Effects of VX765 on osteoarthritis and chondrocyte inflammation in rats / 中国修复重建外科杂志

OBJECTIVE@#To investigate the effects and underlying mechanisms of VX765 on osteoarthritis (OA) and chondrocytes inflammation in rats.@*METHODS@#Chondrocytes were isolated from the knee joints of 4-week-old Sprague Dawley (SD) rats. The third-generation cells were subjected to cell counting kit 8 (CCK-8) analysis to assess the impact of various concentrations (0, 1, 5, 10, 20, 50, 100 μmol/L) of VX765 on rat chondrocyte activity. An in vitro lipopolysaccharide (LPS) induced cell inflammation model was employed, dividing cells into control group, LPS group, VX765 concentration 1 group and VX765 concentration 2 group without obvious cytotoxicity. Western blot, real-time fluorescence quantitative PCR, and ELISA were conducted to measure the expression levels of inflammatory factors-transforming growth factor β 1 (TGF-β 1), interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α). Additionally, Western blot and immunofluorescence staining were employed to assess the expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1). Thirty-two SD rats were randomly assigned to sham surgery group (group A), OA group (group B), OA+VX765 (50 mg/kg) group (group C), and OA+VX765 (100 mg/kg) group (group D), with 8 rats in each group. Group A underwent a sham operation with a medial incision, while groups B to D underwent additional transverse incisions to the medial collateral ligament and anterior cruciate ligament, with removal of the medial meniscus. One week post-surgery, groups C and D were orally administered 50 mg/kg and 100 mg/kg VX765, respectively, while groups A and B received an equivalent volume of saline. Histopathological examination using HE and safranin-fast green staining was performed, and Mankin scoring was utilized for evaluation. Immunohistochemical staining technique was employed to analyze the expressions of matrix metalloproteinase 13 (MMP-13) and collagen type Ⅱ.@*RESULTS@#The CCK-8 assay indicated a significant decrease in cell viability at VX765 concentrations exceeding 10 μmol/L ( P<0.05), so 4 μmol/L and 8 μmol/L VX765 without obvious cytotoxicity were selected for subsequent experiments. Following LPS induction, the expressions of TGF-β 1, IL-6, and TNF-α in cells significantly increased when compared with the control group ( P<0.05). However, intervention with 4 μmol/L and 8 μmol/L VX765 led to a significant decrease in expression compared to the LPS group ( P<0.05). Western blot and immunofluorescence staining demonstrated a significant upregulation of Nrf2 pathway-related molecules Nrf2 and HO-1 protein expressions by VX765 ( P<0.05), indicating Nrf2 pathway activation. Histopathological examination of rat knee joint tissues and immunohistochemical staining revealed that, compared to group B, treatment with VX765 in groups C and D improved joint structural damage in rat OA, alleviated inflammatory reactions, downregulated MMP-13 expression, and increased collagen type Ⅱ expression.@*CONCLUSION@#VX765 can improve rat OA and reduce chondrocyte inflammation, possibly through the activation of the Nrf2 pathway.

Research progress on the role of chondrocyte mitochondrial homeostasis imbalance in the pathogenesis of osteoarthritis / 中国修复重建外科杂志

OBJECTIVE@#To summarize the role of chondrocyte mitochondrial homeostasis imbalance in the pathogenesis of osteoarthritis (OA) and analyze its application prospects.@*METHODS@#The recent literature at home and abroad was reviewed to summarize the mechanism of mitochondrial homeostasis imbalance, the relationship between mitochondrial homeostasis imbalance and the pathogenesis of OA, and the application prospect in the treatment of OA.@*RESULTS@#Recent studies have shown that mitochondrial homeostasis imbalance, which is caused by abnormal mitochondrial biogenesis, the imbalance of mitochondrial redox, the imbalance of mitochondrial dynamics, and damaged mitochondrial autophagy of chondrocytes, plays an important role in the pathogenesis of OA. Abnormal mitochondrial biogenesis can accelerate the catabolic reaction of OA chondrocytes and aggravate cartilage damage. The imbalance of mitochondrial redox can lead to the accumulation of reactive oxygen species (ROS), inhibit the synthesis of extracellular matrix, induce ferroptosis and eventually leads to cartilage degradation. The imbalance of mitochondrial dynamics can lead to mitochondrial DNA mutation, decreased adenosine triphosphate production, ROS accumulation, and accelerated apoptosis of chondrocytes. When mitochondrial autophagy is damaged, dysfunctional mitochondria cannot be cleared in time, leading to ROS accumulation, which leads to chondrocyte apoptosis. It has been found that substances such as puerarin, safflower yellow, and astaxanthin can inhibit the development of OA by regulating mitochondrial homeostasis, which proves the potential to be used in the treatment of OA.@*CONCLUSION@#The mitochondrial homeostasis imbalance in chondrocytes is one of the most important pathogeneses of OA, and further exploration of the mechanisms of mitochondrial homeostasis imbalance is of great significance for the prevention and treatment of OA.

