Inflamación en la hernia del disco intervertebral / Inflammation in the intervertebral disc herniation

Hasta no hace muchos años, se consideró que el dolor ciático, en la hernia del disco intervertebral lumbar, estaba originado por la compresión sobre la raíz nerviosa. Sin embargo, la hernia del disco intervertebral lumbar presenta cuadros muy heterogéneos inexplicables con el simple compromiso mecánico. En los últimos años, numerosos estudios de inmuhistoquímica y de biología molecular han demostrado que el tejido herniado no es un material inerte sino, por el contrario, biológicamente muy activo con capacidad de expresar una serie de mediadores de inflamación entre los que destacan citoquinas proinflamatorias como la interleuquina1, interleuquina 6, interleuquina 8 y el factor de necrosis tumoral. La inflamación parece estar no solo inducida por la irritación química de las sustancias bioactivas liberadas por el núcleo pulposo, sino también mediante una respuesta autoinmune contra el mismo. Por tanto, además del factor mecánico, la mediación bioquímica tiene un papel importante en la fisiopatología del dolor ciático y de la radiculopatía. A través de una extensa revisión sistemática de la literatura se han investigado los mediadores celulares y moleculares que intervienen en dicho proceso inflamatorio alrededor de la hernia del disco intervertebral lumbar y su implicación en el dolor ciático (AU)

Up until fairly recently, it was thought that sciatic pain in the lumbar herniated disc was caused by compression on the nerve root. However, the lumbar herniated disc shows mixed pictures which are difficult to explain by simple mechanical compromise. In recent years various immunology, immunohistochemistry and molecular biology studies have shown that the herniated tissue is not an inert material, but rather it Is biologically very active with the capability of expressing a series of inflammatory mediators: cytokines such as interleukin-1, interleukin-6, interleuquin-8 and tumor necrosis factor being the ones which stand out. The inflammation is not only induced by the chemical irritation of the bioactive substances released by the nucleus pulposus but also by an autoimmune response against itself. Thus, in addition to the mechanical factor, the biomechanical mediation plays an important role in the pathophysiology of sciatic pain and of radiculopathy. Through a review of a wide range of literature, we researched the cellular molecular mediators involved in this inflammatory process around the lumbar herniated disc and its involvement in sciatic pain (AU)

Inflammation in the intervertebral disc herniation. / Inflamación en la hernia del disco intervertebral.

Up until fairly recently, it was thought that sciatic pain in the lumbar herniated disc was caused by compression on the nerve root. However, the lumbar herniated disc shows mixed pictures which are difficult to explain by simple mechanical compromise. In recent years various immunology, immunohistochemistry and molecular biology studies have shown that the herniated tissue is not an inert material, but rather it Is biologically very active with the capability of expressing a series of inflammatory mediators: cytokines such as interleukin-1, interleukin-6, interleuquin-8 and tumor necrosis factor being the ones which stand out. The inflammation is not only induced by the chemical irritation of the bioactive substances released by the nucleus pulposus but also by an autoimmune response against itself. Thus, in addition to the mechanical factor, the biomechanical mediation plays an important role in the pathophysiology of sciatic pain and of radiculopathy. Through a review of a wide range of literature, we researched the cellular molecular mediators involved in this inflammatory process around the lumbar herniated disc and its involvement in sciatic pain.

Immunomodulation of mesenchymal stem cells in discogenic pain.

BACKGROUND CONTEXT: Back pain is a highly prevalent health problem in the world today and has a great economic impact on health-care budgets. Intervertebral disc (IVD) degeneration has been identified as a main cause of back pain. Inflammatory cytokines produced by macrophages or disc cells in an inflammatory environment play an important role in painful progressive degeneration of IVD. Mesenchymal stem cells (MSCs) have shown to have immunosuppressive and anti-inflammatory properties. Mesenchymal stem cells express a variety of chemokines and cytokines receptors having tropism to inflammation sites. PURPOSE: This study aimed to develop an in vitro controlled and standardized model of inflammation and degeneration of IVD with rat cells and to evaluate the protective and immunomodulatory effect of conditioned medium (CM) from the culture of MSCs to improve the conditions presented in herniated disc and discogenic pain processes. STUDY DESIGN: This is an experimental study. METHODS: In this study, an in vitro model of inflammation and degeneration of IVD has been developed, as well as the effectiveness of CM from the culture of MSCs. RESULTS: Conditioned medium from MSCs downregulated the expression of various proinflammatory cytokines produced in the pathogenesis of discogenic pain such as interleukin (IL)-1ß, IL-6, IL-17, and tumor necrosis factor (TNF). CONCLUSION: Mesenchymal stem cells represent a promising alternative strategy in the treatment of IVD degeneration inasmuch as there is currently no treatment which leads to a complete remission of long-term pain in the absence of drugs.

