Adipose tissue is an endocrine organ able to produce a wide series of pleiotropic molecules, defined "adipokines". In addition to the regulation of food intake and energy metabolism, adipokines are ...also implicated in the complex control of bone biology and specifically of bone remodeling. Leptin, the most studied adipokine, promotes satiety and energy expenditure and its circulating levels are proportional to fat mass. Some paradoxical findings originally suggested the involvement of leptin in controlling bone mass. For example, obese postmenopausal women, with elevated circulating leptin and leptin resistance, appear protected against the development of osteoporosis. Moreover, genetically leptin-deficient mice, which are hypogonadal and obese, display a decreased trabecular volume in long bones, but an increased vertebral bone mass, which is reduced by leptin administration. The complex mechanisms of leptin regulation of bone mass appear to involve selected hypothalamic neuronal populations and the sympathetic outflow, with an important role of osteoblastic beta2-adrenergic receptors. Adiponectin is another adipokine, which promotes insulin sensitivity and is reduced in obese and diabetic subjects. Adiponectin appears to exert a negative effect on bone mass and seems to be an independent predictor of lower bone mass. Although the adipokines resistin and visfatin do not seem to significantly affect bone metabolism, the potential impact of them and other adipokines is still to be determined. Moreover, the molecular adipokine-bone interactions should also be considered in the context of the adipokine changes observed in diseases such as obesity and the metabolic syndrome.
Purpose
Healing rate of meniscus repair is higher when the suture is associated with anterior cruciate ligament reconstruction. A possible explanation can be a different pattern of release of growth ...factors between anterior cruciate ligament reconstruction and isolated meniscus surgery. Hypothesis of this study is that the concentrations of bFGF, TGF-β and platelet-derived growth factor (PDGF) in joint fluid, immediately after single-bundle anterior cruciate ligament reconstruction and arthroscopic partial meniscectomy, can be different.
Methods
Twenty consecutive patients underwent partial medial meniscectomy and twenty consecutive patients underwent single-bundle anterior cruciate ligament reconstruction with hamstring grafts were enrolled in the study. Thirty minutes after the end of the surgical procedure, a sample of joint fluid, as well of venous blood, was collected from all the patients. Concentrations of growth factors were determined by enzyme-linked immunosorbent assay.
Results
The peripheral blood concentration of TGF-β, bFGF and PDGF was comparable between partial meniscectomy and anterior cruciate ligament reconstruction groups. No differences between the two surgical techniques were also found in term of TGF-β and bFGF joint fluid concentration, whereas joint PDGF concentration of anterior cruciate ligament reconstruction patients was significantly higher than the one found in partial meniscectomy patients.
Conclusions
A significant growth factors release was detected in the knee joint during arthroscopic surgery. PDGF concentration was significantly higher in anterior cruciate ligament reconstructed knee than in the meniscectomy group. PDGF can play an important role enhancing the healing response of meniscus suture and can be one of the biological reasons of the higher meniscal healing rate in anterior cruciate ligament reconstructed knee.
Inflammation represents a fundamental aspect of the healing process. Besides their primary role in hemostasis, platelets play an active role in the immunological and inflammatory aspect of tissue ...healing. Indeed , they can be directly involved in the inflammatory response by the production and release of several inflammatory mediators, including a variety of cytokines, such as TGF-beta, IL-1 beta, CD40L, and chemokines, such as CXCL7, CXCL4, CXCL4L1, CCl5, CXCL1, CXCL8, CXCL5, CXCL12, CCL2, CCL3. Platelet are not only a source of several chemokine involved in the inflammatory response and tissue healing, but they also express chemokine receptors, in particular CCR1 CCR3 CCR4 and CXCR4, thus being able to being able to regulate the inflammatory response associated to the healing process. However, this local inflammation must be taken under control, and platelets can prevent the excess of leukocytes recruitment by anti-inflammatory cytokines, such as TGF-beta. For this biological properties of platelets, platelet rich plasma therapy (PRP) is considered an innovative and promising approach that has been extended to many field of medicine, ranging from non-union defects, bone fractures, spinal fusion, bone implant and osteointegration, joint arthroplasty, to the treatment of several traumatic or degenerative pathologies of tendons, cartilage and ligaments.
Summary
In this population-based, cross-sectional study in Italian postmenopausal females not affected by diabetes, we showed a link between serum C-peptide and lumbar bone mineral density, ...suggesting that C-peptide exerts an insulin-independent effect on bone mass.
