OBJECTIVE

To evaluate the modulation of wound healing and soft tissue ingrowth in synthetic and allogeneic implants with platelet gel. Attempts to influence wound healing with exogenous growth factors are highly dependent on the timing and dosing of treatment. Platelet gel made from autologous platelet concentrate (PC) and activated with calcium thrombin is increasingly used to enhance healing of surgical and chronic wounds, based on the assumption that proteins found in the blood can promote healing.

METHODS

Adult New Zealand white rabbits underwent phlebotomy, and the blood was used to produce nonconcentrated autologous blood clot, platelet-poor plasma (PPP), and PC for each animal. Disks of porous high-density polyethylene (PHDPE) and acellular dermal graft (ADG) were implanted into each animal in a subcutaneous location. Implants of each type were treated with isotonic sodium chloride solution, PPP, PPP followed immediately with PC, or autologous blood clot (by means of manual impregnation). Animals were killed at 2, 7, 14, and 21 days after implantation. Implants were harvested with surrounding soft tissue and examined by means of light microscopy for evidence of acute and chronic inflammatory cells and vascular and fibroblast invasion.

RESULTS

A platelet gel with platelet concentrations averaging 5.8 times greater than those of peripheral blood significantly improved wound healing and soft tissue ingrowth in surgically implanted grafts. Early inflammatory infiltrates were enhanced in PHDPE and ADG implants by PC and autologous blood clot compared with control implants, as evidenced by significantly increased neutrophil and macrophage counts at day 2. Compared with controls, statistically significant increases in fibroblast and endothelial cell counts were noted at day 7 in PC-treated implants (fibroblasts, 61% increase [P < .001] in PHDPE implants and 52% increase [P < .001] in ADG implants; capillaries, 95% increase [P < .05] in PHDPE and 97% increase [P < .001] in ADG implants). Lymphocyte counts were increased by PC in PHDPE and ADG implants (71% [P < .001] and 100% [P < .05], respectively). There were no statistically significant differences in any cell count variables beyond 7 days.

CONCLUSIONS

Treatment with PC prepared at 5 times the baseline platelet count significantly accelerated maturation of experimental wounds. By 14 days, the degree and quality of wound cellularity were equivalent among all treatment groups. Rapid wound healing was expected with this surgical model, which was chosen to observe the biological effects on early wound healing of a platelet gel in a noncompromised wound. Treatment with PC may be useful in scenarios in which enhancement and acceleration of early wound healing is desired.

Matrix metalloproteinase (MMP)-<em>21</em> and MMP-26 (matrilysin-2) are two recently cloned epithelial metalloproteases. Here we examined their expression in various benign skin disorders, in which macrophages and <em>fibroblasts</em> have been implicated as well as in cultures of these cells. Expression of MMP-<em>21</em> was detected by immunohistochemistry in a subset of macrophages of granulomatous skin lesions and in <em>fibroblasts</em> in dermatofibromas. MMP-<em>21</em> mRNA was found in THP-1, U937, HEL 299 and Hs68 cells. Furthermore, MMP-<em>21</em> protein was detected by immunohistochemistry in cultures of the same cell lines. In culture MMP-<em>21</em> was upregulated by phorbol myristate acetate in THP-1 cells and by retinoic acid (RA) in U937 cells, and downregulated by transforming <em>growth</em> <em>factor</em> beta 1 (TGF-beta1) in HEL 299 as assessed by Taqman quantitative polymerase chain reaction (PCR). Expression of MMP-26 was detected by immunohistochemistry in granulomatous skin diseases and actinic elastosis. MMP-26 at both mRNA and protein levels was only found in HEL 299 cells. In culture it was downregulated by TGF-beta1, RA and IL-1beta as assessed by Taqman quantitative PCR. Our results suggest these two novel MMPs are not only associated with cancer but may be important in connective tissue remodelling and pathobiology of various benign skin disorders.

