Takayuki Kawasaki

Tenascin-C regulates proliferation and migration of cultured astrocytes in a scratch wound assay

Tenascin-C (TNC), an extracellular matrix glycoprotein, is involved in tissue morphogenesis like embryogenesis, wound healing or tumorigenesis. Astrocytes are known to play major roles in wound healing in the CNS. To elucidate the roles of TNC in wound closure by astrocytes, we have examined the morphological changes of cultured astrocytes in a scratch wound assay and measured the content of soluble TNC released into the medium. We have also localized the expression of TNC mRNA, TNC, glial fibrillary acidic protein (GFAP), vimentin and integrin beta1. After wounding, glial cells rapidly released the largest TNC isoform and proliferated in the border zones. Subsequently, they became polarized with unidirectional processes and finally migrated toward the denuded area. The proliferating border zone cells and pre-migratory cells intensely expressed TNC mRNA, TNC-, vimentin-, GFAP- and integrin beta1-like immunoreactivity, while the migratory cells showed generally reduced expression except the front. Exogenous TNC enhanced cell proliferation and migration, while functional blocking with anti-TNC or anti-integrin beta1 antibody reduced both of them. These results suggest that mechanical injury induces boundary astrocytes to produce and release TNC that promotes cell proliferation and migration via integrin beta1 in an autocrine/paracrine fashion.

Spontaneous regeneration of the corticospinal tract after transection in young rats: a key role of reactive astrocytes in making favorable and unfavorable conditions for regeneration.

We demonstrated the occurrence of marked regeneration of the corticospinal tract (CST) after a single transection and failure of regeneration after a repeated transection in young rats. To provide convincing evidence for the complete transection and regeneration we used retrograde neuronal double labeling. Double-labeled neurons that took up the first tracer from the transection site and the second tracer from the injection site caudal to the transection site were observed in the sensorimotor cortex. The anterograde tracing method revealed various patterns of regeneration. In the most successful cases the vast majority of regenerated fibers descended in the normal tract and terminated normally whereas a trace amount of fibers coursed aberrantly. In the less successful cases fibers descended partly normally and partly aberrantly or totally aberrantly. To clarify the role of astrocytes in determining the success or failure of regeneration we compared expression of glial fibrillary acidic protein (GFAP), vimentin and neurofilament (NF) immunoreactivity (IR) in the lesion between single and repeated transections. In either transection, astrocytes disappeared from the CST near the lesion site as early as 3 h after lesioning. However, by 24 h after a single transection, immature astrocytes coexpressing GFAP- and vimentin-IR appeared in the former astrocyte-free area and NF-positive axons crossed the lesion. By contrast, after a repeated transection the astrocyte-free area spread and NF-positive axons never crossed the lesion. It appears likely that the major sign, and possibly cause of failure of regeneration is the prolonged disappearance of astrocytes in the lesioned tract area.

Does scapular dyskinesis affect top rugby players during a game season

BACKGROUND Scapular dyskinesis represents a considerable risk of shoulder injury to overhead athletes; however, there is a shortage of detailed epidemiologic information about scapular dyskinesis among the participants in collision sports. PURPOSE To describe the incidence and relationship of scapular dyskinesis to shoulder discomfort and variables related to the shoulder in top rugby players. METHODS One hundred twenty top rugby football players in Japan were evaluated by means of questionnaires, physical examinations, and a video analysis during their preseason. Data were assessed by a logistic regression analysis calculating odds ratios. The primary outcome was processed to assess the relationship between scapular dyskinesis and other variables at the preseason. The secondary outcome was processed to assess an influence of scapular dyskinesis to shoulder discomfort during their regular season that were reassigned by second questionnaires. RESULTS Scapular dyskinesis was identified in 33 (32%) shoulders, and type III was prominent. Scapular dyskinesis was significantly associated with shoulder discomfort (OR [odds ratio] = 4.4), and was also associated with variables of the affected shoulder. In addition, the players with asymptomatic scapular dyskinesis at the preseason would have high incident with shoulder discomfort during their regular season (OR = 3.6). CONCLUSIONS Scapular dyskinesis was associated significantly with both subjective and objective symptoms of the affected shoulder. These appearances may be of particular relevance in the early screening of chronic shoulder disorders in the rugby population. Further study to investigate and evaluate its reliability is needed to characterize its impact on the participants in collision sports.

