RESUMEN
BACKGROUND: Clinically, magnetic resonance (MR) imaging is the most effective non-invasive tool for assessing IVD degeneration. Histological examination of the IVD provides a more detailed assessment of the pathological changes at a tissue level. However, very few reports have studied the relationship between these techniques. Identifying a relationship may allow more detailed staging of IVD degeneration, of importance in targeting future regenerative therapies. OBJECTIVES: To investigate the relationship between MR and histological grading of IVD degeneration in the cervical and lumbar spine in patients undergoing discectomy. METHODS: Lumbar (N = 99) and cervical (N = 106) IVD samples were obtained from adult patients undergoing discectomy surgery for symptomatic IVD herniation and graded to ascertain a histological grade of degeneration. The pre-operative MR images from these patients were graded for the degree of IVD (MR grade) and vertebral end-plate degeneration (Modic Changes, MC). The relationship between histological and MR grades of degeneration were studied. RESULTS: In lumbar and cervical IVD the majority of samples (93%) exhibited moderate levels of degeneration (ie MR grades 3-4) on pre-operative MR scans. Histologically, most specimens displayed moderate to severe grades of degeneration in lumbar (99%) and cervical spine (93%). MR grade was weakly correlated with patient age in lumbar and cervical study groups. MR and histological grades of IVD degeneration did not correlate in lumbar or cervical study groups. MC were more common in the lumbar than cervical spine (e.g. 39 versus 20% grade 2 changes; p < 0.05), but failed to correlate with MR or histological grades for degeneration. CONCLUSIONS: In this surgical series, the resected IVD tissue displayed moderate to severe degeneration, but there is no correlation between MR and histological grades using a qualitative classification system. There remains a need for a quantitative, non-invasive, pre-clinical measure of IVD degeneration that correlates with histological changes seen in the IVD.
Asunto(s)
Vértebras Cervicales/patología , Degeneración del Disco Intervertebral/diagnóstico , Degeneración del Disco Intervertebral/patología , Vértebras Lumbares/patología , Imagen por Resonancia Magnética , Adulto , Anciano , Anciano de 80 o más Años , Discectomía/métodos , Femenino , Humanos , Desplazamiento del Disco Intervertebral/diagnóstico , Desplazamiento del Disco Intervertebral/patología , Región Lumbosacra/patología , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
OBJECTIVE: This study explored posterior cruciate ligament (PCL) synovio-entheseal complex (SEC) microanatomy to determine whether it may participate in the early osteoarthritis (OA) disease process. METHODS: SEC microanatomy and OA features were evaluated in 14 non-arthritic cadaveric knees (mean age = 69.9) using magnetic resonance imaging (MRI) and histology. MRI images of 49 subjects selected from the progression cohort of the Osteoarthritis Initiative (OAI) were evaluated by a musculoskeletal radiologist using an original semi-quantitative method for features associated with OA at the PCL tibial enthesis. Statistical analysis was performed using chi-square and Wilcoxon signed-rank tests to evaluate associations between SEC configuration and OA features. RESULTS: The PCL formed a SEC-like structure encompassing bone- and ligament-lining intra-articular cartilages to which the posterior root of the medial meniscus contributed. Degenerative features at the PCL-SEC included: neovascularisation (44%), enthesis chondrocyte clustering (44%), collagen matrix fissuring at the enthesis (56%) and in the PCL itself (67%), tidemark duplication (44%), bone remodelling (44%) and microscopic inflammatory changes (33%). In the OAI cohort, SEC-related pathology included bone marrow lesions (BMLs) (69%) and osteophytosis (94%) at locations that corresponded to SEC-related cartilages. Posterior joint recess effusion (49%) was linked to MRI abnormalities at PCL-SEC cartilages (χ2 = 7.27, P = 0.007). CONCLUSIONS: The PCL has a prominent SEC configuration that is associated with microscopic OA changes in aged clinically non-diseased joints. MRI determined knee OA commonly exhibited pathological features at this site which was associated with adjacent joint effusion. Thus, the PCL-SEC could play a hitherto unappreciated role in the early OA disease process.
