Cistanche tubulosa (Schenk) Wight Extract Enhances Hindlimb Performance and Attenuates Myosin Heavy Chain IId/IIx Expression in Cast-Immobilized Mice

Skeletal muscle atrophy-induced hemopexin accelerates onset of cognitive impairment in Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is an unmet medical need worldwide, and physical inactivity is a risk factor for AD. Performing physical exercise is difficult at old age, and thus, decline in physical movement may be a cause of age-associated lowering of the brain function. This study aimed to elucidate the molecular mechanism and onset of the skeletal muscle atrophy-induced acceleration of AD.

METHODS

Pre-symptomatic young 5XFAD or non-transgenic wildtype mice were used. The bilateral hindlimbs were immobilized by placing them in casts for 14 days. Cognitive function was evaluated using the object recognition and spatial memory tests. Further, the hindlimb muscles were isolated for organ culture. Conditioned media (CM) of each muscle was separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Protein expressions in the CM were analysed by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry analysis. The expression levels of candidate proteins were quantified using ELISA. After continuous intracerebroventricular (i.c.v.) infusion of recombinant hemopexin, cognitive function was evaluated. Gene microarray analysis of the hippocampus was performed to investigate the molecules involved in the accelerated memory deficit. Real-time reverse transcription polymerase chain reaction and histological analysis confirmed the expression.

RESULTS

Casting for 2 weeks reduced skeletal muscle weight. Object recognition memory in the cast-attached 5XFAD mice (n = 7, training vs. test, P = 0.3390) was impaired than that in age-matched wildtype (n = 7, training vs. test, P = 0.0523) and non-cast 5XFAD mice (n = 7, training vs. test, P = 0.0473). On 2D-PAGE, 88 spots were differentially expressed in muscle CM. The most increased spot in the cast-attached 5XFAD CM was hemopexin. Hemopexin levels in the skeletal muscle (n = 3, P = 0.0064), plasma (n = 3, P = 0.0386), and hippocampus (n = 3, P = 0.0164) were increased in cast-attached 5XFAD mice than those in non-cast 5XFAD mice. Continuous i.c.v. infusion of hemopexin for 2 weeks induced memory deficits in young 5XFAD mice (n = 4, training vs. test, P = 0.6764). Lipocalin-2 (Lcn2) messenger RNA (mRNA), neuroinflammation-associated factor, was increased in the hippocampus in hemopexin-infused 5XFAD mice than in control mice. LCN2 protein in the hippocampus was localized in the neurons, but not glial cells. Lcn2 mRNA levels in the hippocampus were also increased by cast-immobilization of the hindlimbs (n = 6, P = 0.0043).

CONCLUSIONS

These findings provide new evidence indicating that skeletal muscle atrophy has an unbeneficial impact on the occurrence of memory impairment in young 5XFAD mice, which is mediated by the muscle secreted hemopexin.

Effects of Cistanche tubulosa Wight Extract on Locomotive Syndrome: A Placebo-Controlled, Randomized, Double-Blind Study

In an aging society, preventing dysfunction and restoring function of the locomotive organs are necessary for long-term quality of life. Few interventional studies have investigated supplementation for locomotive syndrome. Additionally, very few interventional clinical studies on locomotive syndrome have been performed as placebo-controlled, randomized, double-blind studies. We previously found that the administration of 30% ethanolic extract of Cistanche tubulosa improved walking ability in a cast-immobilized skeletal muscle atrophy mouse model. Therefore, we conducted a clinical study to evaluate the effects of C. tubulosa (CT) extract on the locomotive syndrome. Twenty-six subjects with pre-symptomatic or mild locomotive syndrome completed all tests and were analyzed in the study. Analyses of muscle mass and physical activity were performed based on the full analysis set. Intake of CT extract for 12 weeks increased step width (two-step test) and gait speed (5 m walking test) in patients over 60 years old compared with those in a placebo control (p = 0.046). In contrast, the skeletal muscle mass of the body trunk and limbs was unchanged following administration of CT extract. Adverse effects were evaluated by blood tests; no obvious adverse events were observed following the intake of CT extract. In conclusion, this placebo-controlled, randomized, double-blind study demonstrated that treatment with CT extract significantly prevented a decline in walking ability without any notable adverse effects in patients with locomotive syndrome.