Lack of exercise, via hindlimb suspension, impedes endogenous neurogenesis

Synergistic therapeutic effects of intracerebral transplantation of human modified bone marrow-derived stromal cells (SB623) and voluntary exercise with running wheel in a rat model of ischemic stroke

BACKGROUND

Mesenchymal stromal cell (MSC) transplantation therapy is a promising therapy for stroke patients. In parallel, rehabilitation with physical exercise could ameliorate stroke-induced neurological impairment. In this study, we aimed to clarify whether combination therapy of intracerebral transplantation of human modified bone marrow-derived MSCs, SB623 cells, and voluntary exercise with running wheel (RW) could exert synergistic therapeutic effects on a rat model of ischemic stroke.

METHODS

Wistar rats received right transient middle cerebral artery occlusion (MCAO). Voluntary exercise (Ex) groups were trained in a cage with RW from day 7 before MCAO. SB623 cells (4.0 × 105 cells/5 μl) were stereotactically injected into the right striatum at day 1 after MCAO. Behavioral tests were performed at day 1, 7, and 14 after MCAO using the modified Neurological Severity Score (mNSS) and cylinder test. Rats were euthanized at day 15 after MCAO for mRNA level evaluation of ischemic infarct area, endogenous neurogenesis, angiogenesis, and expression of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF). The rats were randomly assigned to one of the four groups: vehicle, Ex, SB623, and SB623 + Ex groups.

RESULTS

SB623 + Ex group achieved significant neurological recovery in mNSS compared to the vehicle group (p < 0.05). The cerebral infarct area of SB623 + Ex group was significantly decreased compared to those in all other groups (p < 0.05). The number of BrdU/Doublecortin (Dcx) double-positive cells in the subventricular zone (SVZ) and the dentate gyrus (DG), the laminin-positive area in the ischemic boundary zone (IBZ), and the mRNA level of BDNF and VEGF in SB623 + Ex group were significantly increased compared to those in all other groups (p < 0.05).

CONCLUSIONS

This study suggests that combination therapy of intracerebral transplantation SB623 cells and voluntary exercise with RW achieves robust neurological recovery and synergistically promotes endogenous neurogenesis and angiogenesis after cerebral ischemia, possibly through a mechanism involving the up-regulation of BDNF and VEGF.

Sequestration of Inflammation in Parkinson's Disease via Stem Cell Therapy

Parkinson’s disease is the second most common neurodegenerative disease. Insidious and progressive, this disorder is secondary to the gradual loss of dopaminergic signaling and worsening neuroinflammation, affecting patients’ motor capabilities. Gold standard treatment includes exogenous dopamine therapy in the form of levodopa–carbidopa, or surgical intervention with a deep brain stimulator to the subcortical basal ganglia. Unfortunately, these therapies may ironically exacerbate the already pro-inflammatory environment. An alternative approach may involve cell-based therapies. Cell-based therapies, whether endogenous or exogenous, often have anti-inflammatory properties. Alternative strategies, such as exercise and diet modifications, also appear to play a significant role in facilitating endogenous and exogenous stem cells to induce an anti-inflammatory response, and thus are of unique interest to neuroinflammatory conditions including Parkinson’s disease. Treating patients with current gold standard therapeutics and adding adjuvant stem cell therapy, alongside the aforementioned lifestyle modifications, may ideally sequester inflammation and thus halt neurodegeneration.

The effects of different types of Tai Chi exercises on motor function in patients with Parkinson's disease: A network meta-analysis

Background

Tai Chi can show improvement in balance and motor ability of elderly patients with PD. However, there were few reports on differences in outcomes associated with different types of Tai Chi on improving exercise capacity in elderly patients with PD. We compared the improvement of motor function in Parkinson's patients with different types of Tai Chi, for finding an optimal intervention.

Methods

The following databases were searched from the beginning of the establishment of each database to 10 January 2022: PubMed, EMBASE, The Cochrane Library, CNKI, Wanfang Database, and VIP Database. Randomized controlled trials incorporating different types of Tai Chi for PD were included. The outcome measures were UPDRSIII and BBS. NMA was conducted using Stata 15.0 based on a frequentist framework.