Asunto(s)
Osteoartritis de la Rodilla/patología , Ligamento Cruzado Posterior/patología , Membrana Sinovial/patología , Anciano , Cadáver , Cartílago Articular/patología , Exudados y Transudados , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Sinovitis/patología , Tendones/patologíaRESUMEN
In 2007, three times as many peer reviewed publications covering the biology and biotherapeutics of intervertebral disc (IVD) disease appeared in the literature than in 1997. This is testimony to the upsurge in interest in the IVD, mainly driven by the openings that modern molecular pathology has generated to investigate mechanisms of human disease and the potential offered by novel therapeutic technologies to use data coming from these studies to positively influence chronic discogenic back pain and sciatica. Molecular pathology has shown IVD degeneration, a major cause of low back pain, to be a complex, active disorder in which disturbed cytokine biology, cellular dysfunction and altered load responses play key roles. This has translated into a search for target molecules and disease processes that might be the focus of future, evidence-based therapies for back pain. It is not possible to describe the totality of advances that have been made in understanding the biology of the IVD in recent years, but in this review those areas of biology that are currently influencing, or could conceivably soon impinge on, clinical thinking or practice around IVD degeneration and discogenic back pain are described and discussed.
Asunto(s)
Dolor de Espalda/etiología , Disco Intervertebral/patología , Enfermedades de la Columna Vertebral/patología , Citocinas/fisiología , Humanos , Disco Intervertebral/inervación , Disco Intervertebral/metabolismo , Enfermedades de la Columna Vertebral/complicaciones , Enfermedades de la Columna Vertebral/metabolismo , Estrés MecánicoRESUMEN
The levels of type X collagen in mineralizing normal chicken epiphyses and nonmineralizing rachitic chicken tibial epiphyses were measured and compared. Qualitative immunoperoxidase studies with anti-chick type X collagen monoclonal antibodies on sections from normal and rachitic cartilage demonstrated that the type X collagen levels in rachitic growth plates are reduced. Northern hybridization of mRNA and biosynthetic studies have confirmed that type X collagen synthesis in rickets is also decreased. In hypocalcemic rickets, the level of type X collagen mRNA is reduced by 80% whereas the level of type X collagen mRNA is only reduced by 50% in normocalcemic rickets. These observations provide additional evidence that type X collagen is involved in the process of cartilage mineralization and also suggest that the partial recovery of type X collagen synthesis in normocalcemic rickets may be related to the elevated plasma concentration of calcium. Calcium concentration may therefore play an important role in the control of type X collagen synthesis.
Asunto(s)
Colágeno/biosíntesis , Placa de Crecimiento/metabolismo , Raquitismo/metabolismo , Animales , Anticuerpos Monoclonales , Northern Blotting , Pollos , Colágeno/análisis , Colágeno/genética , Expresión Génica , Placa de Crecimiento/citología , Placa de Crecimiento/patología , Técnicas para Inmunoenzimas , Hibridación de Ácido Nucleico , ARN/genética , ARN/aislamiento & purificación , Valores de Referencia , Raquitismo/patologíaRESUMEN
Neurofibromatosis type 2 (NF2) is associated with the development of several types of benign nervous system tumours, while malignancies are rare. We report a 22-year-old man who presented with retroperitoneal and spinal high-grade sarcomas with epithelial features. Samples showed a mixed epithelioid and spindled cell content with little associated matrix and inconclusive immunochemistry. Genetic analysis of a schwannoma and matched blood samples demonstrated a constitutional de novo substitution at the splice donor site of intron 8 of the NF2 gene and aa acquired large deletion of the entire NF2 gene as a second hit, with some loss of SMARCB1. The sarcoma also showed evidence of loss of SMARCB1 and NF2 with loss of INI1 staining. Unfortunately the mass was unresectable and the patient died 6 months after diagnosis. This malignancy was most consistent with SMARCB1-deficient epithelioid malignant peripheral nerve sheath tumour, although a significant differential was proximal-type epithelial sarcoma. Each differential has previously been reported only once with NF2. This demonstrates an extremely rare potential complication of the condition.
