In the face of urbanisation, surplus energy intake, sedentary habits and obesity, type 2 diabetes has developed into a major health concern worldwide. Commonly overlooked in contemporary obesity research, the liver is emerging as a central regulator of whole body energy homeostasis. Liver-derived proteins known as hepatokines are now considered attractive targets for the development of novel type 2 diabetes treatments. This commentary presents examples of three leading hepatokines: fetuin-A, the first to be described and correlated with increased inflammation and insulin resistance; angiopoietin-like protein (ANGPTL)8/betatrophin, initially proposed for its action on beta cell proliferation, although this effect has recently been brought into question; and <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>), an insulin-sensitising hormone that is an appealing drug target because of its beneficial metabolic actions. Novel discoveries in hepatokine research may lead to promising biomarkers and treatments for metabolic disorders and type 2 diabetes. This is one of a series of commentaries under the banner '50 years forward', giving personal opinions on future perspectives in diabetes, to celebrate the 50th anniversary of Diabetologia (1965-2015).

<em>Fibroblast</em> <em>growth</em> <em>factor</em>-<em>21</em> (FGF-<em>21</em>) is a new metabolic regulator, which is related to antiobesity and insulin sensitivity in vivo. However, the clinical implication of FGF-<em>21</em> is poorly understood. To investigate whether FGF-<em>21</em> may play a role as a metabolic regulator in patients with end-stage renal disease, we measured serum concentrations of FGF-<em>21</em>, inflammatory markers, and metabolic parameters in healthy people (n = 63) and nondiabetic patients receiving peritoneal dialysis (PD, n = 72). The patients were treated with angiotensin receptor blocker for 6 months, and the changes in FGF-<em>21</em> concentration and metabolic parameters were assessed. Compared with controls, serum FGF-<em>21</em> concentration was 8 times higher in patients undergoing PD (754.2 ± 463.5 vs 86.9 ± 60.2 pg/mL, P < .001). In controls, only lipid parameters correlated positively with FGF-<em>21</em> concentration. In contrast, inflammatory markers (interleukin-6, fibrinogen, high-sensitivity C-reactive protein) and homeostasis model assessment of insulin resistance (HOMA-IR) correlated positively and residual renal function correlated inversely with serum FGF-<em>21</em> concentration in PD patients. In a multivariate analysis adjusting these <em>factors</em>, residual renal function, HOMA-IR, and fibrinogen concentration were independent determinants of serum FGF-<em>21</em> concentration. After 6-month angiotensin receptor blocker treatment, serum FGF-<em>21</em> concentration declined significantly by 13% and HOMA-IR and inflammatory markers improved in PD patients. These findings suggest that FGF-<em>21</em> may play a role in insulin resistance in patients with end-stage renal disease.

We investigated the effects of <em>fibroblast</em> <em>growth</em> <em>factor</em>-<em>21</em> (FGF-<em>21</em>) on palmitate-induced insulin resistance in skeletal muscle myotubes. First, to determine the effect of FGF-<em>21</em> on palmitate-induced insulin resistance, we measured 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-d-glucose uptake and levels of proteins involved in insulin signaling pathways (IRS-1 and Akt) in human skeletal muscle myotubes (HSMMs) exposed to palmitate for 24h, and compared HSMMs exposed to palmitate and different doses of recombinant FGF-<em>21</em>. Second, to determine the mechanisms underlying the contribution of FGF-<em>21</em> to palmitate-induced insulin resistance, we compared levels of proteins linked to palmitate-induced insulin resistance (PKC-θ, IKKα/β, JNK, p38, IκBα, and NF-κB) in HSMMs exposed to palmitate and different doses of recombinant FGF-<em>21</em> for 24h. Palmitate-reduced glucose uptake was restored by FGF-<em>21</em>. Palmitate inhibited phosphorylation of Akt and thereby impaired insulin signaling in HSMMs. FGF-<em>21</em> prevented palmitate from inhibiting the phosphorylation of Akt. These results indicate that FGF-<em>21</em> prevented palmitate-induced insulin resistance in HSMMs. Palmitate activated NF-κB in HSMMs, thereby impairing the action of insulin and initiating chronic inflammation. FGF-<em>21</em> inhibited palmitate-induced NF-κB activation in HSMMs. The results of the present study suggest that FGF-<em>21</em> prevents palmitate-induced insulin resistance in HSMMs by inhibiting the activation of stress kinase and NF-κB.

BACKGROUND

A growing body of evidences suggests that transforming growth factor-beta (TGF-beta) is produced in the synovial fluid of patients with rheumatoid arthritis (RA), and that TGF-beta is an important regulator in the course of the disease. Careful studies on the endogenous synthesis of TGF-beta as well as its receptors are therefore necessary to clarify the possible role of TGF-beta in RA.