Biología y mecanobiología del disco intervertebral / Biology and mechanobiology of the intervertebral disc

El disco intervertebral (DIV) se caracteriza por su escasa celularidad y por constituir la estructura avascular más grande del cuerpo humano. Las escasas células del disco tienen que adaptarse a un metabolismo anaerobio con baja tensión de O2 y pH ácido. Además de sobrevivir a un microambiente adverso, están expuestas a un elevado estrés mecánico. La adaptación biológica de las células a las condiciones de acidosis e hiperosmolaridad está regulada por mecanoproteínas responsables de convertir una señal mecánica en respuesta celular, modificando su expresión génica. La mecanobiología nos ayuda a entender mejor la biopatología del DIV y su potencial reparación biológica

The intervertebral disc (IVD) is noted for its low cell content, and being the largest avascular structure of human body. The low amount of cells in the disc have to adapt to an anaerobic metabolism with low oxygen pressure and acidic pH. Apart from surviving in an adverse microenvironment, they are exposed to a high level of mechanical stress. The biological adaptation of cells to acidosis and hyperosmolarity conditions are regulated by mechanoproteins, which are responsible for converting a mechanical signal into a cellular response, thus modifying its gene expression. Mechanobiology helps us to better understand the pathophysiology of IVD and its potential biological repair

[Biology and mechanobiology of the intervertebral disc]. / Biología y mecanobiología del disco intervertebral.

The intervertebral disc (IVD) is noted for its low cell content, and being the largest avascular structure of human body. The low amount of cells in the disc have to adapt to an anaerobic metabolism with low oxygen pressure and acidic pH. Apart from surviving in an adverse microenvironment, they are exposed to a high level of mechanical stress. The biological adaptation of cells to acidosis and hyperosmolarity conditions are regulated by mechanoproteins, which are responsible for converting a mechanical signal into a cellular response, thus modifying its gene expression. Mechanobiology helps us to better understand the pathophysiology of IVD and its potential biological repair.

Acid-sensing ion channel 2 (asic 2) and trkb interrelationships within the intervertebral disc.

The cells of the intervertebral disc (IVD) have an unusual acidic and hyperosmotic microenvironment. They express acid-sensing ion channels (ASICs), gated by extracellular protons and mechanical forces, as well as neurotrophins and their signalling receptors. In the nervous tissues some neurotrophins regulate the expression of ASICs. The expression of ASIC2 and TrkB in human normal and degenerated IVD was assessed using quantitative-PCR, Western blot, and immunohistochemistry. Moreover, we investigated immunohistochemically the expression of ASIC2 in the IVD of TrkB-deficient mice. ASIC2 and TrkB mRNAs were found in normal human IVD and both increased significantly in degenerated IVD. ASIC2 and TrkB proteins were also found co-localized in a variable percentage of cells, being significantly higher in degenerated IVD than in controls. The murine IVD displayed ASIC2 immunoreactivity which was absent in the IVD of TrkB-deficient mice. Present results demonstrate the occurrence of ASIC2 and TrkB in the human IVD, and the increased expression of both in pathological IVD suggest their involvement in IVD degeneration. These data also suggest that TrkB-ligands might be involved in the regulation of ASIC2 expression, and therefore in mechanisms by which the IVD cells accommodate to low pH and hypertonicity.