Electroacupuncture improves motor function of rats with osteoarthritis by alleviating joint inflammation through the Wnt-7B/β-catenin signaling pathway / 南方医科大学学报

OBJECTIVE@#To investigate the effect of electroacupuncture on osteoarthritis in rats and explore the possible mechanism.@*METHODS@#Thirty SD rats were randomly divided into osteoarthritis model group, electro-acupuncture group and control group (n=10), and in the former two groups, early osteoarthritis was induced using a modified DMM surgical modeling method. After successful modeling, the rats in the electro-acupuncture group were treated with electro-acupuncture at bilateral "Housanli" and "Anterior knee point". Behavioral tests of the rats were performed and scored using the LequesneMG scale. Subchondral bone degeneration was observed in each group, and serum levels of IL-1β, ADAMTS-7, MMP-3 and COMP were measured using ELISA. The mRNA and protein expressions of IL-1β, Wnt-7B, β-catenin, ADAMTS-7, and MMP-3 in the cartilage tissue of the knee joints were detected using RT-PCR and Western blotting.@*RESULTS@#In behavioral tests, the rats in the model and electroacupuncture groups had significantly higher LequesneMG scores after modeling than those in the control group (P < 0.05). After 20 days of treatment, LequesneMG scores were significantly lowered in rats in the electroacupuncture as compared with the model rats (P < 0.05). Imaging examination revealed obvious subchondral bone damage in both the electroacupuncture group and the model group, but the damages were significantly milder with former group. Compared with the model rats, the rats receiving electroacupuncture had significantly lower serum levels of IL-1β, ADAMTS-7, MMP-3 and COMP (P < 0.05) with also lower expressions of IL-1β, Wnt-7B, β-catenin, ADAMTS-7 and MMP-3 in the cartilage tissues at both the mRNA and protein levels (P < 0.05).@*CONCLUSION@#Electroacupuncture can alleviate joint pain and improve subchondral bone damage in rats with osteoarthritis by reducing IL-1β levels in the joint cartilage tissue and serum to alleviate joint inflammation and by reducing such cytokines as ADAMTS-7 and MMP-3 via regulating the Wnt-7B/β-catenin signaling pathway.

Experimental study on the regulation of subchondral bone plate osteoprotegerin/receptor activator of nuclear factor kappa-B ligand system by berberine to retard the development of osteoarthritis in rabbits / 中国骨伤

OBJECTIVE@#To investigate the effect of intra-articular berberine injection on the structural remodeling of subchondral bone plate and osteoprotegerin/receptor activator of nuclear factor kappa-B ligand(OPG/RANKL) system expression in rabbits with osteoarthritis(OA).@*METHODS@#Forty 12-month-old male rabbits with an average of(2.73±0.18) kg of body weight, underwent left anterior cruciate ligament transection(ACLT), and were divided into berberine group and placebo groups after operation, 20 rabbits in each group. The berberine group received intra-articular injection of 100 μmol/L berberine 0.3 ml every week for 6 weeks. In placebo group, the same dose of 0.9% sodium chloride injection was injected into the left knee joint cavity every week for 6 weeks. Another 20 12-month-old male rabbits, weighing (2.68±0.18) kg, underwent sham operation on the left knee joint without intra-articular injection intervention (sham operation group). On the last day of the sixth week after operation, three groups of animals were sacrificed to obtain knee joint specimens. The femoral medial condyle samples were obtained for histological evaluation of cartilage and subchondral bone, Mankin scoring system was used to evaluate articular cartilage structure. Image-Pro Plus(IPP) software was used to evaluate subchondral bone plate bone volume(BV), bone volume/total volume(BV/TV), trabecular circumference(TC), mean trabecular thickness (Tb.Th). Real-time quantitative reverse transcription polymerization Enzyme chain reaction(reverse transcription-polymerase chain reaction, RT-PCR) was used to detect the mRNA expression levels of OPG and RANKL in subchondral bone tissue at 6 weeks after operation.@*RESULTS@#The cartilage structure evaluation showed that the surface of cartilage tissue in the sham operation group was smooth and flat, and the safranin coloration was full in the full thickness of the cartilage;the cartilage tissue in the berberine group showed uneven surface layer, and the staining of safranin O was mildly decreased;the surface layer fibrosis was seen in placebo group, Safranin O faded significantly. The Mankin score in the berberine group was lower than that in placebo group(P<0.01), but higher than that in sham operation group(P<0.01). The structural evaluation of subchondral bone plate showed that the trabecular bone in sham-operated group was densely arranged;after berberine intervention, the trabeculae were closely arranged;the subchondral bone trabeculae in placebo group were relatively sparse, and the distance between trabeculae was wider. Subchondral bone plate IPP software evaluation showed that BV, BV/TV, TC, Tb.Th in berberine group were higher than those in placebo group(P<0.01), BV, BV/TV, TC, Tb.Th in berberine group were higher than those in placebo group(P<0.01), while lower than the sham operation group (P<0.01). PCR test results showed that the expression of OPG mRNA in the berberine group was significantly higher than that in placebo group(P<0.01), and OPG mRNA in the berberine group was lower than that in sham operation group (P<0.01). There was no significant difference in mRNA expression of RANKL among three groups(P>0.05);the ratio of OPG/RANKL in berberine group was higher than that in placebo group(P<0.01), but lower than that in sham operation group(P<0.01).@*CONCLUSION@#Intra-articular injection of berberine can effectively inhibit the resorption of subchondral bone in the early stage of OA and delay the development of the disease. The specific mechanism may be that berberine maintains the balance of OPG/RANKL system by up-regulating the expression of OPG gene in subchondral bone.

