Nonalcoholic fatty liver disease should be considered for treatment allocation in standard management algorithms for type 2 diabetes

The gut-liver axis: emerging mechanisms and therapeutic approaches for nonalcoholic fatty liver disease and type 2 diabetes mellitus

Nonalcoholic fatty liver disease (NAFLD), more appropriately known as metabolic (dysfunction) associated fatty liver disease (MAFLD), a prevalent condition in type 2 diabetes mellitus (T2DM) patients, is a complex condition involving hepatic lipid accumulation, inflammation, and liver fibrosis. The gut-liver axis is closely linked to metabolic dysfunction, insulin resistance, inflammation, and oxidative stress that are leading to the cooccurrence of MAFLD and T2DM cardiovascular diseases (CVDs). The purpose of this review is to raise awareness about the role of the gut-liver axis in the progression of MAFLD, T2DM and CVDs with a critical analysis of available treatment options for T2DM and MAFLD and their impact on cardiovascular health. This study analysed over 100 articles on this topic, using online searches and predefined keywords, to understand and summarise published research. Numerous studies have shown a strong correlation between gut dysfunction, particularly the gut microbiota and its metabolites, and the occurrence and progression of MAFLD and type 2 diabetes mellitus (T2DM). Herein, this article also examines the impact of the gut-liver axis on MAFLD, T2DM, and related complications, focusing on the role of gut microbiota dysbiosis in insulin resistance, T2DM and obesity-related cardiovascular complications. The study suggests potential treatment targets for MAFLD linked to T2DM, focusing on cardiovascular outcomes and the molecular mechanism of the gut-liver axis, as gut microbiota dysbiosis contributes to obesity-related metabolic abnormalities.

Prevalence and risk factors of MAFLD and its metabolic comorbidities in community-based adults in China: A cross-sectional study

AIMS

There is a growing interest in the co-management of metabolic dysfunction-associated fatty liver disease (MAFLD) and its metabolic comorbidities. However, there is insufficient epidemiological data regarding MAFLD and its metabolic comorbidities in China. This study aims to investigate the prevalence and risk factors of MAFLD and its metabolic comorbidities.

METHODS

9171 participants were recruited in this cross-sectional study, utilizing a multistage, stratified sampling method. All participants underwent a comprehensive assessment. The diagnosis of MAFLD was based on vibration-controlled transient elastography (VCTE). The prevalence of MAFLD and its metabolic comorbidities was calculated. Binary and ordinary logistic regressions were conducted.

RESULTS

The overall weighted prevalence of MAFLD was 21.18%. Of the 2081 adults with MAFLD, 1866 (89.67%) had more than one metabolic comorbidity, and only 215 (10.33%) did not have comorbidity. Among the population with MAFLD, the prevalence of dyslipidemia, hypertension, hyperuricemia, and diabetes was 67.47%, 43.73%, 39.10%, and 33.88%, respectively. Advanced age, male gender, overweight/obesity, excessive alcohol consumption, and elevated HOMA-IR levels were positively correlated with the number of MAFLD-related metabolic comorbidities.

CONCLUSIONS

A significant proportion of individuals diagnosed with MAFLD presented with metabolic comorbidities. Therefore, engaging in the co-management of MAFLD and its metabolic comorbidities is imperative.

Association between Dietary Pattern, Nutritional Status, Metabolic Factors, and Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) can be harmful to the body to varying degrees, and over a prolonged period, patients may develop steatotic cirrhosis or even develop liver cancer based on cirrhosis. Moreover, its harms are related to its severity. Patients with severe steatosis develop hepatocyte destruction, transaminase abnormalities, and long-term progression to steatotic cirrhosis, or even liver cancer, which should be treated aggressively. In order to provide theoretical basis for the prevention and early intervention of NAFLD, we analysis the relationship between nonalcoholic fatty liver disease(NAFLD) and dietary pattern, nutritional status, metabolic factor A total of 517 participants (200 males and 317 females) recruited in this study were gained from the health check center of The Ningbo Seventh Hospital, Ningbo, China, from September 2018 to August 2019. Patients diagnosed with NAFLD were selected as the study subjects. The data on the dietary pattern, nutritional status, and metabolic factors were collected for further analysis. A total of 517 eligible participants (317 females and 200 males) were involved in this study, with a mean age of 54.7 ± 16.7 years. Dessert and fruit diet, healthy dietary pattern, animal food dietary pattern, high salt diet mode, triglyceride, uric acid, adiponectin, and waist-hip ratio were significantly different between the two groups (P < 0.05). Dietary patterns, nutritional status, metabolic factors, and NAFLD are correlated. Furthermore, applying this correlation law can better manage NAFLD patients.

