Search Results (97)

Diabetes is a risk factor for periodontitis. Increasing evidence suggests that a central player in this link is the vacuolar H+-ATPase (V-ATPase), which provides a physical and functional core for regulation by the catabolic lysosomal AMP-activated protein kinase complex (L-AMPK) and the anabolic mammalian target of rapamycin complex 1 (mTORC1). These complexes detect levels of various cellular nutrients, including glucose at the lysosome, and promote cellular responses to restore homeostasis. The high-glucose conditions of diabetes foster anabolic mTORC1 signaling that increases inflammation and inflammatory bone resorption in response to periodontal infections. Here, we review the structure and composition of V-ATPase, L-AMPK, mTORC1, and other elements of the energy-sensing platform. Mechanisms by which V-ATPase passes signals to the complexes are examined and recent data are reviewed. Current anti-bone resorptive therapeutics, bisphosphonates and denosumab, enhance the risk of medicine-related osteonecrosis of the jaw (MRONJ) and are not used to treat periodontal bone loss. Accumulating data suggest that it may be possible to target inflammatory bone resorption through agents that stimulate L-AMPK, including metformin and glucagon-like peptide-1 agonists. This approach may reduce inflammatory bone resorption without major effects on overall bone remodeling or increased risk of MRONJ. Full article

Background/Objectives: This study aimed to establish the potential osteotropic effect of pine pollen on bone metabolism in male rats during the development of osteopenia induced by orchidectomy (ORX). We also established the effect of gonadectomy and pine pollen on the characteristics of calf muscles. Methods: This study was conducted using 40 male Wistar rats divided into one sham-operated (SHO) and four ORX groups. The SHO rats and one ORX group (negative control) were treated with physiological saline (PhS). The remaining ORX groups received exclusively testosterone (positive control) and two doses of pine pollen (50 and 150 mg/kg b.w.), respectively. The rats were killed 60 days later and their right tibia and left pelvic limbs were isolated. The tibia was analyzed using densitometry, computed tomography, and a bending machine to determine densitometry, structure, and mechanical properties, respectively. The left pelvic limb allowed for measurements of area, density, and fat tissue in the calf muscle. Results: The dose of 150 mg/kg b.w. inhibited the development of atrophic changes, both in the cortical and trabecular bone tissue. The dose of 50 mg/kg b.w. also has a protective effect on bones but is less pronounced and concerns only the trabecular bone tissue. The higher dose of pine pollen inhibited the catabolism of the calf muscles by maintaining the density and surface area as in the SHO group. It also limited the accumulation of intramuscular and subcutaneous adipose tissue. Conclusions: It is worth emphasizing the osteoprotective effectiveness of pine pollen, especially when administered in larger doses, which demonstrates the possibility of its use in the prevention of the development of osteoporosis in males. Full article

Osteoarthritis (OA) is now widely recognized not merely as a cartilage-centric disease but as a multifactorial disorder affecting the entire joint as an organ, including the articular cartilage, subchondral bone, synovium, ligaments, menisci, and the innervating neural elements. This review explores the complex pathophysiology of OA with a focus on the emerging mechanisms of pain and inflammation that extend beyond articular cartilage degradation. Joint inflammation driven by immune activation in response to cellular stress signals promotes the release of pro-inflammatory mediators and catabolic enzymes. Key signaling pathways such as NF-κB, MAPKs, and JAK/STAT amplify these responses, and pain is sustained through peripheral and central sensitization, contributing to exacerbating symptoms even in the absence of visible joint damage. This review also integrates molecular and cellular mechanisms to highlight innovative therapies aimed at modifying both the structural damage and neurosensory drivers of pain. These approaches offer the potential to not only alleviate symptoms but also alter disease progression, signaling a move toward personalized, mechanism-based treatments. Given the intricate interactions among joint tissues, immune activation, and sensory processing, a comprehensive strategy that targets both structural degeneration and neuroinflammation is essential for the future of OA management. Emphasizing the joint as an integrated organ, we advocate for translational research linking molecular pathology with clinically meaningful outcomes. Full article

