Search Results (121)

Working equids are at high risk of musculoskeletal disorders due to strenuous labor, repetitive tasks, and harsh environmental conditions. This retrospective study describes the distribution of radiographically detected musculoskeletal findings in working equids presented to four Society for the Protection of Animals Abroad (SPANA) centers in Morocco, based on 498 animals and 1125 radiographs collected between 2015 and 2022. The study population was mainly composed of horses (78.1%), followed by donkeys (15.3%) and mules (6.6%). Most were males (65.7%), and the majority were between 5 and 15 years old (60.4%). The distal limb (foot, pastern, and fetlock) was the most frequently examined region (62.7%). Among the animals reviewed, 381 (76.5%) exhibited at least one radiographically detected abnormality, while 117 (23.5%) showed no visible osseous change. The most frequent findings included foot-related changes (36.2%), defined as non-fracture podiatric abnormalities, fractures (29.7%), and periosteal new bone formation (22%). Less frequent findings were degenerative joint disease (8.1%), joint subluxation or luxation (1.6%), epiphyseal abnormalities (1.6%), and angular deformities (0.8%). These results provide an overview of radiographically detected osseous changes in working equids under field conditions. They highlight the diagnostic value of radiography in low-resource environments and provide a basis for future field-based studies. Full article

Linear growth is traditionally attributed to the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis, yet “growth without GH” is documented. We report five patients with severe GH deficiency—one congenital and four acquired, who reached normal or tall stature despite persistently low IGF-1. All patients had obesity and metabolic complications (insulin resistance, dyslipidemia, and/or fatty liver). Catch-up or sustained growth occurred before or independent of sex-steroid replacement in most cases. One patient with lifelong hypogonadism showed slow, prolonged growth with delayed epiphyseal fusion. Three patients also received recombinant human GH (rhGH), without a significant impact on overall growth velocity, but with favorable metabolic outcomes. Findings support multifactorial drivers of linear growth beyond the GH/IGF-1 pathway. Likely contributors include insulin signaling associated with adiposity, permissive thyroid hormone action, local growth-plate paracrine pathways, and, in hypogonadism, delayed epiphyseal closure. Genetic modifiers that enhance chondrogenesis or delay growth-plate fusion may contribute. We also reviewed the published literature on “growth without GH,” integrating single-case reports and series to contextualize these mechanisms and outcomes. In conclusion, profound GH deficiency does not preclude near-normal or accelerated growth. In “growth without GH,” therapeutic priorities should pivot from stature to cardiometabolic risk reduction. rhGH may be considered to improve metabolism when individualized and closely monitored, recognizing that height velocity is often adequate. Notably, rhGH consistently improved lipid profiles and steatohepatitis in two patients, suggesting a primarily metabolic benefit. Lifelong follow-up from childhood into adulthood is essential. Full article

The intracellular retention of misfolded extracellular matrix proteins is a common disease mechanism in various rare skeletal diseases. This discovery has driven the study of ER stress and the unfolded protein response (UPR) as a promising therapeutic target in several skeletal dysplasias. In the case of COL10A1 mutations, targeting the UPR resulted in a clinical trial of the repurposed drug carbamazepine; however, for other closely related skeletal disorders, treatment with carbamazepine was ineffective, indicating the need for suitable markers for in vitro screenings of potential drug treatments. Mutations in cartilage oligomeric matrix protein (COMP), a cartilage structural protein, cause both multiple epiphyseal dysplasia (MED) and pseudoachondroplasia (PSACH); together referred to as the COMPopathies, which result from the intracellular retention of mutant COMP to varying degrees. In contrast to other closely related skeletal disorders, caused by mutations in cartilage structural proteins, the involvement of the UPR is less clear, and so far, no common COMPopathy marker has been identified. Here, using cell models of COMPopathies, we identified MMP9 upregulation as a common feature of six pathogenic COMP variants that do not induce a prominent UPR. We further show that the archetypal p.V194D matrilin-3 MED variant (which causes MED) does not induce MMP9 expression, suggesting that MMP9 upregulation could serve as a specific marker of COMPopathies in vitro. Full article