Correlation between synovitis detected on enhanced-magnetic resonance imaging and a histological analysis with a patient-oriented outcome measure for Japanese patients with end-stage knee osteoarthritis receiving joint replacement surgery

Osteoarthritis (OA) is a disease that primarily results in the degeneration and destruction of the articular cartilage. However, synovitis that occurs secondarily by this primary phenomenon is crucial for both the structural and symptomatic progression of the disease. The Japanese Knee Osteoarthritis Measure (JKOM) was created as an outcome measure for Japanese patients with knee OA. This study was conducted to determine whether synovitis in knee OA correlates with the current disability of patients with knee OA who required total knee arthroplasty (TKA). Thirty-four Japanese patients with end-stage knee OA who required TKA were included in this study. The visual analog scale (VAS, 0–100) for pain and the JKOM score, as well as the Western Ontario and McMaster Universities Arthritis Index (WOMAC), were examined before the operation. Synovial samples were taken at the time of the operation. A histological analysis and gadolinium-enhanced magnetic resonance imaging (Gd-MRI) were conducted to evaluate synovitis. Correlations between the synovitis score evaluated by histological analysis and Gd-MRI with either the pain VAS score or the JKOM score were examined using Spearman’s rank correlation coefficient. Neither the synovitis scores evaluated by the histological analysis nor those by a Gd-MRI correlated with the pain VAS score (n = 34, r = 0.25, p = 0.18 and r = 0.08, p = 0.75, respectively) and WOMAC (n = 14, r = 0.35, p = 0.22 and r = 0.45, p = 0.16, respectively) of the patients. However, they significantly correlated with the JKOM score of the patients (n = 34, r = 0.55, p = 0.001 and r = 0.71, p = 0.001, respectively). The severity of synovitis in OA was closely correlated with the current functional impairment and disability of the patients receiving TKA with end-stage knee OA.

Therapeutic home exercise versus intraarticular hyaluronate injection for osteoarthritis of the knee: 6-month prospective randomized open-labeled trial

BackgroundTreatment for osteoarthritis (OA) of the knee is controversial. Only a few studies have compared the effects of intraarticular injection of hyaluronate with those of home exercise for knee OA. We prospectively evaluated the therapeutic effects of each treatment.MethodsA total of 102 female subjects (mean age 70.4 years) were randomly divided into two groups and followed up to the 24th week. The primary outcome measure was judged by three pain/function scales as follows: a visual analogue scale, the Japanese Knee Osteoarthritis Measure, and the Outcome Measures in Rheumatology Clinical Trials and Osteoarthritis Research Society International criteria. For secondary outcome measures, all data were categorized for logistic regression analysis and the chi-squared test to address factors affecting these outcomes.ResultsThe two treatment groups demonstrated equal improvement regarding all three scales, and there was statistically no difference in between-group analyses, although there seemed to be better improvement in range of motion at 24 weeks in the home exercise group. In categorical analysis, OA stage was classified as early and advanced OA at 3 mm of joint space width obtained from standing anteroposterior radiographs. Logistic regression analysis revealed that the OA stage at the baseline of the knee affected these improvements. For early OA the improvement rate regarding hydrops was significantly higher in the home exercise group, whereas for advanced OA there was a tendency for the rate of improvement in ROM to be inferior in the hyaluronidate group.ConclusionsTaking into account the cost, convenience, and invasiveness to patients, exercise is thought to have some advantage over intraarticular injection of hyaluronate for the therapy of OA of the knee.

Additive effects of glucosamine or risedronate for the treatment of osteoarthritis of the knee combined with home exercise: a prospective randomized 18-month trial

We have previously demonstrated the efficacy of therapeutic exercise for osteoarthritis (OA) of the knee. This study was performed to examine the additive effects of glucosamine or risedronate on the exercise therapy. In this study, 142 female patients with moderate OA of the knee, who had been recommended to undergo home exercise at the first visit to the hospital, were randomly given glucosamine hydrochloride, risedronate, or no additive. Although improvement after 18 months was observed in all groups using individual scales for evaluation of pain and function of the knee, no significant differences were observed between the groups regarding any of the scales, indicating no significant additive effect of glucosamine or risedronate. One reason for the lack of effect of glucosamine or risedronate on OA of the knee may be that the effect of these agents was occluded by the effect of therapeutic exercise to improve pain and function of the knee. This finding means that even if glucosamine and risedronate were to have an effect on OA of the knee, the effect would not be greater than the effect of knee exercise to improve the symptoms.

Spontaneous regeneration of the corticospinal tract after transection in young rats: collagen type IV deposition and astrocytic scar in the lesion site are not the cause but the effect of failure of regeneration.

In young rats the corticospinal tract regenerated after a single transection of the spinal cord with a sharp blade, but regeneration failed if the transection was repeated to make a more traumatic injury. To identify cells and associated molecules that promote or impede regeneration, we compared expression of collagen type IV, glial fibrillary acidic protein (GFAP), and vimentin immunoreactivity (IR) at the lesion sites in combination with anterograde axonal tracing between animals with two types of transection. Axonal regeneration occurred as early as 18 hours after transection; regenerating axons penetrated vessel‐like structures with collagen type IV‐IR at the lesion site, while reactive astrocytes coexpressing GFAP‐ and vimentin‐IR appeared in the lesioned white matter. In contrast, when regeneration failed astrocytes were absent near the lesion. By 7 days sheet‐like structures with collagen type IV‐IR and astrocytic scar appeared in the lesioned white matter and persisted until the end of the observation period (31 days). On the basis of their spatiotemporal appearance, collagen type IV‐IR sheet‐like structures and the astrocytic scar follow, rather than cause, the failure of regeneration. The major sign, and perhaps cause, of failure of axonal regeneration is likely the prolonged disappearance of astrocytes around the lesion site in the early postinjury period. J. Comp. Neurol. 464:343–355, 2003.

