Osteokines in Nonalcoholic Fatty Liver Disease.

PURPOSE OF REVIEW: To critically summarize evidence on the potential role of osteokines in the pathogenesis and progression of nonalcoholic fatty liver disease (NAFLD). RECENT FINDINGS: There are emerging data supporting that certain osteokines, which are specific bone-derived proteins, may beneficially or adversely affect hepatic metabolism, and their alterations in the setting of osteoporosis or other bone metabolic diseases may possibly contribute to the development and progression of NAFLD. There is evidence showing a potential bidirectional association between NAFLD and bone metabolism, which may imply the existence of a liver-bone axis. In this regard, osteocalcin, osteoprotegerin, bone morphogenic protein 4 (BMP4) and BMP6 appear to have a positive impact on the liver, thus possibly alleviating NAFLD, whereas osteopontin, receptor activator of nuclear factor kappa Β ligand (RANKL), sclerostin, periostin, BMP8B, and fibroblast growth factor 23 (FGF23) appear to have a negative impact on the liver, thus possibly exacerbating NAFLD. The potential implication of osteokines in NAFLD warrants further animal and clinical research in the field that may possibly result in novel therapeutic targets for NAFLD in the future.

The effect of dulaglutide on glycated hemoglobin is associated with PNPLA3 Ι148Μ gene polymorphism in patients with type 2 diabetes mellitus.

PURPOSE: The evaluation of the effect of dulaglutide on glycated hemoglobin (HbA1c) and non-invasive indices of hepatic steatosis among different genotypes of the PNPLA3 I148M (rs738409) and CETP Taq1B (rs708272) polymorphisms in patients with type 2 diabetes mellitus (T2DM) and non-alcoholic fatty liver disease (NAFLD). METHODS: Relevant data from patients with inadequately controlled T2DM, also displaying NAFLD, administered 1.5 mg dulaglutide weekly for 6 months were retrospectively retrieved. The non-invasive indices, fatty liver index (FLI) and hepatic steatosis index (HSI), were calculated. Genotyping for rs738409 and rs708272 were performed with polymerase chain reaction. RESULTS: Data from 80 patients (39 females), aged 64.4 ± 9.5 years and displaying a baseline BMI of 34.5 ± 5.8 kg/m2, were retrieved at baseline and after 6 months (endpoint) of dulaglutide treatment. Glycated hemoglobin (HbA1c; -0.72 ± 1.10%; p < 0.001), FLI (-5.8 ± 9.8; p < 0.001) and HSI (-1.18 ± 3.51; p = 0.004) significantly decreased after treatment. Lipid profile and liver function tests also improved after treatment. Overall, homozygotes for the reference rs738409 allele (CC) displayed a 2.4-fold decrease (p = 0.002) and heterozygotes (CG) an 1.6-fold decrease (p = 0.013) compared to GG homozygotes after treatment, but the effect was largely limited to female patients. No similar effect was observed in FLI, HSI and other relevant parameters. No association was observed between rs708272 and any of the parameters studied. CONCLUSIONS: rs738409, but not rs708272, was associated with the effect of dulaglutide on HbA1c, but not on presumed hepatic steatosis or other relevant parameters. Sex-specific effects were also noticed.

Effects of Combined Low-Dose Spironolactone Plus Vitamin E versus Vitamin E Monotherapy on Lipidomic Profile in Non-Alcoholic Fatty Liver Disease: A Post Hoc Analysis of a Randomized Controlled Trial.