Metabolic syndrome (MetS) associated with Osteoarthritis (OA) is an increasingly recognised entity. Whilst the degenerative pattern in cuff-tear arthropathy (CTA) has been well documented, the biological processes behind primary shoulder OA and CTA remain less understood. This study investigates transcriptomic differences in these conditions, alongside the impact of MetS in patients undergoing total shoulder replacement. In a multi-centre study, 20 OA patients undergoing total shoulder replacement were included based on specific treatment indications for OA and cuff-tear arthropathy as well as 25 patients undergoing rotator cuff repair (RCR) as a comparator group. Tissues from subchondral bone, capsule (OA and RCR), and synovium were biopsied, and RNA sequencing was performed using Illumina platforms. Differential gene expression was conducted using DESeq2, adjusting for demographic factors, followed by pathway enrichment using the mitch package. Gene expressions in CTA and primary OA was differentially affected. CTA showed mitochondrial dysfunction, GATD3A downregulation, and increased cartilage degradation, while primary OA was marked by upregulated inflammatory and catabolic pathways. The effect of MetS on these pathologies was further shown. MetS further disrupted WNT/β-catenin signalling in CTA, and in OA. Genes such as ACAN, PANX3, CLU, and VAT1L were upregulated, highlighting potential biomarkers for early OA detection. This transcriptomic analysis reveals key differences between end-stage CTA and primary glenohumeral OA. CTA shows heightened metabolic/protein synthesis activity with less immune-driven inflammation. Under MetS, mitochondrial dysfunction (including GATD3A downregulation) and altered Wnt/β-catenin signalling intensify cartilage and bone damage. In contrast, primary OA features strong complement activation, inflammatory gene expression, and collagen remodelling. MetS worsens both conditions via oxidative stress, advanced glycation end products, and ECM disruption—particularly, increased CS/DS degradation. These distinctions support targeted treatments, from antioxidants and Wnt modulators to aggrecanase inhibitors or clusterin augmentation. Addressing specific molecular disruptions, especially those amplified by MetS, may preserve shoulder function, delay surgical intervention, and improve long-term patient outcomes. Full article

Background: Transforming growth factor-β (TGF-β) and interleukin 1β (IL-1β) are key regulators of the chondrogenic differentiation, physiology and pathology of cartilage tissue, with TGF-β promoting chondrogenesis and matrix formation, while IL-1β exerts catabolic effects, inhibiting chondrogenesis and contributing to cartilage degradation. Both cytokines alter the intracellular calcium ion (iCa²⁺) levels; however, the exact pathways are not known. Objectives: This study aimed to evaluate the impact of TGF-β3 and IL-1β on calcium homeostasis in human bone marrow-derived mesenchymal stem cells (hBM-MSCs) and chondrocytes during chondrogenesis. Results: TGF-β3 increased iCa²⁺ levels in both hBM-MSCs and chondrocytes. Furthermore, TGF-β3 increased the functional activity of L-type voltage-operated calcium channels (L-VOCCs) in hBM-MSCs but not in chondrocytes. TGF-β3 and IL-1β reduced L-VOCCs subunit CaV1.2 (CACNA1C) gene expression in chondrocytes. In hBM-MSCs, TGF-β3 and IL-1β increased SERCA pump (ATP2A2) gene expression, while in chondrocytes, this effect was observed only with TGF-β3. Conclusions: TGF-β3 increases iCa²⁺ both in osteoarthritic chondrocytes and hBM-MSCs during chondrogenesis. In hBM-MSCs, TGF-β3-mediated elevation in iCa²⁺ is related to the increased functional activity of L-VOCCs. IL-1β does not change iCa²⁺ in osteoarthritic chondrocytes and hBM-MSCs; however, it initiates the mechanisms leading to further downregulation of iCa²⁺ in both types of cells. The differential and cell-specific roles of TGF-β3 and IL-1β in the calcium homeostasis of osteoarthritic chondrocytes and hBM-MSCs during chondrogenesis may provide a new insight into future strategies for cartilage repair and osteoarthritis treatment. Full article

