Targeted Analysis of Three Hormonal Systems Identifies Molecules Associated with the Presence and Severity of NAFLD

Circulating total and H-specific GDF15 levels are elevated in subjects with MASLD but not in hyperlipidemic but otherwise metabolically healthy subjects with obesity

BACKGROUND

Growth differentiation factor 15 (GDF15) is a mitokine, the role of which, total or H-specific, in modulating energy metabolism and homeostasis in obesity-related diseases, such as metabolic dysfunction associated steatotic liver disease (MASLD), has not been fully elucidated in adult humans. We aimed to investigate the fasting and stimulated levels of GDF15, total and H-specific, glucose-dependent insulinotropic polypeptide (GIP) and C-peptide, in two physiology interventional studies: one focusing on obesity, and the other on MASLD.

METHODS

Study 1 investigated individuals with normal weight or with obesity, undergoing a 3-h mixed meal test (MMT); and study 2, examined adults with MASLD and controls undergoing a 120-min oral glucose tolerance test (OGTT). Exploratory correlations of total and H-specific GDF15 with clinical, hormonal and metabolomic/lipidomic parameters were also performed.

RESULTS

In study 1, 15 individuals were included per weight group. Fasting and postprandial total and H-specific GDF15 were similar between groups, whereas GIP was markedly higher in leaner individuals and was upregulated following a MMT. Baseline and postprandial C-peptide were markedly elevated in people with obesity compared with lean subjects. GIP was higher in leaner individuals and was upregulated after a MMT, while C-peptide and its overall AUC after a MMT was markedly elevated in people with obesity compared with lean subjects. In study 2, 27 individuals were evaluated. Fasting total GDF15 was similar, but postprandial total GDF15 levels were significantly higher in MASLD patients compared to controls. GIP and C-peptide remained unaffected. The postprandial course of GDF15 was clustered among those of triglycerides and molecules of the alanine cycle, was robustly elevated under MASLD, and constituted the most notable differentiating molecule between healthy and MASLD status. We also present robust positive correlations of the incremental area under the curve of total and H-specific GDF15 with a plethora of lipid subspecies, which remained significant after adjusting for confounders.

CONCLUSION

Serum GDF15 levels do not differ in relation to weight status in hyperlipidemic but otherwise metabolically healthy individuals. In contrast, GDF15 levels are significantly increased in MASLD patients at baseline and they remain significantly higher compared to healthy participants during OGTT, pointing to a role for GDF15 as a mitokine with important roles in the pathophysiology and possibly therapeutics of MASLD. Trial registration ClinicalTrials.gov NCT03986684, NCT04430946.

Plasma ALS and Gal-3BP differentiate early from advanced liver fibrosis in MASLD patients

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) is estimated to affect 30% of the world's population, and its prevalence is increasing in line with obesity. Liver fibrosis is closely related to mortality, making it the most important clinical parameter for MASLD. It is currently assessed by liver biopsy - an invasive procedure that has some limitations. There is thus an urgent need for a reliable non-invasive means to diagnose earlier MASLD stages.

METHODS

A discovery study was performed on 158 plasma samples from histologically-characterised MASLD patients using mass spectrometry (MS)-based quantitative proteomics. Differentially abundant proteins were selected for verification by ELISA in the same cohort. They were subsequently validated in an independent MASLD cohort (n = 200).

RESULTS

From the 72 proteins differentially abundant between patients with early (F0-2) and advanced fibrosis (F3-4), we selected Insulin-like growth factor-binding protein complex acid labile subunit (ALS) and Galectin-3-binding protein (Gal-3BP) for further study. In our validation cohort, AUROCs with 95% CIs of 0.744 [0.673 - 0.816] and 0.735 [0.661 - 0.81] were obtained for ALS and Gal-3BP, respectively. Combining ALS and Gal-3BP improved the assessment of advanced liver fibrosis, giving an AUROC of 0.796 [0.731. 0.862]. The {ALS; Gal-3BP} model surpassed classic fibrosis panels in predicting advanced liver fibrosis.

CONCLUSIONS

Further investigations with complementary cohorts will be needed to confirm the usefulness of ALS and Gal-3BP individually and in combination with other biomarkers for diagnosis of liver fibrosis. With the availability of ELISA assays, these findings could be rapidly clinically translated, providing direct benefits for patients.

IGF-1 and IGF-2 as Molecules Linked to Causes and Consequences of Obesity from Fetal Life to Adulthood: A Systematic Review

This study examines the impact of insulin-like growth factor 1 (IGF-1) and insulin-like growth factor 2 (IGF-2) on various aspects of children's health-from the realms of growth and puberty to the nuanced characteristics of metabolic syndrome, diabetes, liver pathology, carcinogenic potential, and cardiovascular disorders. A comprehensive literature review was conducted using PubMed, with a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method employing specific keywords related to child health, obesity, and insulin-like growth factors. This study reveals associations between insulin-like growth factor 1 and birth weight, early growth, and adiposity. Moreover, insulin-like growth factors play a pivotal role in regulating bone development and height during childhood, with potential implications for puberty onset. This research uncovers insulin-like growth factor 1 and insulin-like growth factor 2 as potential biomarkers and therapeutic targets for metabolic dysfunction-associated liver disease and hepatocellular carcinoma, and it also highlights the association between insulin-like growth factors (IGFs) and cancer. Additionally, this research explores the impact of insulin-like growth factors on cardiovascular health, noting their role in cardiomyocyte hypertrophy. Insulin-like growth factors play vital roles in human physiology, influencing growth and development from fetal stages to adulthood. The impact of maternal obesity on children's IGF levels is complex, influencing growth and carrying potential metabolic consequences. Imbalances in IGF levels are linked to a range of health conditions (e.g., insulin resistance, glucose intolerance, metabolic syndrome, and diabetes), prompting researchers to seek novel therapies and preventive strategies, offering challenges and opportunities in healthcare.

Insulin-like growth factor binding protein 3 promoter variant (rs2854744) is associated with nonalcoholic fatty liver disease

Objective

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease and a growing global epidemic. In NAFLD, liver fat surpasses 5% of hepatocytes without the secondary causes of lipid accumulation or excessive alcohol consumption. Given the link between NAFLD and insulin resistance, the possible association between the rs2854744 (-202 G>T) promoter polymorphism of insulin-like growth factor binding protein 3 (IGFBP3) gene and NAFLD was investigated in this study.