MLASA2 is a rare mitochondrial disorder with limited geographic representation in published medical literature. Here, we report the first confirmed case of MLASA2 in a Latin American 16-year-old male harboring a homozygous pathogenic variant p.(Asp311Glu) in the YARS2 gene. The patient presented with sideroblastic anemia and short stature, accompanied by other skeletal dysplasia features not previously associated with MLASA2, including epiphyseal dysplasia, rib edge widening, and poorly defined vertebral structures, but without lactic acidosis. Notably, the patient did not present exercise intolerance but recently exhibited reduced muscle strength. The p.(Asp311Glu) variant, located in the anticodon-binding domain of the mitochondrial tyrosyl-tRNA synthetase (Mt-TyrRS), was consistently predicted to be pathogenic by multiple in silico tools. Molecular modeling revealed that this variant destabilizes the ‘KMSKS’ motif, potentially compromising tRNA recognition fidelity and aminoacylation efficiency. Analysis of runs of homozygosity (ROH) revealed significantly elevated consanguinity (ROH: 31.93%), consistent with a consanguineous mating between biological parents. This case expands the geographic distribution of MLASA2, documents previously unreported phenotypes, suggests a novel pathogenic mechanism, and demonstrates the utility of genomic approaches for diagnosing rare mitochondrial disorders in the absence of complete clinical information and family history. Full article

Pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (MED) are rare, autosomal dominant skeletal dysplasias characterised by disproportionate short stature, joint deformities, and early-onset osteoarthritis. These conditions result from mutations in key cartilage extracellular matrix (ECM) components, including cartilage oligomeric matrix protein (COMP), matrilin-3, and type IX collagen. Although genetically and clinically heterogeneous, PSACH and MED share convergent pathogenic mechanisms. Misfolded mutant ECM proteins are retained within the endoplasmic reticulum (ER) of growth plate chondrocytes, triggering chronic ER stress and impairing chondrocyte proliferation, differentiation, and survival. Moreover, some of the mutant protein is secreted and incorporated into the matrix, leading to altered collagen fibrillogenesis, disrupted proteoglycan distribution, and compromised biomechanical integrity. These alterations extend beyond cartilage, impacting tendons, ligaments, and muscle–tendon junctions, contributing to joint laxity, impaired force transmission, and mild myopathy. This review discusses the structural and functional consequences of ECM disorganisation in PSACH and MED, highlighting its central role in disease progression and emphasising the importance of considering ECM abnormalities when developing therapeutic strategies for rare short stature-associated skeletal disorders. Full article

Osteoarthritis involves complex interactions between articular joint tissues and the immune system, which is implicated in molecular trafficking via barrier-function modulating cytokines. The current study aims to test effects of an acute spike in TNF-α or TGF-β on vascular barrier function at multiple length scales, from the heart to tissue compartments of the knee, and cellular inhabitants of those respective compartments, in a spontaneous guinea pig model of osteoarthritis. First we quantified the intensity of a fluorescent-tagged 70 kDa tracer, similar in size to albumin, the most prevalent transporter protein in the blood, in tissue compartments of bone (periosteum, marrow space, compact bone, and epiphyseal bone) and cartilage (superficial cartilage, calcified cartilage, and the interface between, i.e., the epiphyseal line), as well as at sites of tendon attachment to bone (entheses). We then examined tracer presence and intensity in the respective pericellular and extracellular matrix zones of bone and cartilage. Acute exposure to TGF-β reduced barrier function (increased permeability) at nearest vascular interfaces in four of eight tissue compartments studied, compared to TNF-α where one of eight tissue compartments showed significant diminishment in barrier function. The increase in permeability associated with reduced barrier function was observed at both tissue compartment and cellular length scales. The observation of pericellular transport of the albumin-sized molecules to osteocytes contrasts with previous observations of barrier function in healthy, untreated animals and is indicative of increased molecular transport in pericellular regions of musculoskeletal tissues in cytokine-treated animals. Understanding age- and disease-related changes in molecular transport within musculoskeletal structures, such as the knee joint, is crucial for elucidating the etiology and pathogenesis of osteoarthritis. Full article