Introduction
It is well known that type 1 (T1) diabetes, characterized by insulin and C-peptide deficiency, is associated with a low lumbar bone mineral density and an increased risk for fracture. While a role for insulin in the pathogenesis of osteoporosis has been demonstrated, the association between C-peptide and the bone mineral density has not been investigated. We conducted a study in a cohort of 84 postmenopausal women without diabetes to clarify the association between serum C-peptide and the lumbar bone mineral density.
Methods
Participants underwent a bone mineral density evaluation by DXA and biochemical analysis including the C-peptide assay.
Results
rteen percent of the population had osteoporosis and 38 % had osteopenia. With ANOVA test, we showed that women with the lowest C-peptide concentration had lower lumbar mineral density in comparison to those in all other C-peptide concentration group (
p
= 0.02 among groups after adjustment). The univariate and multivariate analysis showed that C-peptide was positively associated with both lumbar T-score and Z-score besides other well-known factors like age (with T-score
p
< 0.001; beta = −0.38) and BMI (with T-score
p
= 0.009; beta = 0.34), while insulin was not correlated with the lumbar bone mineral density. The area under the receiver operating characteristic (ROC) curve for C-peptide to predict the absence of lumbar osteoporosis was 0.74 (SE = 0.073;
p
= 0.013).
Conclusions
These results suggest that C-peptide may exert an insulin- and BMI-independent effect on lumbar bone mineral density and that further large-scale studies are needed in order to clarify its role in bone mineralization especially in subjects without diabetes.
Purpose
Chronic tendinopathy is a degenerative process causing pain and disability. Current treatments include biophysical therapies, such as pulsed electromagnetic fields (PEMF). The aim of this ...study was to compare, for the first time, the functional in vitro response of human tendon cells to different dosages of PEMF, varying in field intensity and duration and number of exposures.
Methods
Tendon cells, isolated from human semitendinosus and gracilis tendons (hTCs;
n
= 6), were exposed to different PEMF treatments (1.5 or 3 mT for 8 or 12 h, single or repeated treatments). Scleraxis (SCX), COL1A1, COL3A1 and vascular endothelial growth factor-A (VEGF-A) expression and cytokine production were assessed.
Results
None of the different dosages provoked apoptotic events. Proliferation of hTCs was enhanced by all treatments, whereas only 3 mT-PEMF treatment increased cell viability. However, the single 1.5 mT-PEMF treatment elicited the highest up-regulation of SCX, VEGF-A and COL1A1 expression, and it significantly reduced COL3A1 expression with respect to untreated cells. The treated hTCs showed a significantly higher release of IL-1β, IL-6, IL-10 and TGF-β. Interestingly, the repeated 1.5 mT-PEMF significantly further increased IL-10 production.
Conclusions
1.5 mT-PEMF treatment was able to give the best results in in vitro healthy human tendon cell culture. Although the clinical relevance is not direct, this investigation should be considered an attempt to clarify the effect of different PEMF protocols on tendon cells, in particular focusing on the potential applicability of this cell source for regenerative medicine purpose, both in surgical and in conservative treatment for tendon disorders.
Low frequency pulsed electromagnetic field (PEMF) has proven to be effective in the modulation of bone and cartilage tissue functional responsiveness, but its effect on tendon tissue and tendon cells ...(TCs) is still underinvestigated. PEMF treatment (1.5 mT, 75 Hz) was assessed on primary TCs, harvested from semitendinosus and gracilis tendons of eight patients, under different experimental conditions (4, 8, 12 h). Quantitative PCR analyses were conducted to identify the possible effect of PEMF on tendon-specific gene transcription (scleraxis, SCX and type I collagen, COL1A1); the release of pro- and anti-inflammatory cytokines and of vascular endothelial growth factor (VEGF) was also assessed. Our findings show that PEMF exposure is not cytotoxic and is able to stimulate TCs’ proliferation. The increase of SCX and COL1A1 in PEMF-treated cells was positively correlated to the treatment length. The release of anti-inflammatory cytokines in TCs treated with PEMF for 8 and 12 h was significantly higher in comparison with untreated cells, while the production of pro-inflammatory cytokines was not affected. A dramatically higher increase of VEGF-A mRNA transcription and of its related protein was observed after PEMF exposure. Our data demonstrated that PEMF positively influence, in a dose-dependent manner, the proliferation, tendon-specific marker expression, and release of anti-inflammatory cytokines and angiogenic factor in a healthy human TCs culture model.
