Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 40
Filter
1.
Prev Med Rep ; 16: 101018, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31890473

ABSTRACT

Schools are important environments for promotion of healthy behaviors to reduce childhood obesity; however, many barriers prevent schools from sustaining wellness programs. The goal of the Healthy Champions program was to assist schools with identifying areas for improvement through a nutrition and activity-focused assessment, and delivery of a customized score report and welcome kit with materials to promote healthful behavior change. In this study, we aimed to describe participation and assessment results for this program across a five-year period. Enrollment in the Healthy Champions program was open to private and public K-12 schools across Pennsylvania beginning in 2013. School staff completed an assessment that scored aspects of the wellness environment and was used to enroll schools in the program. Schools were awarded star status (0-5) based upon responses and provided a tailored response to improve ratings, and with re-enrollment, became a simple way for schools to track progress. From 2013 to 2018, 592 schools enrolled for at least one year, representing 58 out of 67 counties (87%) in Pennsylvania. Mean star status at baseline was 2.89 out of 5; however, schools enrolled for multiple years (51%) saw significant improvement in star status, independent of school size and rural/urban status.

2.
J Public Health (Oxf) ; 40(3): 591-597, 2018 09 01.
Article in English | MEDLINE | ID: mdl-29036317

ABSTRACT

Background: In 2006, United States public schools participating in federal school meal programs were required to adopt school wellness policies. The effect of these policies on school nutrition environments is well documented; however, evaluation of physical activity policies has received less investigation. We aimed to evaluate how district wellness policies aligned to practice for physical activity implementation in 40 schools with high obesity rates (>24%). Methods: Wellness policies were evaluated using the validated Wellness School Assessment Tool (WellSAT). Concurrently, schools completed the validated Alliance for a Healthier Generation's Healthy Schools Program (HSP) self-assessment to evaluate physical activity practices. Overall, 13 of 20 physical activity measures from WellSAT and 12 of 13 physical activity measures from HSP were aligned to match policy with practice. Results: Most policy items scored 0 or 1, indicating either 'no mention in the policy' or 'containing weak or vague language'. Corresponding HSP results indicated that school physical activity practices are 'not in place' or 'under development'. A strong, positive, correlation (r = 0.92, P < 0.001) indicated that a significant relationship exists between policy and implementation. Conclusions: Results indicate that most districts currently have weak policies regarding physical activity, limiting the potential to positively influence school-based physical activity.


Subject(s)
Exercise , School Health Services/standards , Child , Humans , Organizational Policy , Pediatric Obesity/prevention & control , Pennsylvania , Program Development , School Health Services/organization & administration , Schools/organization & administration , Schools/standards
3.
Transl Psychiatry ; 7(5): e1135, 2017 05 23.
Article in English | MEDLINE | ID: mdl-28534873

ABSTRACT

A social-stress mouse model was used to simulate features of post-traumatic stress disorder (PTSD). The model involved exposure of an intruder (male C57BL/6) mouse to a resident aggressor (male SJL) mouse for 5 or 10 consecutive days. Transcriptome changes in brain regions (hippocampus, amygdala, medial prefrontal cortex and hemibrain), blood and spleen as well as epigenome changes in the hemibrain were assayed after 1- and 10-day intervals following the 5-day trauma or after 1- and 42-day intervals following the 10-day trauma. Analyses of differentially expressed genes (common among brain, blood and spleen) and differentially methylated promoter regions revealed that neurogenesis and synaptic plasticity pathways were activated during the early responses but were inhibited after the later post-trauma intervals. However, inflammatory pathways were activated throughout the observation periods, except in the amygdala in which they were inhibited only at the later post-trauma intervals. Phenotypically, inhibition of neurogenesis was corroborated by impaired Y-maze behavioral responses. Sustained neuroinflammation appears to drive the development and maintenance of behavioral manifestations of PTSD, potentially via its inhibitory effect on neurogenesis and synaptic plasticity. By contrast, peripheral inflammation seems to be directly responsible for tissue damage underpinning somatic comorbid pathologies. Identification of overlapping, differentially regulated genes and pathways between blood and brain suggests that blood could be a useful and accessible brain surrogate specimen for clinical translation.