Asunto(s)
Neurofibromatosis 2/complicaciones , Neoplasias Retroperitoneales/diagnóstico , Sarcoma/diagnóstico , Neoplasias de la Columna Vertebral/diagnóstico , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Diagnóstico Tardío , Diagnóstico Diferencial , Doxorrubicina/uso terapéutico , Resultado Fatal , Humanos , Masculino , Clasificación del Tumor , Neurofibromatosis 2/genética , Neurofibromina 2/genética , Cuidados Paliativos/métodos , Neoplasias Retroperitoneales/tratamiento farmacológico , Neoplasias Retroperitoneales/genética , Neoplasias Retroperitoneales/patología , Proteína SMARCB1/genética , Sarcoma/tratamiento farmacológico , Sarcoma/genética , Sarcoma/patología , Sorafenib/uso terapéutico , Neoplasias de la Columna Vertebral/tratamiento farmacológico , Neoplasias de la Columna Vertebral/genética , Neoplasias de la Columna Vertebral/patología , Adulto JovenRESUMEN
Robust protocols for microarray gene expression profiling of archival formalin-fixed paraffin-embedded tissue (FFPET) are needed to facilitate research when availability of fresh-frozen tissue is limited. Recent reports attest to the feasibility of this approach, but the clinical value of these data is poorly understood. We employed state-of-the-art RNA extraction and Affymetrix microarray technology to examine 34 archival FFPET primary extremity soft tissue sarcomas. Nineteen arrays met stringent QC criteria and were used to model prognostic signatures for metastatic recurrence. Arrays from two paired frozen and FFPET samples were compared: although FFPET sensitivity was low ( approximately 50%), high specificity (95%) and positive predictive value (92%) suggest that transcript detection is reliable. Good agreement between arrays and real time (RT)-PCR was confirmed, especially for abundant transcripts, and RT-PCR validated the regulation pattern for 19 of 24 candidate genes (overall R(2)=0.4662). RT-PCR and immunohistochemistry on independent cases validated prognostic significance for several genes including RECQL4, FRRS1, CFH and MET - whose combined expression carried greater prognostic value than tumour grade - and cmet and TRKB proteins. These molecules warrant further evaluation in larger series. Reliable clinically relevant data can be obtained from archival FFPET, but protocol amendments are needed to improve the sensitivity and broad application of this approach.
Asunto(s)
Perfilación de la Expresión Génica , Neoplasias/metabolismo , Análisis de Secuencia por Matrices de Oligonucleótidos , Biomarcadores de Tumor/genética , Formaldehído , Humanos , Neoplasias/patología , Adhesión en Parafina , Pronóstico , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Fijación del TejidoRESUMEN
OBJECTIVE: To establish if IL-1 or TNF regulates matrix degradation in the non-degenerate or degenerate intervertebral disc (IVD). METHODS: In situ zymography (ISZ) has been used to investigate the role of IL-1 and TNF in the matrix degradation characterizing symptomatic IVD degeneration. ISZ employed three substrates (gelatin, collagen II, casein) and four different challenges, IL-1beta, IL-1 receptor antagonist (IL-1Ra), TNF-alpha and anti-TNF. RESULTS: We have shown for the first time that whilst IL-1beta will stimulate and IL-1 receptor antagonist will inhibit matrix degradation in intact human IVD tissue, neither TNF-alpha nor anti-TNF have any measurable effect on degradation of these matrices. CONCLUSION: This study has addressed a current area of controversy in IVD biology, namely, whether either IL-1 or TNF or both are involved in driving matrix degradation. Our data indicate that IL-1 is a key cytokine mediating matrix degradation in the IVD and therefore a therapeutic target.
Asunto(s)
Matriz Extracelular/patología , Interleucina-1/fisiología , Disco Intervertebral/patología , Enfermedades de la Columna Vertebral/patología , Factor de Necrosis Tumoral alfa/fisiología , Adulto , Anciano , Matriz Extracelular/efectos de los fármacos , Matriz Extracelular/metabolismo , Femenino , Humanos , Interleucina-1/farmacología , Disco Intervertebral/efectos de los fármacos , Disco Intervertebral/metabolismo , Vértebras Lumbares , Masculino , Metaloendopeptidasas/metabolismo , Microscopía Fluorescente , Persona de Mediana Edad , Receptores de Interleucina-1/antagonistas & inhibidores , Enfermedades de la Columna Vertebral/metabolismo , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Factor de Necrosis Tumoral alfa/farmacologíaRESUMEN
This article presents a systematic review of the current biomedical literature surrounding the aetiopathogenesis and histopathological features of bone marrow oedema, reactive bone change and haemorrhage. Bone marrow oedema is generally demonstrated as a non-specific finding on magnetic resonance imaging in association with infections, tumours and avascular necrosis. When it occurs in isolation as a primary event not triggered by any obvious bony pathology in the clinical setting of debilitating joint pain, it constitutes the "bone marrow oedema syndrome". Although the latter diagnosis is based on magnetic resonance (MR) imaging, showing the lesion as areas of signal hyperintensity within the marrow, recent radiology-histology correlational studies have shown variably interstitial marrow oedema, necrosis, fibrosis and trabecular bone abnormalities. In light of these facts, the use of the term bone marrow oedema syndrome in a radiological context might be considered questionable, but histopathological techniques are not sensitive in detecting increased extracellular fluid. Reactive bone changes may be focal or diffuse and usually amount to increased bone formation. Bone marrow haemorrhage, due to trauma, results in bone bruising, a condition in which the size of the bruise and associated osteochondral injury determines the outcome, although the natural history of these lesions is still being researched.