Materials and methods

In this genetic case-control association study, the IGFBP3 rs2854744 genotypes of 315 unrelated individuals, including 156 patients with biopsy-proven NAFLD and 159 controls, were determined using polymerase chain reaction/restriction fragment length polymorphism analyses.

Results

The "GT+TT" genotype of the IGFBP3 rs2854744 polymorphism, compared with the "GG" genotype, was associated with a 2.7-fold increased risk of NAFLD after adjustment for confounding factors (P = 0.009; odds ratio [OR] = 2.71; 95% confidence interval [CI] = 1.19-3.18). Additionally, the IGFBP3 rs2854744 "T" allele, in comparison with the "G" allele, was significantly overrepresented in NAFLD patients than the controls (P = 0.008; OR = 1.85; 95%CI = 1.23-2.94).

Conclusion

Our findings first indicated that the IGFBP3 rs2854744 "GT+TT" genotype is a marker of increased NAFLD susceptibility; however, it needs to be supported by further investigations in other populations.

Circulating hormones in biopsy-proven steatotic liver disease and steatohepatitis: A Multicenter Observational Study

BACKGROUND

The role of metabolic/inflammatory hormonal systems in metabolic dysfunction associated steatotic liver disease (MASLD) remains to be fully elucidated.

PURPOSE

To report the levels of the novel total and H-specific growth differentiation factor-15 (GDF-15) and other established hormonal systems and to describe hormonal patterns in controls and patients with MASLD and its stages.

METHODS

This is a multicenter study from two Gastroenterology-Hepatology Departments (Greece and Australia) and one Bariatric-Metabolic Surgery Department (Italy). Overall, n = 455 serum samples of patients with biopsy-proven MASLD (n = 374) and Controls (n = 81) were recruited.

RESULTS

We report for the first time that total and H-specific GDF-15 levels are higher in MASLD, at-risk metabolic dysfunction associated steatohepatitis (MASH), and severe fibrosis than in Controls. In addition, follistatin-like-3 (FSTL-3), free insulin-like growth factor-1 (IGF-1), leptin, and insulin levels were higher in MASLD patients than in Controls, while adiponectin levels were lower in MASLD subjects than in Controls. Activin-A, follistatin (FST), FSTL-3, and insulin levels significantly increased in severe fibrosis compared to no/mild fibrosis, while free IGF-1 decreased. In addition, adiponectin levels were lower in subjects without fibrosis vs. any fibrosis. Moreover, GDF-15 presented a strong positive association for the likelihood of having MASLD and at-risk MASH, while in adjusted analyses, FST and adiponectin showed inverse associations. Two different patterns of at-risk MASH were revealed through unsupervised analysis (total variation explained=54%). The most frequent pattern met in our sample (34.3%) was characterized by higher levels of total and H-specific GDF-15, follistatins, and activins, as well as low adiponectin levels. The second pattern revealed was characterized by high levels of free IGF-1, insulin, and leptin, with low levels of activin-A and adiponectin. Similar patterns were also generated in the case of overall MASLD.

CONCLUSIONS

Total and H-specific GDF-15 levels increase as MASLD severity progresses. FSTL-3, free IGF-1, leptin, and insulin are also higher, whereas adiponectin and activin-A levels are lower in the MASLD group than in Controls. Hormonal systems, including GDF-15, may not only be involved in the pathophysiology but could also prove useful for the diagnostic workup of MASLD and its stages and may potentially be of therapeutic value.

FSTL3 partially mediates the association of increased nonalcoholic fatty liver disease fibrosis risk with acute myocardial infarction in patients with type 2 diabetes mellitus

BACKGROUND

The study aimed to investigate an association of increased liver fibrosis with acute myocardial infarction (AMI), and to investigate the mediating effect of serum follistatin-like protein 3 (FSTL3) on the association in patients with type 2 diabetes mellitus (T2DM).

METHOD

A total of 1424 participants were included in this study, and were firstly divided into two groups: 429 T2DM patients and 995 T2DM patients with NAFLD to assess the association of NAFLD and AMI. Then 995 T2DM co-existent NAFLD patients were categorized by NAFLD fibrosis risk to explore the association between NAFLD fibrosis risk and AMI. Immunohistochemistry staining and semi-quantitative analysis of liver FSTL3 were performed in 60 patients with NAFLD. There were 323 individuals (191 without AMI and 132 with AMI) in T2DM co-existent NAFLD patients who had serum samples, and serum FSTL3 was tested and mediation effect of FSTL3 in association of NAFLD fibrosis and AMI was performed.

RESULTS

First, increased NAFLD fibrosis risk was an independent risk factor for AMI in patients with T2DM and co-existent NAFLD. In addition, analysis of Gene Expression Omnibus (GEO) database and immunohistochemical staining confirmed the increased expression of FSTL3 in the liver of NAFLD patients with fibrosis. Serum FSTL3 significantly increased in patients with high NAFLD fibrosis risk and AMI, and closely associated with NAFLD fibrosis and AMI severity in T2DM patients with co-existent NAFLD. Most importantly, analysis of the level of mediation revealed that increased serum FSTL3 partially mediated the association of increased NAFLD fibrosis risk with AMI in T2DM patients with co-existent NAFLD.

CONCLUSIONS

NAFLD fibrosis was closely associated with AMI in T2DM patients. FSTL3 expression was enriched in the liver of NAFLD patients with significant and advanced fibrosis, and serum FSTL3 partially mediated the association of increased liver fibrosis risk with AMI in T2DM patients.

Liver fat as risk factor of hepatic and cardiometabolic diseases

Non-alcoholic fatty liver disease (NAFLD) is a disorder characterized by excessive accumulation of fat in the liver that can progress to liver inflammation (non-alcoholic steatohepatitis [NASH]), liver fibrosis, and cirrhosis. Although most efforts for drug development are focusing on the treatment of the latest stages of NAFLD, where significant fibrosis and NASH are present, findings from studies suggest that the amount of liver fat may be an important independent risk factor and/or predictor of development and progression of NAFLD and metabolic diseases. In this review, we first describe the current tools available for quantification of liver fat in humans and then present the clinical and pathophysiological evidence that link liver fat with NAFLD progression as well as with cardiometabolic diseases. Finally, we discuss current pharmacological and non-pharmacological approaches to reduce liver fat and present open questions that have to be addressed in future studies.