METHODS

We examined the expressions of latent TGF-beta 1, -beta 2, and -beta 3, the latent TGF-beta 1-binding protein (LTBP) as well as TGF-beta type II receptor (TGF-beta RII) in the synovial biopsy tissues of 21 patients with RA by immunohistochemistry. Five specimens from these cases representing both active and chronic inactive stages were also examined for the corresponding mRNA by in situ hybridization. Northern blot analysis was performed on 3 synovial membranes taken from the RA patients together with a control synovium.

RESULTS

Abundant LTBP, TGF-beta 1, and TGF-beta RII-positive cells as well as less intensively stained TGF-beta 2 and TGF-beta 3-positive cells were found in the synovial layer. These cells were positive for the histocompatibility antigen, HLA-DR. In lymphocyte aggregates, scattered cells positively labeled for LTBP and TGF-beta 1 were found. They stained in a reticular pattern that was similar to that demonstrated by an antibody against human dendritic cells, and also expressed HLA-DR. In situ hybridization revealed markedly increased signals for LTBP and TGF-beta RII mRNA in tissues with an active inflammatory process, when compared with tissues with less active inflammation. However, no clear differences in the levels of expression for any of the TGF-beta isoforms were found. Specimens with pronounced fibrosis, fibroblasts, and surrounding collagen fibers expressed positive immunoreactivities for all TGF-beta isoforms and LTBP. Northern blot analysis on 4 synovial tissues demonstrated positive signals for LTBP and TGF-beta 1 mRNA in all three RA patients in contrast to a normal control, which did not show any signals. An increased expression of TGF-beta RII mRNA was detected in the tissue from one of the patients.

CONCLUSIONS

An abundant expression of TGF-beta 1 and LTBP, as well as TGF-beta RII was seen in most actively proliferating synovial intimal cells, and the level of the expression varied during the course of the disease. We conclude that TGF-beta is involved tightly in the regulation of the inflammatory process, and it is thus possible that the endogenous TGF-beta functions as a self-regulator that induces the remission periods.

<em>Fibroblast</em> <em>growth</em> <em>factor</em> (FGF)-<em>21</em> is an endocrine member of the FGF family with healthy effects on glucose and lipid metabolism. FGF<em>21</em> reduces glycemia and lipidemia in rodent models of obesity and type 2 diabetes. In addition to its effects improving insulin sensitivity, FGF<em>21</em> causes weight loss by increasing energy expenditure. Activation of the thermogenic activity of brown adipose tissue and promotion of the appearance of the so-called beige/brite type of brown adipocytes in white fat are considered the main mechanisms underlying the leaning effects of FGF<em>21</em>. Paradoxically, however, obesity in rodents and humans is characterized by high levels of FGF<em>21</em> in the blood. Some degree of resistance to the actions of FGF<em>21</em> has been proposed as part of the endocrine alterations in obesity. The resistance in adipose tissue from obese rodents and patients is likely attributable to abnormally low levels of the FGF co-receptor β-Klotho, required for FGF<em>21</em> cellular action. However, native FGF<em>21</em> and FGF<em>21</em> derivatives retain their healthy metabolic and weight-loss effects when used as pharmacological agents to treat obese rodents and humans. FGF<em>21</em> derivatives or molecules mimicking FGF<em>21</em> action appear to be interesting candidates for the development of novel anti-obesity drugs designed to increase energy expenditure.

OBJECTIVE

Stage II and III adenocarcinoma of the rectum has an overall 5-year survival rate of approximately 50%, and tumor recurrence remains a major problem despite an improvement in local control through chemotherapy and radiation. The efficacy of chemoradiation therapy may be significantly compromised as a result of interindividual variations in clinical response and host toxicity. Therefore, it is imperative to identify those patients who will benefit from chemoradiation therapy and those who will develop recurrent disease. In this study, we tested whether a specific pattern of <em>21</em> polymorphisms in 18 genes involved in the critical pathways of cancer progression (i.e., drug metabolism, tumor microenvironment, cell cycle regulation, and DNA repair) will predict the risk of tumor recurrence in rectal cancer patients treated with chemoradiation.

METHODS

A total of 90 patients with Stage II or III rectal cancer treated with chemoradiation were genotyped using polymerase chain reaction (PCR)-based techniques for <em>21</em> polymorphisms.