Subject(s)
Inflammation/metabolism , Stress Disorders, Post-Traumatic/genetics , Amygdala/metabolism , Animals , Behavioral Symptoms/metabolism , Brain/metabolism , Brain/pathology , Disease Models, Animal , Hippocampus/metabolism , Inflammation/blood , Male , Mice , Mice, Inbred C57BL , Neurogenesis/genetics , Neurogenesis/physiology , Neuronal Plasticity/genetics , Neuronal Plasticity/physiology , Prefrontal Cortex/metabolism , Stress, Psychological/metabolism , Transcriptome/genetics
4.
Am J Transplant ; 17(3): 622-634, 2017 03.
Article in English | MEDLINE | ID: mdl-27500557

ABSTRACT

Improved nerve regeneration and functional outcomes would greatly enhance the utility of vascularized composite allotransplantation (VCA) such as hand and upper extremity transplantation. However, research aimed at achieving this goal has been limited by the lack of a functional VCA animal model. We have developed a novel rat midhumeral forelimb transplant model that allows for the characterization of upper extremity functional recovery following transplantation. At the final end point of 12 weeks, we found that animals with forelimb transplantation including median, ulnar and radial nerve coaptation demonstrated significantly improved grip strength and forelimb function as compared to forelimb transplantation without nerve approximation (grip strength: 1.71N ± 0.57 vs. no appreciable recovery; IBB scale: 2.6 ± 0.7? vs. 0.8 ± 0.40; p = 0.0005), and similar recovery to nerve transection-and-repair only (grip strength: 1.71N ± 0.57 vs. 2.03 ± 0.42.6; IBB scale: 2.6 ± 0.7 vs. 2.8 ± 0.8; p = ns). Moreover, all forelimb transplant animals with nerve coaptation displayed robust axonal regeneration with myelination and reduced flexor muscle atrophy when compared to forelimb transplant animals without nerve coaptation. In conclusion, this is the first VCA small-animal model that allows for reliable and reproducible measurement of behavioral functional recovery in addition to histologic evaluation of nerve regeneration and graft reinnervation.


Subject(s)
Disease Models, Animal , Forelimb/surgery , Nerve Regeneration/physiology , Recovery of Function , Vascularized Composite Allotransplantation , Animals , Male , Rats , Rats, Inbred BN , Rats, Inbred Lew
7.
Exp Neurol ; 247: 272-81, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23707299

ABSTRACT

Myelinating Schwann cells express distinct sensory and motor phenotypes as defined by their differing patterns of growth factor production (Hoke et al., 2006). The heterogeneous growth factor requirements of sensory and motor neurons, however, suggest that Schwann cell phenotype might vary across a broad spectrum. To explore this possibility, we selectively denervated six discrete Schwann cell populations: dorsal root, cutaneous nerve, cutaneous unmyelinated axons, muscle nerve afferents, muscle nerve efferents, and ventral root. Real-time RT-PCR for 11 growth factors was performed on the 6 target Schwann cell populations 5, 15, and 30 days after their denervation, and on normal cutaneous nerve, muscle nerve, ventral root, and dorsal root to establish baseline expression levels. Within the denervated axon populations, IGF-1 and VEGF were expressed most prominently in cutaneous nerve, HGF, NGF, and BDNF in cutaneous nerve and dorsal root, GDNF in dorsal root and ventral root, PTN in the ventral root and muscle nerve efferents, and IGF-2 in both afferents and efferents within muscle nerve; expression of CNTF, FGF-2 and NT-3 was not modality or location specific. ELISA for NGF, BDNF, and GDNF confirmed that gene expression correlated with protein concentration. These findings demonstrate that growth factor expression by denervated Schwann cells is not only subject to further regulation within the previously-defined sensory and motor groups, but also varies along a central-peripheral axis. The traditional view of myelinating Schwann cells as a homogenous population is modified by the realization that complex regulation produces a wide variety of Schwann cell phenotypes. Additionally, we found that Schwann cell phenotype is maintained for 2 weeks in vitro, demonstrating that it may survive several cell divisions without instructive cues from either axons or basal lamina.