1,25-dihydroxycholecalciferol [1,25(OH)(2)D(3)] is important in the regulation of cell <em>growth</em>, differentiation, and apoptosis. Previous results from our laboratory demonstrate that 1,25(OH)(2)D(3) inhibits vitamin E succinate (VES) mediated apoptosis in untransformed C3H10T1/2 mouse <em>fibroblast</em> cells. The current work investigated cell survival signaling pathways that may be activated by 1,25(OH)(2)D(3), leading to protection from apoptosis. Results showed that nuclear <em>factor</em> kappaB (NFkappaB) transcriptional activity was significantly increased 1.8-fold over vehicle controls by 1,25(OH)(2)D(3) after 4 h of treatment. Protein kinase B/AKT, a downstream effector of phosphoinositide 3-kinase (PI3K), was activated 4-fold and 8-fold at 2 and 4 h, respectively, after treatment with 1,25(OH)(2)D(3). Pretreatment with two PI3K inhibitors, LY294002 and wortmannin, abolished the activation of NFkappaB by 1,25(OH)(2)D(3), suggesting that this pathway is essential for NFkappaB transcriptional activation. Additionally, the use of a p-<em>21</em> activated kinase (PAK1) inhibitory construct (PAK(R299)) demonstrated that PAK1 was also required for NFkappaB transcriptional activation by 1,25(OH)(2)D(3). Inhibition of NFkappaB activity with transfection of the NFkappaB inhibitory construct (IkappaB(Ala32)) abolished the protective effect of 1,25(OH)(2)D(3) on VES-mediated apoptosis. In summary, NFkappaB transcriptional activation was essential to 1,25(OH)(2)D(3) protection from VES-mediated apoptosis and 1,25(OH)(2)D(3) regulated NFkappaB activity through PI3K and PAK pathways.

Type 2 diabetes is characterized by a deterioration of glucose tolerance, which associates insulin resistance of glucose uptake by peripheral tissues and increased endogenous glucose production. Here we report that the specific suppression of hepatic glucose production positively modulates whole-body glucose and energy metabolism. We used mice deficient in liver glucose-6 phosphatase that is mandatory for endogenous glucose production. When they were fed a high fat/high sucrose diet, they resisted the development of diabetes and obesity due to the activation of peripheral glucose metabolism and thermogenesis. This was linked to the secretion of hepatic hormones like <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> and angiopoietin-like <em>factor</em> 6. Interestingly, the deletion of hepatic glucose-6 phosphatase in previously obese and insulin-resistant mice resulted in the rapid restoration of glucose and body weight controls. Therefore, hepatic glucose production is an essential lever for the control of whole-body energy metabolism during the development of obesity and diabetes.

Thyroid hormone is a potent regulator of metabolic and energy homeostasis implicated in various metabolic diseases. <em>Fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em>(FGF<em>21</em>) is a systemic metabolic regulator known to modulate various biological functions similar to the actions of thyroid hormone. We investigated the differences in plasma FGF<em>21</em> concentrations in patients with varying thyroid function. Ninety drug-naïve subjects who underwent thyroid evaluation at Seoul National University Bundang Hospital were enrolled and classified into euthyroid, subclinical hypothyroid, and overtly hypothyroid groups. Biochemical markers and plasma FGF<em>21</em> levels were measured and analyzed. The mean age of the subjects was 42.6 ± 9.1 years. The mean body mass index (BMI), waist circumference, and fasting glucose concentrations were similar between groups. Overtly hypothyroid subjects exhibited significantly higher concentrations of total cholesterol, triglyceride, and LDL-cholesterol than the other groups (p<0.01). Mean plasma FGF<em>21</em> concentrations in euthyroid, subclinical hypothyroid and overtly hypothyroid groups were 43.2 ± 39.2 pg/mL, 63.6 ± 73.6 pg/mL, and 101.5 ± 74.9 pg/mL, respectively (p<0.01 between groups). Plasma FGF<em>21</em> concentrations remained significantly higher in overtly hypothyroid subjects after adjusting for serum triglyceride concentrations (p<0.005). Multivariate analysis revealed a significant positive linear relationship between serum TSH concentrations and plasma FGF<em>21</em> concentrations (β = 0.192, p = 0.002) and a significant negative linear relationship between free T4 and plasma FGF<em>21</em> concentrations (β = -0.382, p = 0.037) after adjusting for gender, BMI and serum concentrations of triglycerides and glucose. Plasma FGF<em>21</em> levels were significantly increased in patients with hypothyroidism independently of BMI, or lipid or glucose metabolism.

OBJECTIVE

The haematopoietic activity of erythropoietin (EPO) is mediated by the classic EPO receptor (EpoR) homodimer, whereas tissue-protective effects are mediated by a heterocomplex between EpoR and the β-common receptor (βcR). Here, we investigated the effects of a novel, selective ligand of this heterocomplex - pyroglutamate helix B surface peptide (pHBSP) - in mice fed a diet enriched in sugars and saturated fats.

METHODS

Male C57BL/6J mice were fed a high-fat high-sucrose diet (HFHS) for 22 weeks. pHBSP (30 μg·kg(-1) s.c.) was administered for the last 11 weeks. Biochemical assays, histopathological and immunohistochemical examinations and Western blotting were performed on serum and target organs (liver, kidney and skeletal muscle).

