Postoperative atrial fibrillation is a frequent complication in cardiac surgery. The aberrant activation of signal transducer and activator of transcription 3 (STAT3) contributes to the pathogenesis of atrial fibrillation. MicroRNA-<em>21</em> (miR-<em>21</em>) promotes atrial fibrosis. Recent studies support the existence of reciprocal regulation between STAT3 and miR-<em>21</em>. Here, we test the hypothesis that these 2 molecules might form a feedback loop that contributes to postoperative atrial fibrillation by promoting atrial fibrosis.

A sterile pericarditis model was created using atrial surfaces dusted with sterile talcum powder in rats. The inflammatory cytokines interleukin (IL)-1β, IL-6, transforming growth factor-β, and tumor necrosis factor-α, along with STAT3 and miR-<em>21</em>, were highly upregulated in sterile pericarditis rats. The inhibition of STAT3 by S3I-201 resulted in miR-<em>21</em> downregulation, which ameliorated atrial fibrosis and decreased the expression of the fibrosis-related genes, α-smooth muscle actin, collagen-1, and collagen-3; reduced the inhomogeneity of atrial conduction; and attenuated atrial fibrillation vulnerability. Meanwhile, treatment with antagomir-<em>21</em> decreased STAT3 phosphorylation, alleviated atrial remodeling, abrogated sterile pericarditis-induced inhomogeneous conduction, and prevented atrial fibrillation promotion. The culturing of cardiac fibroblasts with IL-6 resulted in progressively augmented STAT3 phosphorylation and miR-<em>21</em> levels. S3I-201 blocked IL-6 induced the expression of miR-<em>21</em> and fibrosis-related genes in addition to cardiac fibroblast proliferation. Transfected antagomir-<em>21</em> decreased the IL-6-induced cardiac fibroblast activation and STAT3 phosphorylation. The overexpression of miR-<em>21</em> in cardiac fibroblasts caused the upregulation of STAT3 phosphorylation, enhanced fibrosis-related genes, and increased cell numbers.

Our results have uncovered a novel reciprocal loop between STAT3 and miR-<em>21</em> that is activated after heart surgery and can contribute to atrial fibrillation.

Members of the <em>fibroblast</em> <em>growth</em> <em>factor</em> (FGF) family play pleiotropic roles in cellular and metabolic homeostasis. During evolution, the ancestor FGF expands into multiple members by acquiring divergent structural elements that enable functional divergence and specification. Heparan sulfate-binding FGFs, which play critical roles in embryonic development and adult tissue remodeling homeostasis, adapt to an autocrine/paracrine mode of action to promote cell proliferation and population <em>growth</em>. By contrast, FGF19, <em>21</em>, and 23 coevolve through losing binding affinity for extracellular matrix heparan sulfate while acquiring affinity for transmembrane α-Klotho (KL) or β-KL as a coreceptor, thereby adapting to an endocrine mode of action to drive interorgan crosstalk that regulates a broad spectrum of metabolic homeostasis. FGF19 metabolic axis from the ileum to liver negatively controls diurnal bile acid biosynthesis. FGF<em>21</em> metabolic axes play multifaceted roles in controlling the homeostasis of lipid, glucose, and energy metabolism. FGF23 axes from the bone to kidney and parathyroid regulate metabolic homeostasis of phosphate, calcium, vitamin D, and parathyroid hormone that are important for bone health and systemic mineral balance. The significant divergence in structural elements and multiple functional specifications of FGF19, <em>21</em>, and 23 in cellular and organismal metabolism instead of cell proliferation and <em>growth</em> sufficiently necessitate a new unified and specific term for these three endocrine FGFs. Thus, the term "FGF Metabolic Axis," which distinguishes the unique pathways and functions of endocrine FGFs from other autocrine/paracrine mitogenic FGFs, is coined.

It is unknown whether long-term pharmacological stimulation of soluble guanylate cyclase (sGC), elevating intracellular cGMP levels, has a beneficial effect on hypertension. The purpose of this study is to investigate the effects of BAY41-2272, an orally available sGC stimulator, on cardiovascular remodeling in hypertensive rats. Eight-week-old male Wistar rats with hypertension induced by angiotensin II infused subcutaneously at 250 ng/kg per minute were treated orally with a low ([L] 2 mg/kg per day) or high ([H] 10 mg/kg per day) dose of BAY41-2272 for 14 days. BAY41-2272-H partially suppressed the rise in blood pressure and reduced the heart weight (4.20+/-0.34 versus 3.68+/-0.20 mg/g; P<0.01), whereas BAY41-2272-L had no effect. However, both doses decreased the angiotensin II-induced left ventricular accumulation of collagen in the perivascular area (L, -20%, P<0.05; H, -30%, P<0.01) and myocardial interstitium (L, -<em>21</em>%, P<0.05; H, -38%, P<0.01), reducing the number of activated <em>fibroblasts</em> surrounding coronary arteries (L, -74%; H, -79%; P<0.05). BAY41-2272 downregulated the angiotensin II-induced left ventricular gene expression of type 1 collagen (L, -41%, P<0.05; H, -49%, P<0.01) and transforming <em>growth</em> <em>factor</em>-beta1 (L, -49%, P<0.05; H, -65%, P<0.01). cGMP levels were elevated by BAY41-2272 not only in the left ventricle, but also in cultured cardiac <em>fibroblasts</em>, resulting in reduced thymidine incorporation into the cells. Thus, stimulation of sGC by BAY41-2272 attenuates fibrosis of the left ventricle in rats with angiotensin II-induced hypertension partly in a pressure-independent manner, suggesting an important role for sGC generating cGMP in inhibiting cardiovascular remodeling.