Results

A total of twenty trials were eligible, including 996 participants. In conventional meta-analysis, as for the UPDRSIII scale, 24-form simplified Tai Chi (SMD = −1.272, 95% CI [−2.036, −0.508], P < 0.05, I² > 50%), Tai Chi exercise program (SMD = −0.839, 95% CI [−1.828, 0.151], P > 0.05, I² > 50%), 8-form simplified Yang style Tai Chi (SMD = −0.325, 95% CI [−1.362, 0.713], P > 0.05, I² > 50%), and 8-form simplified Chen style Tai Chi (SMD = −0.28, 95% CI [−0.97, 0.42], P > 0.05, I² > 50%) were statistically more efficient than the control group. For BBS outcome, 24-form simplified Tai Chi (MD = 3.979, 95% CI [3.364, 4.595], P < 0.05, I² <50%), Tai Chi exercise program (MD = 5.00, 95% CI [2.07, 7.93], P > 0.05, I² > 50%), and 8-form simplified Chen style Tai Chi (MD = 1.25, 95% CI [0.52, 1.98], P < 0.05, I² > 50%) were better than the control group. In the network meta-analysis, the results of UPDRSIII were as follows: 24-form > TCEP > 8-form YS > 8-form CS > control. The ranking probability of BBS was as follows: TCEP > 24-form > 8-form CS > control.

Conclusion

Among the four treatments studied, 24-form Tai Chi and Tai Chi exercise programs have shown better efficacy than other types. Our study provides new insights into exercise therapy for PD and may contribute to the formulation of a clinical exercise prescription.

Systematic review registration

Identifier: CRD42021285005.

Transplantation of modified human bone marrow-derived stromal cells affords therapeutic effects on cerebral ischemia in rats

AIMS

SB623 cells are human bone marrow stromal cells transfected with Notch1 intracellular domain. In this study, we examined potential regenerative mechanisms underlying stereotaxic transplantation of SB623 cells in rats with experimental acute ischemic stroke.

METHODS

We prepared control group, empty capsule (EC) group, SB623 cell group (SB623), and encapsulated SB623 cell (eSB623) group. Transient middle cerebral artery occlusion (MCAO) was performed on day 0, and 24 h after MCAO, stroke rats received transplantation into the envisioned ischemic penumbra. Modified neurological severity score (mNSS) was evaluated, and histological evaluations were performed.

RESULTS

In the mNSS, SB623 and eSB623 groups showed significant improvement compared to the other groups. Histological analysis revealed that the infarction area in SB623 and eSB623 groups was reduced. In the eSB623 group, robust cell viability and neurogenesis were detected in the subventricular zone that increased significantly compared to all other groups.

CONCLUSION

SB623 cells with or without encapsulation showed therapeutic effects on ischemic stroke. Encapsulated SB623 cells showed enhanced neurogenesis and increased viability inside the capsules. This study reveals the mechanism of secretory function of transplanted SB623 cells, but not cell-cell interaction as primarily mediating the cells' functional benefits in ischemic stroke.

Dynamic Foot Stimulations During Short-Term Hindlimb Unloading Prevent Dysregulation of the Neurotransmission in the Hippocampus of Rats