RESULTS

Mice fed with HFHS diet exhibited insulin resistance, hyperlipidaemia, hepatic lipid accumulation and kidney dysfunction. In gastrocnemius muscle, HFHS impaired the insulin signalling pathway and reduced membrane translocation of glucose transporter type 4 and glycogen content. Treatment with pHBSP ameliorated renal function, reduced hepatic lipid deposition, and normalized serum glucose and lipid profiles. These effects were associated with an improvement in insulin sensitivity and glucose uptake in skeletal muscle. Diet-induced overproduction of the myokines IL-6 and <em>fibroblast</em> <em>growth</em> <em>factor</em>-<em>21</em> were attenuated by pHBSP and, most importantly, pHBSP markedly enhanced mitochondrial biogenesis in skeletal muscle.

CONCLUSIONS

Chronic treatment of mice with an EPO derivative, devoid of haematopoietic effects, improved metabolic abnormalities induced by a high-fat high-sucrose diet, by affecting several levels of the insulin signalling and inflammatory cascades within skeletal muscle, while enhancing mitochondrial biogenesis.

During pregnancy, the woman's body undergoes tremendous changes in immune system adaptation. The immunological shifts that occur in pregnancy can partially be explained by alterations in hormonal levels. Furthermore, during pregnancy, many autoimmune diseases go into remission, only to flare again in the early postpartum period. Given these important changes in the clinical course of a number of autoimmune disorders, surprisingly little has been done to investigate the inflammatory profile changes across pregnancy and the postpartum period. Thus, the aim of this study was to describe how inflammatory and anti-inflammatory markers change from late pregnancy to the early postpartum period, using a multiplexed assay consisting of both well-known as well as exploratory proteins. Two-hundred-and-ninety women were included in this study and donated a total of 312 blood samples; 198 in late pregnancy (~gw38) and 114 in the postpartum period (~w8). The plasma blood samples were analyzed for 92 immune system related protein markers using Proseek Multiplex Inflammation I panel, a high-sensitivity assay based on proximity extension assay technology. Fifty-six inflammatory and anti-inflammatory markers were significantly different between pregnancy and the postpartum, of which 50 survived corrections for multiple comparisons. Out of these 50 markers, 41 decreased from pregnancy to postpartum, while the remaining 9 increased in the postpartum period. The top five markers with the greatest decrease in the postpartum period were Leukemia inhibitory <em>factor</em> receptor (LIF-R), Latency-associated peptide Transforming <em>growth</em> <em>factor</em> beta-1 (LAP TGF-beta-1), C-C motif chemokine 28 (CCL28), Oncostatin M (OSM) and <em>Fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>). Top three markers that increased in the postpartum period were Tumor necrosis <em>factor</em> ligand superfamily member 11 (TRANCE), Tumor necrosis <em>factor</em> ligand superfamily member 12 (TWEAK), and C-C motif chemokine/Eotaxin (CCL11). This study revealed that the majority of the markers decreased from pregnancy to postpartum, and only a few increased. Several of the top proteins that were higher in pregnancy than postpartum have anti-inflammatory and immune modulatory properties promoting pregnancy progress. These results clearly reflect the tremendous change in the immune system in the pregnancy to postpartum transition.

<em>Fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) is an attractive target for treating metabolic disease due to its wide-ranging beneficial effects on glucose and lipid metabolism. Circulating FGF<em>21</em> levels are increased in insulin-resistant states; however, endogenous FGF<em>21</em> fails to improve glucose and lipid metabolism in obesity, suggesting that metabolic syndrome is an FGF<em>21</em>-resistant state. Therefore, transcription <em>factors</em> for FGF<em>21</em> are potential drug targets that could increase FGF<em>21</em> expression in obesity and reduce FGF<em>21</em> resistance. Despite many studies on the metabolic effects of FGF<em>21</em>, the transcriptional regulation of FGF<em>21</em> gene expression remains controversial and is not fully understood. As the FGF<em>21</em> transcription <em>factor</em> pathway is one of the most promising targets for the treatment of metabolic syndrome, further investigation of FGF<em>21</em> transcriptional regulation is required.

BACKGROUND

Elevated levels of circulating <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) are commonly encountered in type 2 diabetes, dyslipidemia, and non-alcoholic fatty liver disease, all of which share exaggerated postprandial lipemia as a common proatherogenic feature. How FGF<em>21</em> responds to an oral fat load in man is unknown.

METHODS

We measured liver fat contents and subcutaneous and visceral fat volumes in 47 healthy subjects, who also underwent an oral fat load with measurements of plasma FGF<em>21</em> and free fatty acid (FFA). Triglyceride (TG), apolipoprotein B-48 (apoB-48), and apoB-100 concentrations were measured in triglyceride-rich lipoprotein (TRL) fractions.