BACKGROUND

Fibroblast growth factor 19 (FGF19) and FGF21 are considered to be novel adipokines that improve glucose tolerance and insulin sensitivity. In the current study, we investigated serum FGF19 and FGF21 levels in patients with gestational diabetes mellitus (GDM) and explored their relationships with anthropometric and endocrine parameters.

METHODS

Serum FGF19 and FGF21 levels were determined by enzyme-linked immunosorbent assay (ELISA) in patients with GDM (n = 30) and healthy pregnant controls (n = 60) matched for maternal and gestational age. Serum FGF19 and FGF21 levels were correlated with anthropometric, metabolic, and endocrine parameters.

RESULTS

Circulating levels of FGF19 were significantly reduced in patients with GDM relative to healthy pregnant subjects, whereas FGF21 levels were increased in GDM patients. Serum FGF19 levels independently and inversely correlated with insulin resistance (increased homeostasis model assessment of insulin resistance, HOMA-IR) and were positively related to serum adiponectin in both groups. In contrast, serum FGF21 levels independently and positively correlated with insulin resistance and serum triglycerides and were inversely related to serum adiponectin. In addition, in the combined population of both groups, those women with preconception polycystic ovary syndrome (PCOS) history had the lowest levels of FGF19, which were significantly lower than those in GDM patients without PCOS history and those in controls without PCOS history.

CONCLUSIONS

Circulating FGF19 levels are reduced in GDM patients, in contrast with FGF21 levels. Both serum FGF19 and FGF21 levels are strongly related to insulin resistance and serum levels of adiponectin. Considering the different situation between FGF19 and FGF21, we suggest that reduced serum FGF19 levels could be involved in the pathophysiology of GDM, while increased serum FGF21 levels could be in a compensatory response to this disease.

The incidence and prevalence of chronic and diabetic wounds are increasing and clinical treatments to tackle these epidemics are still insufficient. In this study, we tested the ability of freeze-dried platelet-rich plasma (PRP) and an allogenic micronized acellular dermal matrix alone and in combination to modulate diabetic wound healing. Therapeutic materials were applied to 1.0 cm(2) excisional wounds on genetically diabetic (db/db) mice. Wound-healing kinetics and new tissue formation were studied at 9 and <em>21</em> days posttreatment. Quantitative immunohistochemistry was used to study vascularity and cellular proliferation (days 9 and <em>21</em>), and collagen deposition was evaluated <em>21</em> days postwounding. In vitro, micronized allogenic dermis, when combined with PRP, absorbed nearly 50% of original platelet-derived <em>growth</em> <em>factor</em>, transforming <em>growth</em> <em>factor</em>-beta, vascular endothelial <em>growth</em> <em>factor</em>, and epidermal <em>growth</em> <em>factor</em> from platelets and stimulated <em>fibroblast</em> proliferation. In vivo, micronized dermis increased the formation of vascularized wound tissue by day 9. Freeze-dried PRP alone or in combination with micronized dermis increased wound tissue revascularization and proliferation compared with spontaneous healing. The increase in cell proliferation persisted until day <em>21</em> only when freeze-dried PRP was used in combination with micronized dermis. These results indicate that micronized allogenic dermis may be used to provide a dermal matrix to stimulate tissue formation and the combination with PRP may confer additional beneficial <em>growth</em> <em>factors</em> to chronic or diabetic wounds.

Skeletal muscle is the largest organ, comprising 40% of the total body lean mass, and affects whole-body metabolism in multiple ways. We investigated the signaling pathways involved in this process using TSCmKO mice, which have a skeletal muscle-specific depletion of TSC1 (tuberous sclerosis complex 1). This deficiency results in the constitutive activation of mammalian target of rapamycin complex 1 (mTORC1), which enhances cell <em>growth</em> by promoting protein synthesis. TSCmKO mice were lean, with increased insulin sensitivity, as well as changes in white and brown adipose tissue and liver indicative of increased fatty acid oxidation. These differences were due to increased plasma concentrations of <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>), a hormone that stimulates glucose uptake and fatty acid oxidation. The skeletal muscle of TSCmKO mice released FGF<em>21</em> because of mTORC1-triggered endoplasmic reticulum (ER) stress and activation of a pathway involving PERK (protein kinase RNA-like ER kinase), eIF2α (eukaryotic translation initiation <em>factor</em> 2α), and ATF4 (activating transcription <em>factor</em> 4). Treatment of TSCmKO mice with a chemical chaperone that alleviates ER stress reduced FGF<em>21</em> production in muscle and increased body weight. Moreover, injection of function-blocking antibodies directed against FGF<em>21</em> largely normalized the metabolic phenotype of the mice. Thus, sustained activation of mTORC1 signaling in skeletal muscle regulated whole-body metabolism through the induction of FGF<em>21</em>, which, over the long term, caused severe lipodystrophy.