Background/Objectives: Lipid dysmetabolism seems to contribute to the development and progression of nonalcoholic fatty liver disease (NAFLD). Our aim was to compare serum lipidomic profile between patients with NAFLD having received monotherapy with vitamin E (400 IU/d) and those having received combination therapy with vitamin E (400 IU/d) and low-dose spironolactone (25 mg/d) for 52 weeks. Methods: This was a post hoc study of a randomized controlled trial (NCT01147523). Serum lipidomic analysis was performed in vitamin E monotherapy group (n = 15) and spironolactone plus vitamin E combination therapy group (n = 12). We employed an untargeted liquid chromatography-mass spectrometry lipid profiling approach in positive and negative ionization mode. Results: Univariate analysis revealed 36 lipid molecules statistically different between groups in positive mode and seven molecules in negative mode. Multivariate analysis in negative mode identified six lipid molecules that remained robustly different between groups. After adjustment for potential confounders, including gender, omega-3 supplementation, leptin concentration and homeostasis model assessment-insulin resistance (HOMA-IR), four lipid molecules remained significant between groups: FA 20:5, SM 34:2;O2, SM 42:3;O2 and CE 22:6, all being higher in the combination treatment group. Conclusions: The combination of spironolactone with vitamin E led to higher circulating levels of four lipid molecules than vitamin E monotherapy, after adjustment for potential confounders. Owing to very limited relevant data, we could not support that these changes in lipid molecules may be beneficial or not for the progression of NAFLD. Thus, mechanistic studies are warranted to clarify the potential clinical significance of these findings.

The comparative effect of teriparatide and denosumab on activins, follistatins, and inhibins in women with postmenopausal osteoporosis.

The activins-follistatins-inhibins (AFI) hormonal system affects bone metabolism. Treatments that alter bone metabolism may also alter the AFI molecules. In this non-randomized, open-label, head-to-head comparative study, circulating levels of the AFI system were evaluated in postmenopausal women with osteoporosis treated for 12 mo with either teriparatide (n = 23) or denosumab (n = 22). Τeriparatide treatment increased activin B (P=.01) and activin AB (P=.004) and the ratios activin A/follistatin (P=.006), activin B/follistatin (P=.007), activin AB/follistatin (P<.001), and activin AB/ follistatin-like 3 (FSTL3) (P=.034). The significant P for trend in group × time interactions of activins B and AB and of the ratio activin AB/FSTL3 remained robust after adjustment for BMI and LS BMD but it was lost for activin B after adjustment for previous antiresorptive treatment. The effect of teriparatide on BMD was attenuated when it was adjusted for baseline activins levels or their 12-mo changes. No changes were observed after denosumab treatment. In conclusion, activins B and AB, as well as the ratios of all activins to follistatin and of activin AB to FSTL3 increased with teriparatide treatment, possibly in a compensatory manner. Future studies are needed to study the potentially important role activins may play in bone biology and any associations with the effect of teriparatide on BMD. Clinical Trials identifier: NCT04206618. ClinicalTrials.gov  https://clinicaltrials.gov/search?term=NCT04206618.

Bone and the muscle comprise 2 tissues that are considered to interact with each other, not only through mechanical but also through endocrine signals. Several components of the activins­follistatins­inhibins (AFI) hormonal system have been shown to be secreted by the muscle and affect the bone possibly contributing to this interplay. We have previously investigated the levels of the AFI molecules in case­control studies and reported differences between osteoporotic vs osteopenic vs postmenopausal and premenopausal women with normal BMD. In this 12-mo, non-randomized, open-labeled, head-to-head comparative study, we prospectively compared the effect of antiosteoporotic agents with opposite effect on bone metabolism, that is, teriparatide vs denosumab, on the circulating concentrations of all known molecules of the AFI system in postmenopausal women with osteoporosis. We observed increases of activins after teriparatide treatment, but no effect after denosumab treatment on any of the AFI molecules studied. Since activins are mainly acting in an autocrine way and since activin B and AB have not been extensively studied, further studies in the basic research, preclinical, and clinical research fields are required to expand these observations and fully elucidate physiology and any therapeutic potential.

Animal studies of sodium-glucose co-transporter 2 inhibitors in nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is considered one of the most common chronic liver diseases. Modern lifestyle, characterized by increasing rates of obesity and type 2 diabetes mellitus (T2DM), has led to a "pandemic" of NAFLD that imposes a personal health and socioeconomic burden. Apart from overnutrition and insulin resistance, various metabolic aberrations, gut microbiota and genetic predispositions are involved in the pathogenesis of the disease. The multifactorial nature of NAFLD's pathogenesis makes the development of pharmacological therapies for patients with this disease challenging. Sodium-glucose co-transporter 2 inhibitors (SGLT-2i) are antidiabetic agents that reduce blood glucose mainly by increasing its renal excretion. As T2DM is one of the major contributors to NAFLD, SGLT-2i have emerged as promising agents for the management of NAFLD. In this review, we summarize the main animal studies on SGLT-2i in models of NAFLD.

