The infrapatellar fat pad contributes to spontaneous healing after complete anterior cruciate ligament injury.

Anterior cruciate ligament (ACL) injuries have a very low healing capacity but have recently been shown to heal spontaneously with conservative treatment. This study examined the mechanism of spontaneous ACL healing by focusing on the intra-articular tissues of the knee joint. Skeletally mature Wistar rats (n = 70) were randomly assigned to two groups: the controlled abnormal movement (CAM) and anterior cruciate ligament transection (ACLT) groups. The ACL was completely transected at the mid-portion in both groups. Only the CAM group underwent extra-articular braking to control for abnormal tibial translation. The animals were allowed full cage activity until sacrifice for histological, and molecular biology analyses. The results showed that the behavior of the stump after ACL injury differed between models 12 h after injury. The femoral stump in the ACLT group retreated posteriorly and upwardly. Macrophage polarity analysis revealed that the stump immune response in the CAM group was more activated than that in the ACLT group 6 h after injury. Microarray analysis of the ACL parenchyma and infrapatellar fat pads suggested the involvement of nuclear factor kappa B (NF-κB) signaling. Real-time polymerase chain reaction (PCR) analysis showed that NF-κB gene expression in the infrapatellar fat pad was significantly increased in the CAM group than in the ACLT group. However, there was no difference in the gene expression levels in the ACL parenchyma between models. In conclusion, the healing response of the ACL was activated within 12 h of injury, resulting in differences in the healing response between the models. It has been suggested that infrapatellar fat pads are involved in the healing process and that angiogenesis and antiapoptotic effects through NF-κB signaling may contribute to this mechanism.

Effect of Suppression of Rotational Joint Instability on Cartilage and Meniscus Degeneration in Mouse Osteoarthritis Model.

OBJECTIVE: Joint instability and meniscal dysfunction contribute to the onset and progression of knee osteoarthritis (OA). In the destabilization of the medial meniscus (DMM) model, secondary OA occurs due to the rotational instability and increases compressive stress resulting from the meniscal dysfunction. We created a new controlled abnormal tibial rotation (CATR) model that reduces the rotational instability that occurs in the DMM model. So, we aimed to investigate whether rotational instability affects articular cartilage degeneration using the DMM and CATR models, as confirmed using histology and immunohistochemistry. DESIGN: Twelve-week-old male mice were randomized into 3 groups: DMM group, CATR group, and INTACT group (right knee of the DMM group). After 8 and 12 weeks, we performed the tibial rotational test, safranin-O/fast green staining, and immunohistochemical staining for tumor necrosis factor (TNF)-α and metalloproteinase (MMP)-13. RESULTS: The rotational instability in the DMM group was significantly higher than that of the other groups. And articular cartilage degeneration was higher in the DMM group than in the other groups. However, meniscal degeneration was observed in both DMM and CATR groups. The TNF-α and MMP-13 positive cell rates in the articular cartilage of the CATR group were lower than those in the DMM group. CONCLUSIONS: We found that the articular cartilage degeneration was delayed by controlling the rotational instability caused by meniscal dysfunction. These findings suggest that suppression of rotational instability in the knee joint may be an effective therapeutic measure for preventing OA progression.

Treadmill Exercise after Controlled Abnormal Joint Movement Inhibits Cartilage Degeneration and Synovitis.

Cartilage degeneration is the main pathological component of knee osteoarthritis (OA), but no effective treatment for its control exists. Although exercise can inhibit OA, the abnormal joint movement with knee OA must be managed to perform exercise. Our aims were to determine how controlling abnormal joint movement and treadmill exercise can suppress cartilage degeneration, to analyze the tissues surrounding articular cartilage, and to clarify the effect of treatment. Twelve-week-old ICR mice (n = 24) underwent anterior cruciate ligament transection (ACL-T) surgery on their right knees and were divided into three groups as follows: ACL-T, animals in the walking group subjected to ACL-T; controlled abnormal joint movement (CAJM), and CAJM with exercise (CAJM + Ex) (n = 8/group). Walking-group animals were subjected to treadmill exercise 6 weeks after surgery, including walking for 18 m/min, 30 min/day, 3 days/week for 8 weeks. Safranin-O staining, hematoxylin-eosin staining, and immunohistochemical staining were performed. The OARSI (Osteoarthritis research Society international) score was lower in the CAJM group than in the ACL-T group and was even lower in the CAJM + Ex group. The CAJM group had a lower meniscal injury score than the ACL-T group, and the CAJM + Ex group demonstrated a less severe synovitis than the ACL-T and CAJM groups. The observed difference in the perichondrium tissue damage score depending on the intervention method suggests different therapeutic effects, that normalizing joint motion can solve local problems in the knee joint, and that the anti-inflammatory effect of treadmill exercise can suppress cartilage degeneration.