Background: Patients with end-stage chronic diseases, especially those undergoing hemodialysis (HD), often experience mineral bone disease (MBD), leading to hypocalcemia, hyperphosphatemia, and elevated parathyroid hormone (PTH). Vitamin D deficiency and metabolism disorders are also common, resulting from impaired conversion of 25(OH)D3 to its active form, 1,25(OH)2D3, and reduced inactivation to 24,25(OH)2D3. This study aimed to assess the levels of 25(OH)D2, 25(OH)D3, 24,25(OH)2D3, 3-epi-25(OH)D3, and the vitamin D metabolism ratio (VMR) in patients with maintenance HD. Methods: A cross-sectional study was conducted on 66 HD patients (22–90 years, average 61.3 ± 16.4), with a control group of 206 adults without chronic kidney disease (CKD), both without cholecalciferol supplementation. Results: the HD patients had significantly lower 25(OH)D3 levels (15 ng/mL vs. 22 ng/mL) and higher deficiency rates (69% vs. 39%) compared to the controls. However, both groups showed similarly low levels of optimal vitamin D3. The HD patients had lower 24,25(OH)D3 levels (0.1 vs. 2.1 ng/mL) and a lower VMR (0.9% vs. 9%). 3-epi-25(OH)D3 levels and its ratio to 25(OH)D3 were significantly lower in the HD group. Alphacalcidol supplementation raised 1,25(OH)2D3 levels (30.4 vs. 16.2 pg/mL) without affecting other vitamin D metabolites. The HD patients had higher levels of 25(OH)D2 compared to the controls (0.61 vs. 0.31 ng/mL). Conclusions: Vitamin D3 reserves are lower, and both functional deficiency and impaired catabolism of vitamin D3 are present in HD patients compared to the general population. The VMR index is the most sensitive parameter for vitamin D3 deficiency assessment, highlighting the importance of measuring 24,25(OH)D3. Alphacalcidol supplementation increases 1,25(OH)2D3 levels without affecting other vitamin D metabolites. 25(OH)D2 is the only metabolite that was higher in HD patients than the controls. Full article

Estrogen deficiency is one of several contributing factors to catabolic changes in bone surrounding dental implants, impairing bone repair in defects requiring bone regeneration. Functionalizing bone substitutes is an alternative approach among various strategies to address this challenge. In this study, the aim was to evaluate the effect of functionalizing deproteinized bovine bone (Bio-Oss^®, BO) with genistein via sonication on peri-implant bone defects in ovariectomized rats. The animals were randomly distributed according to the treatment into the following four groups (n = 10): BO sonicated with genistein (BOS + GEN), BO sonicated alone (BOS), untreated BO (BO), and blood clot only (CLOT). After twenty-eight days, implant removal torque was determined, and the peri-implant bone parameters were calculated based on computed microtomography. Additionally, the gene expression of bone turnover markers was evaluated. As a main result, the functionalization with genistein increased implant removal torque and the peri-implant bone volume in the BOS + GEN group compared to both BOS and BO groups (both p < 0.05). These findings suggest that the sonification of deproteinized bovine bone functionalized with genistein improves bone repair in peri-implant bone defects in ovariectomized rats. Full article

The treatment for Maple Syrup Urine Disease (MSUD) consists of a hypoproteic diet with integration therapy to limit leucine intake, ensuring adequate energy, macronutrients, and micronutrients to prevent catabolism and promote anabolism. We conducted a retrospective cross-sectional study at the Metabolic Rare Disease Unit, Fondazione IRCCS San Gerardo dei Tintori, Monza, Italy. Patients with MSUD who were over 3 years old, not treated with liver transplantation, and who provided written consent, were included. The study aimed to describe the dietary treatment of patients with MSUD, evaluate growth data, and analyze the effect of a low-protein and semi-synthetic diet on body composition. Data on height, weight, BMI, waist circumference, food intake, physical activity, and DEXA scans were collected. Thirteen subjects (11 classic MSUD, 2 intermediate MSUD) were included, of which 5 < 18 years old. Results indicated that patients with MSUD follow a balanced diet and have body compositions like healthy subjects in terms of fat and lean mass. A high incidence of osteopenia was observed from a young age, with a positive correlation between protein intake and lean mass and a negative correlation between BCAA-free mixture consumption and bone mineral density z-score. The study highlights the positive effects and potential consequences of the semi-synthetic diet on the body composition of patients with MSUD. A similar study involving all Italian metabolic centers treating MSUD is recommended. Full article