RESULTS

When compared with fasting levels, the concentration of FGF<em>21</em> decreased significantly at 4 h (P < 0.05) and tended to return to fasting levels at 8 h after an oral fat load. Fasting and postprandial FGF<em>21</em> correlated significantly with liver fat as well as with TRLs in the chylomicron and especially in very low-density lipoprotein 1 (VLDL1) and VLDL2 fractions representing remnant particles, but not with FFA. Subjects with increased liver fat (>5%, n = 12) showed impaired suppression of FGF<em>21</em> at 4 h (P < 0.05) and at 8 h (P=0.01) and demonstrated higher postprandial TG area under the curve in plasma and TRL fractions (P ≤ 0.032) compared with those with normal liver fat (≤ 5%, n = 35).

CONCLUSIONS

We observed a significant decrease of FGF<em>21</em> concentration after an oral fat load. Fasting and postprandial FGF<em>21</em> levels were closely related to large VLDL and remnants, but not to plasma FFA. Our pilot findings suggest that the postprandial accumulation of TRL remnants and liver fat may modulate postprandial FGF<em>21</em> levels.

<em>Fibroblast</em> <em>growth</em> <em>factors</em> (FGFs) bind to extracellular matrices, especially heparin-like carbohydrates of heparan-sulfate proteoglycans which stabilize FGFs to protect against inactivation by heat, acid, proteolysis and oxidation. Moreover, binding of FGFs to cell surface proteoglycans promotes to form oligomers, which is essential for receptor oligomerization and activation. In the present study, we determined the solution structure of acidic FGF using a series of triple resonance multi-dimensional NMR experiments and simulated annealing calculations. Furthermore, we prepared the sample complexed with a heparin-derived hexasaccharide which is a minimum unit for aFGF binding. From the chemical shift differences between free aFGF and aFGF-heparin complex, we concluded that the major heparin binding site was located on the regions 110-131 and 17-<em>21</em>. The binding sites are quite similar to those observed for bFGF-heparin hexasaccharide complex, showing that both FGFs recognize heparin-oligosaccharides in a similar manner.

BACKGROUND

New biological markers with predictive or prognostic value are highly warranted in the treatment of ovarian cancer. The platelet-derived growth factor (PDGF) system and fibroblast growth factor (FGF) system are important components in tumor growth and angiogenesis.

METHODS

Pre-surgery peripheral blood samples were collected consecutively from 213 patients (42 with normal ovaries, 54 with benign, 21 with borderline, and 96 with malignant ovarian tumors) undergoing surgery for an untreated pelvic mass. Serum PDGF-AA, PDGF-BB, and FGF2 were quantified on a Luminex analyzer.

RESULTS

Median PDGF-AA, PDGF-BB, and FGF2 levels were higher in patients with ovarian cancer than in those with borderline tumors, and normal ovaries, and PDGF-BB and FGF2 were also higher as compared to patients with benign tumors. PDGF-AA and PDGF-BB were associated with FIGO stage and residual tumor and PDGF-BB was associated with histological subtype.

CONCLUSIONS

PDGF-AA, PDGF-BB, and FGF2 are up-regulated in ovarian cancer and levels of serum PDGF-AA and PDGF-BB seem to be associated with stage and residual tumor in ovarian cancer.

BACKGROUND

The goal of the present study was to investigate the wound-healing potential of marine collagen peptides (MCPs) from chum salmon skin administered to rats following cesarean section (CS).

METHODS

Ninety-six pregnant Sprague-Dawley rats were randomly divided into four groups: a vehicle group and three MCP groups. After CS, rats were intragastrically given MCPs at doses of 0, 0.13, 0.38, 1.15 g/kg*bw, respectively. On postoperative days 7, 14, and <em>21</em>, the uterine bursting pressure, skin tensile strength, hydroxyproline (Hyp) concentrations, and histological and immunohistochemical characteristics of the scar tissue were examined.

RESULTS

In the MCP groups, the skin tensile strength, uterine bursting pressure, and Hyp were significantly higher than those in the vehicle group at all three time points (p<0.05). The formation of capillary, fibroblast, and collagen fiber, the expression of platelet-endothelial cell adhesion molecule-1, basic fibroblast growth factor, and transforming growth factor beta-1 were increased in the MCP groups (p<0.05).

CONCLUSIONS

MCPs could accelerate the process of wounding healing in rats after CS.