Subject(s)
Axons/physiology , Peripheral Nervous System Diseases/pathology , Schwann Cells/metabolism , Animals , Autonomic Denervation , Axons/ultrastructure , Cells, Cultured , Disease Models, Animal , Female , Ganglia, Spinal/cytology , Gene Expression Regulation , Microscopy, Electron, Transmission , Nerve Growth Factors/metabolism , Peripheral Nerves/metabolism , Peripheral Nerves/ultrastructure , Peripheral Nervous System Diseases/metabolism , RNA, Messenger/metabolism , Rats , Rats, Inbred Lew , Schwann Cells/ultrastructure , Skin/innervation , Time Factors
8.
AJNR Am J Neuroradiol ; 34(4): 802-7, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23124644

ABSTRACT

BACKGROUND AND PURPOSE: A number of benign and malignant peripheral nerve tumor and tumorlike conditions produce similar imaging features on conventional anatomic MR imaging. Functional MR imaging using DTI can increment the diagnostic performance in differentiation of these lesions. Our aim was to evaluate the role of 3T anatomic MR imaging and DTI in the characterization of peripheral nerve tumor and tumorlike conditions. MATERIALS AND METHODS: Twenty-nine patients (13 men, 16 women; mean age, 41±18 years; range, 11-83 years) with a nerve tumor or tumorlike condition (25 benign, 5 malignant) underwent 3T MR imaging by using anatomic (n=29), functional diffusion, DWI (n=21), and DTI (n=24) techniques. Images were evaluated for image quality (3-point scale), ADC of the lesion, tractography, and fractional anisotropy of nerves with interobserver reliability in ADC and FA measurements. RESULTS: No significant differences were observed in age (benign, 40±18 versus malignant, 45±19 years) and sex (benign, male/female=12:12 versus malignant, male/female=3:2) (P>.05). All anatomic (29/29, 100%) MR imaging studies received "good" quality; 20/21 (95%) DWI and 21/24 (79%) DTI studies received "good" quality. ADC of benign lesions (1.848±0.40×10(-3) mm2/s) differed from that of malignant lesions (0.900±0.25×10(-3) mm2/s, P<.001) with excellent interobserver reliability (ICC=0.988 [95% CI, 0.976-0.994]). There were no FA or ADC differences between men and women (P>.05). FA of involved nerves was lower than that in contralateral healthy nerves (P<.001) with excellent interobserver reliability (ICC=0.970 [95% CI, 0.946-0.991]). ADC on DTI and DWI was not statistically different (P>.05), with excellent intermethod reliability (ICC=0.943 [95% CI, 0.836-0.980]). Tractography differences were observed in benign and malignant lesions. CONCLUSIONS: 3T MR imaging and DTI are valuable methods for anatomic and functional evaluation of peripheral nerve lesions with excellent interobserver reliability. While tractography and low FA provide insight into neural integrity, low diffusivity values indicate malignancy in neural masses.


Subject(s)
Diffusion Tensor Imaging/methods , Magnetic Resonance Imaging/methods , Nerve Sheath Neoplasms/pathology , Neurilemmoma/pathology , Peripheral Nervous System Neoplasms/pathology , Adolescent , Adult , Aged , Aged, 80 and over , Charcot-Marie-Tooth Disease/pathology , Child , Diffusion Tensor Imaging/standards , Diffusion Tensor Imaging/statistics & numerical data , Female , Follow-Up Studies , Humans , Lymphoma/pathology , Magnetic Resonance Imaging/standards , Magnetic Resonance Imaging/statistics & numerical data , Male , Middle Aged , Neoplasms/pathology , Neurofibromatosis 1/pathology , Observer Variation , Young Adult
9.
Neurology ; 77(10): 980-6, 2011 Sep 06.
Article in English | MEDLINE | ID: mdl-21865571

ABSTRACT

OBJECTIVES: To characterize the natural history of oxaliplatin-associated neuropathy (ON) and determine whether intraepidermal nerve fiber density (IENFD) is a sensitive measure of neuropathy progression. In addition, we sought to assess the potential of ON as a neuroprotection model and gain insight into the relationship between axon loss and neuropathic symptoms. METHODS: Eight subjects receiving oxaliplatin for advanced colorectal cancer were prospectively followed prior to starting chemotherapy and at 30, 90, 180, and 360 days (180 days after completing treatment). Electrophysiology, punch biopsies, symptom assessment, and examinations with calculation of a reduced total neuropathy score (rTNS) were performed at each time point. Changes over time were assessed through Poisson regression for IENFD and a mixed effects model for rTNS and electrophysiology measures. RESULTS: The distal leg IENFD, rTNS, peroneal, and sural amplitudes were all significantly reduced over time, while conduction velocity (peroneal and sural) and distal thigh IENFD were not. Measures of axon loss continued to worsen following discontinuation of oxaliplatin. Five of 8 subjects reported prominent symptoms associated with oxaliplatin administration. CONCLUSIONS: This study demonstrates that oxaliplatin is associated with mild, sensory, and motor axon loss that may not be reversible. Axonal loss was detected by electrophysiology, rTNS, and distal leg IENFD. Several subjects reported prominent sensory symptoms that were not associated with axon loss, and that may or may not represent neuropathy. ON is an attractive paradigm for neuroprotection studies and the distal leg IENFD is an objective measure that requires minimal subject participation or study site expertise.


