasons, and risk factors for EHR after bariatric surgery. METHODS: Using American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) dataset (2012-2013), patients with a diagnosis of obesity and body mass index ≥35 who underwent bariatric surgery were identified. EHR was defined as at least one hospitalization within 30 days of bariatric procedure. The association between readmission and patient factors was assessed using multivariable logistic regression analysis. In addition, reasons for readmission were sought. RESULTS: A total of 36,042 patients were identified. The overall EHR rate was 4.70 % [laparoscopic (lap) adjustable band 1.87 %, lap gastric bypass (GBP) 5.94 %, open GBP 7.86 %, and sleeve gastrectomy 3.73 %], and it occurred at the median of 11 days postoperatively. The rate of EHR significantly decreased from 2012 to 2013 (5.15 vs. 4.32 %, p < 0.001). The median age and BMI were 44 years and 44.7 kg/m(2), respectively, 78.99 % were female, and 70.78 % were white. The most common reason for readmission was nausea/vomiting (12.95 %), followed by abdominal pain (11.75 %) and dehydration (10.54 %). On multivariable analysis, factors most strongly associated with readmission were procedure type (lap band: reference; open GBP: OR 3.78, 95 % CI 2.47-5.80; lap GBP 3.18, 2.39-4.22; sleeve gastrectomy: 2.03, 1.52-2.71; all p < 0.001), steroid use (1.82, 1.33-2.48, p < 0.001), pre-discharge complication (1.64, 1.20-2.24, p < 0.001), and black population (1.51, 1.34-1.71, p < 0.001). CONCLUSIONS: Bariatric centers should consider implementing standardized protocols for outpatient monitoring of patients identified to be at high risk of experiencing early readmission, which in turn would decrease overall costs and improve quality of care.

Endoscopic management of bariatric surgical complications.

PURPOSE OF REVIEW: Bariatric surgery is recognized as the most effective treatment against obesity as it results in significant weight reduction and a high rate of remission of obesity-related comorbidities. However, bariatric surgery is not uncommonly associated with complications and an endoscopic approach to management is preferred over surgical reintervention. This review illustrates the latest developments in the endoscopic management of bariatric surgical complications. RECENT FINDINGS: For successful management of complications, precipitating and perpetuating factors must be addressed in addition to directing therapy at the target pathology. Endoscopy is well tolerated even in the acute postoperative setting when performed carefully with CO2 insufflation. Chronic proximal staple-line leaks/fistulas frequently do not respond to primary closure with diversion therapy, and a new technique of stricturotomy has been reported to improve outcomes. Innovations in the field of transoral endoscopic instruments have led to the development of a single-session entirely internal endoscopic retrograde cholangiopancreatography by creating a gastrogastric anastomosis. SUMMARY: Endoscopy allows for early diagnosis and prompt institution of therapy and should, therefore, be the first-line intervention in the management of complications of bariatric surgery in patients who do not need urgent surgical intervention. Computed tomography-guided drainage may be necessary in patients with drainable fluid collections. VIDEO ABSTRACT: http://links.lww.com/COG/A11.

Lower Circulating C1q/TNF-Related Protein-3 (CTRP3) Levels Are Associated with Obesity: A Cross-Sectional Study.

PURPOSE: C1q/TNF-related protein-3 (CTRP3) is a novel adipokine that lowers blood glucose levels, reduces liver triglyceride synthesis, and is protective against hepatic steatosis in diet-induced obese mouse models. We hypothesized that higher circulating serum levels of CTRP3 would be associated with a lean body mass index (BMI) and a more favorable metabolic profile in humans. The aim of this study was to investigate CTRP3 levels in lean individuals compared to obese individuals. METHODS: This was a cross-sectional study of obese (n=44) and lean control patients (n=60). Fasting metabolic parameters were measured in all patients and serum CTRP3 levels were measured by ELISA. RESULTS: BMI of the lean group was 21.9 ± 0.2 kg/m2 and obese group was 45.2 ± 1.1 kg/m2. We found significantly lower circulating levels of CTRP3 in obese individuals (405 ± 8.3 vs. 436 ± 6.7 ng/mL, p=0.004) compared to the lean group. Serum CTRP3 levels were inversely correlated with BMI (p=0.001), and triglycerides (p<0.001), and significantly associated with gender (p<0.01), ethnicity (p=0.05), HDL-cholesterol (p<0.01), and adiponectin (p<0.01). We found BMI (p<0.01), gender (p<0.01), and ethnicity (p<0.05) to be significant predictors of CTRP3 levels when controlling for age in multiple regression analysis. CONCLUSIONS: CTRP3 is a beneficial adipokine whose circulating levels are significantly lower in obese individuals. Obesity causes dysregulation in adipokine production, including the down-regulation of CTRP3. Lower CTRP3 levels may contribute to the pathophysiology of metabolic disorders associated with obesity. Optimizing CTRP3 levels through novel therapies may improve obesity and its comorbidities.

Lysyl Oxidase as a Serum Biomarker of Liver Fibrosis in Patients with Severe Obesity and Obstructive Sleep Apnea.

STUDY OBJECTIVES: Obstructive sleep apnea (OSA) is associated with the progression of nonalcoholic fatty liver disease (NAFLD). We hypothesized that the hypoxia of OSA increases hepatic production of lysyl oxidase (LOX), an enzyme that cross-links collagen, and that LOX may serve as a biomarker of hepatic fibrosis. DESIGN: Thirty-five patients with severe obesity underwent liver biopsy, polysomnography, and serum LOX testing. A separate group with severe OSA had serum LOX measured before and after 3 mo of CPAP or no therapy, as did age-matched controls. LOX expression and secretion were measured in mouse hepatocytes following exposure to hypoxia. SETTING: The Johns Hopkins Bayview Sleep Disorders Center, and the Hypertension Unit of the Heart Institute at the University of São Paulo Medical School. MEASUREMENTS AND RESULTS: In the bariatric cohort, the apnea-hypopnea index was higher in patients with hepatic fibrosis than in those without fibrosis (42.7 ± 30.2 events/h, versus 16.2 ± 15.5 events/h; P = 0.002), as was serum LOX (84.64 ± 29.71 ng/mL, versus 45.46 ± 17.16 ng/mL; P < 0.001). In the sleep clinic sample, patients with severe OSA had higher baseline LOX than healthy controls (70.75 ng/mL versus 52.36 ng/mL, P = 0.046), and serum LOX decreased in patients with OSA on CPAP (mean decrease 20.49 ng/mL) but not in untreated patients (mean decrease 0.19 ng/mL). Hypoxic mouse hepatocytes demonstrated 5.9-fold increased LOX transcription (P = 0.046), and enhanced LOX protein secretion. CONCLUSIONS: The hypoxic stress of obstructive sleep apnea may increase circulating lysyl oxidase (LOX) levels. LOX may serve as a biomarker of liver fibrosis in patients with severe obesity and nonalcoholic fatty liver disease.