High Sclerostin and Dickkopf-1 (DKK-1) serum levels in children and adolescents with type 1 diabetes mellitus

CONTEXT: Childhood type 1 diabetes (T1DM) is associated with decreased bone mass. Sclerostin and dickkopf-1 (DKK-1) are Wnt inhibitors which regulate bone formation. OBJECTIVE: To evaluate sclerostin and DKK-1 levels in TD1M children and to analyze the influence of the glycaemic control on bone health. DESIGN AND SETTING: Cross-sectional study conducted at a clinical research center. Partecipants: One hundred and six T1DM subjects (12.2 ± 4 years), 66 on multiple daily injections (MDI) and 40 on continuous subcutaneous infusion of insulin (CSII), and 80 controls. RESULTS: The average of bone transmission time (BTT) and amplitude-dependent speed of sound (Ad-Sos) Z-scores was lower in diabetics than controls. Significant increased DKK-1 (3593 ± 1172 vs 2652 ± 689 pg/ml, p<0.006) and sclerostin (29.45 ± 12.32 vs 22.53 ± 8.29, p<0.001) levels were found in diabetics respect to controls, particularly in patients on MDI than ones on CSII. Glycaemic control was improved in CSII patients compared to MDI ones (p<0.001) and was also associated to a significant higher BMI-SDS (p<0.002) and BTT-Z-score (p<0.02). With adjustment for age multiple linear regression analysis for DKK-1 and sclerostin as dependent variables showed that levels of HbA1c%, glucose, 25(OH)-Vitamin D, osteocalcin, PTH, years of diabetes, BMI-SDS and AD-SoS-Z-score are the most important predictors (p<0.0001). CONCLUSIONS: Our study highlighted: 1. the high serum levels of DKK-1 and sclerostin in T1DM children, and their relationship with the altered glycaemic control; 2. the effect of CSII on the improvement of glycaemic control and bone health in T1DM children

Osteogenic differentiation of dental follicle stem cells.

Background: Stem cells are defined as clonogenic cells capable of self-renewal and multi-lineage differentiation. A population of these cells has been identified in human Dental Follicle (DF). Dental Follicle Stem Cells (DFSCs) were found in pediatric unerupted wisdom teeth and have been shown to differentiate, under particular conditions, into various cell types of the mesenchymal tissues. Aim: The aim of this study was to investigate if cells isolated from DF show stem features, differentiate toward osteoblastic phenotype and express osteoblastic markers. Methods: We studied the immunophenotype of DFSCs by flow cytometric analysis, the osteoblastic markers of differentiated DFSCs were assayed by histochemical methods and real-time PCR. Results: We demonstrated that DFSCs expressed a heterogeneous assortment of makers associated with stemness. Moreover DFSCs differentiated into osteoblast-like cells, producing mineralized matrix nodules and expressed the typical osteoblastic markers, Alkaline Phosphatase (ALP) and Collagen I (Coll I). Conclusion: This study suggests that DFSCs may provide a cell source for tissue engineering of bone

Gene expression signature induced by grape intake in healthy subjects reveals wide-spread beneficial effects on peripheral blood mononuclear cells

Abstract Using a transcriptomic approach, we performed a pilot study in healthy subjects to evaluate the changes in gene expression induced by grape consumption. Blood from twenty subjects was collected at baseline (T0), after 21 days of grape-rich diet (T1) and after one-month washout (T2). Gene expression profiling of peripheral blood mononuclear cells from six subjects identified 930 differentially expressed transcripts. Gene functional analysis revealed changes (at T1 and/or T2) suggestive of antithrombotic and anti-inflammatory effects, confirming and extending previous finding on the same subjects. Moreover, we observed several other favourable changes in the transcription of genes involved in crucial processes such as immune response, DNA and protein repair, autophagy and mitochondrial biogenesis. Finally, we detected significant changes in many long non-coding RNAs genes, whose regulatory functions are being increasingly appreciated. Altogether, our data suggest that a grape diet may exert its beneficial effects by targeting different strategic pathways

Effects of recombinant Irisin on the musculoskeletal system of hind-limb suspended mice