Leiomioma intraorbitario. Caso clínico y revisión de la literatura / Orbital leiomyoma. Case report and review of the literature

Los leiomiomas son lesiones de lento crecimiento originarias del músculo liso. La localización orbitaria solo ha sido descrita en 25 casos. Sus características histológicas y la ausencia de recurrencia tras la resección total apoyan su comportamiento benigno. Presentamos un caso de hemangioleiomioma intraconal en una mujer de 55 años tratado quirúrgicamente mediante craneotomía fronto-orbitaria con resección total y sin recurrencia de la lesión tras 15 meses de seguimiento. Se discuten los hallazgos histológicos y radiológicos, enfatizando en el papel pronóstico de la cirugía

Leiomyoma are slowly growing lesions arising from smooth muscle. Orbital location hasbeen reported in 25 cases. Histological findings and no recurrence after total resectionsupport their benign behaviour. We report an intraconal orbital haemangioleiomyoma ina 55-year-old female treated by total resection through fronto-orbital craniotomy, with norecurrence after 15 months of follow-up. Radiological and pathological features are discussed, emphasising the prognostic role of the surgery

Acid-sensing ion channels in healthy and degenerated human intervertebral disc.

Acid-sensing ion channels (ASICs) are a family of H(+)-gated voltage-insensitive ion channels that respond to extracellular acidification by regulating transmembrane Ca(2+) flux. Moreover, ASICs can also be gated by mechanical forces and may function as mechanosensors. The cells of the intervertebral disc (IVD) have an unusual acidic and hyperosmotic microenvironment. Changes in the pH and osmolarity determine the viability of IVD cells and the composition of the extracellular matrix, and both are the basis of IVD degeneration. In this study, the expression of ASICs (ASIC1, ASIC2, ASIC3 and ASIC4) mRNAs and proteins in human healthy and degenerated IVD was evaluated by quantitative reverse transcription-quantitative polymerase chain reaction and Western blot. The distribution of ASIC proteins was determined by immunohistochemistry. The mRNAs for all ASICs were detected in normal human IVD, and significantly increased levels were found in degenerated IVD. Western blots demonstrated the presence of proteins with estimated molecular weights of approximately 68-72 kDa. In both the annulus fibrosus (AF) and nucleus pulposus (NP) of normal IVD, ASIC2 is the most frequently expressed ASIC followed by ASIC3, ASIC1 and ASIC4. In the AF of degenerated IVD, there was a significant increase in the number of ASIC1 and ASIC4 positive cells, whereas in the NP, we found significant increase of expression of ASIC1, ASIC2 and ASIC3. These results describe the occurrence and localization of different ASICs in human healthy IVD, and their increased expression in degenerated IVD, thus suggesting that ASICs may be involved in IVD degeneration.

[Orbital leiomyoma. Case report and review of the literature]. / Leiomioma intraorbitario. Caso clínico y revisión de la literatura.

Leiomyoma are slowly growing lesions arising from smooth muscle. Orbital location has been reported in 25 cases. Histological findings and no recurrence after total resection support their benign behaviour. We report an intraconal orbital haemangioleiomyoma in a 55-year-old female treated by total resection through fronto-orbital craniotomy, with no recurrence after 15 months of follow-up. Radiological and pathological features are discussed, emphasising the prognostic role of the surgery.

La inervación del disco intervertebral / Innervation of the intervertebral disc

Hasta hace poco la inervación del disco intervertebral fue objeto de debate. La introducción de técnicas de inmunohistoquímica asociadas a anticuerpos específicos y los estudios con trazadores nerviosos retrógrados han permitido conocer mejor la inervación del disco en condiciones normales y patológicas así como las características de las terminaciones y sus patrones de distribución en ambas situaciones. Las controversias que existen acerca de las bases estructurales del dolor discogénico han despertado el interés por conocer la influencia de la inervación en el dolor lumbar de origen discal y sus características. Actualmente sabemos que la neoinervación patológica de las fisuras radiales es un factor importante en la génesis del dolor discogénico dentro de un complejo mecanismo en que están implicados factores neurobioquímicos, inflamatorios y biomecánicos (AU)

Until very recently, intervertebral disc innervation was a subject of considerable debate. Nowadays, the introduction of inmunohistochemical techniques associated to specific antibodies and studies with retrograde tracers in nerves have allowed greater understanding of disc innervation in physiological and pathological conditions and also endings characteristics and their patterns of distribution in both situations. The existing controversies regarding structural basis of discogenic pain, have raised the interest of knowing the influence of innervation in back pain from discal origin and its characteristics. Today, we know that pathologic neoinnervation accompanying radial fissures is an important factor in the genesis of discogenic pain; within a complex mechanism in which other neurobiomechemical, inflammatory and biomechanical factors are involved

[Innervation of the intervertebral disc]. / La inervación del disco intervertebral.