Impact of Controlling Abnormal Joint Movement on the Effectiveness of Subsequent Exercise Intervention in Mouse Models of Early Knee Osteoarthritis.

OBJECTIVE: Moderate mechanical stress is necessary for preserving the cartilage. The clinician empirically understands that prescribing only exercise will progress osteoarthritis (OA) for knee OA patients with abnormal joint movement. When prescribing exercise for OA, we hypothesized that degeneration of articular cartilage could be further prevented by combining interventions with the viewpoint of normalizing joint movement. DESIGN: Twelve-week-old ICR mice underwent anterior cruciate ligament transection (ACL-T) surgery in their right knee and divided into 4 groups: ACL-T, controlled abnormal joint movement (CAJM), ACL-T with exercise (ACL-T/Ex), CAJM with exercise (CAJM/Ex). Animals in the walking group were subjected to treadmill exercise 6 weeks after surgery, which included walking for 18 m/min, 30 min/d, 3 d/wk for 4 weeks. Joint instability was measured by anterior drawer test, and safranin-O staining and immunohistochemical staining were performed. RESULTS: OARSI (Osteoarthritis Research Society International) score of ACL-T/Ex group showed highest among 4 groups (P < 0.001). And CAJM/Ex group was lower than ACL-T/Ex group. Positive cell ratio of IL-1ß and MMP-13 in CAJM/Ex group was lower than ACL-T/Ex group (P < 0.05). CONCLUSIONS: We found that the state of the intra-articular environment can greatly influence the effect of exercise on cartilage degeneration, even if exercise is performed under the same conditions. In the CAJM/Ex group where joint movement was normalized, abnormal mechanical stress such as shear force and compression force accompanying ACL cutting was alleviated. These findings may highlight the need to consider an intervention to correct abnormal joint movement before prescribing physical exercise in the treatment of OA.

PIP3-Phldb2 is crucial for LTP regulating synaptic NMDA and AMPA receptor density and PSD95 turnover.

The essential involvement of phosphoinositides in synaptic plasticity is well-established, but incomplete knowledge of the downstream molecular entities prevents us from understanding their signalling cascades completely. Here, we determined that Phldb2, of which pleckstrin-homology domain is highly sensitive to PIP3, functions as a phosphoinositide-signalling mediator for synaptic plasticity. BDNF application caused Phldb2 recruitment toward postsynaptic membrane in dendritic spines, whereas PI3K inhibition resulted in its reduced accumulation. Phldb2 bound to postsynaptic scaffolding molecule PSD-95 and was crucial for localization and turnover of PSD-95 in the spine. Phldb2 also bound to GluA1 and GluA2. Phldb2 was indispensable for the interaction between NMDA receptors and CaMKII, and the synaptic density of AMPA receptors. Therefore, PIP3-responsive Phldb2 is pivotal for induction and maintenance of LTP. Memory formation was impaired in our Phldb2-/- mice.

Relationship between serum uric acid concentration, metabolic syndrome and carotid atherosclerosis.

OBJECTIVE: Carotid intima-media thickness (IMT) is a useful surrogate marker of cardiovascular disease. Associations between hyperuricemia, metabolic syndrome and carotid IMT have been reported, but few of the studies have been conducted in a Japanese population. METHODS: A total of 1,128 subjects (498 men aged, 68+/-14 years and 630 women aged 72+/-12 years) were divided into 4 groups according to serum uric acid (SUA) quartiles. We first investigated the association between SUA concentrations and metabolic syndrome; then, we assessed whether there is an independent association of SUA with carotid IMT in a population subdivided according to gender and metabolic syndrome status. RESULTS: In women, the prevalence of visceral obesity and metabolic syndrome were significantly increased with increased SUA quartiles, but not in men. After adjusting for age, smoking status, LDL-cholesterol, creatinine and history of diabetes mellitus, the odds ratios (95% CI) of sex-specific quartiles of SUA for metabolic syndrome were 1.0, 1.37 (0.79-2.37), 1.37 (0.79-2.38), and 1.80 (1.03-3.15) in men, and 1.0, 1.04 (0.56-1.94), 2.35 (1.30-4.22), and 2.20 (1.16-4.20) in women. After adjusting for various known risk factors, the prevalence of carotid atherosclerosis (IMT> or =1.0 mm) was higher in subjects in the second, third and fourth quartiles of SUA concentration with odds ratios (95% CI) of 2.41 (1.08-5.37), 3.33 (1.49-7.42), and 2.73 (1.17-6.35), respectively in men without metabolic syndrome but not in men with metabolic syndrome or in women with or without metabolic syndrome. CONCLUSION: The prevalence of metabolic syndrome was significantly increased according to SUA values only in women. In men without metabolic syndrome, SUA was found to be an independent risk factor for incidence of carotid atherosclerosis.