LncRNA SNHG7/miR-34a-5p/SYVN1 axis plays a vital role in proliferation, apoptosis and autophagy in osteoarthritis

BACKGROUND: Osteoarthritis (OA) is one of the most common rheumatic diseases of which clinical symptoms includes swelling, synovitis and inflammatory pain, affect patients' daily life. It was reported that non-coding RNAs play vital roles in OA. However, the regulation mechanism of ncRNA in OA pathogenesis has not been fully elucidated. METHODS: The expression of SNHG7, miR-34a-5p and SYVN1 was detected using qRT-PCR in tissues, serum and cells. The protein expression of SYVN1, PCNA, cleavage-caspase 3, beclinl and LC3 were measured using western blot. The RNA immunoprecipitation (RIP), RNA pulldown, and luciferase reporter assays were used to verify the relationship between SNHG7, miR-34a-5p and SYVN1. The MTT and flow cytometry assay was performed to detected cell proliferation and cell apoptosis respectively. RESULTS: In this study, SNHG7 and SYVN1 expression were down-regulated, but miR-34a-5p was up-regulated in OA tissues and IL-1P treated cells compared with normal tissues and chondrocyte. Functional investigation revealed that up-regulated SNHG7 or down-regulated miR-34a-5p could promote cell proliferation and inhibit cell apoptosis and autophagy in OA cells. More than that, RIP, pulldown and luciferase reporter assay was applied to determine that miR-34a-5p was a target miRNA of SNHG7 and SYVN1 was a target mRNA of miR-34-5p. Rescue experiments showed that overexpression of miR-34a reversed high expression of SNHG7-mediated suppression of apoptosis and autophagy as well as promotion of proliferation, while its knockdown inhibited cell apoptosis and autophagy and promoted cell proliferation which could be impaired by silencing SYVN1. In addition, SNHG7 regulated SYVN1 through sponging miR-34a-5p. CONCLUSION: SNHG7 sponged miR-34a-5p to affect cell proliferation, apoptosis and autophagy through targeting SYVN1 which provides a novel sight into the pathogenesis of OA.

Involvement of TLR4 in the protective effect of intra-articular administration of curcumin on rat experimental osteoarthritis

Abstract Purpose In view of the principal role of Toll-like receptor 4 (TLR4) in mediating sterile inflammatory response contributing to osteoarthritis (OA) pathogenesis, we used lipopolysaccharide (LPS), a known TLR4 activator, to clarify whether modulation of TLR4 contributed to the protective actions of intra-articular administration of curcumin in a classical rat OA model surgically induced by anterior cruciate ligament transection (ACLT). Methods The rats underwent ACLT and received 50μl of curcumin at the concentration of 1 mg mL-1 and 10 μg LPS by intra-articular injection once a week for 8 weeks. Morphological changes of the cartilage and synovial tissues were observed. Apoptotic chondrocytes were detected using TUNEL assay. The concentrations of IL-1β and TNF-ɑ in synovial fluid were determined using ELISA kits. The mRNA and protein expression levels of TLR4 and NF-κB p65 were detected by real-time PCR and Western blotting, respectively. Results Intra-articular administration of curcumin significantly improved articular cartilage injury, suppressed synovial inflammation and down-regulated the overexpression of TLR4 and its downstream NF-κB caused by LPS-induced TLR4 activation in rat osteoarthritic knees. Conclusion The data suggested that the inhibition of TLR4 signal might be an important mechanism underlying a protective effect of local curcumin administration on OA.

The effects of chitosan oligosaccharides on OPG and RANKL expression in a rat osteoarthritis model

Abstract Purpose: To investigate the effect of chitosan oligosaccharides (COS) against osteoarthritis (OA) and preliminarily discuss the osteoprotegerin (OPG), receptor activator of NF-κB ligand (RANKL) and RANK expression in a rat OA model. Methods: Thirty-six 6-week-old Male SD rats were randomly divided into three groups: sham-operated group(CON), OA-induction group(OA), COS intervention group(n=12/group). At 4 weeks after the operation, COS (50 ul) intervention weekily for consecutive 5 weeks. The OA and CON groups received an injection of 50 ul physiological saline. At death, 11 weeks following surgery, cartilage was harvested and total RNA and protein were extracted. Both the morphological changes of the cartilage were observed and harvested the total RNA and protein. Meanwhile, the expression of OPG, RANKL and RANK in cartilage were determined. Results: The expression of OPG and RANKL were both enhanced in the cartilage of the OA model. Compared with the OA group, COS treatment improved the cartilage damage (both extent and grade). Furthermore, the COS group showed highly OPG and lower RANKL. Simultaneously, COS treatment upregulated the ratio of OPG/RANKL and downregulated the RANKL/RANK. Conclusion: Chitosan oligosaccharides may be used as a unique biological agent to prevent and treat osteoarthritis, and this effect is associated with modulation of the expression of osteoprotegerin and receptor activator of NF-κB ligand.