We previously showed that Irisin, a myokine released from skeletal muscle after physical exercise, plays a central role in the control of bone mass, driving positive effects on cortical mineral density and geometry in vivo (1). Here we demonstrated that r-Irisin treatment prevents bone loss in hind-limb suspended mice when administered during suspension and recovers bone mass when mice were injected after a suspension period (4 weeks) during which they developed bone loss. Micro computed tomography of femurs showed that r-Irisin treatment positively affected both cortical and trabecular bone. As expected, unloaded mice treated with vehicle displayed a remarkable decrease of cortical and trabecular bone mineral density (BMD), whereas in Irisin-treated unloaded mice no loss of BMD was observed with respect to control mice kept under normal loading. Likewise, by treating mice after they already developed disuse-induced bone loss, r-Irisin was able to restore the damaged mineral component. Furthermore, trabecular bone volume fraction (BV/TV), which dramatically decreased in unloaded mice, was prevented by r-Irisin therapy. In particular, r-Irisin treatment preserved the number of trabeculae (Tb.N) and the fractal dimension, an index of optimal micro-architectural complexity of trabecular bone.We also showed that r-Irisin treatment protects muscle mass suffering from atrophy during unloading. Thus, unloaded mice treated with vehicle displayed a severe loss of muscle mass, as confirmed by ~ 60% decline of vastus lateralis weight and ~33% decrease of fiber cross-sectional area. Conversely, Irisin-treated unloaded mice showed no loss of muscle weight and similar fiber cross-sectional area to control mice. Our data reveal for the first time that r-Irisin treatment prevents and retrieves disuse-induced bone loss and muscle atrophy. These findings may lead to develop an Irisin-based therapy for the prevention and treatment of osteoporosis and sarcopenia in all patients who cannot perform physical activity, as occurs during aging and immobility, and it could also represent a countermeasure for astronauts exposed to microgravity during space flight missions.This work was supported in part by ERISTO grant (to M.G.), by MIUR grant ex60% (to M.G.) and by SIOMMMS grant (to G.C.)

Impaired bone remodeling in children with osteogenesis imperfecta treated and untreated with bisphosphonates: the role of DKK1, RANKL, and TNF-α

In this study, we investigated the bone cell activity in patients with osteogenesis imperfecta (OI) treated and untreated with neridronate. We demonstrated the key role of Dickkopf-1 (DKK1), receptor activator of nuclear factor-κB ligand (RANKL), and tumor necrosis factor alpha (TNF-α) in regulating bone cell of untreated and treated OI subjects. These cytokines could represent new pharmacological targets for OI. Introduction: Bisphosphonates are widely used in the treatment of children with osteogenesis imperfecta (OI) with the objective of reducing the risk of fractures. Although bisphosphonates increase bone mineral density in OI subjects, the effects on fracture incidence are conflicting. The aim of this study was to investigate the mechanisms underlying bone cell activity in subjects with mild untreated forms of OI and in a group of subjects with severe OI treated with cycles of intravenous neridronate. Methods: Sclerostin, DKK1, TNF-α, RANKL, osteoprotegerin (OPG), and bone turnover markers were quantified in serum of 18 OI patients (12 females, mean age 8.86 ± 3.90), 8 of which were receiving cyclic intravenous neridronate, and 21 sex- and age-matched controls. The effects on osteoblastogenesis and OPG expression of media conditioned by the serum of OI patients and anti-DKK1 neutralizing antibody were evaluated. Osteoclastogenesis was assessed in cultures from patients and controls. Results: DKK1 and RANKL levels were significantly increased both in untreated and in treated OI subjects with respect to controls. The serum from patients with high DKK1 levels inhibited both osteoblast differentiation and OPG expression in vitro. High RANKL and low OPG messenger RNA (mRNA) levels were found in lymphomonocytes from patients. High amounts of TNF-α were expressed by monocytes, and an elevated percentage of circulating CD11b-CD51/CD61+ osteoclast precursors was observed in patients. Conclusions: Our study demonstrated the key role of DKK1, RANKL, and TNF-α in regulating bone cell activity of subjects with OI untreated and treated with bisphosphonates. These cytokines could represent new pharmacological targets for OI patients

Irisin injected mice display increased tibial cortical mineral density and polar moment of inertia