Circulating levels of proglucagon-derived peptides are differentially regulated by the glucagon-like peptide-1 agonist liraglutide and the centrally acting naltrexone/bupropion and can predict future weight loss and metabolic improvements: A 6-month long interventional study

AIM

To investigate the changes of circulating levels of all proglucagon-derived peptides (PGDPs) in individuals with overweight or obesity receiving liraglutide (3 mg) or naltrexone/bupropion (32/360 mg), and to explore the association between induced changes in postprandial PGDP levels and body composition, as well as metabolic variables, after 3 and 6 months on treatment.

MATERIALS AND METHODS

Seventeen patients with obesity or with overweight and co-morbidities, but without diabetes, were assigned to receive once-daily oral naltrexone/bupropion 32/360 mg (n = 8) or once-daily subcutaneous liraglutide 3 mg (n = 9). Participants were assessed before treatment initiation and after 3 and 6 months on treatment. At the baseline and 3-month visits, participants underwent a 3-hour mixed meal tolerance test to measure fasting and postprandial levels of PGDPs, C-peptide, hunger and satiety. Clinical and biochemical indices of metabolic function, magnetic resonance-assessed liver steatosis and ultrasound-assessed liver stiffness were measured at each visit.

RESULTS

Both medications improved body weight and composition, carbohydrate and lipid metabolism, and liver fat and function. Naltrexone/bupropion produced a weight-independent increase in the levels of proglucagon (P < .001) and decreases in glucagon-like peptide-2 (GLP-2), glucagon and the major proglucagon fragment (P ≤ .01), whereas liraglutide markedly upregulated total glucagon-like peptide-1 (GLP-1) levels in a weight-independent manner (P = .04), and similarly downregulated the major proglucagon fragment, GLP-2 and glucagon (P < .01). PGDP levels at the 3-month visit were positively and independently correlated with improvements in fat mass, glycaemia, lipaemia and liver function, and negatively with reductions in fat-free mass, at both the 3- and 6-month visits.

CONCLUSIONS

PGDP levels in response to liraglutide and naltrexone/bupropion are associated with improvements in metabolism. Our study provides support for the administration of the downregulated members of the PGDP family as replacement therapy (e.g. glucagon), in addition to the medications currently in use that induced their downregulation (e.g. GLP-1), and future studies should explore whether the addition of other PGDPs (e.g. GLP-2) could offer additional benefits.

Cross-Talk of NADPH Oxidases and Inflammation in Obesity

Obesity is a major risk factor for cardiovascular and metabolic diseases. Multiple experimental and clinical studies have shown increased oxidative stress and inflammation linked to obesity. NADPH oxidases are major sources of reactive oxygen species in the cardiovascular system and in metabolically active cells and organs. An impaired balance due to the increased formation of reactive oxygen species and a reduced antioxidative capacity contributes to the pathophysiology of cardiovascular and metabolic diseases and is linked to inflammation as a major pathomechanism in cardiometabolic diseases. Non-alcoholic fatty liver disease is particularly characterized by increased oxidative stress and inflammation. In recent years, COVID-19 infections have also increased oxidative stress and inflammation in infected cells and tissues. Increasing evidence supports the idea of an increased risk for severe clinical complications of cardiometabolic diseases after COVID-19. In this review, we discuss the role of oxidative stress and inflammation in experimental models and clinical studies of obesity, cardiovascular diseases, COVID-19 infections and potential therapeutic strategies.

Circulating levels of all proglucagon-derived peptides are differentially regulated postprandially by obesity status and in response to high-fat meals vs. high-carbohydrate meals

BACKGROUND & AIMS

We measured all proglucagon-derived peptides (PGDPs) levels in response to administration of three mixed meal tolerance tests (MMTs), examining differences in postprandial PGDP responses in subjects with leanness and obesity or between high-fat vs. high carbohydrate meals.

METHODS

We designed three physiology interventional studies, administering MMTs over a 180-min period to individuals without diabetes after an overnight fast. In Study 1, a 450 kcal MMT was administered to n = 4 normal weight and n = 9 individuals with obesity. In Study 2, a 600 kcal high-fat MMT was administered to n = 15 normal-weight and n = 15 individuals with obesity. In Study 3, n = 32 participants with obesity were assigned to receive a 600-kcal high-fat (n = 15) or an isocaloric high-carbohydrate MMT (n = 17). Fasting and postprandial levels of c-peptide and PGDPs (proglucagon, GLP-1, GLP-2, glicentin, oxyntomodulin, glucagon, major proglucagon fragment [MPGF]) were assessed.

RESULTS

In study 1, individuals with normal weight displayed elevated glicentin postprandial secretion compared with people with obesity (p = 0.002). Following a high-fat MMT with 33% higher energy content in study 2, all postprandial PGDPs levels were elevated (p-time<0.001), irrespective of weight status. In study 3, a prolonged postprandial upregulation of PGDPs during the high-fat MMT was observed in contrast with the acute, short-term (max 60 min) PGDP responses to a high-carbohydrate MMT (p-time∗meal<0.001). Across both studies 2 and 3, the postprandial responses of glucagon and MPGF were higher in subjects with male sex whereas glicentin was higher in subjects with female sex.

CONCLUSIONS

Fat and carbohydrate content of a meal can substantially affect the postprandial levels of PGDPs. Circulating levels of PGDPs are influenced by the energy content of the meal, and additionally, the presence of leanness or obesity affects circulating levels of select PGDPs. These results, which are to be confirmed by additional studies, expand our understanding of PGDP physiology in leanness and obesity.

CLINICALTRIALS

GOV REGISTRATION NUMBERS: (NCT04170010, NCT04430946, NCT04575194).

Circulating levels of gastrointestinal hormones in prediabetes reversing to normoglycemia or progressing to diabetes in a year-A cross-sectional and prospective analysis

AIMS

We aimed to compare the concentrations of GLP-1, glucagon and GIP (established regulators of glucose homeostasis) and glicentin (emerging new metabolic marker)during an OGTT in patients with normal glucose tolerance (NGT), prediabetes and diabetes at onset, and one-year before, when all had prediabetes.

METHODS

GLP-1, glucagon, GIP and glicentin concentrations were measured and compared with markers of body composition, insulin sensitivity and β-cell function at a 5-timepoint OGTT in 125 subjects (30 diabetes, 65 prediabetes, 30 NGT) and in 106 of them one-year before, when all had prediabetes.

RESULTS

At baseline, when all subjects were in prediabetic state, hormonal levels did not differ between groups. One year later, patients progressing to diabetes had lower postprandial increases of glicentin and GLP-1, lower postprandial decrease of glucagon, and higher levels of fasting GIP compared to patients regressing to NGT. Changes in glicentin and GLP-1 AUC within this year correlated negatively with changes in Glucose AUC of OGTT and with changes in markers of beta cell function.