Until very recently, intervertebral disc innervation was a subject of considerable debate. Nowadays, the introduction of inmunohistochemical techniques associated to specific antibodies and studies with retrograde tracers in nerves have allowed greater understanding of disc innervation in physiological and pathological conditions and also endings characteristics and their patterns of distribution in both situations. The existing controversies regarding structural basis of discogenic pain, have raised the interest of knowing the influence of innervation in back pain from discal origin and its characteristics. Today, we know that pathologic neoinnervation accompanying radial fissures is an important factor in the genesis of discogenic pain; within a complex mechanism in which other neurobiomechemical, inflammatory and biomechanical factors are involved.

Giant-cell granuloma of the axis.

Giant-cell granuloma is a benign and nonneoplastic lesion with an expansive and locally destructive behavior. It typically involves the mandible and the maxilla. Only 1 case arising from the odontoid process of the axis has been reported previously. The authors report on a 64-year-old man with a giant-cell granuloma of the axis. They review this uncommon entity, emphasizing the complexity of differentiating between this lesion and other giant-cell tumors.

Brown tumor of the orbital roof as an initial and isolated manifestation of secondary hyperparathyroidism.

Brown tumors appear in advanced stages of hyperparathyroidism. Only 17 cases have been documented in the orbit. We report a case of a young woman with a brown tumor in the orbital roof. Secondary hyperparathyroidism due to chronic renal disease was detected during the preoperative study. The pathogenesis, diagnosis and management of the brown tumor are discussed.

Complexity analysis of the cerebrospinal fluid pulse waveform during infusion studies.

PURPOSE: Nonlinear dynamics has enhanced the diagnostic abilities of some physiological signals. Recent studies have shown that the complexity of the intracranial pressure waveform decreases during periods of intracranial hypertension in paediatric patients with acute brain injury. We wanted to assess changes in the complexity of the cerebrospinal fluid (CSF) pressure signal over the large range covered during the study of CSF circulation with infusion studies. METHODS: We performed 37 infusion studies in patients with hydrocephalus of various types and origin (median age 71 years; interquartile range 60-77 years). After 5 min of baseline measurement, infusion was started at a rate of 1.5 ml/min until a plateau was reached. Once the infusion finished, CSF pressure was recorded until it returned to baseline. We analysed CSF pressure signals using the Lempel-Ziv (LZ) complexity measure. To characterise more accurately the behaviour of LZ complexity, the study was segmented into four periods: basal, early infusion, plateau and recovery. RESULTS: The LZ complexity of the CSF pressure decreased in the plateau of the infusion study compared to the basal complexity (p=0.0018). This indicates loss of complexity of the CSF pulse waveform with intracranial hypertension. We also noted that the level of complexity begins to increase when the infusion is interrupted and CSF pressure drops towards the initial values. CONCLUSIONS: The LZ complexity decreases when CSF pressure reaches the range of intracranial hypertension during infusion studies. This finding provides further evidence of a phenomenon of decomplexification in the pulsatile component of the pressure signal during intracranial hypertension.

Intervertebral disc, sensory nerves and neurotrophins: who is who in discogenic pain?

The normal intervertebral disc (IVD) is a poorly innervated organ supplied only by sensory (mainly nociceptive) and postganglionic sympathetic (vasomotor efferents) nerve fibers. Interestingly, upon degeneration, the IVD becomes densely innervated even in regions that in normal conditions lack innervation. This increased innervation has been associated with pain of IVD origin. The mechanisms responsible for nerve growth and hyperinnervation of pathological IVDs have not been fully elucidated. Among the molecules that are presumably involved in this process are some members of the family of neurotrophins (NTs), which are known to have both neurotrophic and neurotropic properties and regulate the density and distribution of nerve fibers in peripheral tissues. NTs and their receptors are expressed in healthy IVDs but much higher levels have been observed in pathological IVDs, thus suggesting a correlation between levels of expression of NTs and density of innervation in IVDs. In addition, NTs also play a role in inflammatory responses and pain transmission by increasing the expression of pain-related peptides and modulating synapses of nociceptive neurons at the spinal cord. This article reviews current knowledge about the innervation of IVDs, NTs and NT receptors, expression of NTs and their receptors in IVDs as well as in the sensory neurons innervating the IVDs, the proinflammatory role of NTs, NTs as nociception regulators, and the potential network of discogenic pain involving NTs.