It has been recently reported that, after physical activity, the skeletal muscle releases Irisin, the newly identified myokine able of driving transition of white adipocytes into brown [1]. This result supported the role of skeletal muscle as endocrine organ, suggesting that it could target other tissues besides adipose tissue. In our previous work, we demonstrated that conditioned media collected from primary myoblasts of exercised mice were able to increase OB differentiation and this effect was Irisinmediated [2]. Here we show that Irisin has positive effect on cortical mineral density and geometry in vivo. Young male mice were injected with r-Irisin and cortical bone adaptation was analyzed by micro-CT at tibial midshaft. Our results show that cortical tissue mineral density is significantly increased in Irisin-injected mice compared to vehicle-injected littermates (+7.15%; p<0.01). Furthermore, this higher density of calcium hydroxyapatite at cortical site is accompanied by increase in periosteal circumference (+7.5%; p<0.03) and polar moment of Inertia (pMOI +19,21%; p<0,01). A greater pMOI indicates stronger resistance of a long bone to torsion and, together with higher bone mineral density, suggests higher protection against fracture. The effect of Irisin is fully comparable to the effect of physical activity that is widely accepted method for increasing bone mineral density and bone size in healthy populations. In view of further proving the involvement of Irisin in bone metabolism, we validate its direct effect on osteoblasts in vitro. Phosphorylation of the MAP kinase ERK and the expression of Atf4 were significantly increased after Irisin treatment, as well as ALP and pro-Collagen I mRNA expression. Our data highlight a novel link in muscle-fat-bone axis demonstrating that Irisin targets bone tissue directly, driving positive effects on cortical mineral density and geometry in vivo. These findings would expand the research of exercise-mimetic drugs that might be widely used to treat osteoporotic patients who are suffering from immobilization and cannot perform physical activity

Consumption of energy drinks among Italian University students : a cross-sectional multicenter study

Purpose The aim of the study was to evaluate the caffeinated Energy Drinks (EDs) consumption among a large sample of Italian undergraduates and its association with some of the major lifestyle risk factors. Methods Students attending twelve public Italian universities were involved between October 2021 and May 2022. Information on socio-demographic characteristics, ED consumption, and on health-related behaviors of participants was collected by the use of a web-based questionnaire. Results A total of 2165 students participated in the study and 15.2% of them reported having used caffeinated EDs in the last six months, mainly once a month (41.5%). In comparison with non-users, ED users showed a higher proportion of males (p < 0.001) and a higher father’s educational level (p = 0.003), came mainly from Northern universities (p = 0.004) and life sciences degree courses (p < 0.001). Besides, ED users reported higher BMI values (p = 0.003), more particular dietary regimens (p < 0.001), higher levels of weekly moderate–vigorous physical activity (p < 0.001) and participation in sports (p < 0.001) and in team sports (p = 0.003), and higher proportion of smokers (p < 0.001) and alcohol drinkers (p = 0.005). ED use was negatively related with female gender (OR 0.546; 95% CI 0.374–0.798), the Mediterranean diet (OR 0.587; 95% CI 0.362–0.951) and coming from the center of Italy (OR 0.500; 95% CI 0.275–0.909) and positively associated with tobacco smoke (OR 1.712; 95% CI 1.176–2.492) and participation in a team sport (OR 1.686; 95% CI 1.051–2.707). Conclusion These findings could encourage figures engaged in education to increase the students’ awareness on this issue in order to prevent the excessive use of EDs and associated unhealthy behaviors, especially in the most interested subgroups

FSH and TSH in the Regulation of Bone Mass: The Pituitary/Immune/Bone Axis

Recent evidences have highlighted that the pituitary hormones have profound effects on bone, so that the pituitary-bone axis is now becoming an important issue in the skeletal biology. Here, we discuss the topical evidence about the dysfunction of the pituitary-bone axis that leads to osteoporotic bone loss. We will explore the context of FSH and TSH hormones arguing their direct or indirect role in bone loss. In addition, we will focus on the knowledge that both FSH and TSH have influence on proinflammatory and proosteoclastogenic cytokine expression, such as TNFα and IL-1, underlining the correlation of pituitary-bone axis to the immune system

The myokine Irisin recapitulates the effect of physical activity on bone and muscle tissues

The concomitant occurrence of osteoporosis and sarcopenia is very common during the process of aging and pathological conditions characterized by the disuse of the musculoskeletal system. However, to date there are no evidence about the mechanism responsible for the coupling of these two process. During the last decade, studies on the interactions between muscle and bone have made remarkable steps forward, establishing that skeletal muscle is an endocrine organ producing and releasing myokines acting in a paracrine or endocrine fashion. Among these, the newly identified myokine Irisin, produced by skeletal muscle after physical exercise, plays a key role in the bone-muscle functional unit, with a major impact on the skeleton by increasing cortical bone mineral density, modifying its geometry and improving bone strength. Furthermore, in vitro and in vivo studies reported an autocrine effect of Irisin on skeletal muscle and highlighted the autocrine myogenic potential of this myokine. This review summarizes new insights on the topic of Irisin action on bone and skeletal muscle, which support the hypothesis that Irisin may represent a novel molecular entity with exercise-mimetic properties. Hopefully future research may expand the knowledge of its ability to improve bone integrity and muscle activity and could pave the way for the use of Irisin as a new therapy for the prevention and treatment of musculoskeletal disorders, particularly useful for those patients that are not capable of performing physical activity, such as the elderly or bedridden patients