Pharmacological inhibition of mTORC1 activity protects against inflammation-induced apoptosis of nucleus pulposus cells

Lumbar disc herniation is a common disease characterized by the degeneration of intervertebral discs (IVDs), accompanied by imbalance of metabolic and inflammatory homeostasis. Current studies establish that IVD degeneration is induced by increased apoptosis of nucleus pulposus (NP) cells. However, the underlying mechanisms of NP cell survival/apoptosis are not well elucidated. Here, we reveal a novel mechanism by which mTORC1 signaling controls NP cell survival through regulating metabolic homeostasis. We demonstrated that hyperactivated mTORC1 activity induced by inflammatory cytokines engenders the apoptosis of NP cells, whereas pharmacological inhibition of mTORC1 activity promotes NP cell survival. Using an integrative approach spanning metabolomics and biochemical approaches, we showed that mTORC1 activation enhanced glucose metabolism and lactic acid production, and therefore caused NP cell apoptosis. Our study identified mTORC1 in NP cells as a novel target for IVD degeneration, and provided potential strategies for clinical intervention of lumbar disc herniation.

Clinical management of dogs with presumptive diagnosis of thoracolumbar intervertebral disc disease: 164 cases (2006-2017) / Tratamento clínico de cães com diagnóstico presuntivo de doença do disco intervertebral toracolombar: 164 casos (2006-2017)

This study aimed to identify dogs with presumptive diagnosis of cervical intervertebral disc disease (IVDD) submitted to clinical management and to evaluate the outcomes. Data were obtained from the medical records of patients with neurological dysfunction assisted at a University Veterinary Hospital from 2006 to 2017. In addition to the patients' records, dog owners responded to a questionnaire on the success of therapy. Four hundred and thirteen neurological records were evaluated, and 164 met the inclusion criteria of the study. The most common breed was Dachshund, followed by mongrels. Classification of neurological dysfunction in the study sample was as follows: 15.9% with grade I, 25.6% with grade II, 26.8% with grade III, 8.5% with grade IV, and 23.2% with grade V. Outcome was satisfactory in 71.6% of the dogs and unsatisfactory in 28.4% of them. Recurrence was observed in 27.7% of those with satisfactory outcomes. The clinical treatment of dogs with thoracolumbar IVDD is satisfactory, particularly for animals with milder disease grades (I, II, and III). There is possibility of recurrence with conservative therapy and clinical signs may be more severe.(AU)

O objetivo desse estudo foi identificar cães com diagnóstico presuntivo de DDIV toracolombar submetidos ao tratamento clínico, a fim de avaliar a resposta à terapia instituída. Foram revisados os registros neurológicos de cães atendidos pelo Serviço de Neurologia e Neurocirurgia Veterinária no período de 2006 a 2017 de um Hospital Veterinário Universitário. Foi realizada coleta de dados a partir dos registros e por meio de um questionário respondido pelos tutores. Foram avaliadas 413 fichas neurológicas de cães e obtidas informações para inclusão no estudo em 164 delas. As raças mais frequentes foram dachshunds, seguido de cães sem raça definida. Quanto ao grau de disfunção neurológica foi definido como grau I para 15,9% dos cães, grau II para 25,6%, grau III para 26,8%, grau IV para 8,5% e grau V para 23,2%. A recuperação foi satisfatória em 71,6% dos cães e insatisfatória em 28,4%. Dos que se recuperaram satisfatoriamente, 27,7% tiveram recidivas. Com base nos resultados obtidos pode-se concluir que o tratamento clínico em repouso absoluto e administração de anti-inflamatórios e analgésicos opióides para cães com DDIV toracolombar é efetivo, principalmente para cães em graus mais leves da doença (grau I, II e III). Há possibilidade de recidiva com esse tipo de terapia cujos sinais clínicos poderão ser mais graves.(AU)

Biologic Response of Degenerative Living Human Nucleus Pulposus Cells to Treatment with Cytokines

PURPOSE: To investigate the molecular responses of various genes and proteins related to disc degeneration upon treatment with cytokines that affect disc-cell proliferation and phenotype in living human intervertebral discs (IVDs). Responsiveness to these cytokines according to the degree of disc degeneration was also evaluated. MATERIALS AND METHODS: The disc specimens were classified into two groups: group 1 (6 patients) showed mild degeneration of IVDs and group 2 (6 patients) exhibited severe degeneration of IVDs. Gene expression was analyzed after treatment with four cytokines: recombinant human bone morphogenic protein (rhBMP-2), transforming growth factor-beta (TGF-beta), interleukin-1beta (IL-1beta), and tumor necrosis factor-alpha (TNF-alpha). Molecular responses were assessed after exposure of cells from the IVD specimens to these cytokines via real-time polymerase chain reaction and immunofluorescence staining. RESULTS: mRNA gene expression was significantly greater for aggrecan, type I collagen, type II collagen, alkaline phosphatase, osteocalcin, and Sox9 in group 1 than mRNA gene expression in group 2, when the samples were not treated with cytokines. Analysis of mRNA levels for these molecules after morphogen treatment revealed significant increases in both groups, which were much higher in group 1 than in group 2. The average number of IVD cells that were immunofluorescence stained positive for alkaline phosphatase increased after treatment with rhBMP-2 and TGF-beta in group 1. CONCLUSION: The biologic responsiveness to treatment of rhBMP-2, TGF-beta, TNF-alpha, and IL-1beta in the degenerative living human IVD can be different according to the degree of degeneration of the IVD.

Epidural Steroid Injection in Lumbar Disc Herniation.

Low back pain is a problem that is common and costly to society and its effective management remains a challenge. Major cause of morbidity due to low back pain is prolapsed intervertebral disc which mostly affects young adults in their fourth decade of life. Epidural steroid injection (ESI) is a low-risk alternative to surgical intervention in the treatment of lumbar disc herniation. This follow up study was planned to know the results of epidural injections with corticosteroids in symptomatic patients of lumbar disc prolapse. Out of 159 patients who were evaluated before and after the ESI for pain relief, 78% had positive response. No major post-injection complications were reported in this study. Carefully administered epidural steroid injection is a safe and effective modality in the treatment of pain in lumbar disc herniation.

Resveratrol Has Anabolic Effects on Disc Degeneration in a Rabbit Model

This study was done to evaluate whether injections of resveratrol, a natural compound found in the skin of grapes, had anabolic effects on degenerated intervertebral discs in a rabbit model. Two non-continuous lumbar discs were punctured in rabbits to induce disc degeneration. Four weeks and 6 weeks after puncture, the rabbits were treated by injections with dimethylsulfoxide (DMSO) or resveratrol. At 4, 8, and 16 weeks after initial injection, rabbits were sacrificed and the spine was extracted for magnetic resonance image (MRI), mRNA expression, and histological staining. Resveratrol treatment resulted in stronger signal intensity in T2-weighted images. MRI grade showed significantly lower in the resveratrol group than the DMSO group (P = 0.039). In the resveratrol group, aggrecan gene expression was significantly increased than that in the DMSO group at 16 weeks after injection (P = 0.027). MMP-13 mRNA levels in the resveratrol group were significantly decreased than those in the DMSO group at 8 and 16 weeks (P = 0.006 and P = 0.048, respectively). In hematoxylin and eosin stain, resveratrol-treated discs showed the features of regeneration. Histologic grade revealed improvement in resveratrol-treated discs, compared with DMSO-treated discs (P = 0.024). These anabolic effects on degenerated discs indicate that resveratrol is a promising candidate for treatment of degenerative disc disease.