Thioredoxin-interacting protein (TXNIP) has been involved in oxidative stress and activation of the NOD-like receptor protein-3 (NLRP3) inflammasome, directly linking it to the pyroptosis pathway. Furthermore, pyroptosis may contribute to the inflammatory process in osteoarthritis (OA). The purpose of this study was to investigate the role of TXNIP in activating the NLRP3 inflammasome through the pyroptosis pathway in an OA rat model. Destabilization of the medial meniscus (DMM) was induced in the OA model with intra-articular injections of adeno-associated virus (AAV) overexpressing (OE) or knocking down (KD) TXNIP. A total of 48 healthy rats were randomly divided into six groups (N = 8 each). During the experiment, the rats’ weights, mechanical pain thresholds, and thermal pain thresholds were measured weekly. Morphology staining, micro-CT, 3D imaging, and immunofluorescence (IF) staining were used to measure the expression level of TXNIP, and ELISA techniques were employed. OE-TXNIP-AAV in DMM rats aggravated cartilage destruction and subchondral bone loss, whereas KD-TXNIP slowed the progression of OA. The histological results showed that DMM modeling and OE-TXNIP-AAV intra-articular injection caused joint structure destruction, decreased anabolic protein expression, and increased catabolic protein expression and pyroptosis markers. Conversely, KD-TXNIP-AAV slowed joint degeneration. OE-TXNIP-AVV worsened OA by accelerating joint degeneration and damage, while KD-TXNIP-AAV treatment had a protective effect. Full article

Iron is a vital element involved in a plethora of metabolic activities. Mammalian systemic iron homeostasis is mainly modulated by hepcidin, the synthesis of which is regulated by a number of proteins, including the hemochromatosis-associated proteins Hfe and Transferrin Receptor 2 (TfR2). Macrophages play versatile functions in iron homeostasis by storing iron derived from the catabolism of erythrocytes and supplying iron required for erythropoiesis. The absence of Hfe in macrophages causes a mild iron deficiency in aged mice and leads to an overproduction of the iron exporter Ferroportin 1 (Fpn1). Conversely, TfR2 gene silencing in macrophages does not influence systemic iron metabolism but decreases transcription of the macrophage Fpn1 in adult mice and modulates their immune response. This study investigated cellular and systemic iron metabolism in adult and aged male mice with macrophage-specific Hfe and TfR2 silencing (double knock-out, DKO). Serum iron parameters were significantly modified in aged animals, and significant differences were found in hepatic hepcidin transcription at both ages. Interestingly, splenic iron content was low in adult DKOs and splenic Fpn1 transcription was significantly increased in DKO animals at both ages, while the protein amount does not reflect the transcriptional trend. Additionally, DKO macrophages were isolated from mice bone marrow (BMDMs) and showed significant variations in the transcription of iron genes and protein amounts in targeted mice compared to controls. Specifically, Tranferrin Receptor 1 (TfR1) increased in DKO adult mice BMDMs, while the opposite is observed in the cells of aged DKO mice. Fpn1 transcript was significantly decreased in the BMDMs of adult DKO mice, while the protein was reduced at both ages. Lastly, a significant increase in Erythropoietin production was evidenced in aged DKO mice. Overall, our study reveals that Hfe and TfR2 in macrophages regulate hepatic Hepc production and affect iron homeostasis in the spleen and BMDMs, leading to an iron deficiency in aged animals that impairs their erythropoiesis. Full article