Role of HIF-1α signaling pathway in osteoarthritis: A systematic review / Papel da via de sinalização do HIF-1α; na osteoartrite: revisão sistemática

Abstract Osteoarthritis (OA) is the most common form of arthritis and is frequently diagnosed and managed in primary care; it is characterized by loss of articular hyaline cartilage, which is a unique connective tissue that physiologically lacks blood vessels. Articular cartilage survives in a microenvironment devoid of oxygen, which is regulated by hypoxia inducible factor (HIF-1α). HIF-1α is considered the main transcriptional regulator of cellular and developmental response to hypoxia. To date, the relevance of HIF-1α in the assessment of cartilage has increased since its participation is essential in the homeostasis of this tissue. Taking into account the new emerging insights of HIF-1α in the scientific literature in the last years, we focused the present review on the potential role of HIF-1α signaling pathway in OA development, especially in how some genetic factors may influence the maintenance or breakdown of articular cartilage.

Resumo A osteoartrite (OA) é a forma mais comum de artrite e frequentemente é diagnosticada e gerenciada na atenção primária; é caracterizada por perda da cartilagem articular hialina, um tecido conjuntivo único que fisiologicamente carece de vasos sanguíneos. A cartilagem articular sobrevive em um microambiente desprovido de oxigênio, que é regulado pelo fator induzível por hipóxia-1α (HIF-1α). O HIF-1α é considerado o principal regulador transcricional da resposta celular e de desenvolvimento à hipóxia. Na atualidade, a relevância do HIF-1α na avaliação da cartilagem tem aumentado, já que a sua participação é essencial na homeostase desse tecido. Considerando as novas perspectivas emergentes do HIF-1α na literatura científica nos últimos anos, foca-se a presente revisão no potencial papel da via de sinalização do HIF-1α no desenvolvimento da OA, especialmente no modo como alguns fatores genéticos podem influenciar na manutenção ou ruptura da cartilagem articular.

Metabolomics as a promising tool for early osteoarthritis diagnosis

Osteoarthritis (OA) is the main cause of disability worldwide, due to progressive articular cartilage loss and degeneration. According to recent research, OA is more than just a degenerative disease due to some metabolic components associated to its pathogenesis. However, no biomarker has been identified to detect this disease at early stages or to track its development. Metabolomics is an emerging field and has the potential to detect many metabolites in a single spectrum using high resolution nuclear magnetic resonance (NMR) techniques or mass spectrometry (MS). NMR is a reproducible and reliable non-destructive analytical method. On the other hand, MS has a lower detection limit and is more destructive, but it is more sensitive. NMR and MS are useful for biological fluids, such as urine, blood plasma, serum, or synovial fluid, and have been used for metabolic profiling in dogs, mice, sheep, and humans. Thus, many metabolites have been listed as possibly associated to OA pathogenesis. The goal of this review is to provide an overview of the studies in animal models and humans, regarding the use of metabolomics as a tool for early osteoarthritis diagnosis. The concept of osteoarthritis as a metabolic disease and the importance of detecting a biomarker for its early diagnosis are highlighted. Then, some studies in plasma and synovial tissues are shown, and finally the application of metabolomics in the evaluation of synovial fluid is described.

Influence of different body positions in vital capacity in patients on postoperative upper abdominal / Influência de diferentes posições corporais na capacidade vital em pacientes no pós-operatório abdominal superior / Influencia de diferentes posiciones corporales en la capacidad vital en pacientes en el postoperatorio abdominal superior

RATIONALE: The changes in body position can cause changes in lung function, and it is necessary to understand them, especially in the postoperative upper abdominal surgery, since these patients are susceptible to postoperative pulmonary complications. OBJECTIVE: To assess the vital capacity in the supine position (head at 0° and 45°), sitting and standing positions in patients in the postoperative upper abdominal surgery. METHODS: A cross-sectional study conducted between August 2008 and January 2009 in a hospital in Salvador/BA. The instrument used to measure vital capacity was analogic spirometer, the choice of the sequence of positions followed a random order obtained from the draw of the four positions. Secondary data were collected from the medical records of each patient. RESULTS: The sample consisted of 30 subjects with a mean age of 45.2 ± 11.2 years, BMI 20.2 ± 1.0 kg/m2. The position on orthostasis showed higher values of vital capacity regarding standing (mean change: 0.15 ± 0.03 L; p = 0.001), the supine to 45 (average difference: 0.32 ± 0.04 L; p = 0.001) and 0° (0.50 ± 0.05 L; p = 0.001). There was a positive trend between the values of forced vital capacity supine to upright posture (1.68 ± 0.47; 1.86 ± 0.48; 2.02 ± 0.48 and 2.18 ± 0.52 L; respectively). CONCLUSION: Body position affects the values of vital capacity in patients in the postoperative upper abdominal surgery, increasing in postures where the chest is vertical. .

