Nonalcoholic steatohepatitis in bariatric patients with a diagnosis of obstructive sleep apnea

Effects of obstructive sleep apnea on non-alcoholic fatty liver disease in patients with obesity: a systematic review

INTRODUCTION

Obesity has been linked to non-alcoholic fatty liver disease (NAFLD), a widespread chronic liver ailment, as well as obstructive sleep apnea (OSA). The development of NAFLD is influenced by repeated intermittent hypoxia, a feature of OSA.

METHODS

This systematic review (SR) investigated CENTRAL, PubMed, and EMBASE databases. The endpoint of this SR was to assess which OSA-related indicators could predict the presence of NAFLD and the effect of bariatric metabolic surgery (BMS) on improving OSA and NAFLD over time.

RESULTS

Compared to previous SRs published in 2013, 14 new publications were added to our SR, alongside studies conducted prior to 2013. The SR ultimately included 28 studies (18 cross-sectional and 10 cohort trials). In the majority of studies, significant correlations were observed between OSA, OSA-related outcomes, and NAFLD. However, the apnea-hypopnea index (AHI) alone proved to be an inadequate predictor of NAFLD. Instead, respiratory and metabolic changes were found to alleviate oxidative stress induced by hypoxemia. Six studies involved patients who underwent BMS, with one evaluating patients before and after BMS, revealing associations between increased OSA and NAFLD improvement following BMS. Six months after surgery, 100% of patients in the mild-to-moderate OSA group were free from fatty liver, and an 89% reduction was observed in the severe OSA group.

CONCLUSION

For the first time, BMS has been tested in treating both OSA and NAFLD pre and postoperative with positive results. Further research, ideally with histological and functional data, is needed to confirm these findings. The SR identified 14 distinct liver outcome tests; however, high heterogeneity and incomplete data precluded a meta-analysis. It is imperative to pay greater attention to the influence of OSA-related factors and uniformity in liver outcomes testing concerning NAFLD. To accomplish this, study designs should be enhanced by incorporating more comprehensive pre- and postoperative evaluations, extending follow-up periods, and employing a more consistent methodology for liver diagnosis in patients with obesity.

Validation of a Quantification Method for Curcumin Derivatives and Their Hepatoprotective Effects on Nonalcoholic Fatty Liver Disease

Curcumin (CM), demethoxycurcumin (DMC), and bisdemethoxycurcumin (BDMC) are major curcumin derivatives found in the rhizome of turmeric (Curcuma longa L.), and have yielded impressive properties to halt various diseases. In the present study, we carried out a method validation for curcumin derivatives and analyzed the contents simultaneously using HPLC with UV detection. For validation, HPLC was used to estimate linearity, range, specificity, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ). Results showed a high linearity of the calibration curve, with a coefficient of correlation (R²) for CM, DMC, and BDMC of 0.9999, 0.9999, and 0.9997, respectively. The LOD values for CM, DMC, and BDMC were 1.16, 1.03, and 2.53 ng/μL and LOQ values were 3.50, 3.11, and 7.67 ng/μL, respectively. Moreover, to evaluate the ability of curcumin derivatives to reduce liver lipogenesis and compare curcumin derivatives’ therapeutic effects, a HepG2 cell model was established to analyze their hepatoprotective properties. Regarding the in vivo study, we investigated the effect of DMC, CM, and BDMC on nonalcoholic fatty liver disease (NAFLD) caused by a methionine choline deficient (MCD)-diet in the C57BL/6J mice model. From the in vitro and in vivo results, curcumin derivatives alleviated MCD-diet-induced lipid accumulation as well as high triglyceride (TG) and total cholesterol (TC) levels, and the protein and gene expression of the transcription factors related to liver adipogenesis were suppressed. Furthermore, in MCD-diet mice, curcumin derivatives suppressed the upregulation of toll-like receptors (TLRs) and the production of pro-inflammatory cytokines. In conclusion, our findings indicated that all of the three curcuminoids exerted a hepatoprotective effect in the HepG2 cell model and the MCD-diet-induced NAFLD model, suggesting a potential for curcuminoids derived from turmeric as novel therapeutic agents for NAFLD.

Nonalcoholic Fatty Liver Disease and Fibrosis Risk in Patients With Obstructive Sleep Apnea: A Retrospective Analysis

Objectives

Obstructive sleep apnea (OSA) and nonalcoholic fatty liver disease (NAFLD) are prevalent and commonly associated conditions. We aimed to estimate the prevalence of NAFLD and identify liver fibrosis risk using noninvasive scoring methods in a cohort of patients with OSA.