Spaceflight and simulated microgravity both affect learning and memory, which are mostly controlled by the hippocampus. However, data about molecular alterations in the hippocampus in real or simulated microgravity conditions are limited. Adult Wistar rats were recruited in the experiments. Here we analyzed whether short-term simulated microgravity caused by 3-day hindlimb unloading (HU) will affect the glutamatergic and GABAergic systems of the hippocampus and how dynamic foot stimulation (DFS) to the plantar surface applied during HU can contribute in the regulation of hippocampus functioning. The results demonstrated a decreased expression of vesicular glutamate transporters 1 and 2 (VGLUT1/2) in the hippocampus after 3 days of HU, while glutamate decarboxylase 67 (GAD67) expression was not affected. HU also significantly induced Akt signaling and transcriptional factor CREB that are supposed to activate the neuroprotective mechanisms. On the other hand, DFS led to normalization of VGLUT1/2 expression and activity of Akt and CREB. Analysis of exocytosis proteins revealed the inhibition of SNAP-25, VAMP-2, and syntaxin 1 expression in DFS group proposing attenuation of excitatory neurotransmission. Thus, we revealed that short-term HU causes dysregulation of glutamatergic system of the hippocampus, but, at the same time, stimulates neuroprotective Akt-dependent mechanism. In addition, most importantly, we demonstrated positive effect of DFS on the hippocampus functioning that probably depends on the regulation of neurotransmitter exocytosis.

Low Skeletal Muscle Mass Is Associated With Perioperative Neurocognitive Disorder Due To Decreased Neurogenesis in Rats

BACKGROUND

Perioperative neurocognitive disorder (PND) is a postsurgical complication associated with neuroinflammation and impaired hippocampal neurogenesis, in which brain-derived neurotrophic factor (BDNF) plays a key role. Sarcopenia refers to age-related muscle loss that causes cognitive decline, muscle atrophy, and postoperative delirium. Rats with tail suspension (TS) were used to represent a low-activity model, which involves decreased hind limb function by TS. This hind limb unloading by TS can induce sarcopenia in 2 weeks. However, the relationship between PND and muscle atrophy is unclear. In this experiment, we investigated whether preoperative muscle atrophy induced by TS would affect neurogenesis and accelerate PND in rats.

METHODS

Sixty 21-week-old rats were assigned to 4 groups: the TS group, the TS with surgery (TS + S) group, the control group, and the control with surgery (control + S) group. After the abdominal manipulation under 3% sevoflurane anesthesia, cognitive function was assessed using the Morris water maze test and a fear-conditioning test. Neurogenesis was evaluated by checking BDNF secretion and immunohistochemical staining in the hippocampus.

RESULTS

The TS + S group showed impaired swimming latency (difference of means = 12.4 versus control + S; 95% confidence interval [CI], 2.0-22.7; P = .016) (difference of means = 15.2 versus TS; 95% CI, 0.4-30.1; P = .043) and path length (difference of means = 147.8 versus control + S; 95% CI, 20.7-274.9; P = .020) in the maze test and cued fear memory (difference of means = -26.0 versus TS; 95% CI, -46.4 to -5.6; P = .006) (difference of means = -22.3 versus control + S; 95% CI, -42.7 to -1.9; P = .026) in the fear-conditioning test. The postoperative levels of BDNF in the TS + S and TS groups were reduced compared with the other groups (P = .002). The number of neural precursors in the dentate gyrus was significantly lower in the TS + S group (P < .001).

CONCLUSIONS

We observed that preoperative hind limb muscle atrophy, indicated by TS, was associated with an increased occurrence of PND through the reduction in BDNF and neurogenesis after abdominal surgery in young adult rats. Therefore, we concluded that preoperative low skeletal muscle mass can induce PND due to impaired postoperative neurogenesis. Our findings might indicate that low-cost perioperative interventions, such as preoperative exercise, is beneficial to preventing PND.

Plantar Stimulations during 3-Day Hindlimb Unloading Prevent Loss of Neural Progenitors and Maintain ERK1/2 Activity in the Rat Hippocampus

Adult neurogenesis is a flexible process that depends on the environment and correlates with cognitive functions. Cognitive functions are impaired by various factors including space flight conditions and reduced physical activity. Physically active life significantly improves both cognition and the hippocampal neurogenesis. Here, we analyzed how 3-day simulated microgravity caused by hindlimb unloading (HU) or dynamic foot stimulation (DFS) during HU can affect the hippocampal neurogenesis. Adult Wistar rats were recruited in the experiments. The results demonstrated a decrease in the number of doublecortine (DCX) positive neural progenitors, but proliferation in the subgranular zone of the dentate gyrus was not changed after 3-day HU. Analysis of the effects of DFS showed restoration of neural progenitor population in the subgranular zone of the dentate gyrus. Additionally, we analyzed activity of the cRaf/ERK1/2 pathway, which is one of the major players in the regulation of neuronal differentiation. The results demonstrated inhibition of cRaf/ERK1/2 signaling in the hippocampus of HU rats. In DFS rats, no changes in the activity of cRaf/ERK1/2 were observed. Thus, we demonstrated that the process of neurogenesis fading during HU begins with inhibition of the formation of immature neurons and associated ERK1/2 signaling activity, while DFS prevents the development of mentioned alterations.