JUSTIFICATIVA: As alterações no posicionamento corporal podem ocasionar mudanças na função respiratória e é necessário compreendê-las, principalmente no pós-operatório abdominal superior, já que os pacientes estão suscetíveis a complicações pulmonares pós-operatórias. OBJETIVO: Verificar a capacidade vital nas posições de decúbito dorsal (cabeceira a 0° e 45°), sentado e em ortostase em pacientes no pós-operatório de cirurgia abdominal superior. MÉTODOS: Estudo transversal, feito entre agosto de 2008 e janeiro de 2009, em um hospital na cidade de Salvador (BA). O instrumento usado para mensuração da capacidade vital (CV) foi o ventilômetro analógico e a escolha da sequência das posições seguiu uma ordem aleatória obtida a partir de sorteio das quatro posições. Os dados secundários foram colhidos nos prontuários de cada paciente. RESULTADOS: A amostra foi composta por 30 indivíduos com idade média de 45,2 ± 11,2 anos e IMC 20,2 ± 1,0 kg/m2. A posição em ortostase apresentou valores maiores da CV em relação à sedestração (média das diferenças: 0,15 ± 0,03 litros; p = 0,001), ao decúbito dorsal a 45° (média das diferenças: 0,32 ± 0,04 litros; p = 0,001) e 0° (0,50 ± 0,05 litros; p = 0,001). Houve um aumento positivo entre os valores de CVF do decúbito dorsal para a postura ortostática (1,68 ± 0,47; 1,86 ± 0,48; 2,02 ± 0,48 e 2,18 ± 0,52 litros; respectivamente). CONCLUSÃO: A posição do corpo afeta os valores da CV em pacientes no pós-operatório de cirurgia abdominal superior, com aumento nas posturas em que o tórax encontra-se verticalizado. .

JUSTIFICACIÓN: Las alteraciones en el posicionamiento corporal pueden ocasionar cambios en la función respiratoria y es necesario comprenderlas, principalmente en el postoperatorio abdominal superior, ya que los pacientes son susceptibles a complicaciones pulmonares postoperatorias. OBJETIVO: Verificar la capacidad vital en las posiciones de decúbito dorsal (cabeza a 0° y 45°), sentado y en ortostasis en pacientes en el postoperatorio de cirugía abdominal superior. MÉTODOS: Estudio transversal realizado entre agosto de 2008 y enero de 2009, en un hospital en la ciudad de Salvador (BA). El instrumento usado para la medición de la capacidad vital (CV) fue el espirómetro analógico y la elección de la secuencia de las posiciones siguió un orden aleatorio que se obtuvo a partir de un sorteo de las 4 posiciones. Los datos secundarios fueron extraídos de las historias clínicas de cada paciente. RESULTADOS: La muestra se compuso de 30 individuos con edades medias de 45,2 ± 11,2 años e IMC de 20,2 ± 1 kg/m2. La posición en ortostasis presentó valores mayores de CV con relación a la posición sedente (media de las diferencias: 0,15 ± 0,03 L; p = 0,001), al decúbito dorsal a 45° (media de las diferencias: 0,32 ± 0,04 L; p = 0,001) y a 0° (0,50 ± 0,05 L; p = 0,001). Hubo un aumento positivo entre los valores de CV forzada del decúbito dorsal para la postura ortostática (1,68 ± 0,47; 1,86 ± 0,48; 2,02 ± 0,48 y 2,18 ± 0,52 L, respectivamente). CONCLUSIÓN: La posición del cuerpo afecta los valores de la CV en pacientes durante el postoperatorio de cirugía abdominal superior, con aumento en las posturas en las que el tórax está verticalizado. .

Measurement of serum estrogen and estrogen metabolites in pre- and postmenopausal women with osteoarthritis using high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry

Although 17β-estradiol (E2) deficiency has been linked to the development of osteoarthritis (OA) in middle-aged women, there are few studies relating other estrogens and estrogen metabolites (EMs) to this condition. We developed a high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) method to measure the levels of six EMs (i.e., estrone, E2, estriol, 2-hydroxyestrone, 2-hydroxyestradiol, and 16a-hydroxyestrone) in healthy pre- and postmenopausal women and women with OA. This method had a precision ranging from 1.1 to 3.1% and a detection limit ranging from 10 to 15 pg. Compared to healthy women, serum-free E2 was lower in the luteal and postmenopausal phases in women with OA, and total serum E2 was lower in postmenopausal women with OA. Moreover, compared to healthy women, total serum 2-hydroxyestradiol was higher in postmenopausal women with OA and total serum 2-hydroxyestrone was lower in both the luteal and follicular phases in women with OA. In conclusion, our HPLC-ESI-MS/MS method allowed the measurement of multiple biochemical targets in a single assay, and, given its increased cost-effectiveness, simplicity, and speed relative to previous methods, this method is suitable for clinical studies.