Methodology

In this retrospective study of patients with confirmed OSA, patients who underwent abdominal ultrasonography were recruited. The primary outcome was the prevalence of suspected NAFLD (steatosis on ultrasound and/or elevated alanine transaminase [ALT]). The secondary outcomes included the prevalence and predictors of liver fibrosis risk as assessed by the NAFLD fibrosis score (NFS) and fibrosis-4 (FIB-4) score.

Results

A total of 133 patients fulfilled the study inclusion criteria. The average age was 49.8±15.1 years, and 57.1% were females. The average BMI was 37.3±14.5. According to the apnea-hypopnea index (AHI) scores, 37.9%, 29.6%, and 32.6% of participants had mild (5-14), moderate (15-29), and severe (>=30) OSA, respectively. Radiologically defined NAFLD was detected in 44.4% of the participants, and elevated liver enzymes were detected in 63.9% of the patients. High NFS and FIB-4 scores were recorded in 9% and 3.8% of the patients, respectively. According to logistic regression analysis, age and BMI significantly predicted high NFS scores.

Conclusion

NAFLD appears to be common among OSA patients. Age and obesity, but not OSA severity, predicted high liver fibrosis risk as assessed by noninvasive scoring systems.

The association of nonalcoholic steatohepatitis and obstructive sleep apnea

BACKGROUND AND AIM

The association between obstructive sleep apnea (OSA) and abnormal liver enzymes has been reported in multiple studies. The existing literature regarding the relationship between OSA and nonalcoholic steatohepatitis (NASH) is conflicting. Thus we aimed to determine the relationship between OSA and NASH from a large database.

PATIENTS AND METHODS

A cross-sectional study was performed using the 2012 Nationwide Inpatient Sample. We identified adult patients (18-90 years) who had a diagnosis of OSA using the International Classification of Diseases 9th version codes. The control group was comprised of adult individuals with no discharge records of OSA. NASH diagnosis was also identified using the International Classification of Diseases 9th version codes. The association between OSA and NASH was calculated using univariable and multivariable logistic regression.

RESULTS

A total of 30 712 524 hospitalizations were included. The OSA group included 1 490 150 patients versus 29 222 374 in the control non-OSA group. The OSA group average age was 61.8±0.07 years (44.2% females) compared with 57.0±0.11 years (60.1% females) in the non-OSA group. NASH prevalence was significantly higher in the OSA group compared with the non-OSA group [2% (95% confidence interval (CI): 1.9, 2.1) vs. 0.65% (95% CI: 0.63, 0.66), P<0.001]. After adjusting for obesity, diabetes, hypertension, dyslipidemia, the metabolic syndrome and Charlson comorbidity index, OSA patients were three times more likely to have NASH [adjusted odds ratio: 3.1 (95% CI: 3.0-3.3), P<0.001].

CONCLUSION

Patients with OSA are three times more likely to have NASH compared with patients without OSA after controlling for other confounders. These data indicate that OSA should be considered as an independent risk factor for developing NASH.

The impact of obstructive sleep apnea on nonalcoholic fatty liver disease in patients with severe obesity

OBJECTIVE

Obstructive sleep apnea (OSA) is common among candidates for bariatric surgery. OSA and its associated intermittent hypoxia have been implicated in the pathogenesis of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis. A large cohort of bariatric surgery patients was studied in an effort to explore the relationship between OSA severity, hypoxia, metabolic syndrome, and the severity of NAFLD.

METHODS

Bariatric surgery candidates who underwent both polysomnography and liver biopsy were studied. The severity of OSA as determined by the apnea-hypopnea index (AHI) and parameters of hypoxia was studied in relation to extent of abnormalities of liver histology as measured by the presence of hepatic steatosis, inflammation, and fibrosis.

RESULTS

The study cohort included 362 patients with a mean age of 46.2 years and BMI of 49.9 kg/m(2) . On the basis of AHI, 26% of the cohort had no OSA, 32% mild OSA, 22% moderate OSA, and 20% severe OSA. For the study subjects without metabolic syndrome, positive correlations were found between OSA severity, as measured by AHI, and parameters of hypoxia, with the severity of NAFLD.

CONCLUSIONS

OSA severity and its accompanying hypoxia are associated with the severity of NAFLD.

Elevated Serum Liver Enzymes in Patients with Obstructive Sleep Apnea-hypopnea Syndrome

BACKGROUND

Obstructive sleep apnea-hypopnea syndrome (OSAS) is associated with elevated liver enzymes and fatty liver. The purpose of this study was to measure serum liver enzyme levels in patients evaluated by polysomnography (PSG) and the factors associated with liver injury in OSAS patients.

METHODS

All patients referred to PSG for evaluation of sleep apnea symptoms between June 2011 and November 2014 were included in this study. Demographic data and PSG parameters were recorded. Serum alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyl transferase levels were systematically measured. OSAS patients were divided into mild, moderate, and severe groups according to the apnea-hypopnea index (AHI) values of 5-14 events/h, 15-29 events/h, and ≥30 events/h.