Cancer-associated <em>fibroblasts</em> (CAFs) interact closely with cancer cells, supporting their <em>growth</em> and invasion. To investigate the role of microRNA-<em>21</em> (miR-<em>21</em>) in lung adenocarcinoma, and especially in its CAF component, in situ hybridisation was applied to samples from 89 invasive lung adenocarcinoma cases. MiR-<em>21</em> expression was observed in both cancer cells and CAFs. When the patients were stratified by expression, miR-<em>21</em> levels in CAFs (n = 9), but not in cancer cells (n = <em>21</em>), were inversely correlated with patient survival; patients with miR-<em>21</em>high CAFs exhibited lower survival than those with miR-<em>21</em>low CAFs. The underlying mechanism was investigated in vitro. Conditioned medium (CM) from A549 lung cancer cells increased miR-<em>21</em> expression in MRC-5 and IMR-90 lung <em>fibroblasts</em> through the transforming <em>growth</em> <em>factor</em>-β pathway, and induced CAF-like morphology and migratory capacity. MiR-<em>21</em> up-regulation in lung <em>fibroblasts</em> induced a novel CAF-secreted protein, calumenin, as well as known CAF markers (periostin, α-smooth muscle actin, and podoplanin). Moreover, CM from the lung <em>fibroblasts</em> increased A549 cell proliferation in a calumenin-dependent manner. Thus, miR-<em>21</em> expression in lung <em>fibroblasts</em> may trigger <em>fibroblast</em> trans-differentiation into CAFs, supporting cancer progression. Therefore, CAF miR-<em>21</em> represents a pivotal prognostic marker for this scar-forming cancer of the lungs.

<em>Fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) is an endocrine hormone that regulates metabolic homeostasis. Previous work has suggested that impairment of FGF<em>21</em> signaling in adipose tissue may occur through downregulation of the obligate FGF<em>21</em> co-receptor, β-klotho, which leads to "FGF<em>21</em> resistance" during the onset of diet-induced obesity. Here, we sought to determine whether maintenance of β-klotho expression in adipose tissue prevents FGF<em>21</em> resistance and whether other mechanisms also contribute to FGF<em>21</em> resistance in vivo.

We generated adipose-specific β-klotho transgenic mice to determine whether maintenance of β-klotho expression in adipose tissue prevents FGF<em>21</em> resistance in vivo.

β-klotho protein levels are markedly decreased in white adipose tissue, but not liver or brown adipose tissue, during diet-induced obesity. Maintenance of β-klotho protein expression in adipose tissue does not alleviate impaired FGF<em>21</em> signaling in white adipose or increase FGF<em>21</em> sensitivity in vivo.

In white adipose tissue, downregulation of β-klotho expression is not the major mechanism contributing to impaired FGF<em>21</em> signaling in white adipose tissue.

Non-alcoholic fatty liver disease (NAFLD) is associated with obesity and lifestyle, while exercise is beneficial for NAFLD. Dysregulated microRNAs (miRs) control the pathogenesis of NAFLD. However, whether exercise could prevent NAFLD via targeting microRNA is unknown. In this study, normal or high-fat diet (HF) mice were either subjected to a 16-week running program or kept sedentary. Exercise attenuated liver steatosis in HF mice. MicroRNA array and qRT-PCR demonstrated that miR-<em>21</em>2 was overexpressed in HF liver, while reduced by exercise. Next, we investigated the role of miR-<em>21</em>2 in lipogenesis using HepG2 cells with/without long-chain fatty acid treatment (± FFA). FFA increased miR-<em>21</em>2 in HepG2 cells. Moreover, miR-<em>21</em>2 promoted lipogenesis in HepG2 cells (± FFA). <em>Fibroblast</em> <em>growth</em> <em>factor</em> (FGF)-<em>21</em>, a key regulator for lipid metabolism, was negatively regulated by miR-<em>21</em>2 at protein level in HepG2 cells. Meanwhile, FFA downregulated FGF-<em>21</em> both at mRNA and protein levels in HepG2 cells. Also, FGF-<em>21</em> protein level was reduced in HF liver, while reversed by exercise in vivo. Furthermore, siRNA-FGF-<em>21</em> abolished the lipogenesis-reducing effect of miR-<em>21</em>2 inhibitor in HepG2 cells (± FFA), validating FGF-<em>21</em> as a target gene of miR-<em>21</em>2. These data link the benefit of exercise and miR-<em>21</em>2 downregulation in preventing NAFLD via targeting FGF-<em>21</em>.