Hypogonadism and nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD), recently proposed to be renamed to metabolic dysfunction-associated steatotic liver disease (MASLD), is a major global public health concern, affecting approximately 25-30% of the adult population and possibly leading to cirrhosis, hepatocellular carcinoma, and liver transplantation. The liver is involved in the actions of sex steroids via their hepatic metabolism and production of the sex hormone-binding globulin (SHBG). Liver disease, including NAFLD, is associated with reproductive dysfunction in men and women, and the prevalence of NAFLD in patients with hypogonadism is considerable. A wide spectrum of possible pathophysiological mechanisms linking NAFLD and male/female hypogonadism has been investigated. As therapies targeting NAFLD may impact hypogonadism in men and women, and vice versa, treatments of the latter may affect NAFLD, and an insight into their pathophysiological pathways is imperative. This paper aims to elucidate the complex association between NAFLD and hypogonadism in men and women and discuss the therapeutic options and their impact on both conditions.

Association between primary hypothyroidism and metabolic dysfunction-associated steatotic liver disease: an updated meta-analysis.

OBJECTIVE: Epidemiological studies have reported an association between primary hypothyroidism and metabolic dysfunction-associated steatotic liver disease (MASLD). However, the magnitude of the risk and whether this risk changes with the severity of MASLD remains uncertain. We performed a meta-analysis of observational studies to quantify the magnitude of the association between primary hypothyroidism and the risk of MASLD. DESIGN: We systematically searched PubMed, Scopus and Web of Science from database inception to 31 January 2024, using predefined keywords to identify observational studies in which MASLD was diagnosed by liver biopsy, imaging or International Classification of Diseases codes. A meta-analysis was performed using random-effects modelling. RESULTS: We identified 24 cross-sectional and 4 longitudinal studies with aggregate data on ~76.5 million individuals. Primary hypothyroidism (defined as levothyroxine replacement treatment, subclinical hypothyroidism or overt hypothyroidism) was associated with an increased risk of prevalent MASLD (n=24 studies; random-effects OR 1.43, 95% CI 1.23 to 1.66; I2=89%). Hypothyroidism was also associated with a substantially higher risk of metabolic dysfunction-associated steatohepatitis or advanced fibrosis (n=5 studies; random-effects OR 2.84, 95% CI 2.07 to 3.90; I2=0%). Meta-analysis of data from four longitudinal studies showed that there was a marginally non-significant association between hypothyroidism and risk of developing MASLD over a median 4.5-year follow-up (random-effects HR 1.39, 95% CI 0.98 to 1.97; I2=85%). Sensitivity analyses did not modify these findings. The funnel plot did not reveal any significant publication bias. CONCLUSION: This large and updated meta-analysis provides evidence that primary hypothyroidism is significantly associated with both an increased presence of and histological severity of MASLD.

Menopause and metabolic dysfunction-associated steatotic liver disease.

Nonalcoholic fatty liver disease, recently proposed to be renamed metabolic dysfunction-associated steatotic liver disease, is a highly prevalent disease (25-30 % of the global general population) whose prevalence increases after menopause. Apart from the rates of simple steatosis, the severity of the disease (e.g., hepatic fibrosis) increases after menopause. Menopause is associated with higher abdominal adiposity and dysmetabolism of carbohydrate and lipid metabolism, which may contribute to the development and severity of metabolic dysfunction-associated steatotic liver disease and the higher cardiovascular risk observed after menopause. The association between menopause and metabolic dysfunction-associated steatotic liver disease renders menopausal hormone therapy an appealing way to reverse hepatic disease in parallel with the benefits of menopausal hormone therapy in other tissues. In this regard, most animal studies have shown a beneficial effect of estrogens on metabolic dysfunction-associated steatotic liver disease. Still, clinical studies are few, and their data are conflicting. The effect of menopausal hormone therapy on metabolic dysfunction-associated steatotic liver disease may be distinct among estrogen monotherapies and the combinations of estrogens and progestogens. It may also depend on the type of progestogen and the route of administration. However, more studies specifically designed for these aims are needed to draw secure conclusions. This review summarizes the data related to the association between menopause and metabolic dysfunction-associated steatotic liver disease, as well as between menopausal hormone therapy and metabolic dysfunction-associated steatotic liver disease, with a special focus on clinical studies.