RESULTS

A polymorphism in interleukin (IL)-8 was individually associated with risk of recurrence. Classification and regression tree analysis of all polymorphisms and clinical variables developed a risk tree including the following variables: node status, IL-8, intracellular adhesion molecule-1, transforming growth factor-beta, and fibroblast growth factor receptor 4.

CONCLUSIONS

Genomic profiling may help to identify patients who are at high risk for developing tumor recurrence, and those who are more likely to benefit from chemoradiation therapy. A larger prospective study is needed to validate these preliminary data using germline polymorphisms on tumor recurrences in rectal cancer patients treated with chemoradiation.

Evidence suggests epithelial-mesenchymal transition (EMT) as one potential source of <em>fibroblasts</em> in idiopathic pulmonary fibrosis. To assess the contribution of alveolar epithelial cell (AEC) EMT to <em>fibroblast</em> accumulation in vivo following lung injury and the influence of extracellular matrix on AEC phenotype in vitro, Nkx2.1-Cre;mT/mG mice were generated in which AECs permanently express green fluorescent protein (GFP). On days 17-<em>21</em> following intratracheal bleomycin administration, ~4% of GFP-positive epithelial-derived cells expressed vimentin or α-smooth muscle actin (α-SMA). Primary AECs from Nkx2.1-Cre;mT/mG mice cultured on laminin-5 or fibronectin maintained an epithelial phenotype. In contrast, on type I collagen, cells of epithelial origin displayed nuclear localization of Smad3, acquired spindle-shaped morphology, expressed α-SMA and phospho-Smad3, consistent with activation of the transforming <em>growth</em> <em>factor</em>-β (TGFβ) signalling pathway and EMT. α-SMA induction and Smad3 nuclear localization were blocked by the TGFβ type I receptor (TβRI, otherwise known as Alk5) inhibitor SB431542, while AEC derived from Nkx2.1-Cre;Alk5(flox/KO) mice did not undergo EMT on collagen, consistent with a requirement for signalling via Alk5 in collagen-induced EMT. Inability of a pan-specific TGFβ neutralizing antibody to inhibit effects of collagen together with absence of active TGFβ in culture supernatants is consistent with TGFβ ligand-independent activation of Smad signalling. These results support the notion that AECs can acquire a mesenchymal phenotype following injury in vivo and implicate type I collagen as a key regulator of EMT in AECs through signalling via Alk5, likely in a TGFβ ligand-independent manner.

OBJECTIVE

To prospectively determine the reliability and validity of serum <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF-<em>21</em>) as a biomarker for mitochondrial disease in a cross-sectional cohort of adults with mitochondrial disease from a specialist primary care and tertiary referral clinic.

METHODS

We recruited 140 subjects, including 54 adults with mitochondrial disease, 20 patients with nonmitochondrial neuromuscular disease, and 66 control subjects, between November 2011 and October 2012. We compared serum FGF-<em>21</em> concentrations to classical biomarkers, serum creatine kinase, lactate, pyruvate, and lactate to pyruvate ratio, to determine its validity and reliability as a biomarker of mitochondrial disease. We determined the sensitivity, odds ratio (OR), and overall reliability of FGF-<em>21</em> as a marker of mitochondrial disease using statistical analyses.

RESULTS

Median serum FGF-<em>21</em> concentrations were significantly elevated in patients with mitochondrial disease and differed significantly between all experimental groups. FGF-<em>21</em> showed a markedly higher diagnostic OR (45.7 [95% confidence interval = 12.6-166.5], p < 0.0001) when compared to other biomarkers and was the best predictor of disease according to sensitivity and receiver operating characteristic curve analysis. After multivariate logistic regression analysis controlling for potential confounders, FGF-<em>21</em> was the only measured parameter capable of predicting mitochondrial disease.

CONCLUSIONS

This prospective study establishes serum FGF-<em>21</em> levels as a sensitive biomarker of mitochondrial disease and demonstrates that they are the best predictor of this disorder when compared to serum levels of classical indicators: creatine kinase, lactate, pyruvate, and the lactate to pyruvate ratio.