<em>Fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) is a hormone secreted predominantly in the liver, pancreas and adipose tissue. Recently, it has been reported that FGF<em>21</em>-Transgenic mice can extend their lifespan compared with wild type counterparts. Thus, we hypothesize that FGF<em>21</em> may play some roles in aging of organisms. In this study d-galactose (d-gal)-induced aging mice were used to study the mechanism that FGF<em>21</em> protects mice from aging. The three-month-old Kunming mice were subcutaneously injected with d-gal (180mg·kg(-1)·d(-1)) for 8weeks and administered simultaneously with FGF<em>21</em> (1, 2 or 5mg·kg(-1)·d(-1)). Our results showed that administration of FGF<em>21</em> significantly improved behavioral performance of d-gal-treated mice in water maze task and step-down test, reduced brain cell damage in the hippocampus, and attenuated the d-gal-induced production of MDA, ROS and advanced glycation end products (AGEs). At the same time, FGF<em>21</em> also markedly renewed the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and total anti-oxidation capability (T-AOC), and decreased the enhanced total cholinesterase (TChE) activity in the brain of d-gal-treated mice. The expression of aldose reductase (AR), sorbitol dehydrogenase (SDH) and member-anchored receptor for AGEs (RAGE) declined significantly after FGF<em>21</em> treatment. Furthermore, FGF<em>21</em> suppressed inflamm-aging by inhibiting IκBα degradation and NF-κB p65 nuclear translocation. The expression levels of pro-inflammatory cytokines, such as TNF-α and IL-6, decreased significantly. In conclusion, these results suggest that FGF<em>21</em> protects the aging mice brain from d-gal-induced injury by attenuating oxidative stress damage and decreasing AGE formation.

<strong class="sub-title"> Background: </strong> Resident microglia and macrophages are the predominant contributors to neuroinflammation and immune reactions, which play a critical role in the pathogenesis of ischemic brain injury. Controlling inflammatory responses is considered a promising therapeutic approach for stroke. Recombinant human <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (rhFGF<em>21</em>) presents anti-inflammatory properties by modulating microglia and macrophages; however, our knowledge of the inflammatory modulation of rhFGF<em>21</em> in focal cerebral ischemia is lacking. Therefore, we investigated whether rhFGF<em>21</em> improves ischemic outcomes in experimental stroke by targeting microglia and macrophages.

<strong class="sub-title"> Methods: </strong> C57BL/6 mice were subjected to middle cerebral artery occlusion (MCAO) and randomly divided into groups that received intraperitoneal rhFGF<em>21</em> or vehicle daily starting at 6 h after reperfusion. Behavior assessments were monitored for 14 days after MCAO, and the gene expression levels of inflammatory cytokines were analyzed via qRT-PCR. The phenotypic variation of microglia/macrophages and the presence of infiltrated immune cells were examined by flow cytometry and immunostaining. Additionally, magnetic cell sorting (MACS) in combination with fluorescence-activated cell sorting (FACS) was used to purify microglia and macrophages.

<strong class="sub-title"> Results: </strong> rhFGF<em>21</em> administration ameliorated neurological deficits in behavioral tests by regulating the secretion of pro-inflammatory and anti-inflammatory cytokines. rhFGF<em>21</em> also attenuated the polarization of microglia/macrophages toward the M1 phenotype and the accumulation of peripheral immune cells after stroke, accompanied by a temporal evolution of the phenotype of microglia/macrophages and infiltration of peripheral immune cells. Furthermore, rhFGF<em>21</em> treatment inhibited M1 polarization of microglia and pro-inflammatory cytokine expression through its actions on FGF receptor 1 (FGFR1) by suppressing nuclear <em>factor</em>-kappa B (NF-κB) and upregulating peroxisome proliferator-activated receptor-γ (PPAR-γ).

<strong class="sub-title"> Conclusions: </strong> rhFGF<em>21</em> treatment promoted functional recovery in experimental stroke by modulating microglia/macrophage-mediated neuroinflammation via the NF-κB and PPAR-γ signaling pathways, making it a potential anti-inflammatory agent for stroke treatment.

<strong class="sub-title"> Keywords: </strong> Microglia/macrophage; NF-κB; Neuroinflammation; PPAR-γ; Stroke; rhFGF<em>21</em>.

We studied the role of the mineralocorticoid receptor (MR) in the signaling that promotes atrial fibrosis. Left atrial myocardium of patients with atrial fibrillation (AF) exhibited 4-fold increased hydroxyproline content compared with patients in sinus rhythm. Expression of MR was similar, as was 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), which also increased. 11β-HSD2 converts cortisol to receptor-inactive metabolites allowing aldosterone occupancy of MR. 11β-HSD2 was up-regulated by arrhythmic pacing in cultured cardiomyocytes and in a mouse model of spontaneous AF (RacET). In cardiomyocytes, aldosterone induced connective tissue <em>growth</em> <em>factor</em> (CTGF) in the absence but not in the presence of cortisol. Hydroxyproline expression was increased in cardiac <em>fibroblasts</em> exposed to conditioned medium from aldosterone-treated cardiomyocytes but not from cardiomyocytes treated with both cortisol and aldosterone. Aldosterone increased connective tissue <em>growth</em> <em>factor</em> and hydroxyproline expression in cardiac <em>fibroblasts</em>, which were prevented by BR-4628, a dihydropyridine-derived selective MR antagonist, and by spironolactone. Aldosterone activated RhoA GTPase. Rho kinase inhibition by Y-27632 prevented CTGF and hydroxyproline, whereas the RhoA activator CN03 increased CTGF expression. Aldosterone and CTGF increased lysyl oxidase, and aldosterone enhanced miR-<em>21</em> expression. MR antagonists reduced the aldosterone but not the CTGF effect. In conclusion, MR signaling promoted fibrotic remodeling. Increased expression of 11β-HSD2 during AF leads to up-regulation of collagen and pro-fibrotic mediators by aldosterone, specifically RhoA activity as well as CTGF, lysyl oxidase, and microRNA-<em>21</em> expression. The MR antagonists BR-4628 and spironolactone prevent these alterations. MR inhibition may, therefore, represent a potential pharmacologic target for the prevention of fibrotic remodeling of the atrial myocardium.