Circulating Ferritin in Patients with Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-analysis.

Objectives: To synthesize data on circulating ferritin between patients with histologically confirmed nonalcoholic fatty liver disease (NAFLD) and non-NAFLD controls. Methods: A systematic literature search was conducted in PubMed, Scopus, and the Cochrane Library. Thirty-one studies comprising data on 5631 individuals (2929 biopsy-proven NAFLD patients and 2702 controls) were included in the meta-analysis. Results: Higher circulating ferritin levels were observed in NAFLD patients than in controls [standardized mean difference (SMD) 1.14; 95% confidence interval (95% CI) 0.73-1.55], in patients with simple nonalcoholic fatty liver (NAFL) than in controls (SMD 0.57; 95% CI 0.34-0.80), in patients with nonalcoholic steatohepatitis (NASH) than in controls (SMD 0.95; 95% CI 0.69-1.22), and in NASH than in NAFL patients (SMD 0.62; 95% CI 0.25-0.99). There was moderate-to-high heterogeneity among studies in the above pairs of comparisons (I2 = 68-97%); no risk of publication bias was observed by Egger's test (P = 0.81, P = 0.72, P = 0.59, P = 0.42, respectively). The heterogeneity was reduced in the subgroup of biopsy-proven controls in all pairs of comparisons (I2 = 0-65%). The heterogeneity was also reduced after excluding studies with the Newcastle-Ottawa Scale (NOS) score <7 (n = 10) for the comparison of NAFLD patients vs. controls (I2 = 54%, P = 0.02). The meta-regression analysis revealed that the male ratio was positively associated with ferritin SMD in the comparison between NAFLD patients and controls and accounted for 32.7% (P = 0.002) of the heterogeneity in this pair of comparison. Conclusions: Circulating ferritin was higher in NAFLD (or NAFL or NASH) patients compared with controls. Higher levels of circulating ferritin were also associated with the severity of the disease, which, however, should be cautiously interpreted.PROSPERO registration ID: CRD42022354025.

Role of Glucocorticoids in Metabolic Dysfunction-Associated Steatotic Liver Disease.

PURPOSE OF THE REVIEW: To summarize published data on the association between glucocorticoids and metabolic dysfunction-associated steatotic liver disease (MASLD), focusing on the possible pathophysiological links and related treatment considerations. RECENT FINDINGS: Glucocorticoids, commonly used for managing many inflammatory and autoimmune diseases, may contribute to the development and progression of MASLD. Glucocorticoids may induce hyperglycemia and hyperinsulinemia, thus increasing systemic and hepatic insulin resistance, a hallmark of MASLD pathogenesis. Furthermore, glucocorticoids increase adipose tissue lipolysis, and hepatic de novo lipogenesis and decrease hepatic fatty acid ß-oxidation, thus promoting MASLD development. Preclinical evidence also suggests that glucocorticoids may adversely affect hepatic inflammation and fibrosis. 11beta-hydroxysteroid dehydrogenase type 1 (11ß-HSD1) and 5α-reductase are implicated in the link between glucocorticoids and MASLD, the former enzyme increasing and the latter reducing the glucocorticoid action on the liver. Treatment considerations exist due to the pathogenic link between glucocorticoids and MASLD. Since iatrogenic hypercortisolism is common, glucocorticoids should be used at the minimum daily dose to control the subjective disease. Furthermore, the pharmacologic inhibition of 11ß-HSD1 has provided favorable results in MASLD, both in preclinical studies and early MASH clinical trials. Glucocorticoids are closely linked to MASLD pathophysiology, with specific clinical and therapeutic implications.

Diet, exercise, and supplements: what is their role in the management of the metabolic dysfunction-associated steatotic liver disease in children?

