Incomplete Spinal Cord Injury Reverses the Level-Dependence of Spinal Cord Injury Immune Deficiency Syndrome

Spinal cord injury (SCI) is associated with an increased susceptibility to infections, such as pneumonia, which is the leading cause of death in these patients. This phenomenon is referred to as SCI immune deficiency syndrome (SCI-IDS), and has been shown to be more prevalent after high-level transection in preclinical SCI models. Despite the high prevalence of contusion SCIs, the effects of this etiology have not been studied in the context of SCI-IDS. Compared to transection SCIs, which involve a complete loss of supraspinal input and lead to the disinhibition of spinally-generated activity, contusion SCIs may cause significant local deafferentation, but only a partial disruption of sympathetic tone below the level of injury. In this work, we investigate the effects of thoracic (T6-7) and cervical (C6-7) moderate–severe contusion SCIs on the spleen by characterizing splenic norepinephrine (NE) and cortisol (CORT), caspase-3, and multiple inflammation markers at 3- and 7-days post-SCI. In contrary to the literature, we observe an increase in splenic NE and CORT that correspond to an increase in caspase-3 after thoracic SCI relative to cervical SCI. Further, we found differences in expression of leptin, eotaxin, IP-10, and IL-18 that implicate alterations in splenocyte recruitment and function. These results suggest that incomplete SCI drastically alters the level-dependence of SCI-IDS.

Brainstem and Cervical Spinal Cord Fos Immunoreactivity Evoked by Nerve Growth Factor Injection into Neck Muscles in Mice

Although myofascial tenderness is thought to play a key role in the pathophysiology of tension-type headache, very few studies have addressed neck muscle nociception. The neuronal activation pattern following local nerve growth factor (NGF) administration into semispinal neck muscles in anaesthetized mice was investigated using Fos protein immunohistochemistry. In order to differentiate between the effects of NGF administration on c-fos expression and the effects of surgical preparation, needle insertion and intramuscular injection, the experiments were conducted in three groups. In the sham group ( n = 7) cannula needles were only inserted without any injection. In the saline ( n = 7) and NGF groups ( n = 7) 0.9% physiological saline solution or 0.8 µM NGF solution were injected in both muscles, respectively. In comparison with sham and saline conditions, NGF administration induced significantly stronger Fos immunoreactivity in the mesencephalic periaqueductal grey (PAG), the medullary lateral reticular nucleus (LRN), and superficial layers I and II of cervical spinal dorsal horns C1, C2 and C3. This activation pattern corresponds very well to central nervous system processing of deep noxious input. A knowledge of the central anatomical representation of neck muscle pain is an essential prerequisite for the investigation of neck muscle nociception in order to develop a future model of tension-type headache.

Human glial-restricted progenitor transplantation into cervical spinal cord of the SOD1 mouse model of ALS

Cellular abnormalities are not limited to motor neurons in amyotrophic lateral sclerosis (ALS). There are numerous observations of astrocyte dysfunction in both humans with ALS and in SOD1(G93A) rodents, a widely studied ALS model. The present study therapeutically targeted astrocyte replacement in this model via transplantation of human Glial-Restricted Progenitors (hGRPs), lineage-restricted progenitors derived from human fetal neural tissue. Our previous findings demonstrated that transplantation of rodent-derived GRPs into cervical spinal cord ventral gray matter (in order to target therapy to diaphragmatic function) resulted in therapeutic efficacy in the SOD1(G93A) rat. Those findings demonstrated the feasibility and efficacy of transplantation-based astrocyte replacement for ALS, and also show that targeted multi-segmental cell delivery to cervical spinal cord is a promising therapeutic strategy, particularly because of its relevance to addressing respiratory compromise associated with ALS. The present study investigated the safety and in vivo survival, distribution, differentiation, and potential efficacy of hGRPs in the SOD1(G93A) mouse. hGRP transplants robustly survived and migrated in both gray and white matter and differentiated into astrocytes in SOD1(G93A) mice spinal cord, despite ongoing disease progression. However, cervical spinal cord transplants did not result in motor neuron protection or any therapeutic benefits on functional outcome measures. This study provides an in vivo characterization of this glial progenitor cell and provides a foundation for understanding their capacity for survival, integration within host tissues, differentiation into glial subtypes, migration, and lack of toxicity or tumor formation.