Retinal neuronal abnormalities occur before vascular changes in diabetic retinopathy. Accumulating experimental evidence suggests that neurons control vascular pathology in diabetic and other neovascular retinal diseases. Therefore, normalizing neuronal activity in diabetes may prevent vascular pathology. We investigated whether <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) prevented retinal neuronal dysfunction in insulin-deficient diabetic mice. We found that in diabetic neural retina, photoreceptor rather than inner retinal function was most affected and administration of the long-acting FGF<em>21</em> analog PF-05231023 restored the retinal neuronal functional deficits detected by electroretinography. PF-05231023 administration protected against diabetes-induced disorganization of photoreceptor segments seen in retinal cross section with immunohistochemistry and attenuated the reduction in the thickness of photoreceptor segments measured by optical coherence tomography. PF-05231023, independent of its downstream metabolic modulator adiponectin, reduced inflammatory marker interleukin-1β (IL-1β) mRNA levels. PF-05231023 activated the AKT-nuclear <em>factor</em> erythroid 2-related <em>factor</em> 2 pathway and reduced IL-1β expression in stressed photoreceptors. PF-05231023 administration did not change retinal expression of vascular endothelial <em>growth</em> <em>factor</em> A, suggesting a novel therapeutic approach for the prevention of early diabetic retinopathy by protecting photoreceptor function in diabetes.

Foreign body encapsulation represents a chronic fibrotic response and has been a major obstacle that reduces the useful life of implanted biomedical devices. The precise mechanism underlying such an encapsulation is still unknown. We hypothesized that, considering its central role in many other fibrotic conditions, transforming <em>growth</em> <em>factor</em> beta (TGFbeta) may play an important role during the formation of foreign body capsule (FBC). In the present study, we implanted mock sensors in rats subcutaneously and excised FBC samples at day 7, <em>21</em>, and 48-55 postimplantation. The most abundant TGFbeta isoform in all tissues was TGFbeta1, which was expressed minimally in control tissue. The expression of both TGFbeta1 RNA and protein was significantly increased in FBC tissues at all time points, with the highest level in day 7 FBC. The number of cells stained for phosphorylated Smad2, an indication of activated TGFbeta signaling, paralleled the expression of TGFbeta. A similar dynamic change was also observed in the numbers of FBC myo<em>fibroblasts</em>, which in response to TGFbeta, differentiate from quiescent <em>fibroblasts</em> and synthesize collagen. Type I collagen, the most prominent downstream target of TGFbeta in fibrosis, was found in abundance in the FBC, especially during the latter time periods. We suggest that TGFbeta plays an important role in the FBC formation. Inhibition of TGFbeta signaling could be a promising strategy in the prevention of FBC formation, thereby extending the useful life of subcutaneous implants.

OBJECTIVE

Ulcer healing involves expression of various growth factors such as epidermal growth factor (EGF), hepatocyte growth factor (HGF) and basic fibroblast growth factor (bFGF) at the ulcer margin, but the influence of EGF, HGF and bFGF applied locally with or without neutralizing anti-EGF, HGF and bFGF antibodies or cyclooxygenase (COX)-1 and COX-2 inhibitors on ulcer healing and the expression of COX-1 and COX-2 during ulcer healing have only been studied a little.

METHODS

Rats with gastric ulcers induced by serosal application of acetic acid (ulcer area 28 mm2 received a submucosal injection of either (1) vehicle (saline), (2) EGF, (3) HGF, and (4) bFGF with or without antibodies against EGF, HGF and bFGF or indomethacin (2 mg/kg/day i.p.), a nonspecific inhibitor of COX, or NS-398 (10 mg/kg/day i.g.) and Vioxx (5 mg/kg/day i.g.), both highly specific COX-2 inhibitors. A separate group of animals with chronic gastric fistulas was also used to assess gastric secretion during ulcer healing with and without growth factors. Each growth factor and specific antibody against EGF, HGF and bFGF (100 ng/100 microl each) were injected just around the ulcer immediately after ulcer induction and this local injection was repeated on day 2 following anesthesia and laparotomy. On days 13 and 21, the ulcer area was determined by planimetry, gastric blood flow (GBF) at the ulcer margin was examined by the H2-gas clearance technique, and mucosal generation of PGE2 and the gene expression of COX-1 and COX-2 in the non-ulcerated and ulcerated gastric mucosa were assessed. Gastric ulcers healed progressively within 21 days after induction and this effect was accompanied by a significant increase in GBF at the ulcer margin and in the expression of COX-2 in the ulcer area. Local treatment with EGF, HGF and bFGF produced a significant decrease in gastric acid secretion and significantly accelerated the rate of ulcer healing and raised GBF at the ulcer margin causing further significant upregulation of COX-2 but not COX-1 expression in the ulcerated mucosa. The acceleration of ulcer healing and hyperemia at the ulcer margin exhibited by locally applied EGF, HGF and bFGF were similar to those obtained with systemic administration of these growth factors. HGF applied submucosally, upregulated COX-2 expression and this was significantly attenuated by concurrent treatment with antibody against this peptide. Anti-EGF and anti-bFGF antibodies completely abolished the acceleration of the ulcer healing and hyperemia at the ulcer margin induced by these growth factors. Indomethacin and both COX-2 inhibitors significantly prolonged ulcer healing, while suppressing the generation of PGE2 in non-ulcerated and ulcerated gastric mucosa and GBF at the ulcer margin. The acceleration of ulcer healing by EGF, HGF and bFGF and the accompanying rise in GBF at the ulcer margin were significantly attenuated by the concurrent treatment with indomethacin or NS-398 and Vioxx.