RESULTS

A total of 540 patients were enrolled in this study; among these patients, 386 were male. Elevated liver enzymes were present in 42.3% of OSAS patients (32.4% in mild/moderate group; 51.0% in severe group) and 28.1% patients without OSAS. Patients with OSAS had higher body mass index (BMI) (P < 0.01). In the bivariate correlation, the liver enzymes level was negatively correlated with age and the lowest arterial oxygen saturation (SaO 2 ), and was positively correlated with BMI, oxygen desaturation index, percent of total time with oxygen saturation level <90% (TS90%), AHI, total cholesterol (TC), and triglyceride (TG). In logistic regression analysis, Age, BMI, TS90%, TC, and TG were included in the regression equation.

CONCLUSIONS

Our data suggest that OSAS is a risk factor for elevated liver enzymes. The severity of OSAS is correlated with liver enzyme levels; we hypothesize that hypoxia is one of main causes of liver damage in patients with OSAS.

Composite prognostic models across the non-alcoholic fatty liver disease spectrum: Clinical application in developing countries

Heterogeneity in clinical presentation, histological severity, prognosis and therapeutic outcomes characteristic of non-alcoholic fatty liver disease (NAFLD) necessitates the development of scientifically sound classification schemes to assist clinicians in stratifying patients into meaningful prognostic subgroups. The need for replacement of invasive liver biopsies as the standard method whereby NAFLD is diagnosed, graded and staged with biomarkers of histological severity injury led to the development of composite prognostic models as potentially viable surrogate alternatives. In the present article, we review existing scoring systems used to (1) confirm the presence of undiagnosed hepatosteatosis; (2) distinguish between simple steatosis and NASH; and (3) predict advanced hepatic fibrosis, with particular emphasis on the role of NAFLD as an independent cardio-metabolic risk factor. In addition, the incorporation of functional genomic markers and application of emerging imaging technologies are discussed as a means to improve the diagnostic accuracy and predictive performance of promising composite models found to be most appropriate for widespread clinical adoption.

Obstructive sleep apnea is associated with fatty liver and abnormal liver enzymes: a meta-analysis

BACKGROUND

Obstructive sleep apnea (OSA) is associated with the cluster of clinical conditions that comprise the metabolic syndrome, including nonalcoholic fatty liver disease (NAFLD). Our primary purpose was to estimate the effect of OSA on serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Our secondary purpose was to investigate the potential influence of OSA on histological severity of NAFLD to explore whether chronic intermittent hypoxia is associated with inflammation and fibrosis.

METHODS

Our literature search identified 11 studies, from which we extracted information about numbers of control subjects and OSA patients, and ALT, AST, and NAFLD.

RESULTS

From a total of 668 OSA patients and 404 controls, we found that the standardized difference in mean values of ALT and AST levels in patients with OSA was significantly different from that in the controls. Meta-regression showed that the association was independent of body mass index and type 2 diabetes. Fatty liver was associated with OSA in five studies with 400 subjects. OSA was significantly associated with liver fibrosis in 208 subjects, but not with lobular inflammation.

CONCLUSIONS

Routine assessment of liver enzymes and liver damage should be implemented in OSA patients because they have an increase of 13.3% of ALT and 4.4% of AST levels, and a 2.6-fold higher risk of liver fibrosis when they have NAFLD, which is 2.6 times more frequent in OSA patients.

Obstructive sleep apnea is associated with fatty liver and abnormal liver enzymes: a meta-analysis

BACKGROUND

Obstructive sleep apnea (OSA) is associated with the cluster of clinical conditions that comprise the metabolic syndrome, including nonalcoholic fatty liver disease (NAFLD). Our primary purpose was to estimate the effect of OSA on serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Our secondary purpose was to investigate the potential influence of OSA on histological severity of NAFLD to explore whether chronic intermittent hypoxia is associated with inflammation and fibrosis.

METHODS

Our literature search identified 11 studies, from which we extracted information about numbers of control subjects and OSA patients, and ALT, AST, and NAFLD.

RESULTS

From a total of 668 OSA patients and 404 controls, we found that the standardized difference in mean values of ALT and AST levels in patients with OSA was significantly different from that in the controls. Meta-regression showed that the association was independent of body mass index and type 2 diabetes. Fatty liver was associated with OSA in five studies with 400 subjects. OSA was significantly associated with liver fibrosis in 208 subjects, but not with lobular inflammation.

CONCLUSIONS

Routine assessment of liver enzymes and liver damage should be implemented in OSA patients because they have an increase of 13.3% of ALT and 4.4% of AST levels, and a 2.6-fold higher risk of liver fibrosis when they have NAFLD, which is 2.6 times more frequent in OSA patients.