Nrf2, a master regulator of intracellular redox homeostasis, is indicated to participate in fatty acid metabolism in liver. However, its role in diet-induced obesity remains controversial. In the current study, genetically engineered Nrf2-null, wild-type (WT), and Nrf2-activated, Keap1-knockdown (K1-KD) mice were fed either a control or a high-fat Western diet (HFD) for 12 weeks. The results indicate that the absence or enhancement of Nrf2 activity did not prevent diet-induced obesity, had limited effects on lipid metabolism, but affected blood glucose homeostasis. Whereas the Nrf2-null mice were resistant to HFD-induced glucose intolerance, the Nrf2-activated K1-KD mice exhibited prolonged elevation of circulating glucose during a glucose tolerance test even on the control diet. Feeding a HFD did not activate the Nrf2 signaling pathway in mouse livers. <em>Fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (Fgf<em>21</em>) is a liver-derived anti-diabetic hormone that exerts glucose- and lipid-lowering effects. Fgf<em>21</em> mRNA and protein were both elevated in livers of Nrf2-null mice, and Fgf<em>21</em> protein was lower in K1-KD mice than WT mice. The inverse correlation between Nrf2 activity and hepatic expression of Fgf<em>21</em> might explain the improved glucose tolerance in Nrf2-null mice. Furthermore, a more oxidative cellular environment in Nrf2-null mice could affect insulin signaling in liver. For example, mRNA of insulin-like <em>growth</em> <em>factor</em> binding protein 1, a gene repressed by insulin in hepatocytes, was markedly elevated in livers of Nrf2-null mice. In conclusion, genetic alteration of Nrf2 does not prevent diet-induced obesity in mice, but deficiency of Nrf2 improves glucose homeostasis, possibly through its effects on Fgf<em>21</em> and/or insulin signaling.

<em>Fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) is a hormone that regulates important metabolic pathways. FGF<em>21</em> is expressed in several metabolically active organs and interacts with different tissues. The FGF<em>21</em> function is complicated and well debated due to its different sites of production and actions. Striated muscles are plastic tissues that undergo adaptive changes within their structural and functional properties in order to meet their different stresses, recently, they have been found to be an important source of FGF<em>21</em>. The FGF<em>21</em> expression and secretion from skeletal muscles happen in both mouse and in humans during their different physiological and pathological conditions, including exercise and mitochondrial dysfunction. In this review, we will discuss the recent findings that identify FG<em>21</em> as beneficial and/or detrimental cytokine interacting as an autocrine or endocrine in order to modulate cellular function, metabolism, and senescence.

The liking and selective ingestion of palatable foods-including sweets-is biologically controlled, and dysfunction of this regulation may promote unhealthy eating, obesity, and disease. The hepatokine <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) reduces sweet consumption in rodents and primates, whereas knockout of Fgf<em>21</em> increases sugar consumption in mice. To investigate the relevance of these findings in humans, we genotyped variants in the FGF<em>21</em> locus in participants from the Danish Inter99 cohort (n = 6,514) and examined their relationship with a detailed range of food and ingestive behaviors. This revealed statistically significant associations between FGF<em>21</em> rs838133 and increased consumption of candy, as well as nominal associations with increased alcohol intake and daily smoking. Moreover, in a separate clinical study, plasma FGF<em>21</em> levels increased acutely after oral sucrose ingestion and were elevated in fasted sweet-disliking individuals. These data suggest the liver may secrete hormones that influence eating behavior.

Fibroblast growth factor (FGF)19 and FGF21 are hormones that regulate metabolic processes particularly during feeding or starvation, thus ultimately influencing energy production. FGF19 is secreted by the intestines during feeding and negatively regulates bile acid synthesis and secretion, whereas FGF21 is produced in the liver during fasting and plays a crucial role in regulating glucose and lipid metabolism, as well as maintaining energy homeostasis. FGF19 and FGF21 are regarded as late-acting hormones because their functions are only used after insulin and glucagon have completed their actions. Although FGF19 and FGF21 are activated under different conditions, they show extensively functional overlap in terms of improving glucose tolerance, insulin sensitivity, weight loss, and lipid, and energy metabolism, particularly in pathological conditions such as diabetes, obesity, metabolic syndrome, and cardiovascular and renal diseases. Most patients with these metabolic diseases exhibit reduced serum FGF19 levels, which might contribute to its etiology. In addition, the simultaneous increase in serum FGF21 levels is likely a compensatory response to reduced FGF19 levels, and the 2 proteins concertedly maintain metabolic homeostasis. Here, we review the physiological and pharmacological cross talk between FGF19 and FGF21 in relation to the regulation of endocrine metabolism and various chronic diseases.

OBJECTIVE

<em>Fibroblasts</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>), a liver-secreted endocrine <em>factor</em> involved in regulating glucose and lipid metabolism, has been shown to be elevated in patients with non-alcoholic fatty liver disease (NAFLD). This study aimed to evaluate the quantitative correlation between serum FGF<em>21</em> level and hepatic fat content.

METHODS

A total of 138 subjects (72 male and 66 female) aged from 18 to 65 years with abnormal glucose metabolism and B-ultrasonography diagnosed fatty liver were enrolled in the study. Serum FGF<em>21</em> levels were determined by an in-house chemiluminescence immunoassay and hepatic fat contents were measured by proton magnetic resonance spectroscopy.