Muscone protects vertebral end-plate degeneration by antiinflammatory property

Most chronic neck pain is the result of degeneration of the cervical spine. IL-1beta may play an important role in intervertebral disc degeneration. This being the case, inhibiting IL-1beta could provide a therapeutic approach for reducing or preventing disc degeneration. Muscone reportedly relieves pain and suppresses inflammation. Therefore, we asked whether muscone, a potent antiinflammatory agent, could reduce proinflammatory cytokines in vitro (end-plate cartilage cultures) and end-plate degeneration in vivo (a rat model that induces intervertebral disc degeneration). In vitro, muscone reversed IL-1beta-induced upregulation of IL-1beta, tumor necrosis factor alpha, cyclooxygenase 2, inducible nitric oxide synthase, matrix metalloproteinase 13, aggrecanase 2, and nitric oxide and downregulation of Col2alpha1 and aggrecan. Pretreatment with muscone (6.25, 12.5, 25 mumol/L) inhibited the IL-1beta-induced phosphorylation of extracellular signal-regulated kinases 1/2 and c-Jun N-terminal kinase in a dose-dependent manner. In vivo, muscone inhibited the expression of prostaglandin E2, 6-keto-prostaglandin F1alpha, IL-1beta, and tumor necrosis factor alpha and recovered the structural distortion of the degenerative disc. Our findings suggest muscone is a promising agent for treating intervertebral disc degeneration through its antiinflammatory effects.

The cervical lymph node preparation: a novel approach to study lymphocyte homing by intravital microscopy

OBJECTIVE

Lymphocyte recirculation constitutes an integral part of the adaptive immune system. Blood-borne lymphocytes migrate into secondary lymphoid organs, crossing the vascular wall of site-specific high endothelial venules (HEVs). We created a preparation of the cervical lymph node in mice to study lymphocyte homing in vivo.

METHODS AND RESULTS

Our novel approach allowed the detailed analysis of hemodynamics and lymphocyte-HEV endothelium interactions by means of intravital fluorescence microscopy. We confirm the key roles of L-selectin and LFA-1 for lymphocyte homing. Blockade of L-selectin function inhibited lymphocyte rolling and firm adhesion by 92% and 66%. In LFA-1-deficient mice, lymphocyte firm adhesion was reduced by 70%. In addition to the microcirculation studies, the cervical lymph node preparation allowed for visualization of afferent lymphatic transport, which is mainly derived from the oral mucosa.

CONCLUSION

This study reports a novel technical tool for the detailed in vivo analysis of adaptive immune responses.

Inflammatory mechanisms in cervicogenic headache: an integrative view

Cervicogenic headache is a relatively common and still controversial form of headache that originates from the neck structures. The pathophysiology probably results from various local pain-producing factors, such as intervertebral dysfunction, but the frequent coexistence of a history of head traumas still plays an important role. This report represents a series of pathophysiologic studies performed for patients with cervicogenic headache and the results achieved by a new pharmacologic treatment for the disease.

Herniated cervical intervertebral discs spontaneously produce matrix metalloproteinases, nitric oxide, interleukin-6, and prostaglandin E2

STUDY DESIGN

Herniated cervical disc specimens were obtained from patients undergoing surgical discectomy for persistent radiculopathy and cultured in vitro to determine whether various biochemical agents were being produced.

OBJECTIVES

Our hypothesis is that biochemical mediators of inflammation and tissue degradation play a role in cervical intervertebral disc degeneration and in the pathophysiology of cervical radiculopathy.

SUMMARY OF BACKGROUND DATA

Neck pain with or without radiculopathy is a common clinical problem, but the etiology of neck pain and the exact pathophysiology of radiculopathy remain uncertain. We have previously reported the production of various biochemical agents by herniated lumbar disc specimens in vitro. Because of a lack of such studies in the literature with respect to the cervical spine, the purpose of this study was to determine whether similar biochemical agents of inflammation and tissue degradation were being produced by herniated cervical disc specimens.

METHODS

Eighteen herniated cervical discs were obtained from 15 patients undergoing anterior disc surgery. The specimens were cultured and incubated for 72 hours, and the media were subsequently collected for biochemical analysis. Biochemical assays for matrix metalloproteinases, nitric oxide, prostaglandin E2, and a variety of cytokines were performed. As a control group, six cervical discs specimens were obtained from three patients undergoing anterior surgery for traumatic burst fractures, and similar biochemical analyses were performed.

RESULTS

The culture media from the herniated cervical disc specimens showed increased levels of matrix metalloproteinase activity compared with the control discs. Similarly, the levels of nitric oxide, prostaglandin E2, and interleukin-6 were significantly higher in the herniated disc specimens compared with the control discs. Interleukin-1 alpha, interleukin-1 beta, tumor necrosis factor-alpha, interleukin-1 receptor antagonist protein, and substance P were not detected in the culture media of the herniated or control discs.

CONCLUSIONS

Herniated cervical disc specimens were making spontaneously increased amounts of matrix metalloproteinases, nitric oxide, prostaglandin E2, and interleukin-6. These results were similar to those obtained in herniated lumbar disc specimens that we have previously reported. These products may be intimately involved in the biochemistry of disc degeneration and the pathophysiology of radiculopathy.