CONCLUSIONS

(1) Growth factors accelerate ulcer healing due to enhancement in the microcirculation around the ulcer and these effects are specific because they can be abolished by neutralization with antibodies; (2) COX-2-derived prostaglandins and suppression of gastric secretion may play an important role in the acceleration of ulcer healing by various growth factors, and (3) the local effects of EGF, HGF and bFGF on ulcer healing can be reproduced by their systemic application indicating the high efficacy of growth factors to accelerate this healing.

Using the rat mesenteric-window assay, the de novo angiogenic effect of basic <em>fibroblast</em> <em>growth</em> <em>factor</em> (bFGF) in the intact, adult, normally vascularized test tissue was analyzed using quantitative microscopy including image analysis. Basic FGF was injected ip at doses of 10, 100, and 1000 ng twice daily for 4.5 days and the animals, which were not subjected to surgery, were sacrificed in groups every week for 6 consecutive weeks. The scale and dynamics of the angiogenic response were measured in terms of variables related to microvascular spatial expansion and density. The <em>growth</em> <em>factor</em>-induced angiogenesis in a dose-dependent, nonlinear manner and the angiogenesis displayed distinctly dose-dependent kinetics. The middle dose thus caused angiogenesis that peaked already at Day 7, thereby suggesting a direct effect. The high dose caused angiogenesis that peaked at Day 14, which also appears to be compatible with a direct effect. The low dose caused a more prolonged angiogenic response which did not peak until Day <em>21</em> or 28, depending on which variable was measured, which is indicative of an indirect effect. Clearly, the findings suggest that the molecular and cellular mechanisms of bFGF-mediated angiogenesis are dose-dependent.

<em>Fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) is a protein highly synthesized in the liver that exerts paracrine and endocrine control of many aspects of energy homeostasis in multiple tissues. In preclinical models of obesity and type 2 diabetes, treatment with FGF<em>21</em> improves glucose homeostasis and promotes weight loss, and, as a result, FGF<em>21</em> has attracted considerable attention as a therapeutic agent for the treatment of metabolic syndrome in humans. An improved understanding of the biological role of FGF<em>21</em> may help to explain why its therapeutic potential in humans has not been fully realized. This review will cover the complexities in FGF<em>21</em> biology in rodents and humans, with emphasis on its role in protection from central and peripheral facets of obesity.

Non-alcoholic fatty liver disease (NAFLD) is a prevalent obesity-related disease that affects large populations throughout the world due to excessive calorie intake and an increasingly sedentary lifestyle. <em>Fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) has recently emerged as a promising therapeutic candidate for the treatment of obesity and diabetes. FGF<em>21</em> is a starvation-induced pleiotropic hormone with various beneficial metabolic effects, and pharmacological treatment in rodents has been shown to improve insulin sensitivity and decrease simple fatty liver disease. However, its effects on reversing the symptoms of advanced liver disease have yet to be validated. Here, we investigated the protective effects of the LY2405319 compound, an engineered FGF<em>21</em> variant, in a non-alcoholic steatohepatitis (NASH) model using leptin-deficient ob/ob mice and a methionine- and choline-deficient (MCD) diet to induce steatohepatitis. LY2405319 treatment in ob/ob mice corroborated previous results showing that improvements in the metabolic parameters were due to increased mitochondrial oxygen consumption rate and fatty acid oxidation. LY2405319 treatment in ob/ob mice on an MCD diet significantly reduced the symptoms of steatohepatitis, as confirmed by Masson's trichrome staining intensity. Serum levels of AST and ALT were also reduced, suggesting an attenuation of liver injury, while detection of inflammatory markers showed decreased mRNA expression of TGF-β1 and type-I collagen, and decreased phosphorylation of NF-kB p65, JNK1/2, and p38. Collectively, these data show that LY2405319 treatment attenuated MCD diet-induced NASH progression. We propose that the LY2405319 compound is a potential therapeutic candidate for the treatment of advanced liver disease.