Asunto(s)
Enfermedades de la Médula Ósea/diagnóstico , Edema/diagnóstico , Hemorragia/patología , Articulación de la Rodilla/patología , Imagen por Resonancia Magnética/métodos , Osteoporosis/diagnóstico , Femenino , Humanos , Masculino , SíndromeRESUMEN
During intervertebral disc (IVD) degeneration, normal matrix synthesis decreases and degradation of disc matrix increases. A number of proteases that are increased during disc degeneration are thought to be involved in its pathogenesis. Matrix metalloproteinase 7 (MMP 7) (Matrilysin, PUMP-1) is known to cleave the major matrix molecules found within the IVD, i.e., the proteoglycan aggrecan and collagen type II. To date, however, it is not known how its expression changes with degeneration or its exact location. We investigated the localization of MMP 7 in human, histologically graded, nondegenerate, degenerated and prolapsed discs to ascertain whether MMP 7 is up-regulated during disc degeneration. Samples of human IVD tissue were fixed in neutral buffered formalin, embedded in paraffin, and sections stained with hematoxylin and eosin to score the degree of morphological degeneration. Immunohistochemistry was performed to localize MMP 7 in 41 human IVDs with varying degrees of degeneration. We found that the chondrocyte-like cells of the nucleus pulposus and inner annulus fibrosus were MMP 7 immunopositive; little immunopositivity was observed in the outer annulus. Nondegenerate discs showed few immunopositive cells. A significant increase in the proportion of MMP 7 immunopositive cells was seen in the nucleus pulposus of discs classified as showing intermediate levels of degeneration and a further increase was seen in discs with severe degeneration. Prolapsed discs showed more MMP 7 immunopositive cells compared to nondegenerated discs, but fewer than those seen in cases of severe degeneration.
Asunto(s)
Disco Intervertebral/enzimología , Metaloproteinasa 7 de la Matriz/biosíntesis , Enfermedades de la Columna Vertebral/enzimología , Adulto , Anciano , Femenino , Humanos , Inmunohistoquímica , Disco Intervertebral/patología , Desplazamiento del Disco Intervertebral/enzimología , Desplazamiento del Disco Intervertebral/patología , Masculino , Persona de Mediana Edad , Enfermedades de la Columna Vertebral/patología , Regulación hacia ArribaRESUMEN
AIMS: The aim of this study was to analyse human muscle tissue before and after rotator cuff repair to look for evidence of regeneration, and to characterise the changes seen in the type of muscle fibre. PATIENTS AND METHODS: Patients were assessed pre-operatively and one year post-operatively using the Oxford Shoulder Score (OSS) and MRI. The cross-sectional area and distribution of the type of muscle fibre were assessed on biopsies, which were taken at surgery and one year post-operatively. Paired samples from eight patients were analysed. There were three men and five women with a mean age of 63 years (50 to 73). RESULTS: All but one patient showed improvement in OSS (p = 0.004). The mean increase in the cross-sectional area of the muscle was 1220 µm2 (-801 to 3712; p = 0.03). There was a reduction of type 2a fibres (p = 0.02). A clear relationship could not be seen between the MRI findings and the histological appearances. CONCLUSION: This is the first study to provide evidence that atrophy of the supraspinatus muscle is reversible. Changes in the types of fibre are discussed. MRI assessment of muscle atrophy may not be fully representative of myofibre atrophy. Cite this article: Bone Joint J 2016;98-B:1389-94.
Asunto(s)
Artroscopía/métodos , Contracción Muscular/fisiología , Atrofia Muscular/etiología , Recuperación de la Función/fisiología , Regeneración/fisiología , Lesiones del Manguito de los Rotadores/cirugía , Manguito de los Rotadores/cirugía , Anciano , Biopsia , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Atrofia Muscular/diagnóstico , Atrofia Muscular/fisiopatología , Periodo Posoperatorio , Manguito de los Rotadores/diagnóstico por imagen , Manguito de los Rotadores/fisiología , Lesiones del Manguito de los Rotadores/diagnóstico , Lesiones del Manguito de los Rotadores/fisiopatología , Resultado del TratamientoRESUMEN
Recent studies have suggested that the adipocyte-derived hormone, leptin, plays a role in the regulation of metabolism. Here, we tested this hypothesis in the seasonally breeding Siberian hamster, as this species exhibits profound seasonal changes in adiposity and circulating leptin concentrations driven by the annual photoperiodic cycle. Male hamsters were kept in either long (LD) or short (SD) photoperiods. Following exposure to short photoperiods for 8 weeks animals exhibited a significant weight-loss and a 16-fold reduction of serum leptin concentrations. At Week 9, animals in both photoperiods were infused with leptin or PBS via osmotic mini-pump for 14 days. Chronic leptin infusion mimicked LD-like concentrations in SD-housed animals and caused a further decline in body weight and adipose tissue. In LD-housed animals, leptin infusion resulted in a significant elevation of serum concentrations above natural LD-like levels, but had no discernable effect on body weight or overall adiposity. Both bending and compression characteristics and histomorphometric measurements of trabecular bone mass were unaltered by leptin treatment or photoperiod. Our data therefore show that despite a high natural amplitude cycle of leptin, this hormone has no apparent role in the regulation of bone metabolism, and therefore do not support recent propositions that this hormone is an important component in the metabolism of bone tissue.
