Obesity poses a significant and escalating challenge in contemporary society, increasing the risk of developing various metabolic disorders such as dyslipidemia, cardiovascular diseases, non-alcoholic fatty liver disease (NAFLD), type 2 diabetes, and certain types of cancer. The current array of therapeutic interventions for obesity remains insufficient, prompting a pressing demand for novel and more effective treatments. In response, scientific attention has turned to the fibroblast growth factor 21 (FGF21) due to its remarkable and diverse impacts on lipid, carbohydrate, and energy metabolism. This comprehensive review aims to delve into the multifaceted aspects of FGF21, encompassing its discovery, synthesis, functional roles, and potential as a biomarker and therapeutic agent, with a specific focus on its implications for NAFLD.

UNASSIGNED: Fibroblast growth factor 21 (FGF21) is a key hormone factor that regulates glucose and lipid homeostasis. Exercise may regulate its effects and affect disease states. Therefore, we sought to determine how exercise affects FGF21 concentrations in adults.
UNASSIGNED: The review was registered in the International Prospective Systematic Review (PROSPERO, CRD42023471163). The Cochrane Library, PubMed, and Web of Science databases were searched for studies through July 2023. Studies that assessed the effects of exercise training on FGF21 concentration in adults were included. The random effect model, data with standardized mean difference (SMD), and 95% confidence intervals (CI) were used to evaluate the pooled effect size of exercise training on FGF21. The risk of heterogeneity and bias were evaluated. A total of 12 studies involving 401 participants were included.
UNASSIGNED: The total effect size was 0.3 (95% CI [-0.3-0.89], p = 0.33) when comparing participants who exercised to those who were sedentary. However, subgroup analysis indicated that concurrent exercise and a duration ≥10 weeks significantly decreased FGF21 concentrations with an effect size of -0.38 (95% CI [-0.74--0.01], p < 0.05) and -0.38 (95% CI [-0.63--0.13], p < 0.01), respectively.
UNASSIGNED: Concurrent exercise and longer duration may be more efficient way to decrease FGF21 concentrations in adults with metabolic disorder.

Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome characterized by hypophosphatemia, bone mineralization disorders with increased risk of fragility fractures, muscle pain, and progressive weakness. TIO has been associated with increased production of the phosphaturic hormone Fibroblast Growth Factor 23 (FGF23) usually by mesenchymal tumors of soft tissue or bone (Phosphaturic Mesenchymal Tumors-PMTs). In rare cases TIO may be observed in association with other malignancies. We report the case of a 66-year-old woman with an occasional diagnosis of both a PMT and an ovarian cancer during the evaluation of TIO. We also systematically review the literature to discover possible correlations between osteomalacia, FGF23 production, and ovarian cancer. Four studies were eligible for the analysis. Two case reports described an association between TIO development and ovarian cancer, whereas the two case-control studies hypothesized a possible correlation between FGF/FGF receptor axis and cancer development. Although it does not provide conclusive evidence regarding the association between TIO and ovarian cancer, this case report highlights the possibility that in the diagnostic workup of suspected TIO, both FGF23-secreting tumors distinct from PMT and tumors unrelated to the clinical presentation of TIO could be identified. This information is important for guiding successful tumor staging and determining the necessity for surgical intervention and/or eventual adjuvant therapy.

BACKGROUND: Non-alcoholic steatohepatitis (NASH) is an advanced subtype of non-alcoholic fatty liver disease (NAFLD). NASH prevalence is increasing exponentially and carries a high risk for disease progression, cirrhosis, and liver-related mortality. Aldafermin, a fibroblast growth factor 19 (FGF19) analog, is one of the evolving therapeutic agents with the potential to regulate multiple pathways involved in the pathogenesis of NASH. We aimed to investigate the efficacy and safety of aldafermin in patients with NASH.
METHODS: PubMed, Scopus, Cochrane Library, and Web of Science were searched till November 2023 to identify eligible randomized controlled trials (RCTs). Continuous data were pooled as mean difference (MD), while dichotomous data were pooled as risk ratios (RR) with a 95 % confidence interval. A subgroup meta-analysis was conducted to evaluate the efficacy of the two doses (1 mg and 3 mg) of aldafermin.
RESULTS: Four RCTs with a total of 491 patients were included. Aldafermin showed a dose-dependent improvement in the ≥30 % reduction in the liver fat content (RR: 2.16, 95 % CI [1.41 to 3.32]) and (RR: 5.00, 95 % CI [1.34 to 18.64]), alanine aminotransferase levels (MD: -19.79, 95 % CI [-30.28 to -9.3]) and (MD: -21.91, 95 % CI [-29.62 to -14.21]), aspartate aminotransferase levels (MD: -11.79, 95 % CI [-18.06 to -5.51]) and (MD: -13.9, 95 % CI [-18.59 to -9.21]), and enhanced liver fibrosis score (ELF) (MD: -0.13, 95 % CI [-0.29 to 0.02]) and (MD: -0.33, 95 % CI [-0.50 to -0.17]), in the 1 mg and 3 mg subgroups respectively. No significant differences were detected in the aldafermin group regarding histologic endpoints, lipid profile, metabolic parameters, and overall adverse effects, except for the increased occurrence of diarrhea in the aldafermin 3 mg subgroup.
CONCLUSIONS: Aldafermin is a promising well-tolerated therapeutic agent for NASH with evidence supporting its ability to reduce liver fat content, fibrosis serum biomarkers, and liver enzymes. However, its effectiveness in improving histologic fibrosis, while showing numerical trends, still lacks statistical significance. Larger and longer NASH trials are warranted to enhance the robustness of the evidence.