Obesidade versus osteoartrite: muito além da sobrecarga mecânica / Obesity versus osteoarthritis: beyond the mechanical overload

Atualmente, a obesidade é considerada o maior problema de saúde pública do mundo, já atingindo características epidêmicas, segundo a Organização Mundial da Saúde. O acúmulo excessivo de peso é o maior fator de risco, associado a diversas doenças, como diabetes mellitus tipo 2, hipertensão, dislipidemias e doenças osteometabólicas, como osteoporose e osteoartrite. A osteoartrite é a doença reumática mais prevalente, e a principal causa de incapacidade física e diminuição da qualidade de vida da população acima de 65 anos. Acomete principalmente as articulações que suportam peso, como joelhos e quadris. No entanto, juntamente com os casos de obesidade, sua prevalência vem aumentando e em outras articulações, como as das mãos. Assim, supõe-se que a influência da obesidade no desenvolvimento da osteoartrite esteja além da sobrecarga mecânica. O objetivo desta revisão foi correlacionar os possíveis mecanismos que determinam a gênese e o desenvolvimento dessas duas doenças. O aumento da massa adiposa é diretamente proporcional ao consumo exagerado de ácidos graxos saturados, responsáveis pela condição sistêmica de inflamação de baixo grau e resistência à insulina e à leptina. Em níveis elevados, a leptina assume características inflamatórias e age na cartilagem articular, desencadeando o processo inflamatório e alterando a homeostase desse tecido com consequente degeneração. Conclui-se que a obesidade é um fator de risco para a osteoartrite e que a prática de atividade física e modificações na composição da dieta podem reverter o quadro inflamatório e a resistência à leptina, atenuando a progressão ou prevenindo o surgimento da osteoartrite.

Obesity is currently considered a major public health problem in the world, already reaching epidemic characteristics, according to the World Health Organization. Excess weight is the major risk factor associated with various diseases, such as type 2 diabetes mellitus, hypertension, dyslipidemia and osteometabolic diseases, including osteoporosis and osteoarthritis. Osteoarthritis is the most prevalent rheumatic disease and the leading cause of physical disability and reduced quality of life of the population over 65 years. It mainly involves the joints that bear weight - knees and hips. However, along with the cases of obesity, its prevalence is increasing, and even in other joints, such as hands. Thus, it is assumed that the influence of obesity on the development of OA is beyond mechanical overload. The purpose of this review was to correlate the possible mechanisms underlying the genesis and development of these two diseases. Increased fat mass is directly proportional to excessive consumption of saturated fatty acids, responsible for systemic low-grade inflammation condition and insulin and leptin resistance. At high levels, leptin assumes inflammatory characteristics and acts in the articular cartilage, triggering the inflammatory process and changing homeostasis this tissue with consequent degeneration. We conclude that obesity is a risk factor for osteoarthritis and that physical activity and changes in diet composition can reverse the inflammatory and leptin resistance, reducing progression or preventing the onset of osteoarthritis.

MicroRNA-21 controls the development of osteoarthritis by targeting GDF-5 in chondrocytes

Osteoarthritis is a common cause of functional deterioration in older adults and is an immense burden on the aging population. Altered chondrogenesis is the most important pathophysiological process involved in the development of osteoarthritis. However, the molecular mechanism underlying the regulation of chondrogenesis in patients with osteoarthritis requires further elucidation, particularly with respect to the role of microRNAs. MiR-21 expression in cartilage specimens was examined in 10 patients with knee osteoarthritis and 10 traumatic amputees. The effect of miR-21 on chondrogenesis was also investigated in a chondrocyte cell line. The effect of miR-21 on the expression of growth differentiation factor 5 (GDF-5) was further assessed by luciferase reporter assay and western blot. We found that endogenous miR-21 is upregulated in osteoarthritis patients, and overexpression of miR-21 could attenuate the process of chondrogenesis. Furthermore, we identified GDF-5 as the direct target of miR-21 during the regulation of chondrogenesis. Our data suggest that miR-21 has an important role in the pathogenesis of osteoarthritis and is a potential therapeutic target.

Regulation of hypoxia-inducible factor-1α (HIF-1α) expression by interleukin-1β (IL-1 β), insulin-like growth factors I (IGF-I) and II (IGF-II) in human osteoarthritic chondrocytes

OBJECTIVE: Hypoxia-inducible factor 1 alpha regulates genes related to cellular survival under hypoxia. This factor is present in osteroarthritic chondrocytes, and cytokines, such as interleukin-1 beta, participate in the pathogenesis of osteoarthritis, thereby increasing the activities of proteolytic enzymes, such as matrix metalloproteinases, and accelerating cartilage destruction. We hypothesize that Hypoxia Inducible Factor-1 alpha (HIF-1α) can regulate cytokines (catabolic action) and/or growth factors (anabolic action) in osteoarthritis. The purpose of this study was to investigate the modulation of HIF-1α in human osteoarthritic chondrocytes by interleukin-1 beta (IL-1β) and insulin-like growth factors I (IGF-I) and II (IGF-II) and to determine the involvement of the phosphatidylinositol-3kinase (PI-3K) pathway in this process. METHODS: Human osteroarthritic chondrocytes were stimulated with IL-1β, IGF-I and IGF-II and LY294002, a specific inhibitor of PI-3K. Nuclear protein levels and gene expression were analyzed by western blot and quantitative reverse transcription-polymerase chain reaction analyses, respectively. RESULTS: HIF-1α expression was upregulated by IL-1β at the protein level but not at the gene level. IGF-I treatment resulted in increases in both the protein and mRNA levels of HIF-1α , whereas IGF-II had no effect on its expression. However, all of these stimuli exploited the PI-3K pathway. CONCLUSION: IL-1β upregulated the levels of HIF-1α protein post-transcriptionally, whereas IGF-I increased HIF-1α at the transcript level. In contrast, IGF-II did not affect the protein or gene expression levels of HIF-1α . Furthermore, all of the tested stimuli exploited the PI-3K pathway to some degree. Based on these findings, we are able to suggest that Hypoxia inducible Factor-1 exhibits protective activity in chondrocytes during osteoarthritis.