CONCLUSION

Incretins, glucagon and glicentin profiles in prediabetic state cannot predict future glycemic traits, but prediabetes progressing to diabetes is accompanied by deterioration of postprandial increases of GLP-1 and glicentin.

Metabolic Profile Reflects Stages of Fibrosis in Patients with Non-Alcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease worldwide, with fibrosis stage being the main predictor for clinical outcomes. Here, we present the metabolic profile of NAFLD patients with regards to fibrosis progression. We included all consecutive new referrals for NAFLD services between 2011 and 2019. Demographic, anthropometric and clinical features and noninvasive markers of fibrosis were recorded at baseline and at follow-up. Significant and advanced fibrosis were defined using liver stiffness measurement (LSM) as LSM ≥ 8.1 kPa and LSM ≥ 12.1 kPa, respectively. Cirrhosis was diagnosed either histologically or clinically. Fast progressors of fibrosis were defined as those with delta stiffness ≥ 1.03 kPa/year (25% upper quartile of delta stiffness distribution). Targeted and untargeted metabolic profiles were analysed on fasting serum samples using Proton nuclear magnetic resonance (¹H NMR). A total of 189 patients were included in the study; 111 (58.7%) underwent liver biopsy. Overall, 11.1% patients were diagnosed with cirrhosis, while 23.8% were classified as fast progressors. A combination of metabolites and lipoproteins could identify the fast fibrosis progressors (AUROC 0.788, 95% CI: 0.703-0.874, p < 0.001) and performed better than noninvasive markers. Specific metabolic profiles predict fibrosis progression in patients with nonalcoholic fatty liver disease. Algorithms combining metabolites and lipids could be integrated in the risk-stratification of these patients.

The Role of Growth Hormone and Insulin Growth Factor 1 in the Development of Non-Alcoholic Steato-Hepatitis: A Systematic Review

Diabetic and obese patients have a high prevalence of non-alcoholic fatty liver disease (NAFLD). This condition groups a spectrum of conditions varying from simple steatosis to non-alcoholic steatohepatitis (NASH), with or without fibrosis. Multiple factors are involved in the development of NAFLD. However, details about its pathogenesis and factors that promote the progression to NASH are still missing. Growth hormone (GH) and insulin-like growth factor 1 (IGF-1) regulate metabolic, immune, and hepatic stellate cell functions. Increasing evidence suggests they may have roles in the progression from NAFLD to NASH. Following the PRISMA reporting guidelines, we conducted a systematic review to evaluate all clinical and experimental studies published in the literature correlating GH and IGF-1 to inflammation and fibrosis in NAFLD and NASH. Our results showed that GH and IGF-1 have a fundamental role in the pathogenesis of NASH, acting in slightly different ways to produce a synergic effect. Indeed, GH may mediate its protective effect in the pathogenesis of NASH by regulating lipogenesis pathways, while IGF-1 has the same effect by regulating cholesterol transport. Therefore, they could be used as therapeutic strategies in preventing NAFLD progression to NASH.

FSTL3 is highly expressed in adipose tissue of individuals with overweight or obesity and is associated with inflammation

OBJECTIVE

This study aimed to investigate the expression of follistatin-like 3 (FSTL3) in adipose tissue in individuals with overweight or obesity and to explore the role of FSTL3 in human adipocytes, as well as the relationship between serum FSTL3 levels and fat distribution and inflammation.

METHODS

This study enrolled 236 individuals (171 with overweight or obesity; aged 18-67 years). Bulk transcriptome sequencing was performed on subcutaneous and visceral adipose tissue. The function of FSTL3 was studied in human adipocytes. Serum FSTL3 levels were measured using enzyme-linked immunosorbent assay.

RESULTS

Adipose FTSL3 expression was higher in individuals with overweight or obesity than in individuals with normal weight. FSTL3 was mainly expressed in mature adipocytes and stimulated by tumor necrosis factor alpha (TNFα). FSTL3 suppressed inflammatory responses in human adipocytes, whereas FSTL3 knockdown promoted inflammatory responses. Serum FSTL3 levels were correlated with adipose FTSL3 expression and obesity-related indicators (all p < 0.05). Multiple linear regression analysis showed that serum FSTL3 levels were independently associated with the visceral fat area and serum TNFα levels (both p < 0.05).

CONCLUSIONS

FSTL3 was highly expressed in adipose tissue in individuals with overweight or obesity and could suppress adipocyte inflammation. Serum FSTL3 levels might be considered as a biomarker of visceral obesity and inflammation.

Roles of follistatin-like protein 3 in human non-tumor pathophysiologies and cancers

Follistatin-like protein 3 (FSTL3) is a type of FSTLs. By interacting with a disintegrin and metalloproteinase 12 (ADAM12), transforming growth factor-β ligands (activin, myostatin and growth differentiation factor (GDF) 11), FSTL3 can either activate or inhibit these molecules in human non-tumor pathophysiologies and cancers. The FSTL3 gene was initially discovered in patients with in B-cell chronic lymphocytic leukemia, and subsequent studies have shown that the FSTL3 protein is associated with reproductive development, insulin resistance, and hematopoiesis. FSTL3 reportedly contributes to the development and progression of many cancers by promoting tumor metastasis, facilitating angiogenesis, and inducing stem cell differentiation. This review summarizes the current pathophysiological roles of FSTL3, which may be a putative prognostic biomarker for various diseases and serve as a potential therapeutic target.

Covert actions of growth hormone: fibrosis, cardiovascular diseases and cancer

Since its discovery nearly a century ago, over 100,000 studies of growth hormone (GH) have investigated its structure, how it interacts with the GH receptor and its multiple actions. These include effects on growth, substrate metabolism, body composition, bone mineral density, the cardiovascular system and brain function, among many others. Recombinant human GH is approved for use to promote growth in children with GH deficiency (GHD), along with several additional clinical indications. Studies of humans and animals with altered levels of GH, from complete or partial GHD to GH excess, have revealed several covert or hidden actions of GH, such as effects on fibrosis, cardiovascular function and cancer. In this Review, we do not concentrate on the classic and controversial indications for GH therapy, nor do we cover all covert actions of GH. Instead, we stress the importance of the relationship between GH and fibrosis, and how fibrosis (or lack thereof) might be an emerging factor in both cardiovascular and cancer pathologies. We highlight clinical data from patients with acromegaly or GHD, alongside data from cellular and animal studies, to reveal novel phenotypes and molecular pathways responsible for these actions of GH in fibrosis, cardiovascular function and cancer.