OBJECTIVE: This study undertook a scoping review of research on blood fibroblast growth factor 23 (FGF-23) concentrations in healthy non-azotemic cats and cats with chronic kidney disease (CKD) to describe the volume and nature of existing literature, to determine whether published studies provide adequate evidence to support the use of FGF-23 as a biomarker in clinical practice and to identify any existing gaps in knowledge.
METHODS: PRISMA Extension for Scoping Reviews guidelines were used to design and perform the scoping review. Online databases were used to identify observational and clinical studies of blood FGF-23 concentrations in healthy cats and cats with CKD published before December 2022. Study and population characteristics and descriptive data on FGF-23 concentrations were extracted.
RESULTS: A total of 205 publications were reviewed; 17 were retained for inclusion. Most studies were retrospective. Most studies included cats with International Renal Interest Society stage 2-4 CKD, with some variation. Key concepts explored in the literature include FGF-23 concentrations by CKD stage, effect of dietary phosphate restriction on FGF-23 concentrations, relationship between FGF-23 concentrations and blood phosphorus, calcium and magnesium concentrations, and FGF-23 concentrations in cats with progressive CKD. FGF-23 concentrations tended to be higher in cats with CKD compared with healthy cats, with an overlap between healthy and CKD populations, and there was significant variation within stages of CKD.
CONCLUSIONS: FGF-23 is a biomarker of interest for the management and monitoring of phosphate overload in cats. Studies support several potential clinical applications for measuring FGF-23 concentration in practice; however, evidence is limited. Research on FGF-23 in cats with CKD would benefit from longitudinal, prospective studies that standardize CKD diagnosis and categorize cats by stage using current guidelines. Studies should include cats with early-stage, non-azotemic CKD and use commercially available assays so such results are comparable across studies.

Fibroblast growth factor (FGF)-21 analogs are potential therapeutic candidates for metabolic dysfunction-associated steatohepatitis (MASH). This systematic review and meta-analysis aimed to assess the efficacy and safety of the FGF-21 analogs, efruxifermin, pegbelfermin, and pegozafermin for MASH treatment. A comprehensive systematic review and meta-analysis of randomized controlled trials from five major databases was conducted. Primary efficacy outcomes focused on liver histological improvement, while secondary efficacy outcomes encompassed reductions in liver fat content and improvements in biochemical parameters. Safety outcomes examined included treatment-emergent adverse events (TEAEs), treatment-related TEAEs, TEAEs leading to discontinuation, and serious TEAEs. Eight eligible studies involving 963 patients were included in this review. Compared with the placebo group, the FGF-21 analog-treated group exhibited significantly improved primary efficacy outcomes, specifically ≥1 stage improvement in fibrosis with no worsening of MASH (risk ratio [RR] = 1.83; 95% confidence interval [CI] = 1.27-2.62) and at least two-point improvement in the non-alcoholic fatty liver disease activity score with no worsening of fibrosis (RR = 2.85; 95% CI = 2.06-3.95). Despite an increased risk of TEAEs (RR = 1.17; 95% CI = 1.08-1.27) and treatment-related adverse events (RR = 1.75; 95% CI = 1.40-2.19), FGF-21 analogs exhibited an acceptable safety profile. FGF-21 analogs were significantly better in achieving liver histological improvements and beneficial biochemical outcomes compared with placebo, with a tolerable safety pattern. These findings shed light on the efficacy and safety of FGF-21 analogs and provide valuable evidence for their application as MASH therapeutics.

OBJECTIVE: Several agents are under investigation for nonalcoholic fatty liver disease (NAFLD). We assessed the comparative efficacy of pharmacologic interventions for patients with NAFLD focusing on magnetic resonance imaging (MRI) biomarkers.
METHODS: We searched Medline, Embase, and CENTRAL. We included randomized controlled trials of more than 12 weeks of intervention that recruited patients with biopsy-confirmed or MRI-confirmed NAFLD and assessed the efficacy of interventions on liver fat content (LFC) and fibrosis by means of MRI. We performed random-effects frequentist network meta-analyses and assessed confidence in our estimates using the CINeMA (Confidence in Network Meta-Analysis) approach.
RESULTS: We included 47 trials (8583 patients). Versus placebo, thiazolidinediones were the most efficacious for the absolute change in LFC, followed by vitamin E, fibroblast growth factor (FGF) analogs, and glucagon-like peptide-1 receptor agonists (GLP-1 RAs) with mean differences ranging from -7.46% (95% confidence interval [-11.0, -3.9]) to -4.36% (-7.2, -1.5). No differences between drug classes were evident. Patients receiving GLP-1 RAs or glucose-dependent insulinotropic polypeptide (GIP)/GLP-1 RAs were more likely to achieve ≥30% relative reduction in LFC. Among agents, efruxifermin produced the largest reduction in LFC compared to placebo [-13.5% (-18.5, -8.5)], followed by pioglitazone, while being superior to most interventions. The effect of interventions on magnetic resonance elastography assessed fibrosis was small and insignificant. The confidence in our estimates was low to very low.
CONCLUSIONS: Several drug classes may reduce LFC in patients with NAFLD without a significant effect on fibrosis; nevertheless, trial duration was small, and confidence in the effect estimates was low.