<AbstractText>Intravenous iron enables rapid correction of iron-deficiency anemia, but certain formulations induce <em>fibroblast</em> <em>growth</em> <em>factor</em> 23-mediated hypophosphatemia.</AbstractText><AbstractText>To compare risks of hypophosphatemia and effects on biomarkers of mineral and bone homeostasis of intravenous iron isomaltoside (now known as ferric derisomaltose) vs ferric carboxymaltose.</AbstractText><AbstractText>Between October 2017 and June 2018, 245 patients aged 18 years and older with iron-deficiency anemia (hemoglobin level ≤11 g/dL; serum ferritin level ≤100 ng/mL) and intolerance or unresponsiveness to 1 month or more of oral iron were recruited from 30 outpatient clinic sites in the United States into 2 identically designed, open-label, randomized clinical trials. Patients with reduced kidney function were excluded. Serum phosphate and 12 additional biomarkers of mineral and bone homeostasis were measured on days 0, 1, 7, 8, 14, <em>21</em>, and 35. The date of final follow-up was June 19, 2018, for trial A and May 29, 2018, for trial B.</AbstractText><AbstractText>Intravenous administration of iron isomaltoside, 1000 mg, on day 0 or ferric carboxymaltose, 750 mg, infused on days 0 and 7.</AbstractText><AbstractText>The primary end point was the incidence of hypophosphatemia (serum phosphate level <2.0 mg/dL) between baseline and day 35.</AbstractText><AbstractText>In trial A, 123 patients were randomized (mean [SD] age, 45.1 [11.0] years; 95.9% women), including 62 to iron isomaltoside and 61 to ferric carboxymaltose; 95.1% completed the trial. In trial B, 122 patients were randomized (mean [SD] age, 42.6 [12.2] years; 94.1% women), including 61 to iron isomaltoside and 61 to ferric carboxymaltose; 93.4% completed the trial. The incidence of hypophosphatemia was significantly lower following iron isomaltoside vs ferric carboxymaltose (trial A: 7.9% vs 75.0% [adjusted rate difference, -67.0% {95% CI, -77.4% to -51.5%}], P < .001; trial B: 8.1% vs 73.7% [adjusted rate difference, -65.8% {95% CI, -76.6% to -49.8%}], P < .001). Beyond hypophosphatemia and increased parathyroid hormone, the most common adverse drug reactions (No./total No.) were nausea (iron isomaltoside: 1/125; ferric carboxymaltose: 8/117) and headache (iron isomaltoside: 4/125; ferric carboxymaltose: 5/117).</AbstractText><AbstractText>In 2 randomized trials of patients with iron-deficiency anemia who were intolerant of or unresponsive to oral iron, iron isomaltoside (now called ferric derisomaltose), compared with ferric carboxymaltose, resulted in lower incidence of hypophosphatemia over 35 days. However, further research is needed to determine the clinical importance of this difference.</AbstractText><AbstractText>ClinicalTrials.gov Identifiers: NCT03238911 and NCT03237065.</AbstractText>

Glucocorticoids (GCs) regulate energy supply in response to stress by increasing hepatic gluconeogenesis during fasting. Long-term GC treatment induces hepatic steatosis and weight gain. GC signaling is coordinated via the GC receptor (GR) GRα, as the GRβ isoform lacks a ligand-binding domain. The roles of the GR isoforms in the regulation of lipid accumulation is unknown. The purpose of this study was to determine whether GRβ inhibits the actions of GCs in the liver, or enhances hepatic lipid accumulation. We show that GRβ expression is increased in adipose and liver tissues in obese high-fat fed mice. Adenovirus-mediated delivery of hepatic GRβ overexpression (GRβ-Ad) resulted in suppression of gluconeogenic genes and hyperglycemia in mice on a regular diet. Furthermore, GRβ-Ad mice had increased hepatic lipid accumulation and serum triglyceride levels possibly due to the activation of NF-κB signaling and increased tumor necrosis <em>factor</em> α (TNFα) and inducible nitric-oxide synthase expression, indicative of enhanced M1 macrophages and the development of steatosis. Consequently, GRβ-Ad mice had increased glycogen synthase kinase 3β (GSK3β) activity and reduced hepatic PPARα and <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) expression and lower serum FGF<em>21</em> levels, which are two proteins known to increase during fasting to enhance the burning of fat by activating the β-oxidation pathway. In conclusion, GRβ antagonizes the GC-induced signaling during fasting via GRα and the PPARα-FGF<em>21</em> axis that reduces fat burning. Furthermore, hepatic GRβ increases inflammation, which leads to hepatic lipid accumulation.