Subject(s)
Antineoplastic Agents/adverse effects , Organoplatinum Compounds/adverse effects , Polyneuropathies/chemically induced , Polyneuropathies/physiopathology , Adult , Aged , Aged, 80 and over , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/physiopathology , Female , Humans , Longitudinal Studies , Male , Middle Aged , Oxaliplatin , Polyneuropathies/diagnosis , Prospective Studies
10.
Neurology ; 75(13): 1150-8, 2010 Sep 28.
Article in English | MEDLINE | ID: mdl-20739646

ABSTRACT

BACKGROUND: Combination antiretroviral therapy (cART) has improved the survival of patients with HIV/AIDS but its impact remains uncertain on the changing prevalence and incidence of neurologic disorders with ensuing effects on mortality. METHODS: The prevalence and incidence of neurologic disorders were examined in patients receiving active care in a regional HIV care program from 1998 to 2008. The mortality hazard ratio (HR) was calculated by Cox proportional hazard models with adjustment for demographic and clinical variables. RESULTS: Of 1,651 HIV-infected patients assessed, 404 (24.5%) were identified as having one or more neurologic disorders, while 41% of AIDS-affected persons exhibited neurologic disease. Symptomatic distal sensory polyneuropathy (DSP, 10.0%) and HIV-associated neurocognitive disorder (HAND, 6.2%) represented the most prevalent disorders among 53 recognized neurologic disorders. Patients with at least one neurologic disorder exhibited higher mortality rates (17.6% vs 8.0%, p < 0.0001), particularly AIDS-related deaths (9.7% vs 3.2%, p < 0.0001), compared with those without neurologic disorders. The highest mortality HR was associated with opportunistic infections of CNS (HR 5.3, 95% confidence interval [CI] 2.5-11.2), followed by HAND (HR 3.1, 95% CI 1.8-5.3) and the presence of any neurologic disorder (HR 2.0, 95% CI 1.2-3.2). The risk of AIDS-related death with a neurologic disorder was increased by 13.3% per 100 cells/mm(3) decrement in blood CD4+ T-cell levels or by 39% per 10-fold increment in plasma viral load. CONCLUSIONS: The burden and type of HIV-related neurologic disease have evolved over the past decade and despite the availability of cART, neurologic disorders occur frequently and predict an increased risk of death.


Subject(s)
HIV Infections/complications , HIV Infections/mortality , Nervous System Diseases/etiology , Adult , Community Health Planning , Female , HIV Infections/diagnosis , HIV Infections/epidemiology , Humans , Incidence , Male , Nervous System Diseases/diagnosis , Nervous System Diseases/epidemiology , Predictive Value of Tests , Prevalence , Proportional Hazards Models , Retrospective Studies
11.
Am J Bioeth ; 9(5): 31-6, 2009 May.
Article in English | MEDLINE | ID: mdl-19396681

ABSTRACT

The prospect of using cell-based interventions (CBIs) to treat neurological conditions raises several important ethical and policy questions. In this target article, we focus on issues related to the unique constellation of traits that characterize CBIs targeted at the central nervous system. In particular, there is at least a theoretical prospect that these cells will alter the recipients' cognition, mood, and behavior-brain functions that are central to our concept of the self. The potential for such changes, although perhaps remote, is cause for concern and careful ethical analysis. Both to enable better informed consent in the future and as an end in itself, we argue that early human trials of CBIs for neurological conditions must monitor subjects for changes in cognition, mood, and behavior; further, we recommend concrete steps for that monitoring. Such steps will help better characterize the potential risks and benefits of CBIs as they are tested and potentially used for treatment.