Asunto(s)
Huesos/anatomía & histología , Leptina/metabolismo , Phodopus/anatomía & histología , Phodopus/metabolismo , Estaciones del Año , Animales , Fenómenos Biomecánicos , Peso Corporal/efectos de los fármacos , Huesos/efectos de los fármacos , Cricetinae , Femenino , Infusiones Intravenosas , Masculino , Fotoperiodo , Reproducción/fisiologíaRESUMEN
BACKGROUND: Renal osteodystrophy is a common complication of end-stage renal disease (ESRD) and is a major cause of morbidity in patients with ESRD. High serum levels of phosphorus, calcium and parathyroid hormone are associated with the development of this disease. The effects on bone of treatment with lanthanum carbonate, a new phosphate binder, and calcium carbonate were assessed in patients with ESRD. METHODS: This was an open-label, multicenter, parallel-group study. Patients were recruited within 12 weeks of commencing dialysis. Following screening, phosphate binder administration was stopped, tetracycline labeling administered and a transiliac bone biopsy taken. After randomization to lanthanum carbonate or calcium carbonate, patients were titrated to an optimum dose for 8 weeks and maintained at this dose for 44 weeks. The bone was then labeled and a second biopsy taken. Biopsy samples were analyzed histomorphometrically. RESULTS: Paired bone biopsies from 33 lanthanum carbonate- and 30 calcium carbonate-treated patients were suitable for analysis. None of the patients on either treatment developed osteomalacia. Assessment of activation frequency changes showed that 41% of biopsies from lanthanum carbonate-treated patients moved towards normal (observed values at the follow-up biopsy were closer to expected values than were the baseline values, so patients were considered to be improved) compared with 23% of calcium carbonate-treated patients (p = 0.15). CONCLUSIONS: This study indicates that there was no evidence of aluminum-like toxicity with lanthanum carbonate after 1 year of treatment in ESRD patients commencing dialysis, and there appeared to be a beneficial effect on bone-cell function and activity compared with calcium carbonate.
Asunto(s)
Carbonato de Calcio/uso terapéutico , Trastorno Mineral y Óseo Asociado a la Enfermedad Renal Crónica/tratamiento farmacológico , Fallo Renal Crónico/complicaciones , Lantano/uso terapéutico , Adulto , Anciano , Anciano de 80 o más Años , Biopsia , Calcitriol/sangre , Calcio/sangre , Trastorno Mineral y Óseo Asociado a la Enfermedad Renal Crónica/etiología , Femenino , Humanos , Masculino , Fósforo/sangre , Diálisis Renal , Resultado del TratamientoRESUMEN
OBJECTIVES: To determine the temporal and spatial expression of the connective tissue precursors, procollagen and tropoelastin mRNA in normal and pulmonary hypertensive porcine pulmonary arteries from birth onwards. METHODS: Using in situ hybridisation, connective tissue gene expression for procollagen alpha1(I) and alpha1(III) and tropoelastin was studied in intrapulmonary arteries from normal piglets, 5 min-16 weeks, and from piglets made pulmonary hypertensive by exposure to hypobaric hypoxia for 3 days, from birth, 3 or 14 days of age. In addition, Type III pN-procollagen, tropoelastin and collagen I and III were studied by immunohistochemistry. Quantitative or semi-quantitative techniques were applied to both in situ and immunohistochemical studies. RESULTS: Procollagen alpha1(I) and alpha1(III) mRNA expression increased rapidly in the media and adventitia between birth and 3 days of age (P<0.05). The increase was transient and the number of cells expressing procollagen mRNA decreased to the low newborn number after 6 days of age. Type III pN-procollagen immunostaining was greatest in newborn elastic and muscular arteries and then decreased. Collagen I and III increased mainly after 6 days of age. In animals exposed to chronic hypobaric hypoxia from birth, the increase in procollagens I and III mRNA was prevented. Exposure to hypoxia from 3 or 14 days led to little change in either gene expression or in procollagen and mature collagen from the normal. Tropoelastin gene expression was high at birth in the endothelium and media for the first 6 days, and then decreased. Normally, tropoelastin decreased in the media and increased in the adventitia after 16 days of age. Hypoxia had no effect on the mRNA but led to increased tropoelastin. CONCLUSION: We demonstrated marked, rapid changes in temporal and cell specific connective tissue gene expression in normal pulmonary arteries immediately after birth as the vasculature remodels. Each gene appeared to have its own timetable of expression and responded differently to hypoxia-induced hypertension.