Nowadays non-alcoholic fatty liver disease (NAFLD) is becoming the most common chronic liver pathology both in adults and children. NAFLD manifestation ranges from a simple liver steatosis to steatohepatitis (nonalcoholic steatohepatitis - NASH), which may progress to advanced fibrosis, cirrhosis and end-stage liver disease. Due to the coexistence of visceral obesity, insulin resistance and dyslipidemia, NAFLD is considered to be the hepatic manifestation of metabolic syndrome. In recent years, in the pathogenesis of metabolic syndrome, type 2 diabetes mellitus, cardiovascular disease and also NAFLD, more and more attention has been paid to the so-called organokines, proteins with both paracrine or/and endocrine activities. These include most known adipokines (mainly produced by adipose tissue), myokines (mainly produced by skeletal muscles) and hepatokines exclusively or predominantly produced by the liver. It was shown that the liver may affect the lipids and glucose metabolism by hepatokines released into the blood and NAFLD seems to be associated with altered hepatokines production. Fetuin-A, <em>fibroblast</em> <em>growth</em> <em>factor</em>-<em>21</em> (FGF-<em>21</em>), selenoprotein P, sex hormone-binding globulin (SHBG), angiopoietin-related <em>growth</em> <em>factor</em> (also known as angiopoietin-related protein 6) and leukocyte derived chemotaxin 2 (LECT2) are considered as the most important hepatokines. In this review, we provide an overview of the main hepatokines and we summarize the association of liver-derived proteins with the development and progression of NAFLD.

Bile acids are signaling molecules that play a critical role in regulation of hepatic metabolic homeostasis by activating nuclear farnesoid X receptor (Fxr) and membrane G-protein-coupled receptor (Takeda G-protein-coupled receptor 5; Tgr5). The role of FXR in regulation of bile acid synthesis and hepatic metabolism has been studied extensively. However, the role of TGR5 in hepatic metabolism has not been explored. The liver plays a central role in lipid metabolism, and impaired response to fasting and feeding contributes to steatosis and nonalcoholic fatty liver and obesity. We have performed a detailed analysis of gallbladder bile acid and lipid metabolism in Tgr5-/- mice in both free-fed and fasted conditions. Lipid profiles of serum, liver and adipose tissues, bile acid composition, energy metabolism, and messenger RNA and protein expression of the genes involved in lipid metabolism were analyzed. Results showed that deficiency of the Tgr5 gene in mice alleviated fasting-induced hepatic lipid accumulation. Expression of liver oxysterol 7α-hydroxylase in the alternative bile acid synthesis pathway was reduced. Analysis of gallbladder bile acid composition showed marked increase of taurocholic acid and decrease of tauro-α and β-muricholic acid in Tgr5-/- mice. Tgr5-/- mice had increased hepatic fatty acid oxidation rate and decreased hepatic fatty acid uptake. Interestingly, fasting induction of <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> in liver was attenuated. In addition, fasted Tgr5-/- mice had increased activation of hepatic <em>growth</em> hormone-signal transducer and activator of transcription 5 (GH-Stat5) signaling compared to wild-type mice.

TGR5 may play a role in determining bile acid composition and in fasting-induced hepatic steatosis through a novel mechanism involving activation of the GH-Stat5 signaling pathway. (Hepatology 2017;65:813-827).

OBJECTIVE

Type 2 diabetes arises from insulin resistance of peripheral tissues followed by dysfunction of β-cells in the pancreas due to metabolic stress. Both depletion and supplementation of neutral amino acids have been discussed as strategies to improve insulin sensitivity. Here we characterise mice lacking the intestinal and renal neutral amino acid transporter B(0)AT1 (Slc6a19) as a model to study the consequences of selective depletion of neutral amino acids.

METHODS

Metabolic tests, analysis of metabolite levels and signalling pathways were used to characterise mice lacking the intestinal and renal neutral amino acid transporter B(0)AT1 (Slc6a19).

RESULTS

Reduced uptake of neutral amino acids in the intestine and loss of neutral amino acids in the urine causes an overload of amino acids in the lumen of the intestine and reduced systemic amino acid availability. As a result, higher levels of glucagon-like peptide 1 (GLP-1) are produced by the intestine after a meal, while the liver releases the starvation hormone <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>). The combination of these hormones generates a metabolic phenotype that is characterised by efficient removal of glucose, particularly by the heart, reduced adipose tissue mass, browning of subcutaneous white adipose tissue, enhanced production of ketone bodies and reduced hepatic glucose output.

CONCLUSIONS

Reduced neutral amino acid availability improves glycaemic control. The epithelial neutral amino acid transporter B(0)AT1 could be a suitable target to treat type 2 diabetes.

As one of fibroblast growth factor (FGF) family members, FGF21 has been extensively investigated for its potential as a drug candidate to combat metabolic diseases. In the present study, recombinant human FGF21 (rhFGF21) was modified with polyethylene glycol (PEGylation) in order to increase its in vivo biostabilities and therapeutic potency. At N-terminal residue rhFGF21 was site-selectively PEGylated with mPEG20 kDa-butyraldehyde. The PEGylated rhFGF21 was purified to near homogeneity by Q Sepharose anion-exchange chromatography. The general structural and biochemical features as well as anti-diabetic effects of PEGylated rhFGF21 in a type 2 diabetic rat model were evaluated. By N-terminal sequencing and MALDI-TOF mass spectrometry, we confirmed that PEG molecule was conjugated only to the N-terminus of rhFGF21. The mono-PEGylated rhFGF21 retained the secondary structure, consistent with the native rhFGF21, but its biostabilities, including the resistance to physiological temperature and trypsinization, were significantly enhanced. The in vivo immunogenicity of PEGylated rhFGF21 was significantly decreased, and in vivo half-life time was significantly elongated. Compared to the native form, the PEGylated rhFGF21 had a similar capacity of stimulating glucose uptake in 3T3-L1 cells in vitro, but afforded a significantly long effect on reducing blood glucose and triglyceride levels in the type 2 diabetic animals. These results suggest that the PEGylated rhFGF21 is a better and more effective anti-diabetic drug candidate than the native rhFGF21 currently available. Therefore, the PEGylated rhFGF21 may be potentially applied in clinics to improve the metabolic syndrome for type 2 diabetic patients.