Subject(s)
Affect , Behavior , Brain Tissue Transplantation/ethics , Cell Transplantation/ethics , Central Nervous System Diseases/surgery , Clinical Trials as Topic/ethics , Cognition , Informed Consent , Biomedical Research/ethics , Brain Tissue Transplantation/adverse effects , Cell Transplantation/adverse effects , Ethics, Research , Humans , Neuropsychological Tests , Research Subjects , Surveys and Questionnaires , Therapeutic Human Experimentation/ethics
12.
Neuroscience ; 154(2): 767-83, 2008 Jun 23.
Article in English | MEDLINE | ID: mdl-18456410

ABSTRACT

Erythropoietin (EPO) and its receptor (EPO-R), mediate neuroprotection from axonopathy and apoptosis in the peripheral nervous system (PNS). We examined the impact and potential mechanisms of local EPO signaling on regenerating PNS axons in vivo and in vitro. As a consequence of injury, peripheral nerve axons and DRG neurons have a marked increase in the expression of EPO and EPO-R. Local delivery of EPO via conduit over 2 weeks to rat sciatic nerve following crush injury increased the density and maturity of regenerating myelinated axons growing distally from the crush site. In addition, EPO also rescued retrograde degeneration and atrophy of axons. EPO substantially increased the density and intensity of calcitonin gene-related peptide (CGRP) expression within outgrowing axons. Behavioral improvements in sensorimotor function also occurred in rats exposed to near nerve EPO delivery. EPO delivery led to decreased nuclear factor kappaB (NFkB) activation but increased phosphorylation of Akt and STAT3 within nerve and dorsal root ganglia neurons indicating rescue from an injury phenotype. Spinal cord explant studies also demonstrated a similar dose-dependent effect of EPO upon motor axonal outgrowth. Local EPO signaling enhances regenerating peripheral nervous system axons in addition to its known neuroprotection. Exogenous EPO may have a therapeutic role in a large number of peripheral nerve diseases through its impact on regeneration.


Subject(s)
Axons/drug effects , Erythropoietin/pharmacology , Nerve Regeneration/drug effects , Signal Transduction/drug effects , Animals , Behavior, Animal/drug effects , Blotting, Western , Dose-Response Relationship, Drug , Down-Regulation/drug effects , Electrophysiology , Ganglia, Spinal/drug effects , Ganglia, Spinal/pathology , Hand Strength , Immunohistochemistry , Male , Nerve Crush , Neural Conduction/drug effects , Organ Culture Techniques , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , Rats , Rats, Sprague-Dawley , Recombinant Proteins , Reverse Transcriptase Polymerase Chain Reaction , Sciatic Nerve/injuries , Sciatic Nerve/pathology , Sciatic Nerve/physiology , Spinal Cord/physiology
13.
Neurology ; 71(4): 288-93, 2008 Jul 22.
Article in English | MEDLINE | ID: mdl-18463365

ABSTRACT

BACKGROUND: Attempts to translate basic stem cell research into treatments for neurologic diseases and injury are well under way. With a clinical trial for one such treatment approved and in progress in the United States, and additional proposals under review, we must begin to address the ethical issues raised by such early forays into human clinical trials for cell-based interventions for neurologic conditions. METHODS: An interdisciplinary working group composed of experts in neuroscience, cell biology, bioethics, law, and transplantation, along with leading disease researchers, was convened twice over 2 years to identify and deliberate on the scientific and ethical issues raised by the transition from preclinical to clinical research of cell-based interventions for neurologic conditions. RESULTS: While the relevant ethical issues are in many respects standard challenges of human subjects research, they are heightened in complexity by the novelty of the science, the focus on the CNS, and the political climate in which the science is proceeding. CONCLUSIONS: Distinctive challenges confronting US scientists, administrators, institutional review boards, stem cell research oversight committees, and others who will need to make decisions about work involving stem cells and their derivatives and evaluate the ethics of early human trials include evaluating the risks, safety, and benefits of these trials, determining and evaluating cell line provenance, and determining inclusion criteria, informed consent, and the ethics of conducting early human trials in the public spotlight. Further study and deliberation by stakeholders is required to move toward professional and institutional policies and practices governing this research.