The growth plate is a specialized cartilage structure near the ends of long bones that orchestrates longitudinal bone growth during fetal and postnatal stages. Within this region reside a dynamic population of growth plate skeletal stem cells (gpSSCs), primarily located in the resting zone, which possess self-renewal and multilineage differentiation capacity. Recent advances in cell-lineage tracing, single-cell transcriptomics, and in vivo functional studies have revealed distinct subpopulations of gpSSCs, which are defined by markers such as parathyroid hormone-related protein (PTHrP), CD73, axis inhibition protein 2 (Axin2), forkhead box protein A2 (FoxA2), and apolipoprotein E (ApoE). These stem cells interact intricately with their niche, particularly after the formation of the secondary ossification center, through stage-specific regulatory mechanisms involving several key signaling pathways. This review summarizes the current understanding of gpSSC identity, behavior, and regulation, focusing on how these cells sustain growth plate function through adapting to biomechanical and molecular cues. Full article

Background: The epiphyseal vascularization of long bones generates a particular flow pattern that is important for adequate angiogenesis to be achieved. Imaging reveals that vessel development in murine long bone involves the expansion and anastomotic fusion of endothelial buds. Impaired blood flow leads to defective angiogenesis and osteogenesis and downregulation of Notch signaling in endothelial cells. We examined whether altered blood flow and endothelial signaling via the Notch pathway—a highly conserved cell–cell communication mechanism that regulates angiogenesis and vascular remodeling—contributes to hip joint degeneration. Material and Methods: In our study, we used two groups of patients. The first is a control group of 15 patients without degenerative joint pathology. The second group consists of 51 patients diagnosed with an advanced form of degenerative joint pathology. On both study groups, we used immunohistochemical markers that highlight the endothelium of epiphyseal capillaries, the collagen matrix, and the presence of joint lubricant-secreting cells. Ultrastructural analysis was performed on hematoxylin-eosin slides that were exposed to a surface electron microscope, following a previously tested protocol. Results: The results of our study show that there are numerous anastomoses between epiphyseal vessels and that these capillaries persist even after pathological bone resorption, for a certain period of time. Discussions: Our results are complementary to recent studies on this research topic that emphasize the possibility that the main cause of joint degeneration is vascular. Revascularization of an area of bone demineralization after bone infarction has become a reality. Conclusions: This study opens new perspectives regarding the research on epiphyseal capillary vascularization and the modern concept of morpho functional rehabilitation of the hip joint. Full article

Spondyloepimetaphyseal dysplasia type Isidor-Toutain (RPL13-SEMD) is an autosomal dominant skeletal dysplasia caused by heterozygous pathogenic variants in the RPL13 gene, encoding the ribosomal protein eL13. To date, 13 pathogenic variants in RPL13 have been reported, all clustering within intron 5 and exon 6, suggesting this hotspot region is critical for the function of ribosomes in skeletal tissues. Here, we present clinical and radiological characteristics of seven individuals, five children and two adults, from four unrelated families with RPL13-SEMD caused by two novel variants (c.477+5G>C and c.539_541del) and two previously reported variants (c.477+1G>C and c.548G>A) in RPL13. RNA analysis demonstrated that c.477+5G>C leads to a 54-nucleotide extension of exon 5, resulting in an 18-amino acid insertion. The phenotypic spectrum ranged from mild manifestations, such as Blount-like tibial deformity without significant short stature or Perthes-like femoral epiphyseal changes, to severe skeletal deformities with disproportionate short stature, accompanied by extraskeletal features (e.g., penoscrotal hypospadias, coccygeal abnormalities). For the first time, we describe Blount-like tibial deformity as a feature of this dysplasia, which resolves with age. Our study provides additional insights into the clinical, radiological, and genotypic features of RPL13-SEMD through detailed analysis of patients and their affected relatives. Full article