Non-alcoholic fatty liver disease-related fibrosis and sarcopenia: An altered liver-muscle crosstalk leading to increased mortality risk

In the last few decades, the loss of skeletal muscle mass and function, known as sarcopenia, has significantly increased in prevalence, becoming a major global public health concern. On the other hand, the prevalence of non-alcoholic fatty liver disease (NAFLD) has also reached pandemic proportions, constituting the leading cause of hepatic fibrosis worldwide. Remarkably, while sarcopenia and NAFLD-related fibrosis are independently associated with all-cause mortality, the combination of both conditions entails a greater risk for all-cause and cardiac-specific mortality. Interestingly, both sarcopenia and NAFLD-related fibrosis share common pathophysiological pathways, including insulin resistance, chronic inflammation, hyperammonemia, alterations in the regulation of myokines, sex hormones and growth hormone/insulin-like growth factor-1 signaling, which may explain reciprocal connections between these two disorders. Additional contributing factors, such as the gut microbiome, may also play a role in this relationship. In skeletal muscle, phosphatidylinositol 3-kinase/Akt and myostatin signaling are the central anabolic and catabolic pathways, respectively, and the imbalance between them can lead to muscle wasting in patients with NAFLD-related fibrosis. In this review, we summarize the bidirectional influence between NAFLD-related fibrosis and sarcopenia, highlighting the main potential mechanisms involved in this complex crosstalk, and we discuss the synergistic effects of both conditions in overall and cardiovascular mortality.

Role of diabetologists in the management of nonalcoholic fatty liver disease: Primary prevention and screening/management of fibrosis and cirrhosis

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease (NAFLD) is a common condition, especially among individuals with type 2 diabetes (T2D). Presence of T2D increases the risk of progression of simple steatosis to more severe liver conditions, such as nonalcoholic steatohepatitis (NASH) and fibrosis (NASH-fibrosis). Since majority of patients with T2D are managed by diabetologists (including physicians and endocrinologists), their roles in the management of coexisting NAFLD are not well defined, partly due to lack of unambiguous guidelines.

METHODS

A literature search was performed with Medline (PubMed), Scopus and Google Scholar electronic databases till January 2022, using relevant keywords (nonalcoholic fatty liver disease and diabetologist; screening of NASH; management of NASH) to extract relevant studies describing prevention and screening of NAFLD/NASH, especially in people with T2D.

RESULTS

Diabetologists have two main roles for the management of patients with T2D and coexisting NAFLD. The most important role is to prevent the development of NASH-fibrosis in patients with simple steatosis (primary prevention). This can be achieved by reinforcing the importance of lifestyle measures, and by early use of glucose-lowering agents with beneficial effects on the liver. The second important role of diabetologists is to screen all patients with T2D for liver fibrosis and compensated cirrhosis, and provide appropriate referral for timely management of complications (secondary prevention).

CONCLUSION

Diabetologists can play a central role in mitigating the epidemic of NAFLD in individuals with T2D. However, diabetologists need to be aware about their roles in NASH-fibrosis prevention and screening. Furthermore, longitudinal studies should explore the role of newer glucose-lowering drugs in the primary prevention of NASH-fibrosis in individuals with coexisting T2D and simple steatosis.

Low skeletal muscle mass is associated with liver fibrosis in individuals with type 2 diabetes and nonalcoholic fatty liver disease

BACKGROUND AND AIM

Type 2 diabetes (T2D) and low skeletal muscle mass (SMM) are associated with increased risk of nonalcoholic fatty liver disease (NAFLD). However, data regarding the association between low SMM and NAFLD-related liver fibrosis in individuals with T2D are scarce. Therefore, we aimed to investigate the association between low SMM and liver fibrosis in individuals with T2D and NAFLD.

METHODS

Controlled attenuation parameter (CAP) of ≥ 248 dB/m was taken as cutoff suggesting NAFLD. Clinically relevant liver fibrosis and advanced liver fibrosis were defined as liver stiffness measurement (LSM) by transient elastography (TE) of ≥ 8.0 and ≥ 9.6 kPa, respectively. SMM was measured using dual energy X-ray absorptiometry (DEXA). Low SMM was defined as appendicular SMM index of < 7.0 kg/m² for men and < 5.4 kg/m² for women.

RESULTS

Of the 487 consecutive patients with T2D, 366 (75.1%) had NAFLD. Among individuals with NAFLD, 118 (32.2%) and 64 (17.5%) had clinically relevant liver fibrosis and advanced liver fibrosis, respectively. Low SMM was diagnosed in 78 (21.3%) individuals with NAFLD. Patients with low SMM were older (56.1 vs 52.8 years) and had longer duration of diabetes (10.3 vs 8.1 years). Low SMM was an independent risk factor associated with clinically relevant liver fibrosis (P = 0.002) and advanced liver fibrosis (P ≤ 0.0001). Associations between low SMM and clinically relevant- and advanced liver fibrosis were maintained even after sequential adjustment for confounding variables through the multivariate regression analysis.

CONCLUSIONS

Low SMM is independently associated with liver fibrosis in individuals with T2D and NAFLD.