Metabolic dysfunction-associated steatotic liver disease (MASLD), previously known as nonalcoholic fatty liver disease (NAFLD), is the main cause of chronic liver disease in children and adolescents. Indeed, epidemiological studies have shown that MASLD affects up to 40% of children with obesity. Despite the recent approval of medications that target weight loss in adolescents that could have benefits on pediatric MASLD, lifestyle interventions, such as diet and exercise, remain the mainstay of our therapeutic approach. More specifically, studies on diet alone have focused on the possible role of carbohydrate or fat restriction, albeit without a definite answer on the best approach. Weight loss after dietary intervention in children with obesity and MASLD has a beneficial effect, regardless of the diet used. In relation to the role of exercise in MASLD reversal, indirect evidence comes from studies showing that a sedentary lifestyle leading to poor fitness, and low muscle mass is associated with MASLD. However, research on the direct effect of exercise on MASLD in children is scarce. A combination of diet and exercise seems to be beneficial with several studies showing improvement in surrogate markers of MASLD, such as serum alanine aminotransferase and hepatic fat fraction, the latter evaluated with imaging studies. Several dietary supplements, such as vitamin E, probiotics, and omega-3 fatty acid supplements have also been studied in children and adolescents with MASLD, but with equivocal results. This review aims to critically present available data on the effects of lifestyle interventions, including diet, exercise, and dietary supplements, on pediatric MASLD, thus suggesting a frame for future research that could enhance our knowledge on pediatric MASLD management and optimize clinicians' approach to this vexing medical condition.

Partial validation of a six-month high-fat diet and fructose-glucose drink combination as a mouse model of nonalcoholic fatty liver disease.

PURPOSE: The need to investigate the pathogenesis and treatment of nonalcoholic fatty liver disease (NAFLD) has led to the development of multiple mouse models. The aim of this study was to validate a fast food diet (FFD) mouse model that is introduced as being close to the human disease. METHODS: Eight to nine weeks old male and female C57BL/6 J mice were randomly allocated to a FFD group or to a chow diet (CD) group. Every four weeks, mice were weighed, and blood samples were collected for the measurement of glucose, alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglycerides (TGs) and total cholesterol. After 25 weeks, mice were sacrificed, and liver tissue was histologically evaluated. RESULTS: FFD mice gained more weight (p = 0.049) and presented a higher liver-to-body weight ratio (p < 0.001) compared to CD mice. FFD group presented with greater steatosis, hepatocellular ballooning and NAFLD activity score (NAS), whereas lobular inflammation and fibrosis were not significantly different compared to CD. When stratified by sex, NAS was different between FFD and CD groups in both male and female mice. Group by time interaction was significant for weight, ALT and cholesterol, but not for glucose, AST and TGs. CONCLUSION: FFD mice presented with morphologic and biochemical features of NAFLD and with greater hepatic steatosis, hepatocellular ballooning and NAS, but not lobular inflammation and fibrosis, compared to CD mice. These results only partly validate the FFD mouse model for NAFLD, at least for a 6-month feeding period.

Animal studies on glucagon-like peptide-1 receptor agonists and related polyagonists in nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is a prevalent metabolic liver disease closely associated with the epidemics of obesity and type 2 diabetes mellitus (T2DM), but without licensed pharmacological treatment to date. As glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1RAs) are approved anti-diabetic and anti-obesity medications, they were also considered a potential therapeutic option for NAFLD. Preclinical studies suggest that GLP-1RAs have a beneficial effect on major NAFLD histological outcomes, i.e., hepatic steatosis and inflammation, through multiple intrahepatic mechanisms, including increased fatty acid ß-oxidation, activation of autophagy, suppression of inflammation, and oxidative stress. Data on hepatic fibrosis are limited or inconclusive, although some studies reported improvement in indices of fibrosis or prevention of fibrosis initiation or reduction of collagen deposition. Whether the positive impact of GLP-1RAs on hepatic histology is indirect, i.e., through their action on extrahepatic tissues, or whether their action is direct, i.e., through activating GLP-1R on the hepatocytes, is still a controversial issue. Alongside GLP-1RAs, newly emerging peptide polyagonists (i.e., synthetic molecules that combine the amino acid sequences of more than one peptide, thus having the ability to bind more than one receptor) are now being investigated in NAFLD with high expectations. This review summarizes the existing knowledge derived from animal studies on the effects of GLP-1RAs and GLP-1RA related peptide polyagonists on NAFLD in an attempt to illuminate areas of uncertainty and provide the groundwork for future animal and clinical research in the field.