ACL Reconstruction Preserving the ACL Remnant Achieves Good Clinical Outcomes and Can Reduce Subsequent Graft Rupture

Background: Although anterior cruciate ligament (ACL) reconstruction techniques that preserve remnant tissues have been described, complete preservation may be difficult, with little known about its clinical advantages. Purpose: To compare clinical outcomes in patients undergoing ACL reconstruction with and without ACL remnant preservation. Study Design: Case-control study. Methods: Of 372 patients who underwent surgical treatment of an ACL injury between September 2006 and July 2010, 154 had no remaining identifiable ligament tissue and were excluded from this study. Attempts were made to preserve the ACL remnant as much as possible in the remaining 218 patients. These patients were divided into 2 groups: those in whom the remnant was preserved (group 1, n = 85) and those in whom the remnant was not preserved (group 2, n = 98). Patients were followed for at least 24 months. Outcomes, including graft rupture, were compared in the 2 groups. Results: Time from injury to surgery was significantly shorter (7.3 ± 16.3 vs 16.0 ± 30.3 months; P < .05) and the preinjury Tegner activity was significantly higher (7.6 ± 1.4 vs 7.1 ± 1.2; P < .05; 95% confidence interval, 1.2-13.7) in group 1 than in group 2. The postoperative negative ratio of the pivot-shift test was similar in the 2 groups (87% vs 81%). Anterior stability of the knee, as measured by a KT-2000 arthrometer, was significantly better in group 1 than in group 2 (1.0 ± 0.8 vs 1.3 ± 1.0 mm; P < .05). ACL graft rupture occurred in 1 patient (1.1%) in group 1 and in 7 patients (7.1%) in group 2 (P < .05). Regression analysis showed that preservation of the remnant decreased the likelihood of graft rupture (odds ratio, 11.2; 95% confidence interval, 1.2-101.7). Conclusion: These findings confirmed that preserving the remnant tissue of the ACL may facilitate recovery of function and decrease graft rupture after primary reconstruction.

A longitudinal study of the relationship between the status of bone marrow abnormalities and progression of knee osteoarthritis

BackgroundBone marrow abnormalities (BMAs) detected on magnetic resonance imaging (MRI) are suggested to be involved in the pathogenesis of osteoarthritis (OA), and the size of the BMAs is associated with the progression of OA. However, it still remains unclear as to whether the associations of BMA size and OA severity are observed equally or whether they differ from early to advanced stages of OA. In the present study we examined whether BMA enlargement and OA progression differed according to the severity of OA.MethodsOne hundred and eighty patients with knee OA were enrolled in the present study, and 122 of these patients completed this study. Radiography and knee MRI were done two times in all patients, at the baseline and 6 months or later at the time of patient follow-up. The severity of OA was evaluated by radiography using the Kellgren-Lawrence (K-L) grade. The patients who showed a deterioration in the K-L grade during the follow-up examination (59/122) were defined as the deterioration group. T2-weighted fat-suppressed MR images were used to score the size of the BMAs according to the whole-organ magnetic resonance imaging score (WORMS). A new scoring system, the spacial BMA score (s-score) was defined to assess the size of the BMAs three-dimensionally.ResultsIn patients with K-L grade 2, the s-score changes during the follow-up period in the deterioration group were significantly increased in comparison to those in the no-change group (P = 0.04), and no significant s-score changes were observed in patients with either K-L grade 1 or 3 (P = 0.07 and 0.57) between the deterioration group and the no-change group during the follow-up examination. In patients with K-L grade 3, the s-score at the baseline in the deterioration group was higher than that in the no-change group (P = 0.05).ConclusionsThe relationship between the size and enlargement of BMAs and the progression of OA changed depending upon the severity of OA.

Spatiotemporal distribution of GAP-43 in the developing rat spinal cord: a histological and quantitative immunofluorescence study.

In the rat spinal cord we studied developmental changes in spatiotemporal expression of the growth-associated protein GAP-43, which is known to play an important role in neural development, axonal regeneration, and modulation of synaptic function. GAP-43 was expressed predominantly in the white matter at embryonic day 13 to postnatal day 7, evenly in the white and gray matter at the 2nd to the 3rd postnatal week, and predominantly in the gray matter after the 5th postnatal week. The shifting of predominance was quantitatively assessed. On the basis of histological findings and quantitative assessment of GAP-43 immunoreactivity, it appears likely that the development proceeds from the phase of mostly axonal elongation during the embryonic period and the 1st postnatal week, via the phase of axonal elongation and formation of end arbors and synaptic organization during the 2nd to the 4th postnatal week, to the phase of final maturation of synaptic organization. GAP-43 was continuously expressed through adulthood in neuropil of the gray matter, the pyramidal tract, and the dorsal portion of the lateral funiculus that was identified as serotonergic by confocal laser scanning microscopic studies. The continuous expression may imply perpetual remodeling in these structures even in adulthood.