RESULTS

Serum FGF<em>21</em> increased progressively with the increase of hepatic fat content, but when hepatic fat content increased to the fourth quartile, FGF<em>21</em> tended to decline. Serum FGF<em>21</em> concentrations were positively correlated with hepatic fat content especially in subjects with mild/moderate hepatic steatosis (r = 0.276, p = 0.009). Within the range of hepatic steatosis from the first to third quartile, FGF<em>21</em> was superior to any other traditional clinical markers including ALT to reflect hepatic fat content. When the patients with severe hepatic steatosis (the fourth quartile) were included, the quantitative correlation between FGF<em>21</em> and hepatic fat content was weakened.

CONCLUSIONS

Serum FGF<em>21</em> was a potential biomarker to reflect the hepatic fat content in patients with mild or moderate NAFLD. In severe NAFLD patients, FGF<em>21</em> concentration might decrease due to liver inflammation or injury.

Fenofibrate (FF), as a peroxisome-proliferator-activated receptor α (PPARα) agonist, has been used clinically for decades to lower lipid levels. In the present study, we examined whether FF can be repurposed to prevent the pathogenesi of the heart in Type 1 diabetes and to describe the underlying mechanism of its action. Streptozotocin (STZ)-induced diabetic mice and their age-matched control mice were treated with vehicle or FF by gavage every other day for 3 or 6 months. FF prevented diabetes-induced cardiac dysfunction (e.g. decreased ejection fraction and hypertrophy), inflammation and remodelling. FF also increased cardiac expression of <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) and sirtuin 1 (Sirt1) in non-diabetic and diabetic conditions. Deletion of FGF<em>21</em> gene (FGF<em>21</em>-KO) worsened diabetes-induced pathogenic effects in the heart. FF treatment prevented heart deterioration in the wild-type diabetic mice, but could not do so in the FGF<em>21</em>-KO diabetic mice although the systemic lipid profile was lowered in both wild-type and FGF<em>21</em>-KO diabetic mice. Mechanistically, FF treatment prevented diabetes-impaired autophagy, reflected by increased microtubule-associated protein 1A/1B-light chain 3, in the wild-type diabetic mice but not in the FGF<em>21</em>-KO diabetic mice. Studies with H9C2 cells in vitro demonstrated that exposure to high glucose (HG) significantly increased inflammatory response, oxidative stress and pro-fibrotic response and also significantly inhibited autophagy. These effects of HG were prevented by FF treatment. Inhibition of either autophagy by 3-methyladenine (3MA) or Sirt1 by sirtinol (SI) abolished FF's prevention of HG-induced effects. These results suggested that FF could prevent Type 1 diabetes-induced pathological and functional abnormalities of the heart by increasing FGF<em>21</em> that may up-regulate Sirt1-mediated autophagy.

OBJECTIVE

<em>Fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF-<em>21</em>) is a liver-derived metabolic regulator induced by energy deprivation. However, its regulation in humans is incompletely understood. We addressed the origin and regulation of FGF-<em>21</em> secretion in humans.

METHODS

By determination of arterial-to-venous differences over the liver and the leg during exercise, we evaluated the organ-specific secretion of FGF-<em>21</em> in humans. By four different infusion models manipulating circulating glucagon and insulin, we addressed the interaction of these hormones on FGF-<em>21</em> secretion in humans.

RESULTS

We demonstrate that the splanchnic circulation secretes FGF-<em>21</em> at rest and that it is rapidly enhanced during exercise. In contrast, the leg does not contribute to the systemic levels of FGF-<em>21</em>. To unravel the mechanisms underlying the regulation of exercise-induced hepatic release of FGF-<em>21</em>, we manipulated circulating glucagon and insulin. These studies demonstrated that in humans glucagon stimulates splanchnic FGF-<em>21</em> secretion whereas insulin has an inhibitory effect.

CONCLUSIONS

Collectively, our data reveal that 1) in humans, the splanchnic bed contributes to the systemic FGF-<em>21</em> levels during rest and exercise; 2) under normo-physiological conditions FGF-<em>21</em> is not released from the leg; 3) a dynamic interaction of glucagon-to-insulin ratio regulates FGF-<em>21</em> secretion in humans.