Methods paper: Performance characteristics of novel assays for circulating levels of proglucagon-derived peptides and validation in a placebo controlled cross-over randomized clinical trial

BACKGROUND

The measurement of proglucagon-derived peptides (PGDPs) is a challenging task mainly due to major overlaps in their molecular sequence in addition to their low circulating levels. Here, we present the technical characteristics of novel ELISA assays measuring C-peptide and all six PGDPs including, for the first time, major proglucagon fragment (MPGF), and we validate them by performing a pilot in vivo cross-over randomized clinical trial on whether coffee consumption may affect levels of circulating PGDPs.

METHODS

The performance and technical characteristics of novel ELISA assays from Ansh measuring GLP-1, GLP-2, oxyntomodulin, glicentin, glucagon, MPGF and C-peptide were first evaluated in vitro in procured samples from a commercial vendor as well as in deidentified human samples from three previously performed clinical studies. Their performance was further evaluated in vivo in the context of a cross-over randomized controlled trial, in which 33 subjects consumed in random order and together with a standardized meal, 200 ml of either (a) instant coffee with 3 mg/kg caffeine, or (b) instant coffee with 6 mg/kg caffeine, (c) or water.

RESULTS

All assays demonstrated high accuracy (spike and recovery and average linearity recovery ±15%), precision (inter-assay CV ≤ 6.4%), specificity (no significant cross-reactivities) and they were sensitive in low concentrations. Measurements of glicentin in archived random human samples using the Ansh assay correlated strongly with the glicentin measurements of Mercodia assay (r = 0.968) and of GLP-1 modestly with Millipore GLP-1 assay (r = 0.440). Oxyntomodulin, glicentin and glucagon concentrations were 2-5 fold higher in plasma compared to serum and serum concentrations correlated modestly (for oxyntomodulin and glicentin) or poorly (for glucagon) with the plasma concentrations. The evaluated assays detected a postprandial increase of gut-secreted PGDPs (GLP-1, GLP-2, oxyntomodulin and glicentin) and a postprandial decrease of pancreas-secreted PGDPs (glucagon, MPGF) in response to consuming coffee in comparison to consuming water with breakfast (enter here composition of breakfast). Only coffee consumption at the high dose alter levels of gut-secreted PGDPs and both at low and high dose to lower levels of pancreas-secreted PGDPs compared to water consumption during breakfast.

CONCLUSION

Accurate, precise and specific measurement of six PGDPs is possible with novel assays. A randomized controlled trial demonstrated in vivo utility of those assays and supports the notion that coffee may exert part of its beneficial effects on glucose homeostasis in the short term through the regulation of PGDPs.

Upregulated IGFBP3 with Aging Is Involved in Modulating Apoptosis, Oxidative Stress, and Fibrosis: A Target of Age-Related Erectile Dysfunction

Aging has been deemed the primary factor in erectile dysfunction (ED). Herein, age-related changes in the erectile response and histomorphology were detected, and the relationship between aging and ED was investigated based on gene expression levels. Thirty male Sprague–Dawley (SD) rats were randomly divided into 6 groups, and intracavernous pressure (ICP) and mean arterial pressure (MAP) were measured. Subsequently, the corpus cavernosum (CC) was harvested and prepared for histological examinations of apoptosis, oxidative stress (OS), and fibrosis. Then, the microarray dataset (GSE10804) was analyzed to identify differentially expressed genes (DEGs) in ED progression, and hub genes were selected. In addition, aged CC smooth muscle cells (CCSMCs) were isolated to evaluate the function of the hub gene by siRNA interference, qRT–PCR, immunofluorescence staining, enzyme-linked immunosorbent assay, western blot analysis, CCK-8 assay, EdU staining, and flow cytometry approaches. The ICP/MAP and smooth muscle cell (SMC)/collagen ratios declined with aging, while apoptosis and OS levels increased with aging. The enriched functions and pathways of the DEGs were investigated, and 15 hub genes were identified, among which IGFBP3 was significantly upregulated. The IGFBP3 upregulation was verified in the CC of aging rats. Furthermore, aged CCSMCs were transfected with siRNA to knock down IGFBP3 expression. The viability and proliferation of the CCSMCs increased, while apoptosis, OS, and fibrosis decreased. Our findings demonstrate that the erectile response of SD rats declines in parallel with enhanced CC apoptosis, OS, and fibrosis with aging. Upregulation of IGFBP3 plays an important role; furthermore, downregulation of IGFBP3 improves the viability and proliferation of CCSMCs and alleviates apoptosis, OS, and fibrosis. Thus, IGFBP3 is a potential therapeutic target for age-related ED.

Impact of vascular liver disease on the menstrual cycle and metabolic status in premenopausal women

BACKGROUND

Vascular liver disease (VLD) are rare liver diseases, which affect women at reproductive ages. Main complications are bleeding (portal hypertension, thrombopenia or anticoagulation related) and thromboembolism. Failure of liver function can occur. Thus endocrine abnormalities management and contraception are challenging.

PURPOSE

to evaluate the impact on the menstrual cycles and related endocrine abnormalities in women with VLD and respective roles of liver function and portal hypertension.

STUDY DESIGN

This was a single-center observational cohort study. Forty-seven premenopausal women with vascular liver disease were included for endocrine and gynecological assessments. Endocrine evaluation was performed at inclusion. Tolerance of contraception was followed up and assessed at 3 and 12 months.

PARTICIPANTS, SETTING, METHODS

Forty-seven women (aged 16-50) followed in a Reference Center for Liver Vascular Disease between February 2009 and November 2016 were included and addressed for gynecological and endocrinological management. Twenty-five women had extrahepatic portal vein obstruction, 17 had Budd Chiari Syndrome and five had a porto-sinusoidal vascular disease. We explored gonadotropin at baseline and after GnRH, testosterone, sex hormone binding globulin (SHBG), androstenedione, GH axis and glucose metabolism. All women underwent pelvic ultrasonography.

RESULTS

Vascular liver disease was associated with abnormal menstrual cycles in 53% of the women and clinical and/or biological hyperandrogenism and/or a polycystic ovary morphology was identified in 38%. Portal hypertension was correlated to higher testosterone levels (P = 0.04), whereas higher elevated levels SHBG in 28%, correlated with liver failure (P = 0.01). Sixteen had glucose intolerance profile or diabetes. IGF-1 levels were highly correlated with hepatic failure. Abnormal uterine bleeding occurred in 21% of women, 87% of which were due to gynecological pathologies revealed by anticoagulant treatment. Progestin contraception was well tolerated and helped to control bleeding.