Subject(s)
Brain Diseases/therapy , Cell- and Tissue-Based Therapy/ethics , Clinical Trials as Topic/ethics , Neurology/ethics , Neurology/standards , Animals , Biomedical Research/ethics , Biomedical Research/standards , Biomedical Research/trends , Cell- and Tissue-Based Therapy/methods , Cell- and Tissue-Based Therapy/standards , Clinical Trials Data Monitoring Committees/standards , Clinical Trials Data Monitoring Committees/trends , Clinical Trials as Topic/standards , Ethics Committees, Research/standards , Ethics Committees, Research/trends , Humans , Neurology/trends , Risk Assessment , Stem Cell Transplantation/ethics , Stem Cell Transplantation/methods , Stem Cell Transplantation/standards , Time Factors , United States , United States Food and Drug Administration/standards , United States Food and Drug Administration/trends
14.
J Neurosci ; 26(38): 9646-55, 2006 Sep 20.
Article in English | MEDLINE | ID: mdl-16988035

ABSTRACT

Schwann cell phenotype is classified as either myelinating or nonmyelinating. Additional phenotypic specialization is suggested, however, by the preferential reinnervation of muscle pathways by motoneurons. To explore potential differences in growth factor expression between sensory and motor nerve, grafts of cutaneous nerve or ventral root were denervated, reinnervated with cutaneous axons, or reinnervated with motor axons. Competitive reverse transcription-PCR was performed on normal cutaneous nerve and ventral root and on graft preparations 5, 15, and 30 d after surgery. mRNA for nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor, hepatocyte growth factor, and insulin-like growth factor-1 was expressed vigorously by denervated and reinnervated cutaneous nerve but minimally by ventral root. In contrast, mRNA for pleiotrophin (PTN) and glial cell line-derived neurotrophic factor was upregulated to a greater degree in ventral root. ELISA confirmed that NGF and BDNF protein were significantly more abundant in denervated cutaneous nerve than in denervated ventral root, but that PTN protein was more abundant in denervated ventral root. The motor phenotype was not immutable and could be modified toward the sensory phenotype by prolonged reinnervation of ventral root by cutaneous axons. Retrograde labeling to quantify regenerating neurons demonstrated that cutaneous nerve preferentially supported cutaneous axon regeneration, whereas ventral root preferentially supported motor axon regeneration. Schwann cells thus express distinct sensory and motor phenotypes that are associated with the support of regeneration in a phenotype-specific manner. These findings suggest that current techniques of bridging gaps in motor and mixed nerve with cutaneous graft could be improved by matching axon and Schwann cell properties.


Subject(s)
Axons/metabolism , Motor Neurons/metabolism , Nerve Regeneration/physiology , Neurons, Afferent/metabolism , Phenotype , Schwann Cells/metabolism , Animals , Female , Gene Expression Regulation/physiology , Male , Neuronal Plasticity/physiology , Rats , Rats, Inbred Lew
15.
Neurology ; 64(1): 139-41, 2005 Jan 11.
Article in English | MEDLINE | ID: mdl-15642920

ABSTRACT

The presence of an APOE epsilon4 allele may be a risk factor for neuropathy severity in diabetes. The authors assessed the frequency of APOE epsilon4 in patients presenting with sensory predominant neuropathy. APOE epsilon4 frequency among patients with early diabetic neuropathy and impaired glucose tolerance-associated neuropathy was 16 to 17%, and not different from patients with idiopathic neuropathy (17%) or published normative values (16%). APOE epsilon4 may not function as a susceptibility gene in sensory predominant neuropathy.


Subject(s)
Apolipoproteins E/genetics , Diabetic Neuropathies/genetics , Genetic Predisposition to Disease/genetics , Peripheral Nervous System Diseases/genetics , Sensation Disorders/genetics , Apolipoprotein E4 , Female , Humans , Male , Middle Aged
16.
Exp Neurol ; 173(1): 77-85, 2002 Jan.
Article in English | MEDLINE | ID: mdl-11771940

ABSTRACT

In the peripheral nervous system, regeneration of motor and sensory axons into chronically denervated distal nerve segments is impaired compared to regeneration into acutely denervated nerves. In order to find possible causes for this phenomenon we examined the changes in the expression pattern of the glial cell-line-derived neurotrophic factor (GDNF) family of growth factors and their receptors in chronically denervated rat sciatic nerves as a function of time with or without regeneration. Among the GDNF family of growth factors, only GDNF mRNA expression was rapidly upregulated in Schwann cells as early as 48 h after denervation. This upregulation peaked at 1 week and then declined to minimal levels by 6 months of denervation. The changes in the protein expression paralleled the changes in the expression of the GDNF mRNA. The mRNAs for receptors GFRalpha-1 and GFRalpha-2 were upregulated only after maximal GDNF upregulation and remained elevated as late as 6 months. There were no significant changes in the expression of GFRalpha-3 or the tyrosine kinase coreceptor, RET. When we examined the expression of GDNF in a delayed regeneration paradigm, there was no upregulation in the distal chronically denervated tibial nerve even when the freshly axotomized peroneal branch of the sciatic nerve was sutured to the distal tibial nerve. This study suggests that one of the reasons for impaired regeneration into chronically denervated peripheral nerves may be the inability of Schwann cells to maintain important trophic support for both motor and sensory neurons.