The circulating levels of hyaluronate were determined in 36 patients with scleroderma and in 36 control subjects matched for age and sex. The mean serum hyaluronate concentration in patients with progressive systemic sclerosis (n = 25) was 131 +/- 67 (SD) microgram/l and significantly greater (p less than 0.001) than that of the controls (mean level 49 +/- <em>21</em> (SD) microgram/l). Hyaluronate levels in patients with localised scleroderma (n = 4) were 141 +/- 47 (SEM) microgram/l and in patients with scleroderma-associated overlap syndromes (n = 7) 202 +/- 54 (SEM) microgram/l. The increase in serum hyaluronate probably reflected an enhanced synthesis or outflow of hyaluronate from the connective tissue, or both; it could not be explained by affection of the liver, which is the catabolic site of hyaluronate. The hyaluronate values were not related to certain serological indicators of inflammatory activity or to the extent of the skin lesions or the severity of internal organ manifestations. A positive correlation was noted between circulating platelet counts and hyaluronate levels (p less than 0.001). Plasma beta-thromboglobulin was measured in 15 of the patients with systemic sclerosis and found to correlate positively with platelet counts. Raised levels of beta-thromboglobulin were associated with the highest hyaluronate values. Platelet-derived <em>growth</em> <em>factor</em>, which stimulates connective tissue cells and is stored in the alpha-granules of platelets together with beta-thromboglobulin, was shown to enhance hyaluronate synthesis in <em>fibroblast</em> cultures. The results suggest an involvement in scleroderma of connective tissue activating substances released from platelets.

BACKGROUND

Elevated fibroblast growth factor 23 (FGF-23) concentrations associate with left ventricular hypertrophy (LVH) and adverse outcomes in adult patients with chronic kidney disease. We hypothesized that similar associations are present in pediatric patients on maintenance hemodialysis.

METHODS

In this retrospective study of 26 young patients on chronic hemodialysis, aged 6-21 years, cardiac structure and geometry were measured by echocardiography, and circulating levels of FGF-23 and calciotropic hormones were obtained.

RESULTS

FGF-23 levels were uniformly elevated in all patients from three- to 835-fold above the upper limit of normal. The average LV mass index (LVMI) was 43 ± 13 g/m(2.7) and reflected LVH in 55 % of patients. Log-transformed FGF-23 concentrations correlated with LVMI (p = 0.03) and were independently associated with the interventricular septal thickness Z-score (p < 0.001). Concentric LVH was associated with the highest FGF-23 concentrations and the highest LVMI measurements (p < 0.001). Each 1 standard deviation increase in log-transformed FGF-23 levels was associated with a 17 % increase in LVMI.

CONCLUSIONS

FGF-23 levels are strongly associated with increased LVMI and with prevalent LVH in pediatric hemodialysis patients. Our cross-sectional findings provide observational evidence supporting the hypothesis linking FGF-23 to cardiac hypertrophy in patients with chronic kidney disease.

Demonstrating temporal variation in the expression of messenger RNA (mRNA) for <em>growth</em> <em>factors</em> may give some indication as to whether <em>growth</em> <em>factor</em> synthesis is regulated in wound healing. The aim of this study was to evaluate the expression of insulin-like <em>growth</em> <em>factors</em> (IGF) I and II in the wound. Two wound models, an incisional model and a subcutaneous sponge implant model, were used in this study. The RNA was extracted and reverse transcribed and mRNA was amplified using polymerase chain reaction (PCR). Semiquantitation of PCR products was accomplished using [3H]dGTP incorporation. Levels of expression for both IGF-I and -II were found to be low in unwounded skin and at 12 hr postwounding. However, in both wound models expression increased substantially from 1 to <em>21</em> days postwounding. Both <em>factors</em> also were found to be expressed by <em>fibroblasts</em> and polymorphonuclear leukocytes (PMN). Additionally, two transcripts were found for IGF-II, the larger of which appeared to be specific for PMN and possibly cells involved in angiogenesis. Levels of message expressed in healing wounds for IGF-I and -II appear to be regulated with the highest levels of message found at time points coinciding with <em>fibroblast</em> predominance in the wound. Since <em>fibroblasts</em> are known to both secrete and respond to IGF-I, it is possible that IGF-I and IGF-II are acting to influence <em>fibroblast</em> differentiation and function in the later stages of wound healing.

BACKGROUND

Recently we reported that intracoronary administration of basic fibroblast growth factor (bFGF), a potent angiogenic peptide, increases collateral blood flow in dogs subjected to progressive left circumflex coronary artery (LCx) occlusion. The aim of the present study was to examine the effect of systemically administered bFGF on collateral blood flow and to assess its pharmacokinetics and potential side effects.