Association between risk factors and carotid enlargement.

OBJECTIVE: The aim of this study was to evaluate the influence of conventional cardiovascular risk factors on the degree of adaptive response of the carotid arterial wall to atherosclerotic disease. PATIENTS AND METHODS: We evaluated the diameter and intima-media thickness (IMT) of common carotid artery (CCA) by ultrasonography in 351 men aged 70.3 (range, 14-97) years and 474 women aged 75.6 (range, 19-103) years in the medical department of Seiyo Municipal Nomura Hospital. We assessed cross-sectionally the relationships between CCA diameter and IMT and cardiovascular risk factors by gender. RESULTS: In multiple linear regression analyses, after controlling for traditional cardiovascular risk factors, a significant correlation was found between CCA diameters and age (p=0.034), body mass index (BMI) (p<0.001), smoking status (p=0.039), alcohol consumption (<0.001) and uric acid (UA) (p=0.021) in men, and between CCA diameters and age (<0.001), BMI (p<0.001), systolic blood pressure (SBP) (p=0.013) and antihypertensive drug use (p=0.005) in women. Analysis of covariance showed that the two regression lines between carotid IMT and diameter in those with or without plaque were significantly different in both men (F=16.4; p<0.001) and women (F=15.0; p<0.001). After adjustment for carotid IMT and plaque, associations with carotid diameters still persisted for age (p<0.001), BMI (p<0.001), smoking status (p=0.006), alcohol consumption (p<0.001) and SBP (p=0.001) in men, and age (p=0.005), BMI (p<0.001), SBP (p=0.047) and UA (p=0.001) in women. CONCLUSION: This study shows that the CCA diameters correlated with conventional cardiovascular risk factors including alcohol consumption. These findings suggest that the CCA diameters may reflect the ability of adaptive remodeling to the atherosclerosis before plaque formation and can be an important factor during the development of atherosclerosis.

Metabolic syndrome as a predictor of ischemic stroke in elderly persons.

OBJECTIVE: To estimate the prevalence and risk of ischemic stroke associated with metabolic syndrome. METHODS AND PATIENTS: In 197 stroke patients (80 cases of atherothrombotic infarction, 97 lacunar infarction, 16 cardioembolic infarction, 4 others) and 356 age- and sex-matched control subjects aged 65 years and older in Seiyo Municipal Nomura Hospital, we investigated the association between metabolic syndrome and risk factor-dependent augmentation of ischemic stroke in subjects with several risk factors for atherosclerosis. The diagnosis of cerebral infarction in each patient was confirmed by CT findings of the brain and metabolic syndrome was defined as at least 3 of the 5 following conditions: visceral obesity, hypertension (HT), hypertriglyceridemia, low HDL-cholesterol and diabetes mellitus (DM). RESULTS: After adjustment for sex, age, and smoking, metabolic syndrome was significantly related to atherothrombotic infarction (odds ratio, 3.08; 95% confidence interval, 1.69-5.61). Of the individual components, visceral obesity, HT and DM were independent risk factors for atherothrombotic infarction. Increased risk for atherothrombotic infarction was also associated with increases in the 5 component conditions of the metabolic syndrome. CONCLUSION: The clustering of cardiovascular risk factors called metabolic syndrome increases the risk of cardiovascular morbidity, and its identification may thus be important in risk assessment and treatment of patients.

Association between uric acid and carotid atherosclerosis in elderly persons.

OBJECTIVE: Several cohort studies have shown a link between serum uric acid (SUA) and subsequent cardiovascular disease. However, such an association did not remain significant after adjusting for concomitant risk factors for atherosclerosis in some studies. Thus, the role of SUA as an independent risk factor remains controversial. We therefore investigated the association between SUA and sclerotic lesions of common carotid atherosclerosis. PATIENTS AND METHODS: We evaluated sclerotic lesions of the common carotid arterial intima-media thickness (IMT) by ultrasonography in 398 men aged 74+/-8 (range, 60-97) years and 521 women aged 75+/-8 (range, 60-104) years. To investigate the relation between SUA and various factors, all subjects were divided into three groups based on the tertile of SUA. RESULTS: Stepwise multiple linear regression analysis using IMT as an objective variable, adjusted by various risk factors as explanatory variables showed that SUA [B, 0.0099; 95% confidence interval (CI), 0.0022-0.0175] was a significant independent contributing factor along with known risk factors such as age, sex, smoking status, systolic blood pressure, diastolic blood pressure, antihypertensive drug use, HDL-cholesterol, and LDL-cholesterol. Multiple logistic regression analysis for carotid IMT as a tertile of SUA and dependent variables showed that the adjusted odds ratio was 1.25 (95% CI, 0.87-1.78) for those in the middle tertile (4.2-5.5 mg/dl), and 1.66 (95% CI, 1.16-2.39) for those in the highest tertile (5.6-14.1 mg/dl) compared to that for subjects in the lowest tertile of SUA levels (0.51-4.1 mg/dl). CONCLUSION: We suggest that SUA is a risk factor or marker for ultrasonographically determined IMT.