CONCLUSION AND IMPLICATIONS

endocrine abnormalities, prior described in association with cirrhosis, are also identified in patients with vascular liver disease, and require specific management. Glucose intolerance profile is frequent, further studies are needed to assess significant consequences on cardio-vascular system.

Towards Understanding the Direct and Indirect Actions of Growth Hormone in Controlling Hepatocyte Carbohydrate and Lipid Metabolism

Growth hormone (GH) is critical for achieving normal structural growth. In addition, GH plays an important role in regulating metabolic function. GH acts through its GH receptor (GHR) to modulate the production and function of insulin-like growth factor 1 (IGF1) and insulin. GH, IGF1, and insulin act on multiple tissues to coordinate metabolic control in a context-specific manner. This review will specifically focus on our current understanding of the direct and indirect actions of GH to control liver (hepatocyte) carbohydrate and lipid metabolism in the context of normal fasting (sleep) and feeding (wake) cycles and in response to prolonged nutrient deprivation and excess. Caveats and challenges related to the model systems used and areas that require further investigation towards a clearer understanding of the role GH plays in metabolic health and disease are discussed.

Elafibranor and liraglutide improve differentially liver health and metabolism in a mouse model of non-alcoholic steatohepatitis

BACKGROUND & AIMS

This study aimed to assess and compare the effects of the GLP-1 analog liraglutide and the PPARα/δ agonist elafibranor on liver histology and their impact on hepatic lipidome, metabolome, Kupffer and hepatic stellate cell activation in a model of advanced non-alcoholic fatty liver disease (NAFLD).

METHODS

Male C57BL/6JRj mice with biopsy-confirmed hepatosteatosis and fibrosis induced by 36-week Amylin liver NASH (AMLN) diet (high-fat, fructose and cholesterol) were randomized to receive for 12 weeks: (a) liraglutide (0.4 mg/kg/day s.c.), (b) elafibranor (30 mg/kg/day p.o.) and (c) vehicle. Metabolic status, liver pathology, markers of inflammation, Kupffer and stellate cell activation, and metabolomics/lipidomics were assessed at study completion.

RESULTS

Elafibranor and liraglutide improved weight, insulin sensitivity, glucose homeostasis and NAFLD activity score (pre-to-post biopsy). Elafibranor had a profound effect on hepatic lipidome, demonstrated by reductions in glycerides, increases in phospholipids, and by beneficial regulation of mediators of fatty acid oxidation, inflammation and oxidative stress. Liraglutide had a major impact on inflammatory and fibrogenic markers of Kupffer and hepatic stellate cell activation (Galectin-3, Collagen type I alpha 1, alpha-smooth muscle actin). Liraglutide exerted beneficial effects on bile acid and carbohydrate metabolism, demonstrated by restorations of the concentrations of bile acids, glycogen metabolism by-products and pentoses, thus facilitating glycogen utilization turnover and nucleic acid formation.

CONCLUSIONS

Liraglutide and elafibranor robustly but through different pathways improve overall metabolic health and liver status in NAFLD. These data indicate important differences in the respective mechanisms of action and support the notion for their evaluation as combination therapies in the future.

Adiponectin, Leptin, and IGF-1 Are Useful Diagnostic and Stratification Biomarkers of NAFLD

Background: Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease where liver biopsy remains the gold standard for diagnosis. Here we aimed to evaluate the role of circulating adiponectin, leptin, and insulin-like growth factor 1 (IGF-1) levels as non-invasive NAFLD biomarkers and assess their correlation with the metabolome.

Materials and Methods: Leptin, adiponectin, and IGF-1 serum levels were measured by ELISA in two independent cohorts of biopsy-proven obese NAFLD patients and healthy-liver controls (discovery: 38 NAFLD, 13 controls; validation: 194 NAFLD, 31 controls) and correlated with clinical data, histology, genetic parameters, and serum metabolomics.

Results: In both cohorts, leptin increased in NAFLD vs. controls (discovery: AUROC 0.88; validation: AUROC 0.83; p < 0.0001). The leptin levels were similar between obese and non-obese healthy controls, suggesting that obesity is not a confounding factor. In the discovery cohort, adiponectin was lower in non-alcoholic steatohepatitis (NASH) vs. non-alcoholic fatty liver (AUROC 0.87; p < 0.0001). For the validation cohort, significance was attained for homozygous for PNPLA3 allele c.444C (AUROC 0.63; p < 0.05). Combining adiponectin with specific serum lipids improved the assay performance (AUROC 0.80; p < 0.0001). For the validation cohort, IGF-1 was lower with advanced fibrosis (AUROC 0.67, p < 0.05), but combination with international normalized ratio (INR) and ferritin increased the assay performance (AUROC 0.81; p < 0.01).

Conclusion: Serum leptin discriminates NAFLD, and adiponectin combined with specific lipids stratifies NASH. IGF-1, INR, and ferritin distinguish advanced fibrosis.

Fasting oxyntomodulin, glicentin, and gastric inhibitory polypeptide levels are associated with activation of reward- and attention-related brain centres in response to visual food cues in adults with obesity: A cross-sectional functional MRI study

Postprandial increases in gastrointestinal hormones are associated with reduced energy intake, partially through direct effects on the brain. However, it remains unknown whether the fasting levels of gastrointestinal hormones are associated with altered brain activity in response to visual food stimuli. We therefore performed a whole-brain regression cross-sectional analysis to assess the association between fasting brain activations according to functional magnetic resonance imaging, performed during viewing of highly desirable versus less desirable food images, with fasting levels of five gastrointestinal hormones (glucagon-like peptide [GLP]-1, GLP-2, oxyntomodulin, glicentin and gastric inhibitory polypeptide [GIP]) in 36 subjects with obesity. We observed that fasting blood levels of GIP were inversely associated with the activation of attention-related areas (visual cortices of the occipital lobe, parietal lobe) and of oxyntomodulin and glicentin with reward-related areas (insula, putamen, caudate for both, and additionally orbitofrontal cortex for glicentin) and the hypothalamus when viewing highly desirable as compared to less desirable food images. Future studies are needed to confirm whether fasting levels of oxyntomodulin, glicentin and GIP are associated with the activation of brain areas involved in appetite regulation and with energy intake in people with obesity.