RESULTS

Forty-seven dogs were subjected to progressive ameroid-induced occlusion of the LCx, an intervention known to induce the development of collateral vessels. In phase I of the investigation, dogs were randomized to receive bFGF 1.74 mg/d (n = 10) or saline (n = 9) as a left atrial injection for 4 weeks. Relative collateral blood flow was assessed serially with radiolabeled microspheres in the conscious state during maximal coronary vasodilatation. Initiation of bFGF treatment was temporally associated with a marked acceleration of collateral development; however, collateral flow in control dogs improved toward the end of the study, approaching that of bFGF-treated dogs at the 38-day end point. Phase II of the investigation was a three-armed study of extended duration to determine whether bFGF caused a sustained increase in collateral function. Dogs were randomized to receive bFGF 1.74 mg/d for 9 weeks (n = 7), bFGF 1.74 mg/d for 5 weeks followed by placebo for 4 weeks (n = 11), or placebo for 9 weeks (n = 10). Relative and absolute collateral blood flow were assessed serially with microspheres during maximal coronary vasodilatation. Between the 10th and 17th days after ameroid placement, bFGF-treated dogs exhibited marked improvement in collateral flow such that maximal collateral conductance exceeded that of controls by 24% at the 5-week crossover point. Final collateral conductance was similar in dogs receiving bFGF for 5 and 9 weeks despite withdrawal of treatment in the former group. bFGF administration was associated with a 21% increase in final collateral conductance as well as a 49% increase in collateral zone vascular density. Prolonged bFGF administration was also associated with a decrease in arterial pressure, moderate thrombocytopenia, and moderate, reversible anemia.

CONCLUSIONS

Systemic administration of bFGF enhanced collateral conductance in dogs with progressive single-vessel coronary occlusion. The beneficial effect of bFGF occurred primarily between the 7th and 14th days of therapy, and regression of collateral development was not noted after withdrawal of treatment. The present investigation provides impetus to the concept that collateral development can be enhanced pharmacologically-specifically by bFGF-raising the possibility that such an intervention might eventually be applied clinically.

<em>Fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) is an emerging regulator of local and systemic metabolic homeostasis. Treatment with pharmacological levels of FGF<em>21</em> alleviates obesity and associated metabolic diseases including diabetes. However, beyond anti-obesogenic effects, the normal roles and underlying mechanisms of FGF<em>21</em> as an endocrine hormone remain unclear. A recent wave of studies has revealed that FGF<em>21</em> is a stress-induced endocrine <em>factor</em> in liver, muscle, and other tissues that targets adipose tissue and adipocytes through the FGFR1-betaKlotho complex. Adipose tissues and adipocytes within diverse tissues respond with metabolites and adipokine signals that affect functions of body tissues systemically and cells within the local microenvironment adjacent to adipocytes. Normally this is to prevent impaired tissue-specific function and damage to diverse tissues secreting FGF<em>21</em> in response to chronic stress. Therefore, diverse stressed tissues and the adipose tissue and adipocytes constitute a beneficial endocrine and paracrine communication network through FGF<em>21</em>. Here we attempt to unify these developments with beneficial pharmacological effects of FGF<em>21</em> on obesity in respect to inter-organ stress communication and mechanisms.

BACKGROUND

Rheumatoid arthritis (RA) is characterised by invasion of cartilage, bone and tendon by inflamed synovium. Previous studies in our laboratory have shown that hypoxia is a feature of RA synovitis. In the present study, we investigated the consequences of hypoxia on angiogenesis and synovial fibroblast migration in RA.

METHODS

Synovial tissue was harvested from RA patients, and synovial membrane cells were cultured under conditions either of hypoxia (1% oxygen) or normoxia (21% oxygen). Protein levels of matrix metalloproteinases (MMPs) and angiogenic factors were measured, while RNA was extracted for PCR quantification of MMPs/tissue inhibitors of MMP (TIMPs) and angiogenic factors. Migration of RA synovial fibroblasts through collagen, and the effect of RA synovial cell supernatants in an in vitro angiogenesis assay, were utilised to determine the functional relevance of changes in mRNA/protein.

RESULTS

We observed upregulation under hypoxic conditions of MMPs responsible for collagen breakdown, specifically collagenase MMP-8, and the gelatinases MMP-2 and MMP-9, at both mRNA and protein levels. Increased MT1-MMP mRNA was also observed, but no effect on TIMP-1 or TIMP-2 was detected. RA fibroblast migration across collagen was significantly increased under hypoxic conditions, and was dependent on MMP activity. Furthermore, expression of angiogenic stimuli, such as vascular endothelial growth factor (VEGF), and VEGF/placental growth factor heterodimer, was also increased. Crucially, we show for the first time that hypoxia increased the angiogenic drive of RA cells, as demonstrated by enhanced blood vessel formation in an in vitro angiogenesis assay.