The aim of the study was to assess serum <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) concentrations in Chinese type 2 diabetic patients with and without retinopathy and to assess the association between FGF<em>21</em> and the severity of retinopathy. 117 diabetic patients were compared with 68 healthy controls. Fasting blood glucose, serum total cholesterol, serum triglycerides, serum insulin, and serum FGF<em>21</em> levels were estimated. FGF<em>21</em> concentrations in the patients were significantly higher than those in control. In the patient group there was a significant positive correlation between FGF<em>21</em>, insulin level, and homeostasis model assessment index. Serum FGF<em>21</em> concentrations in patients with proliferative diabetic retinopathy or nonproliferative diabetic retinopathy were significantly higher than those in patients without diabetic retinopathy. When the presence of diabetes was defined as the final variable in the conditional logistic regression model with the FGF<em>21</em> concentration as the continuous variable, FGF<em>21</em> was significantly involved in the model. This study shows that the increase in serum concentration of FGF<em>21</em> was associated with the severity of diabetic retinopathy and suggests that FGF<em>21</em> may play a role in the pathogenesis of diabetic retinopathy and its degree.

Bile acids (BAs) are signaling molecules controlling energy homeostasis that can be both toxic and protective for the liver. BA alterations have been reported in obesity, insulin resistance (IR), and nonalcoholic steatohepatitis (NASH). However, whether BA alterations contribute to NASH independently of the metabolic status is unclear.

To assess BA alterations associated with NASH independently of body mass index and IR.

Patients visiting the obesity clinic of the Antwerp University Hospital (a tertiary referral facility) were recruited from 2006 to 2014.

Obese patients with biopsy-proven NASH (n = 32) and healthy livers (n = 26) were matched on body mass index and homeostasis model assessment of IR.

Transcriptomic analyses were performed on liver biopsies. Plasma concentrations of <em>21</em> BA species and 7α-hydroxy-4-cholesten-3-one, a marker of BA synthesis, were determined by liquid chromatography-tandem mass spectrometry. Plasma <em>fibroblast</em> <em>growth</em> <em>factor</em> 19 was measured by enzyme-linked immunosorbent assay.

Plasma BA concentrations did not correlate with any hepatic lesions, whereas, as previously reported, primary BA strongly correlated with IR. Transcriptomic analyses showed unaltered hepatic BA metabolism in NASH patients. In line, plasma 7α-hydroxy-4-cholesten-3-one was unchanged in NASH. Moreover, no sign of hepatic BA accumulation or activation of BA receptors-farnesoid X, pregnane X, and vitamin D receptors-was found. Finally, plasma fibroblast growth factor 19, secondary-to-primary BA, and free-to-conjugated BA ratios were similar, suggesting unaltered intestinal BA metabolism and signaling.

In obese patients, BA alterations are related to the metabolic phenotype associated with NASH, especially IR, but not liver necroinflammation.

The cardioprotective effects of SGLT2 (sodium-glucose cotransporter 2) inhibitors may be related to their ability to induce a fasting-like paradigm, which triggers the activation of nutrient deprivation pathways to promote cellular homeostasis. The most distinctive metabolic manifestations of this fasting mimicry are enhanced gluconeogenesis and ketogenesis, which are not seen with other antihyperglycemic drugs. The principal molecular stimulus to gluconeogenesis and ketogenesis is activation of SIRT1 (sirtuin-1) and its downstream mediators: PGC-1α (proliferator-activated receptor gamma coactivator 1-alpha) and FGF<em>21</em> (<em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em>). These three nutrient deprivation sensors exert striking cardioprotective effects in a broad range of experimental models. This benefit appears to be related to their actions to alleviate oxidative stress and promote autophagy-a lysosome-dependent degradative pathway that disposes of dysfunctional organelles that are major sources of cellular injury. Nutrient deprivation sensors are suppressed in states of perceived energy surplus (ie, type 2 diabetes mellitus and chronic heart failure), but SGLT2 inhibitors activate SIRT1/PGC-1α/FGF<em>21</em> signaling and promote autophagy. This effect may be related to their action to trigger the perception of a system-wide decrease in environmental nutrients, but SGLT2 inhibitors may also upregulate SIRT1, PGC-1α, and FGF<em>21</em> by a direct effect on the heart. Interestingly, metformin-induced stimulation of AMP-activated protein kinase (a nutrient deprivation sensor that does not promote ketogenesis) has not been shown to reduce heart failure events in clinical trials. Therefore, promotion of ketogenic nutrient deprivation signaling by SGLT2 inhibitors may explain their cardioprotective effects, even though SGLT2 is not expressed in the heart.

Keywords: autophagy; fasting; lysosomes; metformin; pharmacology.

OBJECTIVE

<em>Fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) reduces plasma glucose and triglycerides, and increases free fatty acid oxidation in animal models of diabetes. The aim of the present study was to assess the relationships of serum FGF<em>21</em> with glucose oxidation (GOx) and lipid oxidation (LOx) in the baseline and insulin-stimulated conditions in lean and obese subjects.

METHODS

Cross-sectional study.

METHODS

Eighty-four subjects with normal glucose tolerance, 42 lean (body mass index (BMI) <25 kg m(-2)) and 42 overweight or obese (BMI between 25 and 40 kg m(-2)).

