Glutathione-S-Transferase and Thiol Stress in patients with acute renal failure

Introduction: Tubular damage is common finding in acute renal failure (ARF). Various etiologies have been put forth to explain the tubular damage in ARF, one important mechanism among them is oxidative damage to renal tubules. Several biomolecules including low-molecular weight peptides and enzymes in urine have been proposed as early markers of renal failure. Current study has been undertaken to study the thiol stress and glutathione-S-transferase (GST) levels in ARF patients. Method: 58 ARF patients and 55 healthy controls were selected based on inclusion and exclusion criteria. Serum thiols, GST, malanoldehyde (MDA) and urine thiols were determined by spectrophotometer based methods. Results: Serum thiols and urine thiols were significantly decreased (p<0.0001), and serum GST and MDA levels were significantly increased (p<0.0001) in ARF patients compared to healthy controls. Serum GST and MDA correlated positively in ARF cases (r2 = 0.6938, p<0.0001). Conclusion: There is significant thiol stress and increased lipid peroxidation in ARF patients which leads to tubular cell membrane damage and release of GST into blood stream and into urine. This may be possible mechanism for the increased presence of GST in urine (enzymuria) found in other studie

Activation of stress-activated protein kinase in osteoarthritic cartilage: evidence for nitric oxide dependence

AbstractObjective We have demonstrated in bovine chondrocytes that nitric oxide (NO) mediates IL1 dependent apoptosis under conditions of oxidant stress. This process is accompanied by activation of c-Jun NH2-terminal kinase (JNK; also called stress-activated protein kinase). In these studies we examined activation of JNK in explant cultures of human osteoarthritic cartilage obtained at joint replacement surgery and we characterized the role of peroxynitrite to act as an upstream trigger.Design A novel technique to isolate chondrocyte proteins (<10% of total cartilage protein) from cartilage specimens was developed. It was used to analyse JNK activation by a western blot technique. To examine the hypothesis that chondrocyte JNK activation is a result of increased peroxynitrite, in vitro experiments were performed in which cultured chondrocytes were incubated with this oxidant.Results Activated JNK was detected in the cytoplasm of osteoarthritis (OA) affected chondrocytes but not in that of controls. In vitro, chondrocytes produce NO and superoxide anion. IL-1 (48h), which induces nitric oxide synthase, resulted in an activation of JNK; this effect was reversed by N-monomethylarginine (NMA). TNFα treated chondrocytes at 48h produce superoxide anion (EPR method). Exposure of cells to peroxynitrite led to an accumulation of intracellular oxidants, in association with JNK activation and cell death by apoptosis.Conclusion We suggest that JNK activation is among the IL-1 elicited responses that injure articular chondrocytes and this activation of JNK is dependent on intracellular oxidant formation (including NO peroxynitrite). In addition, the extraction technique here described is a novel method that permits the quantitation and study of proteins such as JNK involved in the signaling pathways of chondrocytes within osteoarthritic cartilage

Deletion of Panx3 Prevents the Development of Surgically Induced Osteoarthritis

© 2015, Springer-Verlag Berlin Heidelberg. Abstract: Osteoarthritis (OA) is a highly prevalent, disabling joint disease with no existing therapies to slow or halt its progression. Cartilage degeneration hallmarks OA pathogenesis, and pannexin 3 (Panx3), a member of a novel family of channel proteins, is upregulated during this process. The function of Panx3 remains poorly understood, but we consistently observed a strong increase in Panx3 immunostaining in OA lesions in both mice and humans. Here, we developed and characterized the first global and conditional Panx3 knockout mice to investigate the role of Panx3 in OA. Interestingly, global Panx3 deletion produced no overt phenotype and had no obvious effect on early skeletal development. Mice lacking Panx3 specifically in the cartilage and global Panx3 knockout mice were markedly resistant to the development of OA following destabilization of medial meniscus surgery. These data indicate a specific catabolic role of Panx3 in articular cartilage and identify Panx3 as a potential therapeutic target for OA. Lastly, while Panx1 has been linked to over a dozen human pathologies, this is the first in vivo evidence for a role of Panx3 in disease. Key message: Panx3 is localized to cartilage lesions in mice and humans.Global Panx3 deletion does not result in any developmental abnormalities.Mice lacking Panx3 are resistant to the development of osteoarthritis.Panx3 is a novel therapeutic target for the treatment of osteoarthritis

Synovial changes detected by ultrasound in people with knee osteoarthritis - a meta-analysis of observational studies

Objectives To examine the prevalence of synovial effusion, synovial hypertrophy and positive Doppler signal (DS) detected by ultrasound (US) in people with knee osteoarthritis (OA) and/or knee pain compared to that in the general population. Method A systematic literature search was undertaken in Medline, EMBASE, Allied and Complementary Medicine, PubMed Web of Science, and SCOPUS databases in May 2015. Frequencies of US abnormalities in people with knee OA/pain, in the general population or asymptomatic controls were pooled using the random effects model. Publication bias and heterogeneity between studies were examined. Results Twenty four studies in people with knee pain/OA and five studies of the general population or asymptomatic controls met the inclusion criteria. The pooled prevalence of US effusion, synovial hypertrophy and positive DS in people with knee OA/pain were 51.5% (95% CI 40.2 to 62.8), 41.5% (26.3–57.5) and 32.7% (8.34–63.24), respectively, which were higher than those in the general population or asymptomatic controls (19.9% (95%CI 7.8–35.3%), 14.5% (0–58.81), and 15.8 (3.08–35.36), respectively). People with knee OA (ACR criteria or radiographic OA) had greater prevalence of US abnormalities than people with knee pain (P = 0.037, P = 0.010 and P = 0.009, respectively). Conclusions US detected effusion, synovial hypertrophy and DS are more common in people with knee OA/pain, compared to the general population. These abnormalities relate more to presence of OA structural changes than to pain