Association between abdominal wall fat index on ultrasonography and carotid atherosclerosis in non-obese men.

We tried to investigate whether accumulation of visceral fat, assessed by a simple but widely used ultrasonographic method, was associated with common carotid atherosclerosis in non-obese men ranging from 16 to 79 years old. The subjects were consecutive 297 male in-patients whose body mass index ranged from 18.5 kg/m(2) to 25 kg/m(2). An ultrasonographic evaluation using a 7.5 MHz linear type B-mode probe was performed by a specialist to determine the intima-media thickness (IMT) of the common carotid artery and the maximal thickness of peritoneal fat (Pmax) at the anterior surface of the liver and the minimal thickness of subcutaneous fat (Smin) of the abdomen. The Pmax/Smin ratio, which was termed the abdominal wall fat index (AFI), was then calculated. The mean age +/- standard deviation in this series was 65 +/- 13 (range, 15-79) years. Multiple regression analysis using IMT as an objective variable, adjusted by various risk factors as explanatory variables, showed that AFI [beta, 0.0538; 95% confidence interval (CI), 0.0116-0.0960] was a significant independent contributing factor along with known risk factors such as age, smoking status, systolic blood pressure, HDL-cholesterol and LDL-cholesterol. We found that AFI was useful in evaluating disorders of metabolism and atherosclerosis in non-obese men.

Metabolic syndrome amplifies the LDL-cholesterol associated increases in carotid atherosclerosis.

OBJECTIVE: Carotid intima-media thickness (IMT) is a useful surrogate marker of cardiovascular disease. In addition to low-density lipoprotein cholesterol (LDL-C), metabolic syndrome has been linked to the pathogenesis of atherosclerosis. The present study investigated whether the clustering of multiple components of metabolic syndrome has a greater impact on vascular parameters than individual components of metabolic syndrome, and assessed the association between carotid IMT and LDL-C and metabolic syndrome. METHODS: Carotid IMT was evaluated on B-mode ultrasonography in 760 patients (340 men aged 64+/-16 years and 420 women aged 69+/-13 years) in the Medical Department of Seiyo Municipal Nomura Hospital. The subjects did not demonstrate any clinical signs of cardiovascular disease. We investigated the association between carotid IMT and confounding risk factors including LDL-C and metabolic syndrome using the 2005 Japanese criteria. RESULTS: Carotid IMT increased with increasing numbers of metabolic syndrome components (p for trend<0.001). Multiple regression models, including age, sex, body mass index, smoking status, LDL-C, diabetes mellitus as well as each individual component of metabolic syndrome as continuous variables, showed that both metabolic syndrome (beta=0.100; p=0.029) and LDL-C (beta=0.210, p<0.001) were independent determinants of carotid IMT. Metabolic syndrome amplified the LDL-C associated increases in carotid atherosclerosis. CONCLUSIONS: Even after taking into account each individual component of MS, the clustering of visceral obesity with at least 2 of the 3 components, and LDL-C are independently associated with increased carotid IMT. This suggests that the components of metabolic syndrome interact to synergistically impact vascular thickness.

Stomatin-related olfactory protein, SRO, specifically expressed in the murine olfactory sensory neurons.

We identified a stomatin-related olfactory protein (SRO) that is specifically expressed in olfactory sensory neurons (OSNs). The mouse sro gene encodes a polypeptide of 287 amino acids with a calculated molecular weight of 32 kDa. SRO shares 82% sequence similarity with the murine stomatin, 78% with Caenorhabditis elegans MEC-2, and 77% with C. elegans UNC-1. Unlike other stomatin-family genes, the sro transcript was present only in OSNs of the main olfactory epithelium. No sro expression was seen in vomeronasal neurons. SRO was abundant in most apical dendrites of OSNs, including olfactory cilia. Immunoprecipitation revealed that SRO associates with adenylyl cyclase type III and caveolin-1 in the low-density membrane fraction of olfactory cilia. Furthermore, anti-SRO antibodies stimulated cAMP production in fractionated cilia membrane. SRO may play a crucial role in modulating odorant signals in the lipid rafts of olfactory cilia.