Circulating leptin in patients with nonalcoholic fatty liver disease-related liver fibrosis: a systematic review and a meta-analysis.

BACKGROUND AND AIM: Clinical data on the association between leptin levels and nonalcoholic fatty liver disease (NAFLD)-related liver fibrosis are conflicting. This meta-analysis aimed to compare circulating leptin between NAFLD patients with versus without liver fibrosis or non-NAFLD controls. METHODS: A systematic search was conducted in PubMed, Scopus, and the Cochrane Library. Fifteen studies were included, reporting data from 964 individuals (422 NAFLD patients with fibrosis, 297 NAFLD patients without fibrosis, 245 no-NAFLD controls). RESULTS: Leptin standardized mean difference (SMD) was higher in NAFLD patients with fibrosis (F1-F4) than in controls (SMD: 2.27; 95% confidence interval [CI]: 0.81-3.73); however, this association did not remain robust after the exclusion of studies with morbidly obese individuals. No difference was observed in leptin SMD between NAFLD patients with fibrosis and those without fibrosis (F0), and NAFLD patients without fibrosis versus controls. Heterogeneity was high (I2: 66-98%) among studies. Meta-regression analysis revealed a positive association of leptin SMD with homeostasis model assessment-insulin resistance, when comparing NAFLD patients with fibrosis versus NAFLD patients without fibrosis (beta: 0.53; 95% CI: 0.04-1.03), and a negative association of leptin SMD with age, when comparing NAFLD patients with fibrosis versus controls (beta: -0.29; 95% CI: -0.53 to -0.05). CONCLUSION: Circulating leptin was higher in NAFLD patients with liver fibrosis than non-NAFLD controls, an association, however, attenuated after the exclusion of a study with morbidly obese individuals. Circulating leptin was not different between NAFLD patients with and without fibrosis, or NAFLD patients without fibrosis and controls.

The relationship between length of denosumab treatment for postmenopausal osteoporosis and serum TRAcP5b measured six months after the last injection.

To test the hypothesis that during treatment with denosumab osteomorphs and precursors recycle to higher number of osteoclasts with time, we measured TRAcP5b in serum taken 6 months after the last injection in postmenopausal women treated for 1-10 years. Serum TRAcP5b values were not related to time of exposure to denosumab. PURPOSE: In women with postmenopausal osteoporosis the aetiology of the observed inverse relationship between duration of denosumab (Dmab) therapy and bone loss after its discontinuation is currently unknown. In studies in mice inhibition of RANKL is associated with an increase in osteomorphs and osteoclast precursors that recycle into osteoclasts and may accumulate with time. We hypothesized that longer inhibition of RANKL by Dmab will be followed by the synchronous formation of a larger number of osteoclasts after stopping treatment. To test this hypothesis, we measured serum TRAcP5b, a marker of osteoclast numbers, in postmenopausal women treated with Dmab for different periods of time up to 10 years. METHODS: TRAcP5b, C-terminal telopeptide of type 1 collagen (CTX) and procollagen type 1 N-terminal propeptide (P1NP) were measured at 6.0 months ± 15 days after last Dmab injection in 59 women who had received Dmab for 4.0 ± 2.3 years (range 1-10 years). Of these, 38 were treatment naïve (group 1) and 21 had received other treatments prior Dmab (group 2). RESULTS: Duration of Dmab treatment was not related to serum TRAcP5b values or to TRAcP5b/CTX ratio either in the whole cohort or in each of the two groups separately. In contrast, serum TRAcP5b values were significantly correlated with serum CTX values (rs = 0.619; p < 0.001), but not with serum P1NP values or BMD at all skeletal sites. CONCLUSION: Our observations indicate that serum TRAcP5b, measured at 6 months after a Dmab injection, is not a useful early marker for time-dependent increased accumulation of osteoclasts in humans and for identification of patients at risk for a higher rebound increase in bone resorption.