CONCLUSIONS

Hypoxia may be responsible for rendering RA synovial lining proangiogenic and proinvasive, thus leading to the debilitating features characteristic of RA.

Ets-1 proto-oncogene is a transcription <em>factor</em> involved in several cellular functions, including the activation of several proteases participating in tumor invasion and metastasis. The objective of this study was to analyze the possible correlation between Ets-1 mRNA expression and survival in advanced-stage ovarian carcinomas, studying two patient groups with extremely different disease outcome. Sections from 66 primary ovarian carcinomas and metastatic lesions from 41 patients diagnosed with advanced-stage ovarian carcinoma (International Federation of Gynecologists and Obstetricians stages III and IV) were evaluated for expression of Ets-1 using mRNA in situ hybridization. Patients were divided into long-term (n = 17) and short-term (n = 24) survivors. The mean values for disease-free survival and overall survival were 116 and 133 months for long-term survivors, as compared to 3 and <em>21</em> months for short-term survivors, respectively. Expression of Ets-1 mRNA was detected in carcinoma cells and stromal cells in 28 of 66 (42%) and 22 of 66 (33%) lesions, respectively. Ets-1 expression showed an association with mRNA expression of vascular endothelial <em>growth</em> <em>factor</em> (P = 0.001 for carcinoma cells; P = 0.004 for stromal cells), basic <em>fibroblast</em> <em>growth</em> <em>factor</em> (P = 0.049 for carcinoma cells), and membrane type-1 matrix metalloproteinase (P = 0.045), which were previously studied in this patient cohort. Ets-1 mRNA was detected more often in both carcinoma and stromal cells in tumors of short-term survivors (P = 0.038 for carcinoma cells). In univariate survival analysis for all cases, Ets-1 expression in both tumor (P = 0.018) and stroma (P = 0.026) correlated with poor survival. These findings were reproduced in an analysis of primary tumors alone (P = 0.039 for tumor cells; P < 0.001 for stromal cells). Ets-1 mRNA expression in stromal cells retained its predictive power in a multivariate survival analysis in which all molecules studied previously in this patient cohort were included (P = 0.007). To our knowledge, this is the first evidence associating Ets-1 mRNA expression and poor survival in human epithelial malignancy. Ets-1 is thus a novel prognostic marker in advanced-stage ovarian carcinoma. The association between Ets-1 mRNA expression and the expression of membrane type-1 matrix metalloproteinase and angiogenic genes, first documented here in a study of patient material, points to the central role of this transcription <em>factor</em> in tumor progression in ovarian carcinoma.

The LDLR is a critical factor in the regulation of blood cholesterol levels that are altered in different human diseases. The level of LDLR in the cell is regulated by both transcriptional and post-transcriptional events. The E3 ubiquitin ligase, myosin regulatory light chain-interacting protein (Mylip)/inducible degrader of the LDL-R (Idol) was shown to induce degradation of LDLR via protein ubiquitination. We have here studied novel factors and mechanisms that may regulate Mylip/Idol in human hepatocyte cells and in mouse macrophages. We observed that FGF21 that is present in serum in different conditions reduced Mylip/Idol at the RNA and protein level, and increased LDLR levels and stability in the cells. FGF21 also enhanced expression of Canopy2 (Cnpy2)/MIR-interacting Saposin-like protein (Msap) that is known to interact with Mylip/Idol. Overexpression of Cnpy2/Msap increased LDLRs, and knockdown experiments showed that Cnpy2/Msap is crucial for the FGF21 effect on LDLRs. Experiments using DiI-labeled LDL particles showed that FGF21 increased lipoprotein uptake and the effect of FGF21 was additive to that of statins. Our results are consistent with an important role of FGF21 and Cnpy2/Msap in the regulation of LDLRs in cultured cells, which warrants further studies using human samples.

Normal adult bovine aortic endothelial cells were infected with various recombinant retroviruses expressing one, two, or three human basic <em>fibroblast</em> <em>growth</em> <em>factor</em> (bFGF) proteins normally synthesized by an alternative use of translation initiation codons. We show here that the constitutive expression of the AUG-initiated from (18 kDa) leads the transfected cells to form colonies in soft agar. The expression of the high molar weight (HMW) forms (22.5 and <em>21</em> kDa) initiated at one of the two CUG initiation codons allows cell immortalization, whereas the tumorigenic potential is reached when the three forms are constitutively expressed. Furthermore, we provide evidence that constitutive expression of (HMW) bFGF forms has a down-regulation effect on bFGF synthesis from the gene naturally active in parental endothelial cells.