Subject(s)
Drosophila Proteins , Membrane Glycoproteins , Mononeuropathies/physiopathology , Nerve Tissue Proteins/metabolism , RNA, Messenger/metabolism , Receptors, Nerve Growth Factor , Regeneration , Schwann Cells/metabolism , Animals , Axotomy , Chronic Disease , Denervation , Disease Models, Animal , Glial Cell Line-Derived Neurotrophic Factor , Glial Cell Line-Derived Neurotrophic Factor Receptors , Male , Mononeuropathies/pathology , Nerve Growth Factors/genetics , Nerve Growth Factors/metabolism , Nerve Tissue Proteins/genetics , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins/metabolism , Proto-Oncogene Proteins c-ret , Rats , Rats, Sprague-Dawley , Receptor Protein-Tyrosine Kinases/genetics , Receptor Protein-Tyrosine Kinases/metabolism , Receptors, Cell Surface/genetics , Receptors, Cell Surface/metabolism , Schwann Cells/pathology , Sciatic Neuropathy/pathology , Sciatic Neuropathy/physiopathology , Tibial Neuropathy/pathology , Tibial Neuropathy/physiopathology , Up-Regulation/genetics
17.
Exp Neurol ; 172(2): 398-406, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11716563

ABSTRACT

The long-term relationship between the peripheral nerve trunk and its vascular supply, the vasa nervorum, has not been considered in the context of denervation and regeneration. While the microvessels of peripheral nerve are not thought to influence Wallerian degeneration itself, in this work we explored how vasa nervorum respond to denervation of the nerve trunk. Our hypotheses were that the presence of axons had a significant impact on the vasa nervorum and that the absence of reinnervation might eventually lead to an unfavorable ischemic regenerative microenvironment. We studied rat sciatic nerve trunks for up to 6 months following transection and either prevented regeneration or allowed it to proceed. Vasa nervorum were studied in several ways: (i) measurements of local endoneurial blood flow using microelectrode hydrogen clearance polarography; (ii) measurements of erythrocyte flux (flow) in the extrinsic nerve plexus using laser Doppler flowmetry; (iii) India ink perfusion of microvessels in unfixed nerve; (iv) mRNA expression of vascular endothelial growth factor (VEGF) using reverse transcription polymerase chain reaction. Early after injury, there were rises in endoneurial and extrinsic flow, microvessel numbers, and VEGF mRNA expression. Angiogenesis was apparently confined to the epineurial and perineurial compartments. Later, however, there were substantial declines in flow observed in long-term (6-month) denervated sciatic nerve trunks associated with declines in the caliber of new microvessels. Reinnervated sciatic nerves had restored endoneurial blood flow. The findings confirm important relationships between axon presence and local blood flow. Angiogenesis is a feature of the injured peripheral nerve, but long term denervated nerve trunks have declines of flow despite retaining new microvessels.


Subject(s)
Denervation , Ischemia/etiology , Sciatic Nerve/blood supply , Vasa Nervorum/physiopathology , Animals , Endothelial Growth Factors/genetics , Lymphokines/genetics , Male , RNA, Messenger/metabolism , Rats , Rats, Sprague-Dawley , Regional Blood Flow , Reverse Transcriptase Polymerase Chain Reaction , Time Factors , Vasa Nervorum/pathology , Vascular Endothelial Growth Factor A , Vascular Endothelial Growth Factors
19.
J Neuropathol Exp Neurol ; 59(9): 798-807, 2000 Sep.
Article in English | MEDLINE | ID: mdl-11005260