Identification of Differential Expression Cytokines in Hemolysis, Elevated Liver Enzymes, and Low Platelet Syndrome by Proteome Microarray Analysis and Further Verification

To screen the differential expression cytokines (DECs) in hemolysis, elevated liver enzymes, and low platelet (HELLP) syndrome, establish its differential cytokines spectra, and provide the clues for its diagnosis and pathogenic mechanism researches. Sera from four HELLP syndrome patients and four healthy controls were detected by proteome microarray. Then the analysis of Gene Ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and protein–protein interaction (PPI) network were performed and possible hub proteins were selected out, further verified by Enzyme Linked Immunosorbent Assay (ELISA) in sera from 21 HELLP syndrome patients and 21 healthy controls. Thirty DECs were defined according to P-value and fold change between HELLP group and control group. GO enrichment analysis showed that DECs were mainly involved in the regulation of inflammatory response and have relationship to growth factor binding, transmembrane receptor protein kinase, and cytokine receptor activity. Seven possible hub proteins were defined by PPI analysis, including IGFBP-3/Follistatin-like 1/FLRG/Fetuin A and MMP-13/Thrombospondin-5/Aggrecan. ELISA showed higher serum levels of Fetuin A/IGFBP-3/FLGR/MMP-13/Thrombospondin-5 in HELLP group than those in controls, while the levels of Follistatin-like 1 and Aggrecan were lower in HELLP patients (all P < 0.05 or <0.01).The serological DECs spectra of HELLP syndrome was established and seven possible hub proteins that may be more closely related to the disease have been verified, providing new clues for its pathogenesis, diagnosis, and clinical treatment.

Association between circulating follistatin-like-1 and metabolic syndrome in middle-aged and old population: A cross-sectional study

AIM

Follistatin-like-1 (FSTL-1) is considered to be a novel cytokine, and it is associated with metabolic diseases. However, it is necessary to investigate further the association of FSTL-1 with metabolic syndrome (MetS) and insulin resistance (IR). We performed a cross-sectional study to investigate the associated of circulating FSTL-1 with the MetS.

MATERIALS AND METHODS

A cross-sectional study was performed in 487 Chinese people, including 231 control subjects and 256 patients with MetS. Bioinformatics analysis was used to determine the protein and pathways associated with FSTL-1. The protein and protein interaction (PPI) network was constructed and analysed. Serum FSTL-1 concentrations were determined by an ELISA assay. The association of FSTL-1 with MetS components and IR was assessed.

RESULTS

Serum FSTL-1 levels were markedly higher in patients with newly diagnosed MetS than in controls (7.5 [5.6-9.2] vs 5.8 [5.0-7.7] μg/L, P < .01). According to bioinformatics analysis, the top high-degree genes were identified as the core genes, including SPARCL1, CYR61, LTBP1, IL-6, BMP2, BMP4, FBN1, FN1 CHRDL1 and FSTL-3. These genes are mainly enriched in pathways including TGF-ß, AGE-RAGE signalling pathway in diabetic complications, and Hippo signalling pathways; in basal cell carcinoma, cytokine-cytokine receptor interaction and in amoebic and Yersinia infections. Furthermore, serum FSTL-1 levels were positively associated with fasting plasma glucose (FPG), waist circumference (WC), blood pressure, triglyceride levels and visceral adiposity index (VAI). We found that serum FSTL-1 levels were markedly associated with MetS and IR by binary logistic regression analysis.

CONCLUSIONS

We conclude that FSTL-1 may be a novel cytokine related to MetS and IR.

Leptin in Leanness and Obesity: JACC State-of-the-Art Review

Leptin has emerged over the past 2 decades as a key hormone secreted by adipose tissue that conveys information on energy stores. Leptin is considered an important regulator of both neuroendocrine function and energy homeostasis. Numerous studies (mainly preclinical and much less in humans) have investigated the mechanisms of leptin's actions both in the healthy state as well as in a wide range of metabolic diseases. In this review, the authors present leptin physiology and review the main findings from animal studies, observational and interventional studies, and clinical trials in humans that have investigated the role of leptin in metabolism and cardiometabolic diseases (energy deficiency, obesity, diabetes, cardiovascular diseases, nonalcoholic fatty liver disease). The authors discuss the similarities and discrepancies between animal and human biology and present clinical applications of leptin, directions for future research, and current approaches for the development of the next-generation leptin analogs.

Relationship of IGF-1 and IGF-Binding Proteins to Disease Severity and Glycemia in Nonalcoholic Fatty Liver Disease

CONTEXT

Growth hormone (GH) and IGF-1 help regulate hepatic glucose and lipid metabolism, and reductions in these hormones may contribute to development of nonalcoholic fatty liver disease (NAFLD).

OBJECTIVE

To assess relationships between hepatic expression of IGF1 and IGF-binding proteins (IGFBPs) and measures of glycemia and liver disease in adults with NAFLD. Secondarily to assess effects of GH-releasing hormone (GHRH) on circulating IGFBPs.

DESIGN

Analysis of data from a randomized clinical trial of GHRH.

SETTING

Two US academic medical centers.

PARTICIPANTS

Participants were 61 men and women 18 to 70 years of age with HIV-infection, ≥5% hepatic fat fraction, including 39 with RNA-Seq data from liver biopsy.

MAIN OUTCOME MEASURES

Hepatic steatosis, inflammation, and fibrosis by histopathology and measures of glucose homeostasis.

RESULTS

Hepatic IGF1 mRNA was significantly lower in individuals with higher steatosis and NAFLD Activity Score (NAS) and was inversely related to glucose parameters, independent of circulating IGF-1. Among the IGFBPs, IGFBP2 and IGFBP4 were lower and IGFBP6 and IGFBP7 (also known as IGFBP-related protein 1) were higher with increasing steatosis. Hepatic IGFBP6 and IGFBP7 mRNA levels were positively associated with NAS. IGFBP7 mRNA increased with increasing fibrosis. Hepatic IGFBP1 mRNA was inversely associated with glycemia and insulin resistance, with opposite relationships present for IGFBP3 and IGFBP7. GHRH increased circulating IGFBP-1 and IGFBP-3, but decreased IGFBP-2 and IGFBP-6.

CONCLUSIONS

These data demonstrate novel relationships of IGF-1 and IGFBPs with NAFLD severity and glucose control, with divergent roles seen for different IGFBPs. Moreover, the data provide new information on the complex effects of GHRH on IGFBPs.