Calcium and phosphate are essential for cell functions, and their serum concentrations result from the balance between intestinal absorption, bony storage, and urinary excretion. Fibroblast growth ...factor 23 (FGF23), expressed by osteocytes and osteoblasts, acts in the kidney, leading to hypophosphatemia and low 1,25‐dihydroxycholecalciferol synthesis, but suppresses parathyroid function. The aim of this study was to explore the effects of a high‐energy demanding cycling race on this bone–kidney–parathyroid axis. We studied nine cyclists during the 2011 Giro d'Italia stage race. Pre‐analytical and analytical phases followed academic and anti‐doping recommendations. Serum parathyroid hormone (PTH), 25(OH)D, total calcium, inorganic phosphorus, and plasma FGF23 were measured on days −1, 12, and 22 and corrected for changes in plasma volume. Dietary calcium and phosphorus, anthropometric parameters (height, weight, and body mass index) and indexes of metabolic effort (net energy expenditure, power output) were recorded. Dietary calcium and phosphorus intakes were kept at the same levels throughout the race. Twenty‐five (OH)D, PTH, and calcium concentrations remained stable. FGF23 increased 50% with a positive correlation with the indexes of metabolic effort and, consequently, phosphorous decreased, although only in the first half. The strong metabolic effort acts on the bone–kidney–parathyroid system, and the rise in FGF23 plasma concentration might be aimed at maintaining calcium and phosphorus homeostasis.
The mechanism by which aplidine, a marine natural product in early clinical development as an anticancer agent, induces cell growth inhibition and apoptosis has been investigated in the human ...leukemia cell line MOLT-4. This cell line is characterized not only by the ability to secrete VEGF, but also for the presence on its surface of the VEGF receptor-1 (VEGFR-1). Previous studies from our laboratory concerned with evaluating early changes in gene expression induced by aplidine in MOLT-4 cells have shown that the drug decreases the expression of VEGFR-1 (Marchini et al. Proc Am Assoc Cancer Res 2000; 41: 833). Here, we report the ability of aplidine to block the VEGF/VEGFR-1 loop. We found that aplidine blocked VEGF secretion that was temporally followed by a decrease in both VEGF and VEGFR-1 production. Aplidine did not directly affect either VEGF transcription or stabilization of its mRNA. Transfection of MOLT-4 cells with an antisense VEGF cDNA construct, resulted in inhibition of colony formations. One clone, transfected with sense VEGF cDNA, secreting 8-10 times more VEGF than parental cells, was less sensitive to aplidine-induced cytotoxicity and apoptosis than control cells. Moreover, addition of VEGF in the medium decreased the activity of aplidine in MOLT-4 cells. These data demonstrate that aplidine inhibits the growth and induces apoptosis in MOLT-4 cells through the inhibition of VEGF secretion which blocks the VEGF/VEGFR-1 autocrine loop necessary for the growth of these cells.
BACKGROUND AND PURPOSE DF 2156A is a new dual inhibitor of IL‐8 receptors CXCR1 and CXCR2 with an optimal pharmacokinetic profile. We characterized its binding mode, molecular mechanism of action and ...selectivity, and evaluated its therapeutic potential.
EXPERIMENTAL APPROACH The binding mode, molecular mechanism of action and selectivity were investigated using chemotaxis of L1.2 transfectants and human leucocytes, in addition to radioligand and 35S‐GTPγS binding approaches. The therapeutic potential of DF 2156A was evaluated in acute (liver ischaemia and reperfusion) and chronic (sponge‐induced angiogenesis) experimental models of inflammation.
KEY RESULTS A network of polar interactions stabilized by a direct ionic bond between DF 2156A and Lys99 on CXCR1 and the non‐conserved residue Asp293 on CXCR2 are the key determinants of DF 2156A binding. DF 2156A acted as a non‐competitive allosteric inhibitor blocking the signal transduction leading to chemotaxis without altering the binding affinity of natural ligands. DF 2156A effectively and selectively inhibited CXCR1/CXCR2‐mediated chemotaxis of L1.2 transfectants and leucocytes. In a murine model of sponge‐induced angiogenesis, DF 2156A reduced leucocyte influx, TNF‐α production and neovessel formation. In vitro, DF 2156A prevented proliferation, migration and capillary‐like organization of HUVECs in response to human IL‐8. In a rat model of liver ischaemia and reperfusion (I/R) injury, DF 2156A decreased PMN and monocyte‐macrophage infiltration and associated hepatocellular injury.
CONCLUSION AND IMPLICATIONS DF 2156A is a non‐competitive allosteric inhibitor of both IL‐8 receptors CXCR1 and CXCR2. It prevented experimental angiogenesis and hepatic I/R injury in vivo and, therefore, has therapeutic potential for acute and chronic inflammatory diseases.
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