Drosophila melanogaster: A Powerful Tiny Animal Model for the Study of Metabolic Hepatic Diseases

Animal experimentation is limited by unethical procedures, time-consuming protocols, and high cost. Thus, the development of innovative approaches for disease treatment based on alternative models in a fast, safe, and economic manner is an important, yet challenging goal. In this paradigm, the fruit-fly Drosophila melanogaster has become a powerful model for biomedical research, considering its short life cycle and low-cost maintenance. In addition, biological processes are conserved and homologs of ∼75% of human disease-related genes are found in the fruit-fly. Therefore, this model has been used in innovative approaches to evaluate and validate the functional activities of candidate molecules identified via in vitro large-scale analyses, as putative agents to treat or reverse pathological conditions. In this context, Drosophila offers a powerful alternative to investigate the molecular aspects of liver diseases, since no effective therapies are available for those pathologies. Non-alcoholic fatty liver disease is the most common form of chronic hepatic dysfunctions, which may progress to the development of chronic hepatitis and ultimately to cirrhosis, thereby increasing the risk for hepatocellular carcinoma (HCC). This deleterious situation reinforces the use of the Drosophila model to accelerate functional research aimed at deciphering the mechanisms that sustain the disease. In this short review, we illustrate the relevance of using the fruit-fly to address aspects of liver pathologies to contribute to the biomedical area.

Retrospective analysis (2009-2017) of factors associated with progression and regression of non-alcoholic fatty liver disease (Hepatic steatosis) in patients with type 2 diabetes seen at a tertiary diabetes centre in Southern India

AIM

To identify the profiles and factors associated with progression/regression of ultrasound-derived hepatic steatosis with type 2 diabetes mellitus seen at a tertiary diabetes center in southern India.

METHODS

Participants were individuals with type 2 diabetes mellitus with at least two consecutive ultrasound measurements available. Hepatic steatosis was assessed using high-resolution B-mode ultrasonography. Admittedly ultrasonography has lower sensitivity and specificity, however, it is the only modality available in a routine clinical setting to screen for hepatic steatosis. Progression or regression of hepatic steatosis was assessed after a mean follow-up of 3.0 ± 2.1 years and correlated with clinical and biochemical parameters.

RESULTS

A total of 1835 participants with type 2 diabetes mellitus were studied, of whom 88.6% had some form of hepatic steatosis at baseline which included mild steatosis (grade 1) in 982 (53.5%), moderate steatosis (grade 2) in 628 (34.2%) and severe steatosis (grade 3) in 15 (0.8%). Hepatic steatosis progression, regression or no change in grade of hepatic steatosis were seen in 21.5%, 26.6% and 51.9% of participants. Increase in body weight, body mass index, glycated haemoglobin, serum triglycerides and gamma glutamyl transferase were the factors associated with progression of hepatic steatosis, whereas regression showed reduction in body weight, body mass index, fasting plasma glucose and glycated haemoglobin.

CONCLUSION

Among South Indian type 2 diabetes patients with hepatic steatosis, severity of steatosis progressed in 1/3rd while it regressed in 1/4th. These retrospective data need proper ascertainment in controlled studies.

Prevalence of clinically relevant liver fibrosis due to nonalcoholic fatty liver disease in Indian individuals with type 2 diabetes

Background and Aim

Type 2 diabetes (T2D) in associated with higher prevalence and worse outcomes of nonalcoholic fatty liver disease (NAFLD). However, data regarding the prevalence of clinically relevant liver fibrosis (CRLF) in Indian individuals with T2D are scarce. We investigated the prevalence of, and factors associated with, CRLF in Indians with T2D.

Methods

We conducted a prospective study of 601 consecutive adults with T2D. Steatosis was diagnosed using ultrasonography. Liver stiffness measurement (LSM) by transient elastography of ≥8.0 kPa was taken as cutoff suggesting CRLF. Individuals with LSM > 13.0 kPa underwent dynamic magnetic resonance imaging (MRI) of liver for detecting changes consistent with cirrhosis.

Results

The prevalence of steatosis was 84.2%. Higher body mass index (BMI, P = 0.022), alanine aminotransferase (ALT; P = 0.001), and lower high‐density lipoprotein (HDL; P = 0.002) were independent factors associated with steatosis. The prevalence of CRLF was 28.2%. Higher BMI (P = 0.001), aspartate aminotransferase (AST; P < 0.0001), gamma‐glutamyl transpeptidase (GGT; P < 0.0001), and concomitant hypertension (P = 0.03) were independent factors associated with CRLF. Elevated ALT and AST (≥40 units/L) levels were present in 70.6 and 51.6% individuals with CRLF, respectively. Thirty‐one (7.2%) individuals had LSM > 13.0 kPa. Among them, 25 individuals underwent dynamic MRI of liver, which revealed features consistent with cirrhosis in 18 patients.

Conclusion

CRLF, an established risk factor for cirrhosis and overall mortality, affects at least one out of four (25%) Indians with T2D. These results support screening of all patients with T2D and NAFLD for liver fibrosis.