Age-related nitration/dysfunction of myogenic stem cell activator HGF.

Mechanical perturbation triggers activation of resident myogenic stem cells to enter the cell cycle through a cascade of events including hepatocyte growth factor (HGF) release from its extracellular tethering and the subsequent presentation to signaling-receptor c-met. Here, we show that with aging, extracellular HGF undergoes tyrosine-residue (Y) nitration and loses c-met binding, thereby disturbing muscle homeostasis. Biochemical studies demonstrated that nitration/dysfunction is specific to HGF among other major growth factors and is characterized by its locations at Y198 and Y250 in c-met-binding domains. Direct-immunofluorescence microscopy of lower hind limb muscles from three age groups of rat, provided direct in vivo evidence for age-related increases in nitration of ECM-bound HGF, preferentially stained for anti-nitrated Y198 and Y250-HGF mAbs (raised in-house) in fast IIa and IIx myofibers. Overall, findings highlight inhibitory impacts of HGF nitration on myogenic stem cell dynamics, pioneering a cogent discussion for better understanding age-related muscle atrophy and impaired regeneration with fibrosis (including sarcopenia and frailty).

Prevalence and Characteristics of Frailty at 6 months FollOwing Total Hip and Knee Arthroplasty in Patients With End-Stage OA.

Introduction: Lower-limb osteoarthritis (OA) in the elderly can be a risk factor for frailty, which is the preliminary of disability, but it may be reversible with appropriate interventions. We aimed to use the Kihon Check List (KCL) to assess multiple domains of frailty and to identify the characteristics of frailty in patients with hip or knee OA following total joint arthroplasty. Materials and Methods: This study included 136 ≥ 65-year-old patients (mean age: 73.0 years) who underwent total arthroplasty with end-stage hip and knee OA. We assessed frailty status, instrumental activities of daily living (IADL), and health-related quality of life (HRQoL) according to the KCL, functional ambulatory index (FAI) and EuroQol-5 Dimension (EQ5D), respectively, as well as the extent of pain preoperatively and at postoperative 6 months. Results: Using KCL, seventy-eight (57.4%) patients were frail preoperatively, but the prevalence significantly decreased to 52 patients (38.2%) at postoperative 6 months. Total arthroplasty intervention provided significant improvements in the total KCL scores, including the physical domain (P < .01), pain (P < .01), FAI scores (P < .01), and EQ5D (P < .01), but not the social domain. Multivariate logistic regression analysis identified age at surgery (OR: .93, 95% CI: .86-.99) and preoperative FAI score (OR: 1.10, 95% CI: 1.03-1.19) as independent predictors of postoperative frailty. Conclusions: Total arthroplasty procedures on patients with hip and knee OA reduced their KCL score, but social aspects were less improved than physical aspects in the shortterm. Older age and preoperative lower IADL score can be useful for accurately estimating less improvement of frailty in the early postoperative phase. Our results suggest that long term follow-up of OA is needed to provide comprehensive interventions, including in social aspects, especially for patients with lower activity.

Factors affecting short-term functional gain following total knee arthroplasty in patients aged from 75 years at a postacute rehabilitation setting.

The intensive rehabilitation of older patients after total knee arthroplasty (TKA) is vital for short-term improvement in mobility and daily living activities. We aimed to investigate the effectiveness of multidisciplinary rehabilitation and assess the early postoperative predictors that are associated with functional gain in TKA patients aged from 75 years in a postacute care setting. This study included 190 patients following primary TKA who were admitted at the postacute rehabilitation hospital. The main outcome measures were the motor component of functional independence measure (M-FIM), M-FIM effectiveness, numerical rating scale, knee extension strength and range of motion, 10-m walk test, Berg balance scale (BBS), and mini-mental state examination (MMSE). The functional gain between patient age groups of ≥75 ( n = 105) and <75 ( n = 85) years were compared. Although patients aged ≥75 years showed lower improvement in BBS score compared with <75 years, the M-FIM gains and other physical functions were similar in both age groups. In multivariate analysis, the results for M-FIM at admission (ß: -0.703; P = 0.001), BBS (ß: 0.342; P = 0.032) and MMSE (ß: 0.446; P = 0.021) were independently associated with functional gain in the patients following TKA aged ≥75 years. Multidisciplinary inpatient rehabilitation was beneficial for basic functional gain except for improvement in balance ability in patients after TKA aged ≥75 years. Functional level, balance ability and cognitive status in the early postoperative period can be useful predictors for short-term functional gain in the postacute care phase.

Factors Affecting the Length of Convalescent Hospital Stay Following Total Hip and Knee Arthroplasty.

OBJECTIVES: : An important role of convalescent rehabilitation wards is the short-term improvement of mobility and activities of daily living (ADL). We aimed to identify predictors associated with the length of stay (LOS) in a convalescent hospital after total hip and knee arthroplasty. METHODS: : This study included 308 patients hospitalized in a convalescent ward following total hip or total knee arthroplasty. The following factors were examined: age, sex, orthopedic comorbidities, motor component of the functional independence measure (M-FIM), M-FIM gain, pain, 10-m walk test, timed up and go (TUG) test, functional ambulation category (FAC), cognitive function, and nutritional status. LOS was categorized as shorter (≤40 days) or longer (>40 days), based on the national average LOS in a convalescent ward, and was statistically analyzed with predictor variables. RESULTS: : In our hospital, the average LOS was 36.9 ± 21.4 days, and the average M-FIM at admission to the convalescent ward and the M-FIM gain were 71.1 ± 7.0 and 16.3 ± 6.9, respectively. In univariate analysis, there was a significant correlation between LOS and M-FIM at admission and M-FIM gain, pain, TUG time, and FAC. Logistic multivariate analysis identified M-FIM at admission (odds ratio [OR] 0.93, 95% confidence interval [CI] 0.88-0.98) and TUG time (OR 1.10, 95% CI 1.03-1.18) as independent predictors of LOS. CONCLUSIONS: : The M-FIM and TUG test can be used to accurately estimate LOS and to plan rehabilitation treatment in a convalescent rehabilitation ward after lower-limb arthroplasty. Furthermore, preoperative or early postoperative intervention may lead to better quality motor activity and shorter LOS during the convalescent period.