IFN regulatory <em>factor</em>-1 (IRF-1) regulates the IFN system, inhibits cell <em>growth</em>, and has tumor-suppressor activities. p<em>21</em> is a universal cyclin-dependent kinase inhibitor, the induction of which depends on both p53 and IRF-1 in mouse embryonic <em>fibroblasts</em>. The expression of p<em>21</em> in hepatocellular carcinomas (HCCs) is regulated by wild-type p53. We examined the expressions of IRF-1 and p<em>21</em> in 32 HCCs by quantitative reverse transcription-PCR and the mutation p53 gene in 32 HCCs by single-strand conformation polymorphism and direct sequencing. The expression of IRF-1 mRNA in 15 of 32 HCCs was lower than that in adjacent noncancerous tissue. IRF-1 mRNA expression was reduced in 0 of 3 specimens of well-differentiated HCC, 9 of <em>21</em> (42%) specimens of moderately differentiated HCC, and 6 of 8 (75%) specimens of poorly differentiated HCC. IRF-1 mRNA expression was significantly lower in tumors with portal thrombus than in those without portal thrombus (P = 0.003). p53 mutations were detected in 7 of 32 HCCS: p<em>21</em> expression was reduced in 6 of the 7 (86%) HCCs with p53 mutations. In contrast, p<em>21</em> expression was reduced in 13 of 25 (52%) HCCs with wild-type p53. IRF-1 expression was reduced in 7 of 13 (53%) HCCs with both wild-type p53 and reduced expression of p<em>21</em>. These results suggest that IRF-1 may be a tumor-suppressor gene for HCC and that IRF-1 is related to p<em>21</em> expression in HCC with wild-type p53.

The conventional method for the derivation of human embryonic stem cells (hESCs) involves inner cell mass (ICM) co-culture with a feeder layer of inactivated mouse or human embryonic <em>fibroblasts</em> in an in vitro fertilisation culture dish. <em>Growth</em> <em>factors</em> potentially involved in primary derivation of hESCs may be lost or diluted in such a system. We established a microdrop method which maintained feeder cells and efficiently generated hESCs. Embryos were donated for stem cell research after fully informed patient consent. A feeder cell layer was made by incubating inactivated mouse embryonic <em>fibroblasts</em> (MEFs) feeder cells in a 50 microl drop of medium (DMEM/10% foetal calf serum) under mineral oil in a small tissue culture dish. MEFs formed a confluent layer and medium was replaced with human embryonic stem medium supplemented with 10% Plasmanate (Bayer) and incubated overnight. Cryopreserved embryos were thawed and cultured until the blastocyst stage and the zona pellucida removed with pronase (2 mg/ml; Calbiochem). A zona-free intact blastocyst was placed in the feeder microdrop and monitored for ES derivation with medium changed every 2-3 d. Proliferating hESCs were passaged into other feeder drops and standard feeder preparation by manual dissection until a stable cell line was established. Six hESC lines (Shef 3-8) were derived. From a total of 46 blastocysts (early to expanded), five hESC lines were generated (Shef 3-7). Shef 3-6 were generated on MEFs from 25 blastocysts. Shef7 was generated on human foetal gonadal embryonic <em>fibroblasts</em> from a further <em>21</em> blastocysts. From our experience, microdrop technique is more efficient than conventional method for derivation of hESCs and it is much easier to monitor early hESC derivation. The microdrop method lends itself to good manufacturing practice derivation of hESCs.

Platelet-derived <em>growth</em> <em>factor</em> (PDGF-BB homodimer) and transforming <em>growth</em> <em>factor</em>-beta 1 (TGF-beta 1) are potent wound-healing hormones that accelerate incisional repair. To identify more precisely and quantitatively the stage(s) of wound healing influenced by <em>growth</em>-<em>factor</em> therapy, we investigated the three sequential tissue repair processes--inflammatory cell influx, intracellular procollagen type I (PC-I) synthesis, and collagen cross-linking--in recombinant <em>growth</em> <em>factor</em>--treated wounds. Using newly developed automated, quantitative image-analysis techniques, we observed that PDGF-BB markedly augmented the directed migration of macrophages into wounds during the first week after wounding and triggered and earlier and more sustained influx of PC-I--containing <em>fibroblasts</em> into the wound when compared with results in TGF-beta 1-treated or control wounds (p = 0.015 at day 2; p = 0.007 at day <em>21</em>). In contrast, automated image analysis revealed TGF-beta 1-treated wound <em>fibroblasts</em> had a nearly twofold increase in intracellular levels of PC-I protein when compared with PDGF-BB-treated or control wound <em>fibroblasts</em> (p = 0.004 at day 4). However, the influence of TGF-beta 1 was transient, and the longer duration of PDGF-BB activity suggested a later influence, perhaps on the collagen remodeling phase, which is ultimately required for increased wound strength. To address this possibility, collagen cross-linking in <em>growth</em> <em>factor</em>-treated wounds was inhibited by beta-aminoproprionitrile (BAPN) treatment, and wound breaking strength was analyzed. Both PDGF-BB and TGF-beta 1 continued to enhance repair in BAPN-treated rats, indicating that they do not function primarily at the level of collagen cross-linking. Thus, PDGF-BB appears to enhance the inflammatory phase of wound healing to indirectly trigger PC-I synthesis, whereas TGF-beta 1 quantitatively enhances PC-I synthesis directly, accounting for their differing duration of activities within healing wounds.