Inflamación en osteoartritis / Osteoarthritis inflammation

La osteoartritis es una enfermedad de alto impacto que produce importante morbilidad y discapacidad en adultos sobre 60 años. Su proceso patológico se caracteriza por degeneración del cartílago articular, asociado a inflamación secundaria, lo que produce cambios proliferativos con la formación de osteofitos y esclerosis del hueso subcondral. Actualmente existe evidencia de la importancia del proceso inflamatorio subyacente, destacando la participación de polimorfismos genéticos que fomentan el proceso inflamatorio. Asociado a esto, se ha evidenciado un cambio en el fenotipo del condrocito, el cual produce mayor cantidad de IL-1-beta y TNF-alfa, las que activan el catabolismo del cartílago. Además, se postula que la sinovial actuaría como un potenciador de la inflamación, pues los fibroblastos ahí presentes son capaces de producir diversas sustancias proinflamatorias, tales como citoquinas, prostaglandinas y óxido nítrico. Por otra parte, alteraciones mecánicas y la obesidad pueden activar al condrocito, fomentado su cambio de fenotipo, lo que aumenta la producción de citoquinas proinflamatorias que aumentan el daño cartilaginoso. Sin embargo, aún no existe claridad sobre los “gatillantes” exactos del proceso inflamatorio en OA.

Osteoarthritis (OA) is a disease of high impact that produces significant morbidity and disability in adults over 60 years. His disease process is characterized by degeneration of articular cartilage, associated with secondary inflammation that produces proliferative changes with osteophyte formation and subchondral bone sclerosis. There is evidence of the importance of the underlying inflammatory process, highlighting the involvement of genetic polymorphisms that promote the inflammatory process. Associated with this has shown a change in chondrocyte phenotype which produces more IL-1-beta and TNF-alpha, which activate the catabolism of cartilage. Furthermore, it is postulated that synovial act as an enhancer of inflammation present there as fibroblasts are capable of producing various proinflammatory substances such as cytokines, prostaglandins and nitric oxide. Moreover, mechanical alterations and obesity can activate the chondrocyte phenotype promoted the change of increasing the production of proinflammatory cytokines that promote cartilage damage. However, even there is no clarity on the exact “gatillantes” the inflammatory process in OA.

Effect of hydrostatic pressure of various magnitudes on osteoarthritic chondrocytes exposed to IL-1β.

Background & objectives: Several in vitro studies have shown the importance of mechanical compression or hydrostatic pressure (HP) as a modulator of cartilage metabolism. The present study was undertaken to evaluate the in vitro effects of cyclical low HP (1-5 MPa) and continuous high HP (24 MPa) applied in the presence or absence of interleukin (IL)-1β on human osteoarthritis (OA) chondrocytes. Methods: Chondrocytes obtained from OA cartilage were cultivated for 48 h and then exposed to pressurization in the presence or absence of IL-1β. After pressurization, the culture medium was collected to detect the amount of proteoglycans (PG) and nitric oxide (NO) and the chondrocytes were immediately fixed for transmission electron microscopy (TEM) and processed for immunocytochemistry to localize the inducible nitric oxide synthase (iNOS). Results: A significant increase in the level of PG and a small, non-significant, decrease in NO production were observed upon exposure to cyclical low HP. On the other hand, exposure to continuous high HP resulted in a significant decrease in the PG levels and a significant increase in NO production. The presence of IL-1β led to a significant decrease in PG levels as well as a significant increase in NO production. The cyclical low HP did not increase the PG levels significantly but caused a statistically significant decrease in NO production in cultures damaged with IL-1β. The continuous high HP in chondrocyte cultures stimulated with IL-1β did not significantly decrease PG production, but significantly increased NO production. The results concerning metabolic production were further confirmed by morphological findings obtained by TEM and immunocytochemical studies. Interpretation & conclusion: The findings of this study confirmed that the response of chondrocytes varies with magnitude and frequency of HP. These findings are important to understand aetiopathogenetic mechanisms of OA and to find out which type of physical activity may be best suited for the prevention and therapy of OA.

Parallel changes in fibronectin and alpha5beta1 integrin in articular cartilage in type II collagen-induced arthritis.