Circulating profile of Activin-Follistatin-Inhibin Axis in women with hypothalamic amenorrhea in response to leptin treatment

BACKGROUND

Chronic energy deficiency observed in women that exercise strenuously affects reproductive function, often leading to hypothalamic amenorrhea (HA). In such conditions, hypoleptinemia and robust changes in the Activin-Follistatin-Inhibin Axis (AFI) are observed. Treatment with leptin restores menstruation in many (60% responders) but not all (40% non-responders) women, suggesting that leptin is not the only regulator of reproductive function related to energy balance. In this work, we aimed to identify differences in hormonal profiles between leptin responders and non-responders among women with HA, with particular focus on the AFI axis.

METHODS

AFI axis and reproductive hormones (LH, FSH, Estradiol, ΑΜΗ) were measured in blood in: a) An open-label interventional study, b) a randomized placebo-controlled trial, both investigating responders versus non-responders/women with HA treated with leptin.

RESULTS

Women with HA that responded to leptin treatment have higher circulating levels/peak values of Inhibin A, Estradiol (E2), higher LH/FSH ratio and a trend to lower AMH compared with non-responders.

CONCLUSIONS

Components of the AFI axis are associated with improvement of reproductive function in women with HA treated with leptin. ΑΜΗ may serve as a marker of ovarian recovery under HA treatment.

The role of omics in the pathophysiology, diagnosis and treatment of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a multifaceted metabolic disorder, whose spectrum covers clinical, histological and pathophysiological developments ranging from simple steatosis to non-alcoholic steatohepatitis (NASH) and liver fibrosis, potentially evolving into cirrhosis, hepatocellular carcinoma and liver failure. Liver biopsy remains the gold standard for diagnosing NAFLD, while there are no specific treatments. An ever-increasing number of high-throughput Omics investigations on the molecular pathobiology of NAFLD at the cellular, tissue and system levels produce comprehensive biochemical patient snapshots. In the clinical setting, these applications are considerably enhancing our efforts towards obtaining a holistic insight on NAFLD pathophysiology. Omics are also generating non-invasive diagnostic modalities for the distinct stages of NAFLD, that remain though to be validated in multiple, large, heterogenous and independent cohorts, both cross-sectionally as well as prospectively. Finally, they aid in developing novel therapies. By tracing the flow of information from genomics to epigenomics, transcriptomics, proteomics, metabolomics, lipidomics and glycomics, the chief contributions of these techniques in understanding, diagnosing and treating NAFLD are summarized herein.

GIPC-Regulated IGFBP-3 Promotes HSC Migration In Vitro and Portal Hypertension In Vivo Through a β1-Integrin Pathway

BACKGROUND & AIMS

Transforming growth factor (TGF-β)-induced activation of quiescent hepatic stellate cells (HSCs) and their transformation to myofibroblasts is a key event in liver fibrosis and portal hypertension. GIPC (also referred to as synectin) is a downstream signal activation molecule of TGF-β and other receptors. In this study, we sought to identify novel genes targeted by TGF-β and GIPC and elucidate if and how they may contribute to liver fibrosis.

METHODS

We performed sequential messenger RNA sequencing analysis on TGF-β-stimulated HSCs and then on TGF-β-stimulated HSCs in the presence and absence of GIPC also referred to as synectin (GIPC) knockdown. Insulin-like growth factor binding protein-3 (IGFBP-3) transport protein emerged as a top activation target of both TGF-β and GIPC. Quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, targeted chromatin immunoprecipitation, and Western blot analysis were done for further confirmation.

RESULTS

IGFBP-3, an insulin growth factor transport protein, emerged as a top activation target of both TGF-β and GIPC, which was confirmed by quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, and Western blot analysis. Targeted chromatin immunoprecipitation showed that GIPC increases the histone 3 lysine 27 (H3K27) acetylation activating mark and concurrently decreases the H3K27 inhibitory trimethylation (H3K27m3) mark, providing an epigenetic correlate to the gene regulation changes. In vivo, global knockout of IGFBP-3 mice resulted in attenuation of HSC activation markers and attenuation of portal pressure in response to chronic liver injury models. Analysis of serum levels from cirrhotic patients also showed an IGFBP-3 increase of more than 2-fold compared with healthy controls. Finally, in vitro mechanism studies showed that IGFBP-3 promotes HSC migration through integrin-dependent phosphorylation of protein kinase B.

CONCLUSIONS

TGF-β up-regulates IGFBP-3 through GIPC, leading to increased HSC migration in vitro and promotes portal hypertension in vivo. These studies support the role of IGFBP-3 as a potential pathophysiologic target or biomarker in chronic liver disease.

Targeted Analysis of Three Hormonal Systems Identifies Molecules Associated with the Presence and Severity of NAFLD

AIMS

To investigate circulating levels and liver gene expression of 3 hormonal pathways associated with obesity, insulin resistance, and inflammation to identify leads towards potential diagnostic markers and therapeutic targets in patients with nonalcoholic fatty liver disease (NAFLD).

METHODS

We compared circulating levels of (1) proglucagon-derived hormones (glucagon-like peptide [GLP]-1, GLP-2, glicentin, oxyntomodulin, glucagon, major proglucagon fragment [MPGF]), (2) follistatins-activins (follistatin-like [FSTL]3, activin B), (3) IGF axis (insulin-like growth factor [IGF]-1, total and intact IGF binding protein [IGFBP]-3 and IGFBP-4, and pregnancy-associated plasma protein [PAPP]-A) in 2 studies: (1) 18 individuals with early stage NAFLD versus 14 controls (study 1; early NAFLD study) and in (2) 31 individuals with biopsy proven NAFLD (15 with simple steatosis [SS] and 16 with nonalcoholic steatohepatitis [NASH]), vs 50 controls (24 lean and 26 obese) (study 2). Liver gene expression was assessed in 22 subjects (12 controls, 5 NASH, 5 NASH-related cirrhosis).

RESULTS

Patients in early stages of NAFLD demonstrate higher fasting MPGF and lower incremental increase of glicentin during oral glucose tolerance test than controls. In more advanced stages, FSTL3 levels are higher in NASH than simple steatosis and, within NAFLD patients, in those with more severe lobular and portal inflammation. The IGF-1/intact IGFBP-3 ratio is lower in patients with liver fibrosis. Genes encoding follistatin, activin A, activin B, and the IGF-1 receptor are higher in NASH.

CONCLUSION

MPGF and glicentin may be involved in early stages of NAFLD, whereas FSTL3 and IGF-1/intact IGFBP3 in the progression to NASH and liver fibrosis respectively, suggesting potential as diagnostic markers or therapeutic targets.