A reconciling hypothesis centred on brain-derived neurotrophic factor to explain neuropsychiatric manifestations in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune chronic inflammatory disease characterized by synovitis leading to joint destruction, pain and disability. Despite efficient antirheumatic drugs, neuropsychiatric troubles including depression and cognitive dysfunction are common in RA but the underlying mechanisms are unclear. However, converging evidence strongly suggests that deficit in brain-derived neurotrophic factor (BDNF) signalling contributes to impaired cognition and depression. Therefore, this review summarizes the current knowledge on BDNF in RA, proposes possible mechanisms linking RA and brain BDNF deficiency including neuroinflammation, cerebral endothelial dysfunction and sedentary behaviour, and discusses neuromuscular electrical stimulation as an attractive therapeutic option.

Multiple doses of cell therapy and neurorehabilitation in amyotrophic lateral sclerosis: A case report

Cell therapy, along with intensive rehabilitation has been shown to significantly improve outcomes in amyotrophic lateral sclerosis (ALS), in addition to standard therapy. We present a 40-years-old male ALS patient, suffering for the past four years, who underwent multiple doses of cell therapy at our institution. Along with riluzole treatment and lithium co-administration, his treatment involved multiple intrathecal transplants of autologous bone marrow-derived mononuclear cells, followed by multidisciplinary neurorehabilitation. The outcome measures of ALSFunctional Rating Scale Revised score remained stable, and importantly, Six Minute Walk Test distance improved from 475.2 m to 580.8 m, over a span of 16 months. Improved outcomes are indicative of slowing down of disease progression. Multiple doses of intrathecal autologous cell therapy along with rehabilitation and lithium, in addition to standard riluzole treatment is a novel approach for decelerating disease progression and qualitatively improving living conditions for ALS patients and their caregivers.

Cell encapsulation enhances antidepressant effect of the mesenchymal stem cells and counteracts depressive-like behavior of treatment-resistant depressed rats

Despite the advances in pharmacological therapies, only the half of depressed patients respond to currently available treatment. Thus, the need for further investigation and development of effective therapies, especially those designed for treatment-resistant depression, has been sorely needed. Although antidepressant effects of mesenchymal stem cells (MSCs) have been reported, the potential benefit of this cell therapy on treatment-resistant depression is unknown. Cell encapsulation may enhance the survival rate of grafted cells, but the therapeutic effects and mechanisms mediating encapsulation of MSCs remain unexplored. Here, we showed that encapsulation enhanced the antidepressant effects of MSCs by attenuating depressive-like behavior of Wistar Kyoto (WKY) rats, which are considered as a promising animal model of treatment-resistant depression. The implantation of encapsulated MSCs (eMSCs) into the lateral ventricle counteracted depressive-like behavior and enhanced the endogenous neurogenesis in the subventricular zone (SVZ) and the dentate gyrus (DG) of the hippocampus, whereas the implantation of MSCs without encapsulation or the implantation of eMSCs into the striatum did not show such ameliorative effects. eMSCs displayed robust and stable secretion of vascular endothelial growth factor (VEGF), brain-derived neurotrophic factor, fibroblast growth factor-2, and ciliary neurotrophic factor (CNTF), and the implantation of eMSCs into the lateral ventricle activated relevant pathways associated with these growth factors. Additionally, eMSCs upregulated intrinsic expression of VEGF and CNTF and their receptors. This study suggests that the implantation of eMSCs into the lateral ventricle exerted antidepressant effects likely acting via neurogenic pathways, supporting their utility for depression treatment.