Asunto(s)
Tejido Conectivo/metabolismo , Hipertensión/congénito , Procolágeno/genética , Arteria Pulmonar/metabolismo , Tropoelastina/genética , Animales , Animales Recién Nacidos/metabolismo , Autorradiografía/métodos , Colágeno/análisis , Expresión Génica , Hipertensión/metabolismo , Inmunohistoquímica/métodos , Hibridación in Situ/métodos , ARN Mensajero/análisis , PorcinosRESUMEN
The cytokine interleukin-6 (IL-6) is considered an important regulator of bone cell function and may play a central role in bone disease states characterized by increased bone remodeling, such as Paget's disease. Indeed, recent in vitro data suggest that IL-6 may be an autocrine/paracrine factor for pagetic osteoclasts. However, its expression and role in vivo are not known. Using in situ hybridization we investigated the spatial localization of expression of IL-6, IL-6 receptor (IL-6R), and the transcription factor (NF-IL-6) in pagetic bone. Our results show that osteoblasts in the normal remodeling bone of osteoarthritis (controls) and in Paget's disease express IL-6, IL-6R, and NF-IL-6 genes with higher levels of IL-6 and IL-6R mRNA in pagetic bone. Osteoclasts in both osteoarthritic and pagetic bone express IL-6R mRNA and NF-IL-6, but only pagetic osteoclasts expressed IL-6, suggesting that in Paget's disease IL-6 can act as an autocrine factor on osteoclasts. These results provide evidence for a major role of the IL-6 regulatory pathway in the phenotype of the pagetic osteoclasts and lead us to suggest a model linking possible paramyxovirus infection and IL-6 regulation in the pagetic osteoclast.
Asunto(s)
Huesos/metabolismo , Proteínas de Unión al ADN/genética , Interleucina-6/genética , Proteínas Nucleares/genética , Osteítis Deformante/metabolismo , Osteoblastos/metabolismo , Receptores de Interleucina/genética , Remodelación Ósea , Huesos/patología , Proteínas Potenciadoras de Unión a CCAAT , Proteínas de Unión al ADN/biosíntesis , Expresión Génica , Humanos , Hibridación in Situ , Interleucina-6/biosíntesis , Proteínas Nucleares/biosíntesis , Osteítis Deformante/genética , Osteítis Deformante/patología , Osteoartritis/metabolismo , Osteoartritis/patología , Osteoclastos/metabolismo , Fenotipo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Receptores de Interleucina/biosíntesis , Receptores de Interleucina-6 , Respirovirus/fisiologíaRESUMEN
We report a cross-sectional study of 54 adult female renal transplant recipients. We measured bone mineral density (BMD) of the lumbar spine, femoral neck, total hip, and mid- and total radius, and 38 patients underwent transiliac crest bone biopsy. Osteopenia was widespread with 31/54 (57%) of patients osteoporotic at one or more sites. Seventeen out of 54 (32%) of the patients had a prevalent low-trauma fracture. There was a clear trend in BMD reduction across spine, hip and midradius, with the predominantly cortical midradial site showing the greatest loss. We found no relationship between BMD and body mass index, parathyroid hormone (PTH), dose of immunosuppressant, years since transplantation, age at menopause, or years since menopause. Histologically, abnormal biopsies could be classified into three categories: hyperparathyroid (n = 20), adynamic (n = 14), and osteomalacic (n = 2). Mean PTH was lower (p = NS) and mean cumulative prednisolone dose was higher (p = 0.04) in the adynamic group compared with the hyperparathyroid group, but because of overlap between groups neither was an effective discriminator of histology. We suggest that bone biopsy is indicated in these patients to direct appropriate treatment. At the cellular level, there were significant negative correlations between osteoclast function (eroded surface, r = 0.47, p = 0.003) and osteoblast numbers (osteoblast surface, r = -0.40, p = 0.01) and cumulative exposure to prednisolone. We postulate that suppression of osteoblast function by prednisolone with unopposed bone resorption may result in relative hypercalcaemia and low PTH. This progressive reduction in bone turnover may promote or prolong the adynamic state.