Osteoarthritis (OA) is a degenerative joint disorder that is distinguished by inflammation and chronic cartilage damage. Interleukin-1β (IL-1β) is a proinflammatory cytokine that plays an important role in the catabolic processes that underlie the pathogenesis of OA. In this study, we investigate the therapeutic efficacy of exosomes derived from untreated bone-marrow-derived mesenchymal stem cells (BMMSC-Exo) and those treated with cinnamaldehyde (BMMSC-CA-Exo) for preventing the in vitro catabolic effects of IL-1β on chondrocytes. We stimulated chondrocytes with IL-1β to mimic the inflammatory microenvironment of OA. We then treated these chondrocytes with BMMSC-Exo and BMMSC-CA-Exo isolated via an aqueous two-phase system and evaluated their effects on the key cellular processes using molecular techniques. Our findings revealed that treatment with BMMSC-Exo reduces the catabolic effects of IL-1β on chondrocytes and alleviates inflammation. However, further studies directly comparing treatments with BMMSC-Exo and BMMSC-CA-Exo are needed to determine if CA preconditioning can provide additional anti-inflammatory benefits to the exosomes beyond those of CA preconditioning or treatment with regular BMMSC-Exo. Through a comprehensive molecular analysis, we elucidated the regulatory mechanisms underlying this protective effect. We found a significant downregulation of proinflammatory signaling pathways in exosome-infected chondrocytes, suggesting the potential modulation of the NF-κB and MAPK signaling cascades. Furthermore, our study identified the molecular cargo of BMMSC-Exo and BMMSC-CA-Exo, determining the key molecules, such as anti-inflammatory cytokines and cartilage-associated factors, that may contribute to their acquisition of chondroprotective properties. In summary, BMMSC-Exo and BMMSC-CA-Exo exhibit the potential as therapeutic agents for OA by antagonizing the in vitro catabolic effects of IL-1β on chondrocytes. The regulation of the proinflammatory signaling pathways and bioactive molecules delivered by the exosomes suggests a multifaceted mechanism of action. These findings highlight the need for further investigation into exosome-based therapies for OA and joint-related diseases. Full article

A low-energy hit, such as a slight fall from a bed, results in a bone fracture, especially in the hip, which is a life-threatening risk for the older adult and a heavy burden for the social economy. Patients with low-energy traumatic bone fractures usually suffer a higher level of bony catabolism accompanied by osteoporosis. Bone marrow-derived stem cells (BMSCs) are critical in osteogenesis, leading to metabolic homeostasis in the healthy bony microenvironment. However, whether the BMSCs derived from the patients who suffered osteoporosis and low-energy traumatic hip fractures preserve a sustained mesodermal differentiation capability, especially in osteogenesis, is yet to be explored in a clinical setting. Therefore, we aimed to collect BMSCs from clinical hip fracture patients with osteoporosis, followed by osteogenic differentiation comparison with BMSCs from healthy young donors. The CD markers identification, cytokines examination, and adipogenic differentiation were also evaluated. The data reveal that BMSCs collected from elderly osteoporotic patients secreted approximately 122.8 pg/mL interleukin 6 (IL-6) and 180.6 pg/mL vascular endothelial growth factor (VEGF), but no PDGF-BB, IL-1b, TGF-b1, IGF-1, or TNF-α secretion. The CD markers and osteogenic and adipogenic differentiation capability in BMSCs from these elderly osteoporotic patients and healthy young donors are equivalent and compliant with the standards defined by the International Society of Cell Therapy (ISCT). Collectively, our data suggest that the elderly osteoporotic patients-derived BMSCs hold equivalent differentiation and proliferation capability and intact surface markers identical to BMSCs collected from healthy youth and are available for clinical cell therapy. Full article