Exercise-Induced Neuroprotection and Recovery of Motor Function in Animal Models of Parkinson's Disease

Parkinson's disease (PD) is manifested by progressive motor, autonomic, and cognitive disturbances. Dopamine (DA) synthesizing neurons in the substantia nigra (SN) degenerate, causing a decline in DA level in the striatum that leads to the characteristic movement disorders. A disease-modifying therapy to arrest PD progression remains unattainable with current pharmacotherapies, most of which cause severe side effects and lose their efficacy with time. For this reason, there is a need to seek new therapies supporting the pharmacological treatment of PD. Motor therapy is recommended for pharmacologically treated PD patients as it alleviates the symptoms. Molecular mechanisms behind the beneficial effects of motor therapy are unknown, nor is it known whether such therapy may be neuroprotective in PD patients. Due to obvious limitations, human studies are unlikely to answer these questions; therefore, the use of animal models of PD seems indispensable. Motor therapy in animal models of PD characterized by the loss of dopaminergic neurons has neuroprotective and neuroregenerative effects, and the completeness of neuronal protection may depend on (i) degree of neuronal loss, (ii) duration and intensity of exercise, and (iii) time elapsed between insult and commencing of training. As the physical activity is neuroprotective for dopaminergic neurons, the question arises what is the mechanism of this protective action. A current hypothesis assumes a central role of neurotrophic factors in the neuroprotection of dopaminergic neurons, even though it is still not clear whether increased DA level in the nigrostriatal axis results from neurogenesis of dopaminergic neurons in the SN, recovery of the phenotype of dopaminergic neurons, increased sprouting of the residual dopaminergic axons in the striatum, or generation of local striatal neurons from inhibitory interneurons. In the present review, we discuss studies describing the influence of physical exercise on the PD-like changes manifested in animal models of the disease and focus our interest on the current state of knowledge on the mechanism of neuroprotection induced by physical activity as a supportive therapy in PD.

Voluntary exercise delays progressive deterioration of markers of metabolism and behavior in a mouse model of Parkinson's disease

Although a good deal is known about the genetics and pathophysiology of Parkinson's disease (PD), and information is emerging about its cause, there are no pharmacological treatments shown to have a significant, sustained capacity to prevent or attenuate the ongoing neurodegenerative processes. However, there is accumulating clinical results to suggest that physical exercise is such a treatment, and studies of animal models of the dopamine (DA) deficiency associated with the motor symptoms of PD further support this hypothesis. Exercise is a non-pharmacological, economically practical, and sustainable intervention with little or no risk and with significant additional health benefits. In this study, we investigated the long-term effects of voluntary exercise on motor behavior and brain biochemistry in the transgenic MitoPark mouse PD model with progressive degeneration of the DA systems caused by DAT-driven deletion of the mitochondrial transcription factor TFAM in DA neurons. We found that voluntary exercise markedly improved behavioral function, including overall motor activity, narrow beam walking, and rotarod performance. There was also improvement of biochemical markers of nigrostriatal DA input. This was manifested by increased levels of DA measured by HPLC, and of the DA membrane transporter measured by PET. Moreover, exercise increased oxygen consumption and, by inference, ATP production via oxidative phosphorylation. Thus, exercise augmented aerobic mitochondrial oxidative metabolism vs glycolysis in the nigrostriatal system. We conclude that there are clear-cut physiological mechanisms for beneficial effects of exercise in PD.