Asunto(s)
Trasplante de Riñón/efectos adversos , Osteoporosis/etiología , Adulto , Densidad Ósea , Calcio/sangre , Estudios Transversales , Densitometría , Femenino , Fracturas Óseas/epidemiología , Fracturas Óseas/etiología , Humanos , Terapia de Inmunosupresión , Trasplante de Riñón/inmunología , Osteoporosis/epidemiología , Osteoporosis/inmunología , Osteoporosis/patología , Hormona Paratiroidea/sangre , Fosfatos/sangre , PrevalenciaRESUMEN
Endochondral ossification is a carefully coordinated developmental process that converts the cartilaginous model of the embryonic skeleton to bone with accompanying long bone growth. To identify genes that regulate this process we performed a complementary DNA (cDNA) subtractive hybridization of fetal bovine proliferative chondrocyte cDNA from epiphyseal cartilage cDNA. The subtracted product was used to screen a fetal bovine cartilage cDNA library. Ten percent of the clones identified encoded the bovine orthologue of the human ribosomal protein "QM." Northern and western blot analysis confirmed that QM was highly expressed by cells isolated from epiphyseal cartilage as opposed to proliferative chondrocytes. In contrast, no detectable difference in the expression of mRNA for the ribosomal protein S11 was detected. Immunohistochemical analysis of fetal bovine limb sections revealed that QM was not expressed by the majority of the epiphyseal chondrocytes but only by chondrocytes in close proximity to capillaries that had invaded the epiphyseal cartilage. Strongest QM expression was seen in osteoblasts in the diaphyseal region of the bone adjoining the growth plate, within the periosteum covering the growth plate and within secondary centers of ossification. Hypertrophic chondrocytes within the growth plate adjoining the periosteum also were positive for QM as were chondrocytes in the perichondrium adjoining the periosteum. In vitro investigation of the expression of QM revealed higher QM expression in nonmineralizing osteoblast and pericyte cultures as compared with mineralizing cultures. The in vivo and in vitro expression pattern of QM suggests that this protein may have a role in cell differentiation before mineralization.
Asunto(s)
Desarrollo Óseo/fisiología , Proteínas Portadoras/genética , Condrocitos/metabolismo , Proteínas Ribosómicas/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Northern Blotting/métodos , Southern Blotting/métodos , Western Blotting/métodos , Proteínas Portadoras/metabolismo , Bovinos , Células Cultivadas , Condrocitos/citología , ADN Complementario , Perfilación de la Expresión Génica , Placa de Crecimiento/citología , Humanos , Inmunohistoquímica , Ratones , Datos de Secuencia Molecular , Pericitos/citología , Pericitos/metabolismo , Proteína Ribosómica L10 , Proteínas Ribosómicas/metabolismo , VertebradosRESUMEN
Although estrogens profoundly influence skeletal growth and maturation, their mechanism of action is still unclear. To identify their target cells in bone, estrogen receptors were located by immunofluorescence using the H222 monoclonal antibody in cryosections (both undecalcified and briefly decalcified) of hyperplastic mandibular condyle (persistent asymmetric mandibular growth) from a 14-year-old girl and radius and ulna from an 18-month-old female pig (epiphyseal fusion) and from a 3-month-old guinea pig (epiphyses open). Bone was removed from the animals at the peak of estrus. The most striking feature in all three species was the high proportion (approximately 50%) of receptor positive osteocytes. Although all sections contained active bone-forming surfaces, we were unable to identify clearly osteoblasts or lining cells that were estrogen receptor positive. In pig bone only, distinctive groups of receptor positive chondrocytes, with a pericellular localization of collagen type 1, were detected above the growth plate but below secondary centers of ossification. This observation suggests that osteocytes are major skeletal estrogen target cells and may be involved in coordinating the response of surface bone cells to the hormone, and further that chondrocytes may be involved in estrogen-induced epiphyseal growth plate fusion.