Background: Since cytokine receptor-like factor 1 (CRLF1) has been implicated in tissue regeneration, we hypothesized that CRLF1 released by mesenchymal stem cells can promote the repair of osteochondral defects. Methods: The degree of a femoral osteochondral defect repair in rabbits after intra-articular injections of bone marrow-derived mesenchymal stem cells (BMSCs) that were transduced with empty adeno-associated virus (AAV) or AAV containing CRLF1 was determined by morphological, histological, and micro computer tomography (CT) analyses. The effects of CRLF1 on chondrogenic differentiation of BMSCs or catabolic events of interleukin-1beta-treated chondrocyte cell line TC28a2 were determined by alcian blue staining, gene expression levels of cartilage and catabolic marker genes using real-time PCR analysis, and immunoblot analysis of Smad2/3 and STAT3 signaling. Results: Intra-articular injections of BMSCs overexpressing CRLF1 markedly improved repair of a rabbit femoral osteochondral defect. Overexpression of CRLF1 in BMSCs resulted in the release of a homodimeric CRLF1 complex that stimulated chondrogenic differentiation of BMSCs via enhancing Smad2/3 signaling, whereas the suppression of CRLF1 expression inhibited chondrogenic differentiation. In addition, CRLF1 inhibited catabolic events in TC28a2 cells cultured in an inflammatory environment, while a heterodimeric complex of CRLF1 and cardiotrophin-like Cytokine (CLC) stimulated catabolic events via STAT3 activation. Conclusion: A homodimeric CRLF1 complex released by BMSCs enhanced the repair of osteochondral defects via the inhibition of catabolic events in chondrocytes and the stimulation of chondrogenic differentiation of precursor cells. Full article

Circulating 25-hydroxyvitamin D (25(OH)D) is the generally accepted indicator of vitamin D status. Since hydroxylation of 25(OH)D to 24-25-dihydroxyvitamin D (24,25(OH)2D) is the first step of its catabolism, it has been suggested that a low 24,25(OH)D level and a low vitamin D metabolite ratio (VMR), i.e., 24,25(OH)2D divided by 25(OH)D, may indicate high vitamin D requirements and provide additional diagnostic information beyond serum 25(OH)D. We, therefore, evaluated whether the classification of “functional vitamin D deficiency”, i.e., 25(OH)D below 50 nmol/L, 24,25(OH)2D below 3 nmol/L and a VMR of less than 4%, identifies individuals who benefit from vitamin D supplementation. In participants of the Styrian Vitamin D Hypertension trial, a randomized controlled trial (RCT) in 200 hypertensive patients with serum 25(OH)D below 75 nmol/L, who received either 2.800 international units of vitamin D per day or placebo over 8 weeks, 51 participants had functional vitamin D deficiency. In these individuals, there was no treatment effect of vitamin D supplementation on various parameters of bone metabolism and cardiovascular risk except for a significant effect on parathyroid hormone (PTH) and expected changes in vitamin D metabolites. In conclusion, a low vitamin D metabolite profile did not identify individuals who significantly benefit from vitamin D supplementation with regard to bone markers and cardiovascular risk factors. The clinical significance of functional vitamin D deficiency requires further evaluation in large vitamin D RCTs. Full article

Breast cancer (BC) is currently one of the most common cancers in women worldwide with a rising tendency. Epigenetics, generally inherited variations in gene expression that occur independently of changes in DNA sequence, and their disruption could be one of the main causes of BC due to inflammatory processes often associated with different lifestyle habits. In particular, hormone therapies are often indicated for hormone-positive BC, which accounts for more than 50–80% of all BC subtypes. Although the cure rate in the early stage is more than 70%, serious negative side effects such as secondary osteoporosis (OP) due to induced estrogen deficiency and chemotherapy are increasingly reported. Approaches to the management of secondary OP in BC patients comprise adjunctive therapy with bisphosphonates, non-steroidal anti-inflammatory drugs (NSAIDs), and cortisone, which partially reduce bone resorption and musculoskeletal pain but which are not capable of stimulating the necessary intrinsic bone regeneration. Therefore, there is a great therapeutic need for novel multitarget treatment strategies for BC which hold back the risk of secondary OP. In this review, resveratrol, a multitargeting polyphenol that has been discussed as a phytoestrogen with anti-inflammatory and anti-tumor effects at the epigenetic level, is presented as a potential adjunct to both support BC therapy and prevent osteoporotic risks by positively promoting intrinsic regeneration. In this context, resveratrol is also known for its unique role as an epigenetic modifier in the regulation of essential signaling processes—both due to its catabolic effect on BC and its anabolic effect on bone tissue. Full article