Exercise Similarly Facilitates Men and Women's Selective Attention Task Response Times but Differentially Affects Memory Task Performance

Previous research has found that acute, moderate-intensity physical exercise enhances selective attention and memory and that men and women show differential performance on tasks measuring these skills. Although exercise and participant sex have been examined separately, it remains unknown whether acute, moderate-intensity exercise differentially affects men and women’s selective attention and memory encoding and retrieval. Participants in the present study completed two 10-min sessions of either moderate-intensity exercise comprised of jumping rope alternating with walking in place or an active control protocol comprised of watching wellness videos alternating with walking in place. Each participant completed a selective attention task and a task assessing recognition and object location memory immediately after exercising. Exercise was related to overall faster performance during the selective attention task, with no differences in men and women’s performance. Women showed better recognition memory compared to men. Exercise specifically improved object location memory among men, but only among participants who completed the memory task second. These findings suggest that acute, moderate-intensity exercise differentially affects men and women’s memory, which may be related to complex interactions between exercise, sex hormones, and the neurotrophin BDNF.

Reduction of Movement in Neurological Diseases: Effects on Neural Stem Cells Characteristics

Both astronauts and patients affected by chronic movement-limiting pathologies face impairment in muscle and/or brain performance. Increased patient survival expectations and the expected longer stays in space by astronauts may result in prolonged motor deprivation and consequent pathological effects. Severe movement limitation can influence not only the motor and metabolic systems but also the nervous system, altering neurogenesis and the interaction between motoneurons and muscle cells. Little information is yet available about the effect of prolonged muscle disuse on neural stem cells characteristics. Our in vitro study aims to fill this gap by focusing on the biological and molecular properties of neural stem cells (NSCs). Our analysis shows that NSCs derived from the SVZ of HU mice had shown a reduced proliferation capability and an altered cell cycle. Furthermore, NSCs obtained from HU animals present an incomplete differentiation/maturation. The overall results support the existence of a link between reduction of exercise and muscle disuse and metabolism in the brain and thus represent valuable new information that could clarify how circumstances such as the absence of load and the lack of movement that occurs in people with some neurological diseases, may affect the properties of NSCs and contribute to the negative manifestations of these conditions.

Lifestyle-dependent brain change: a longitudinal cohort MRI study

We investigated both independent and interconnected effects of 3 lifestyle factors on brain volume, measuring yearly changes using large-scale longitudinal magnetic resonance imaging, in middle-aged to older adults. We measured brain volumes in a cohort (n = 984, 49-79 years) from the Korean Genome and Epidemiology Study group, using baseline and follow-up estimates after 4 years. In our analysis, the accelerated brain atrophy in normal aging was observed across regions (e.g., brain tissue: -0.098 ± 0.01 mL/y, p < 0.001). An independent lifestyle-specific trend of brain atrophy across time was also evident in men, where smoking (p = 0.012) and physical activity (p = 0.014) showed the strongest association with the atrophy rate. Linear regression analysis of the interconnected effect revealed that brain atrophy is mitigated by intense physical activity in smoking males. Lifestyle factors did not show any significant effect on brain volume in women. These results provide important information regarding lifestyle factors that affect brain aging in mid-to-late adulthood. Our findings may aid in the identification of preventive measures against dementia.

Running exercise protects against myelin breakdown in the absence of neurogenesis in the hippocampus of AD mice

Neurogenesis might influence oligodendrogenesis and selectively instruct myelination in the mammalian brain. Running exercise could induce neurogenesis and protect the myelin sheaths in the dentate gyrus of AD mice. It is unclear whether running exercise can protect myelin sheaths in the absence of neurogenesis in the hippocampus of AD mice. Six-month-old male APP/PS1 transgenic mice were randomly assigned to a control group (Tg control) or a running group (Tg runner), and age-matched non-transgenic littermates were used as a wild-type group (WT control). The Tg runner mice were subjected to a running protocol for four months. The behaviors of the mice in the three groups were then assessed using the Morris water maze, and related quantitative parameters of the myelin sheaths within the CA1 field were investigated using unbiased stereological and electron microscopy techniques. Learning and spatial memory performance, CA1 volume, the volumes of the myelinated fibers, and myelin sheaths in the CA1 field were all significantly worse in the Tg control mice than in the WT control mice. Learning and spatial memory performance, CA1 volume and the volume of the myelin sheaths in the CA1 field were all significantly greater in the Tg runner mice than in the Tg control mice. These results reveal demyelinating lesions in the CA1 field of Alzheimer's disease (AD) mice and indicate that running exercise could protect against myelin sheath degeneration in the absence of neurogenesis, thereby reducing CA1 atrophy and delaying the onset and progression of AD.