Background/Objectives: Timing of fixation of stable slipped capital femoral epiphysis (SCFE) is controversial. As pressure mounts to limit inpatient admissions and procedures, our aim was to investigate whether treatment of SCFE in a delayed manner is a safe alternative to immediate fixation. Our hypothesis was that there would be no difference in complications for stable slips treated immediately (<24 h) versus semi-electively (>24 h) with screw fixation. Methods: A retrospective review was performed at two academic institutions during a 10-year-period yielding 91 SCFEs. Data collected included patient demographics, time to treatment, radiographic measurements (Southwick angle), and complications. Between-group analysis was performed using Welch’s t-test and Fisher’s exact test. Results: 91 stable SCFEs were identified with a median age of 12.3 years (IQR: 11.4–13.3). A total of 62 (68%) slips were treated immediately while 29 (32%) were treated in a semi-elective manner with a median time from diagnosis to surgery of 4 days (range: 2–11 days). There were no instances of >18° increase in Southwick angle in either group or conversion from stable to unstable slips during the semi-elective period. Overall, 12 (13%) patients experienced complications, but no difference in complication rate was observed between groups (15% vs. 10%, p = 0.75). However, the complication profile varied between groups. Of note, two patients (2%, 2/91) experienced AVN, both of which were treated in a semi-elective manner and underwent in situ pinning. Conclusions: There was no difference in complication rate between stable SCFEs treated immediately or semi-electively; however, the complication profile differed by group. No SCFEs in either group had >18° worsening of the Southwick angle between the time of diagnosis and the time of fixation and there were no conversions of stables slips to unstable slips while waiting for semi-elective surgery. These findings suggest that performing semi-elective surgical fixation within 11 days of diagnosing stable, mild SCFEs appears to be a safe alternative to inpatient admission at the time of diagnosis. Full article

Secondary osteonecrosis (ON) is a common complication in paediatric cancer survivors. Combining multipotent mesenchymal stromal cells (MSCs) with core decompression surgery halts disease progression and stimulates bone regeneration. However, the success of advanced therapy medicinal products (ATMPs) requires versatile “off-the-shelf” tissue engineering products (TEPs). This study evaluated the safety and efficacy of TEPs loaded with allogeneic MSCs from Wharton’s jelly (WJ-MSCs) in a large-animal model of bone regeneration to support a paediatric investigational plan for ON patients. WJ-MSC-laden fibrin-based hydrogels combined with a synthetic bone substitute (PRO-DENSE^TM) were tested in 16 juvenile sheep (8 males and 8 females) distributed in four experimental groups. Each animal received four cylindrical bone defects in the femoral and tibial epiphyses and was assessed at 6 and 12 weeks. Safety was confirmed, and bone regeneration was observed across all groups. A combination of WJ-MSCs with PRO-DENSE^TM led to improved histological scores, osteogenesis, and construct integration. Trabecular bone volume also increased more in cellular groups over time. However, effects were inconsistent across groups, reflecting the variability seen in clinical trials and highlighting the significant impact of factors such as immunogenetic compatibility, MSC batch potency, and interaction with the recipient’s microenvironment on the therapeutic effectiveness and successful clinical translation of allogeneic ATMPs. Full article

Background: Forearm fractures are the most common fractures in children, accounting for 41% of all paediatric fractures. Most research focuses on distal forearm fractures, but studies encompassing the entire forearm are limited. Objective: This retrospective study describes the distribution and patterns of paediatric forearm fractures over a five-year period. Methods: We conducted a retrospective cohort study of children aged 0–15 years who received a radiograph of the forearm, wrist or elbow between March 2019 and December 2023 in the study region. Fractures were manually identified and registered from radiological reports. Fracture location, type (complete/incomplete), and epiphyseal involvement were analyzed across different age groups. Statistical analysis was performed using chi-square tests and descriptive statistics. Results: We identified 4547 forearm fractures from 4291 children. The median age was 10 years, and 57% of the patients were male. Fracture patterns varied significantly across age groups (p < 0.001), with older children experiencing more distal, complete, radial, and epiphyseal fractures. Younger children had a higher proportion of incomplete fractures and fewer distal or epiphyseal fractures. No significant differences in Salter–Harris classifications were found between age groups (p = 0.69). Conclusions: Fracture patterns in paediatric forearm fractures vary with age, with older children showing a higher incidence of complete, distal, and epiphyseal fractures. This study provides a detailed characterization of paediatric forearm fractures, which may inform clinical management and preventive strategies, particularly in tailoring age-specific care. Further research should explore the long-term outcomes of these fracture patterns. Full article