Asunto(s)
Huesos/metabolismo , Placa de Crecimiento/patología , Receptores de Estrógenos/metabolismo , Adolescente , Animales , Anticuerpos Monoclonales , Huesos/citología , Huesos/fisiología , Colágeno/análisis , Colágeno/metabolismo , Femenino , Fémur/citología , Fémur/metabolismo , Fémur/fisiología , Secciones por Congelación , Placa de Crecimiento/citología , Placa de Crecimiento/fisiología , Cobayas , Humanos , Técnicas para Inmunoenzimas , Mandíbula/metabolismo , Mandíbula/patología , Mandíbula/fisiología , Radio (Anatomía)/citología , Radio (Anatomía)/metabolismo , Radio (Anatomía)/fisiología , Receptores de Estrógenos/fisiología , Porcinos , Tibia/citología , Tibia/metabolismo , Tibia/fisiología , Cúbito/citología , Cúbito/metabolismo , Cúbito/fisiología , Útero/metabolismo , Útero/fisiologíaRESUMEN
Phorbol 12-myristate 13-acetate (100 nM), a potent protein kinase C and macrophage activator, has a biphasic affect on 25(OH)D3-1 alpha-hydroxylase activity in synovial fluid macrophages from arthritis patients. After 5 h, 1 alpha, 25(OH)D3 synthesis fell from 5.2 +/- 0.1 to 1.6 +/- 0.2 pmol/h per 10(6) cells, however, after 24 h and 48 h, synthesis increased to 17.4 +/- 0.3 and 22.3 +/- 1.4 pmol/h per 10(6) cells, respectively. Although an independent short-term mechanism is suggested, protein kinase C may promote macrophage activation, thus increasing long-term 25(OH)D3-1 alpha-hydroxylase expression. Intracellular calcium and cAMP are unlikely to activate the enzyme, since 0.1 microM of the calcium ionophore, A23187, and 1 mM dibutyryl-cAMP inhibited synthesis by 87% and 79%, respectively, after 24 h.
Asunto(s)
Artritis/metabolismo , Calcitriol/biosíntesis , Macrófagos/metabolismo , Acetato de Tetradecanoilforbol/farmacología , Artritis Gotosa/metabolismo , Artritis Reumatoide/metabolismo , Bucladesina/farmacología , Calcimicina/farmacología , Células Cultivadas , Relación Dosis-Respuesta a Droga , Humanos , Macrófagos/efectos de los fármacos , Líquido Sinovial/citologíaRESUMEN
Platelet-derived growth factor (PDGF) has been shown to have effects on bone and cartilage cells in vitro, but its role in vivo in bone repair is not clear. We studied biopsy material from 16 normally healing fractures at a variety of times after injury, using immunohistochemistry for PDGF and in situ hybridization for PDGF A and B chains. PDGF A-chain gene was found to be expressed by many cell types over a prolonged period during fracture healing. These cells included endothelial and mesenchymal cells in granulation tissue and osteoblasts, chondrocytes, and osteoclasts later during fracture healing. PDGF B-chain gene expression was more restricted, being detected principally in osteoblasts at the stage of bone formation. PDGF was detected using immunohistochemistry in the cell types expressing PDGF A. These findings indicate that PDGF is expressed during normal human fracture repair, and the in vitro data also suggest that PDGF is likely to be an important local regulator in this process.
Asunto(s)
Curación de Fractura/fisiología , Factor de Crecimiento Derivado de Plaquetas/biosíntesis , Biopsia , Expresión Génica , Humanos , Inmunohistoquímica , Hibridación in Situ , Factor de Crecimiento Derivado de Plaquetas/genéticaRESUMEN
Estrogens are considered essential to the mechanism for closure of epiphyses in both males and females. The mechanism for this, however, is still unclear. It is likely that estrogen acts directly on growth plate chondrocytes, but the localization of the cells expressing the estrogen receptor (ER) has yet to be ascertained. Moreover, in rodents, growth plates remain open well into adult life. Whether the distribution of estrogen target cells in rodent epiphyses differs from that in other species, is also unclear. We therefore compared localization of estrogen target cells (denoted by ER-alpha protein expression) in species in which growth plates fuse, with that in rodents. Thus, we have investigated ER-alpha protein expression in femoral growth plates from male and female rabbits, just at sexual maturity (6 months), when growth plate fusion was just commencing, and in rats of equivalent developmental stage (9 weeks). ER-alpha was detected in undecalcified cryosections by immunofluorescence with 1D5 monoclonal antibody, raised to human ER-alpha; uterine sections were positive controls. ER-alpha-positive cells were localized to the proliferative/early hypertrophic zone of male and female rabbits. By contrast, cells in the similar region of the mature rat growth plate were ER-alpha-negative in both genders, although receptor could be readily detected in uteri of mature female rats. In growth plates of immature male and female rats (6 weeks), however, ER-alpha was clearly expressed by cells of the proliferative/early hypertrophic zone, but was barely detectable in uteri from immature females. Our findings support the view that estrogen may act directly on the growth plate and, in species in which there is epiphyseal fusion, may thus have a role in this process. If ER-alpha expression is lost at sexual maturity, as in rodents, growth plates may remain open into adulthood. Our results also show the changes in ER-alpha expression in growth plates of maturing rats may be opposite to that in the uterus and raise the possibility that receptor expression may be controlled differently in reproductive and skeletal tissues.