Regenerative Rehabilitation: An Innovative and Multifactorial Approach to Recovery From Stroke and Brain Injury

There is currently a dearth of treatment options for stroke or traumatic brain injury that can restore cognitive and motor function. Regenerative and translational medicine have ushered forth promising new methods for mediating recovery in the central nervous system, the most salient of which are rehabilitation and stem cell therapies that, when combined, result in more pronounced recovery than one approach alone.

Limiting exercise inhibits neuronal recovery from neurological disorders

Patients who are bedridden often suffer from muscular atrophy due to reduced daily activities and can become depressed. However, patients who undergo physical therapy sometimes demonstrate positive benefits including a reduction of stressful and depressed behavior. Regenerative medicine has seen improvements in two stem cell-based therapies for central nervous system disorders. One therapy is through the transfer of exogenous stem cells. The other therapy is a more natural method and focuses on the increasing endogenous neurogenesis and restoring the neurological impairments. This study overviews how immobilization-induced disuse atrophy affects neurogenesis in rats, specifically hypothesizing that immobilization diminishes circulating trophic factor levels, like vascular endothelial growth factors or brain-derived neurotrophic factor, which in turn limits neurogenesis. This hypothesis requires the classification of the stem cell microenvironment by probing growth factors in addition to other stress-related proteins that correlate with exercise-induced neurogenesis. There is research examining the effects of increased exercise on neurogenesis while limiting exercise, which better demonstrates the pathological states of immobile stroke patients, remains relatively unexplored. To examine the effects of immobilization on neurogenesis quantitative measurements of movements, 5-bromo-2deoxyuridine labeling of proliferative cells, biochemical assays of serum, cerebrospinal fluid and neurological levels of trophic factors, growth factors, and stress-related proteins will indicate levels of neurogenesis. In further research, studies are needed to show how in vivo stimulation, or lack thereof, affects stem cell microenvironments to advance treatment procedures for strengthening neurogenesis in bedridden patients. This paper is a review article. Referred literature in this paper has been listed in the references section. The datasets supporting the conclusions of this article are available online by searching various databases, including PubMed. Some original points in this article come from the laboratory practice in our research center and the authors' experiences.

Hippocampal neurogenesis of Wistar Kyoto rats is congenitally impaired and correlated with stress resistance

The hippocampus is thought to be an important region for depression. However, the relationship between hippocampal neurogenesis and depression is still controversial. Wistar Kyoto (WKY) rats are frequently used as a depression model. WKY rats are known to show physiologically abnormal features, and these features resemble abnormalities seen in depressed patients. However, the neurogenesis of WKY rats is still unknown. In this study, we first evaluated the neurogenesis of WKY rats and compared it to that of Wistar (WIS) rats. No strain effect was observed in the number of cells positive for 5-bromo-2'-deoxyuridine (BrdU) and BrdU/Doublecortin (Dcx) in the subventricular zone (SVZ). However, the number of BrdU- and BrdU/Dcx-positive cells in the dentate gyrus (DG) of the hippocampus was significantly lower in WKY rats than in WIS rats. Next, we evaluated the correlation between neurogenesis and behavior tests. Behavior tests did not affect neurogenesis in either strain. Hippocampal neurogenesis correlated negatively with the results of a forced swim test (FST) on day 2 in each strain. That is, rats with a lower level of native neurogenesis in the DG showed a higher level of learned helplessness induced by the inescapable stress of the FST on day 1. Our findings indicate that hippocampal neurogenesis in WKY rats is congenitally impaired in contrast to that in WIS rats. Native cell proliferation and neurogenesis in the DG are correlated with stress resistance. These findings may be useful for developing new targets for depression treatment.