Apert syndrome is an autosomal dominant condition characterized by craniosynostosis and severe syndactyly, caused by two recurrent mutations in the <em>fibroblast</em> <em>growth</em> <em>factor</em> receptor 2 gene (FGFR2). The genotype-phenotype correlations of <em>21</em> patients with Apert syndrome were analysed as to the craniofacial appearance following surgery and the degree of syndactlyly. The craniofacial appearance following craniofacial surgery was better in patients with the P253R mutation, whereas these patients showed a more pronounced severity of the syndactyly.

Proteoglycan 4 (Prg4), known for its lubricating and protective actions in joints, is a strong candidate regulator of skeletal homeostasis and parathyroid hormone (PTH) anabolism. Prg4 is a PTH-responsive gene in bone and liver. Prg4 null mutant mice were used to investigate the impact of proteoglycan 4 on skeletal development, remodeling, and PTH anabolic actions. Young Prg4 mutant and wild-type mice were administered intermittent PTH(1-34) or vehicle daily from 4 to <em>21</em> days. Young Prg4 mutant mice had decreased <em>growth</em> plate hypertrophic zones, trabecular bone, and serum bone formation markers versus wild-type mice, but responded with a similar anabolic response to PTH. Adult Prg4 mutant and wild-type mice were administered intermittent PTH(1-34) or vehicle daily from 16 to 22 weeks. Adult Prg4 mutant mice had decreased trabecular and cortical bone, and blunted PTH-mediated increases in bone mass. Joint range of motion and animal mobility were lower in adult Prg4 mutant versus wild-type mice. Adult Prg4 mutant mice had decreased marrow and liver <em>fibroblast</em> <em>growth</em> <em>factor</em> 2 (FGF-2) mRNA and reduced serum FGF-2, which were normalized by PTH. A single dose of PTH decreased the PTH/PTHrP receptor (PPR), and increased Prg4 and FGF-2 to a similar extent in liver and bone. Proteoglycan 4 supports endochondral bone formation and the attainment of peak trabecular bone mass, and appears to support skeletal homeostasis indirectly by protecting joint function. Bone- and liver-derived FGF-2 likely regulate proteoglycan 4 actions supporting trabeculae formation. Blunted PTH anabolic responses in adult Prg4 mutant mice are associated with altered biomechanical impact secondary to joint failure.

OBJECTIVE

<em>Fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) levels have been linked with beneficial effects on glucose and lipid metabolism in animals. It is elevated in humans with the metabolic syndrome. This study investigates independent <em>factors</em> associated with serum FGF<em>21</em> levels.

METHODS

Cross-sectional study done in healthy blue-collar workers.

METHODS

A medical history was taken, and FGF<em>21</em> (measured using an ELISA commercial kit), glucose, uric acid, plasma lipids, total/high-molecular weight (HMW) adiponectin, and retinal-binding protein 4 (RBP4) were measured in <em>21</em>0 individuals with (n=81) and without (n=129) metabolic syndrome.

RESULTS

The median of serum FGF<em>21</em> levels were higher in subjects with metabolic syndrome (339.5 vs 276.4 ng/l, P=0.01). Serum FGF<em>21</em> levels correlated positively with body mass index (BMI; r=0.23, P=0.001) and age (r=0.17, P=0.01). After adjusting for age and BMI, a significant positive correlation persisted for fasting glucose, uric acid, and physical activity in both males (r=0.<em>21</em>, r=0.11, and r=0.19, all P<0.05) and females (r=0.20, r=0.19, and r=0.14, all P<0.05). In addition, FGF<em>21</em> also correlates negatively with RBP4 (r=-0.27, P=0.02), total (r=-0.26, P=0.03), and HMW adiponectin (r=-0.30, P=0.01) in women. A multiple linear regression model analysis identified that BMI (standardized beta (SB)=0.247; P=0.008), glucose (SB=0.226; P=0.003), uric acid (SB=0.191; P=0.04), and physical activity (SB=0.223; P=0.004) are independent <em>factors</em> influencing serum FGF<em>21</em> levels (F=10.05, r(2)=0.19, P<0.001). In addition, fasting hyperglycemia>> or =100 mg/dl, excess body weight with BMI>> or =25 kg/m(2), and uric acid>> or =5.5 mg/dl predicted higher serum FGF<em>21</em> levels.

CONCLUSIONS

Serum FGF<em>21</em> levels are influenced by BMI, fasting glycemia, uric acid, and physical activity.