METHODS

Euglycemic hyperinsulinemic clamp and indirect calorimetry in the baseline state and during last 30 min of the clamp. The change in respiratory quotient (ΔRQ) in response to insulin was used as a measure of metabolic flexibility. Serum FGF<em>21</em> was determined in the baseline state and after the clamp.

RESULTS

Obese subjects had higher LOx in the baseline and insulin-stimulated conditions, lower insulin-stimulated GOx and ΔRQ (all P<0.05). Fasting serum FGF<em>21</em> did not differ between the groups. Insulin infusion resulted in an increase in serum FGF<em>21</em> in the obese (P=0.0001), but not in the lean group (P=0.76). Postclamp serum FGF<em>21</em> was higher in the obese subjects (P=0.0007). In this group, postclamp FGF<em>21</em> was related to LOx during the clamp (r=0.32, P=0.044), change in GOx and LOx in response to insulin (r=-0.44, P=0.005; r=0.47, P=0.002; respectively) and ΔRQ (r=-0.50, P=0.001).

CONCLUSIONS

An increase in serum FGF<em>21</em> in response to insulin in obese subjects might represent inappropriate response, possibly associated with metabolic inflexibility in obesity and insulin resistance.

<em>Fibroblast</em> <em>Growth</em> <em>Factor</em> <em>21</em> (FGF<em>21</em>) elicits an array of metabolic effects. However, the physiological role of FGF<em>21</em> during thermal challenges is not clear. In this study, we assessed the tissue source of FGF<em>21</em> and its site of action to regulate core body temperature in response to cold. Using mice lacking FGF<em>21</em> specifically in the liver (FGF<em>21</em> LivKO) or adipose tissues (FGF<em>21</em> AdipoKO), we performed a series of cold exposure studies to examine the tissue specific induction of FGF<em>21</em> in response to cold. We also examined the physiological site of FGF<em>21</em> action during cold exposure by impairing FGF<em>21</em> signaling to adipose tissues or the central nervous system (CNS) using genetic ablation of the FGF<em>21</em> co-receptor β-klotho in adipose tissues (KLB AdipoKO) or pharmacological blockage of FGF<em>21</em> signaling. We found that only liver-derived FGF<em>21</em> enters circulation during acute cold exposure and is critical for thermoregulation. While FGF<em>21</em> signaling directly to adipose tissues during cold is dispensable for thermoregulation, central FGF<em>21</em> signaling is necessary for maximal sympathetic drive to brown adipose tissue to maintain thermoregulation during cold. These data demonstrate a previously unrecognized role for FGF<em>21</em> in the maintenance of body temperature in response to cold.

Backgroud: Myocardial fibrosis results in myocardial remodelling and dysfunction. Celastrol, a traditional oriental medicine, has been suggested to have cardioprotective effects. However, its underlying mechanism is unknown. This study investigated the ability of celastrol to prevent cardiac fibrosis and dysfunction and explored the underlying mechanisms.

METHODS

Animal and cell models of cardiac fibrosis were used in this study. Myocardial fibrosis was induced by transverse aortic constriction (TAC) in mice. Cardiac hypertrophy and fibrosis were evaluated based on histological and biochemical measurements. Cardiac function was evaluated by echocardiography. The levels of transforming <em>growth</em> <em>factor</em> beta 1 (TGF-β1), extracellular signal regulated kinases 1/2 (ERK1/2) signalling were measured using Western blotting, while the expression of miR-<em>21</em>was analyzed by real-time qRT-PCR in vitro and in vivo. In vitro studies, cultured cardiac <em>fibroblasts</em> (CFs) were treated with TGF-β1 and transfected with microRNA-<em>21</em>(miR<em>21</em>).

RESULTS

Celastrol treatment reduced the increased collagen deposition and down-regulated α-smooth muscle actin (α-SMA), atrial natriuretic peptide (ANP), brain natriuretic peptides (BNP), beta-myosin heavy chain (β-MHC), miR-<em>21</em> and p-ERK/ERK. Cardiac dysfunction was significantly attenuated by celastrol treatment in the TAC mice model. Celastrol treatment reduced myocardial fibroblast viability and collagen content and down-regulated α-SMA in cultured CFs in vitro. Celastrol also inhibited the miR-<em>21</em>/ERK signalling pathway. Celastrol attenuated miR-<em>21</em> up-regulation by TGF-β1 and decreased elevated p-ERK/ERK levels in CFs transfected with miR-<em>21</em>.

CONCLUSIONS

MiR-<em>21</em>/ERK signalling could be a potential therapeutic pathway for the prevention of myocardial fibrosis. Celastrol ameliorates myocardial fibrosis and cardiac dysfunction, these probably related to miR-<em>21</em>/ERK signaling pathways in vitro and in vivo.