ABSTRACT

The changes of nitric oxide synthase (NOS) activity and expression in experimental diabetic neuropathy have not been examined. Increases in ganglia NOS might be similar to those that follow axotomy, whereas declines in endothelial NOS (eNOS) and immunological NOS (iNOS) might explain dysfunction of microvessels or macrophages. In this work, we studied NOS activity in lumbar dorsal root ganglia (DRG) of rats with both short- and long-term experimental streptozotocin-induced diabetes and correlated it with expression of each of the 3 NOS isoforms. NOS enzymatic activity in DRG increased after 12 months of diabetes. This increase, however, was not accompanied by an increase in neuronal NOS immunohistochemistry or mRNA. Immunohistochemical and RT-PCR studies did not identify changes of eNOS expression in 12-month sciatic nerves or DRG from diabetics. Two-month diabetic DRG had increased eNOS mRNA and there was novel eNOS labeling of capsular DRG and perineurial cells. iNOS mRNA levels were lower in diabetics at both time points in peripheral nerves but were unchanged in DRG. Diabetic ganglia showed an increase in NOS activity not explained by novel NOS isoform synthesis. The increases may compensate for NO "quenching" by endproducts of glycosylation. Declines in iNOS may indicate impaired macrophage function.


Subject(s)
Diabetes Mellitus, Experimental/physiopathology , Diabetic Neuropathies/enzymology , Ganglia, Spinal/enzymology , Gene Expression Regulation, Enzymologic , Nitric Oxide Synthase/genetics , Animals , Blood Glucose/metabolism , Diabetes Mellitus, Experimental/enzymology , Diabetes Mellitus, Experimental/genetics , Diabetic Neuropathies/genetics , Diabetic Neuropathies/physiopathology , Male , Motor Neurons/physiology , Neural Conduction , Neurons, Afferent/physiology , Nitric Oxide Synthase/metabolism , Nitric Oxide Synthase Type I , Nitric Oxide Synthase Type II , Nitric Oxide Synthase Type III , RNA, Messenger/genetics , Rats , Rats, Sprague-Dawley , Reverse Transcriptase Polymerase Chain Reaction , Sciatic Nerve/physiopathology , Tibial Nerve/physiopathology , Transcription, Genetic
20.
Eur J Neurosci ; 12(7): 2323-32, 2000 Jul.
Article in English | MEDLINE | ID: mdl-10947811

ABSTRACT

Neuropathic pain is a disabling feature of peripheral nerve injury. Following injury, local inflammation and the release of mediators may contribute to ectopic mechanosensitivity of the nerve-trunk and pain hypersensitivity. In the present study we investigated whether nitric oxide (NO) action and local nitric oxide synthase (NOS) expression play a role in pain hypersensitivity and A fibre-mediated ectopic hyperexcitability following a chronic constriction injury to a rat sciatic nerve. Using immunohistochemical methods we provide evidence for a unique endothelial constitutive nitric oxide synthase (ecNOS) immunoreactivity localized in early axonal endbulb-like structures of injured peripheral nerve axons. Moreover, we show that following nerve injury there is increased ecNOS-mRNA expression within the lumbar sympathetic ganglia, and that axoplasmic transport in sympathetic and other axons rather than local non-neural synthesis accounts for its accumulation in nerve fibres. We also demonstrate here that local inhibition of NOS action with the broad-spectrum inhibitor NG-nitro-L-arginine-methyl ester (L-NAME), but not more specific inhibitors of other NOS isoforms, has stereospecific, dose- and time-dependent analgesic effects that were reversed by local administration of L-arginine, the natural precursor of NO. In further work, using a teased fibre preparation, we show that administration of L-NAME, but not D-NAME, to the injury site also blocks ectopic mechanosensitivity of injured A-fibres. Our results indicate that an early and transient local ecNOS expression within early axonal endbulb-like structures, some arising from sympathetic axons, plays a critical role in the development of neuropathic pain.


Subject(s)
Hyperalgesia/metabolism , Nerve Fibers, Myelinated/enzymology , Nitric Oxide Synthase/genetics , Nitric Oxide Synthase/metabolism , Sciatic Nerve/injuries , Animals , Axonal Transport/physiology , Electrophysiology , Enzyme Inhibitors/pharmacology , Gene Expression Regulation, Enzymologic/physiology , Hot Temperature , Immunohistochemistry , Male , Mechanoreceptors/drug effects , Mechanoreceptors/enzymology , NG-Nitroarginine Methyl Ester/pharmacology , Nerve Endings/enzymology , Nitric Oxide Synthase/analysis , Nitric Oxide Synthase Type III , Nociceptors/drug effects , Nociceptors/enzymology , RNA, Messenger/analysis , Rats , Rats, Sprague-Dawley , Sciatic Nerve/cytology , Sciatic Nerve/enzymology
SELECTION OF CITATIONS
SEARCH DETAIL
...