Interactions of cells with extracellular matrix (ECM) are mediated through specific cell surface receptors, belonging to the integrin family of transmembrane proteins. Integrins have been shown to be involved in chondrocyte-matrix interactions in the cartilage. In this study, the status of a matrix glycoprotein fibronectin (FN) and its receptor alpha5beta1 integrin in the articular cartilage in collagen type II-induced experimental arthritis in rats, as well as in synovial fluid from osteoarthritic patients was investigated. Experimental arthritis was induced by intradermal injection of type-II collagen (300 microg/100 g body wt) and Freund's complete adjuvant. Saline-treated animals served as control. Clinical severity was indicated by increase in paw volume. Significant increase in the activities of lysosomal enzymes beta-glucuronidase and beta-hexosaminidase was observed in synovial effusate, serum and cartilage of arthritic animals, when compared to untreated control, indicating dysfunction of cartilage. Changes in FN and alpha5beta1 integrin were studied by ELISA. A progressive increase was observed in the FN level in synovial effusate and cartilage of arthritic animals, when compared to untreated controls. FN levels were also significantly high in synovial fluid of osteoarthritic patients. A significant increase in the levels of alpha5beta1 integrin was found in cartilage of arthritic rats. Parallel changes in FN and alpha5beta1 integrin indicated that alterations in FN and alpha5beta1 integrin in chondrocytes constituted one of the molecular mechanisms during progression of arthritis.

The relationship of the expression of estrogen receptor in cartilage cell and osteoarthritis induced by bilateral ovariectomy in guinea pig / 华中科技大学学报（医学）（英德文版）

To investigate the estrogen receptor (ER) expression in cartilage cell in the development of osteoarthritis induced by bilateral ovariectomy in guinea pig and to find their relationship. 30 two-month-old female guinea pigs were randomly divided into two groups (n = 15 each): sham operation (control) group and ovariectomized group (OVX); Scanning electorne microscope (SEM) and transmission electron microscope (TEM) were obtained to analysis the cartilage degeneration of the hind limb knee joint after 6 and 12 weeks of ovariectomy. Dextran-Coated-Charcoal (DCC) was taken to quantitively detect the expression of ER. The serum levels of estrogen and gestone were detected by immune contest assay. The results showed that ER do exist in the cartilages of the guinea pigs, with higher expression in the control group than in OVX group at the same time point (P < 0.05). It was increased also at 12 th week after operation than that of preoperation. The blood serum levels of estrogen and gestone showed a similar tendency to the expression of ER. Joint cartilage degeneration detected by SEM and TEM could be found at 6 th week, but severe degenerative lesions at 12 th week in the OVX group compared with the control group (P < 0.01). The data suggested that bilateral ovariectomy in guinea pig lead to severe osteoarthritis which mighgt be related to the lower serum level of estrogen and the downregulation of the expression of ER in the cartilage also.

Effects of ageing and arthritic disease on nitric oxide production by human articular chondrocytes

Nitric oxide (NO) has been considered as an important mediator in inflammatory phases and in loss of cartilage. In inflammatory arthritis, NO levels are correlated with disease activity and articular cartilage is able to produce large amounts of NO with the appropriate inducing factor such as cytokines. The old animals are shown to have a greater sensitivity to NO than young animals. This study evaluated the basal production of NO in normal and OA-affected chondroyctes from young and old patients and compared the levels of NO formation in response to IL-1beta. The results showed that the basal levels were 7-fold higher in old chondrocytes than those of young cells. However, the IL-1beta induced NO production was seen to decrease with age. Aminoguianidine (AG), a competitive inhibitor of iNOS, inhibited NO formation completely in both chondrocytes from young and old individuals. However, at the same concentration of AG it caused partial inhibition of NO and iNOS formation in chondrocytes from OA-affected individuals. In addition, although the IL-1beta induced NO production was much lesser than that of young chondrocytes, the inhibition of collagen production by IL-1beta was prominent in old chondrocytes and OA-affected chondrocytes. These results suggest that age-related differences in the regulation of NO production and collagen production, which may affect the ageing cells and osteoarthritic changes in some way.

Effects of ageing and arthritic disease on nitric oxide production by human articular chondrocytes

Nitric oxide (NO) has been considered as an important mediator in inflammatory phases and in loss of cartilage. In inflammatory arthritis, NO levels are correlated with disease activity and articular cartilage is able to produce large amounts of NO with the appropriate inducing factor such as cytokines. The old animals are shown to have a greater sensitivity to NO than young animals. This study evaluated the basal production of NO in normal and OA-affected chondroyctes from young and old patients and compared the levels of NO formation in response to IL-1beta. The results showed that the basal levels were 7-fold higher in old chondrocytes than those of young cells. However, the IL-1beta induced NO production was seen to decrease with age. Aminoguianidine (AG), a competitive inhibitor of iNOS, inhibited NO formation completely in both chondrocytes from young and old individuals. However, at the same concentration of AG it caused partial inhibition of NO and iNOS formation in chondrocytes from OA-affected individuals. In addition, although the IL-1beta induced NO production was much lesser than that of young chondrocytes, the inhibition of collagen production by IL-1beta was prominent in old chondrocytes and OA-affected chondrocytes. These results suggest that age-related differences in the regulation of NO production and collagen production, which may affect the ageing cells and osteoarthritic changes in some way.