Metabolic-associated steatotic liver disease (MASLD) is closely associated with obesity. MASLD affects over 1 billion adults globally but there are few treatment options available. Glucagon is a key metabolic regulator, and its actions include the reduction of liver fat through direct and indirect means. Chronic glucagon signalling deficiency is associated with hyperaminoacidaemia, hyperglucagonaemia and increased circulating levels of glucagon-like peptide 1 (GLP-1) and fibroblast growth factor 21 (FGF-21). Reduction in glucagon activity decreases hepatic amino acid and triglyceride catabolism; metabolic effects include improved glucose tolerance, increased plasma cholesterol and increased liver fat. Conversely, glucagon infusion in healthy volunteers leads to increased hepatic glucose output, decreased levels of plasma amino acids and increased urea production, decreased plasma cholesterol and increased energy expenditure. Patients with MASLD share many hormonal and metabolic characteristics with models of glucagon signalling deficiency, suggesting that they could be resistant to glucagon. Although there are few studies of the effects of glucagon infusion in patients with obesity and/or MASLD, there is some evidence that the expected effect of glucagon on amino acid catabolism may be attenuated. Taken together, this evidence supports the notion that glucagon resistance exists in patients with MASLD and may contribute to the pathogenesis of MASLD. Further studies are warranted to investigate the direct effects of glucagon on metabolism in patients with MASLD.

BACKGROUND: Phosphaturic mesenchymal tumors (PMTs) are rare mesenchymal tumors, associated with long-standing, non-specific but often debilitating symptoms in the affected patients. These tumors display characteristic histopathological features and in case, identified timely, can be a boon for patients, given an excision is completely curative.
OBJECTIVE: To evaluate the clinical and histopathological features of 10 PMTs, diagnosed at our institution, along with clinical outcomes in those patients.
METHODS: This was a retrospective study, wherein 10 PMTs, diagnosed from January 2013 to July 2022, were included.
RESULTS: The average age at the time of diagnosis was 40 years with an M:F ratio of 4:1. Clinical features included lumps, weakness, bone pain, difficulty in moving and walking, and pathologic fractures. The biochemical analysis showed normal serum calcium levels (average = 9.5 mg/dL), with low serum phosphorus (average = 2.2 mg/dL) and raised serum fibroblast growth factor 23 (FGF23) levels, in all the cases, wherever available. On histopathology, all tumors showed cells arranged in a hemangiopericytomatous pattern, including oval to short spindle forms. Multinucleate giant cells were present in nine tumors, and characteristic \"grungy calcifications\" was observed in eight tumors. Prominent pseudo cystic spaces were seen in eight tumors. A significant number of mitotic figures and tumor necrosis were not seen in any tumor. In five cases where follow-up was available, there was complete resolution of symptoms post-resection with no recurrence or metastasis. All those patients were free of disease until the last follow-up.
CONCLUSIONS: This constitutes the first largest comprehensive study on these rare tumors from our country. PMTs can be diagnosed based on certain histopathological features and correlation with clinicoradiological and biochemical findings. These are invariably benign neoplasms. Patients are relieved of their debilitating symptoms after adequate surgical tumor resection. Therefore, their correct and timely diagnosis is crucial.

The aim of this study was to investigate the efficacy of physical exercise in chronic kidney disease, describing its impact on the Klotho-FGF23 axis. PubMed, Web of Science and Scopus databases, updated to January 2023, were searched. The present study employed mean difference and a 95% confidence interval (CI) to examine the efficacy of the intervention. Heterogeneity was assessed through inconsistency statistics (I2). Out of the 299 studies identified, a total of 4 randomized controlled trials (RCTs), comprising 272 participants, met the eligibility criteria. Compared with the control group, physical exercise significantly decreased the concentrations of FGF23 (MD: -102.07 Pg/mL, 95% CI: -176.23.47, -27.91 I2= 97%, p = 0.001), and a significantly increased the concentrations of Klotho protein: (MD: 158.82 Pg/mL, 95% CI: 123.33, -194.31, I2 = 0%, p = 0.001). The results of our study indicated that the exercise has a direct relationship with Klotho-FGF23 axis. We can conclude that physical exercise in patients with CKD produces beneficial effects on the pathophysiological components related to this disease, including cardiorespiratory fitness and vascular functions. As observed, both endurance and aerobic physical exercise increase Klotho production and decrease FGF23 levels. Evidence indicates that exercise attenuates the progression of CKD, improves uremic parameters and down-regulates inflammation-related markers.