Hyaluronan, a key component of the extracellular matrix, plays a crucial role in joint development and maintenance. In order to determine the role of hyaluronan function in joint development and homeostasis, conditional loss-of-function experiments of Hyaluronan Synthase 2 (Has2) were carried out in mice. Has2 depletion in limb mesenchymal cells led to severely shortened limbs with appendicular joints that are deformed, decreased proteoglycan content as characterized by Safranin-O staining, and severely pitted epiphyseal ends of long bones and deformed joints as viewed by micro-CT reconstructions. The embryonic deletion of Has2 in mesoderm mesenchyme of limbs by Prx1-Cre confirmed its involvement in joint development, while in situ hybridization and hyaluronan staining confirmed Has2 expression and abundant accumulation of hyaluronan in the onset of joint formation, the joint interzone. These findings position Has2 as the main hyaluronan-making enzyme in articular cartilage and highlight its essential function in joint formation and retention of proteoglycans of the extracellular matrix of the cartilage. Full article

Leptin-deficient (ob/ob) and leptin receptor (Lepr)-deficient db/db mice develop a mild form of osteoclast-rich osteopetrosis, most evident in long bone epiphyses, implying leptin is important for normal replacement of cartilage during skeletal maturation. However, it is unclear whether leptin acts as a permissive or regulatory factor and whether its actions are mediated via peripheral pathways. Here we show the osteopetrotic phenotype is not evident in ob/+ or db/+ mice, suggesting that leptin acts as a critical but permissive factor for skeletal maturation. The importance of leptin is further supported by our results showing that interventions known to increase bone resorption (mild cold stress, simulated microgravity, or particle-induced inflammation) did not advance skeletal maturation in ob/ob mice whereas long-duration hypothalamic leptin gene therapy was effective. Additionally, administration of leptin by subcutaneously implanted osmotic pumps (400 ng/h) for 2 weeks accelerated skeletal maturation in ob/ob mice. Because leptin has the potential to act on the skeleton through peripheral pathways, we interrogated osteoclast-lineage cells for the presence of Lepr and evaluated skeletal response to the introduction of bone marrow Lepr⁺ cells into db/db mice. We identified Lepr on marrow MCSFR⁺CD11b⁺ osteoclast precursors and on osteoclasts generated in vitro. We then adoptively transferred Lepr⁺ marrow cells from GFP mice or wildtype (WT) mice into Lepr^- db/db mice. Following engraftment, most MCSFR⁺ CD11b⁺ cells in marrow expressed GFP. Whereas db/db→db/db had minimal influence on epiphyseal cartilage, WT→db/db decreased cartilage. These findings suggest peripheral leptin signaling is required for normal osteoclast-dependent replacement of cartilage by bone during skeletal maturation. Full article

This report provides a concise selective representative overview of the predictor factors for progression in Idiopathic Scoliosis (IS). The Cobb angle method, rib hump deformity, imaging and advanced techniques for assessing skeletal maturity serve as key elements in evaluating prognostic factors for IS progression based on the patient’s age at diagnosis—particularly in Infantile Idiopathic Scoliosis (IIS), Juvenile Idiopathic Scoliosis (JIS), and Adolescent Idiopathic Scoliosis (AIS). The commonly used approaches for determining skeletal maturity include the assessment of the iliac apophysis and scoliosis curve deterioration, the Sanders skeletal maturity staging system, the distal radius and ulna (DRU) classification for predicting growth spurts and curve progression in IS, as well as the ossification of vertebral epiphyseal rings, the humeral head, and the calcaneal apophysis. Prognostic factors influencing IS progression are further discussed in relation to the patient’s age at onset—whether in infancy, childhood, or adolescence—as well as in both untreated and braced AIS patients. Additionally, the apical convex rib–vertebra angle in AIS is explored as an indicator of progression. Predictors for curve progression at skeletal maturity are outlined, along with various models for forecasting IS deterioration. Lastly, the Rib and Segmental Rib Index, a rib cage deformity parameter, is introduced as a predictor of scoliosis progression. In conclusion, this concise and selective overview of predictor factors for progression in IS highlights the current understanding of IS progression factors. It also introduces the Rib and Segmental Rib Index—a rib cage deformity parameter—as a predictor of IS progression. Full article