Negative rebound in hippocampal neurogenesis following exercise cessation

Physical exercise can improve brain function, but the effects of exercise cessation are largely unknown. This study examined the time-course profile of hippocampal neurogenesis following exercise cessation. Male C57BL/6 mice were randomly assigned to either a control (Con) or an exercise cessation (ExC) group. Mice in the ExC group were reared in a cage with a running wheel for 8 wk and subsequently placed in a standard cage to cease the exercise. Exercise resulted in a significant increase in the density of doublecortin (DCX)-positive immature neurons in the dentate gyrus (at week 0). Following exercise cessation, the density of DCX-positive neurons gradually decreased and was significantly lower than that in the Con group at 5 and 8 wk after cessation, indicating that exercise cessation leads to a negative rebound in hippocampal neurogenesis. Immunohistochemistry analysis suggests that the negative rebound in neurogenesis is caused by diminished cell survival, not by suppression of cell proliferation and neural maturation. Neither elevated expression of ΔFosB, a transcription factor involved in neurogenesis regulation, nor increased plasma corticosterone, were involved in the negative neurogenesis rebound. Importantly, exercise cessation suppressed ambulatory activity, and a significant correlation between change in activity and DCX-positive neuron density suggested that the decrease in activity is involved in neurogenesis impairment. Forced treadmill running following exercise cessation failed to prevent the negative neurogenesis rebound. This study indicates that cessation of exercise or a decrease in physical activity is associated with an increased risk for impaired hippocampal function, which might increase vulnerability to stress-induced mood disorders.

Effect of hindlimb unloading on stereological parameters of the motor cortex and hippocampus in male rats

Hindlimb unloading (HU) can cause motion and cognition dysfunction, although its cellular and molecular mechanisms are not well understood. The aim of the present study was to determine the stereological parameters of the brain areas involved in motion (motor cortex) and spatial learning - memory (hippocampus) under an HU condition. Sixteen adult male rats, kept under a 12 : 12 h light-dark cycle, were divided into two groups of freely moving (n=8) and HU (n=8) rats. The volume of motor cortex and hippocampus, the numerical cell density of neurons in layers I, II-III, V, and VI of the motor cortex, the entire motor cortex as well as the primary motor cortex, and the numerical density of the CA1, CA3, and dentate gyrus subregions of the hippocampus were estimated. No significant differences were observed in the evaluated parameters. Our results thus indicated that motor cortical and hippocampal atrophy and cell loss may not necessarily be involved in the motion and spatial learning memory impairment in the rat.

Detrimental effects of physical inactivity on neurogenesis

Patients diagnosed with neurological disorders exhibit a variety of physical and psychiatric symptoms, including muscle atrophy, general immobility, and depression. Patients who participate in physical rehabilitation at times show unexpected clinical improvement, which includes diminished depression and other stress-related behaviors. Regenerative medicine has advanced two major stem cell-based therapies for central nervous system (CNS) disorders, transplantation of exogenous stem cells, and enhancing the endogenous neurogenesis. The latter therapy utilizes a natural method of re-innervating the injured brain, which may mend neurological impairments. In this study, we examine how inactivity-induced atrophy, using the hindlimb suspension model, alters neurogenesis in rats. The hypothesis is that inactivity inhibits neurogenesis by decreasing circulation growth or trophic factors, such as vascular endothelial growth or neurotrophic factors. The restriction modifies neurogenesis and stem cell differentiation in the CNS, the stem cell microenvironment is examined by the trophic and growth factors, including stress-related proteins. Despite growing evidence revealing the benefits of “increased” exercise on neurogenesis, the opposing theory involving “physical inactivity,” which simulates pathological states, continues to be neglected. This novel theory will allow us to explore the effects on neurogenesis by an intransigent stem cell microenvironment likely generated by inactivity. 5-bromo-2-deoxyuridine labeling of proliferative cells, biochemical assays of serum, cerebrospinal fluid, and brain levels of trophic factors, growth factors, and stress-related proteins are suggested identifiers of neurogenesis, while evaluation of spontaneous movements will give insight into the psychomotor effects of inactivity. Investigations devised to show how in vivo stimulation, or lack thereof, affects the stem cell microenvironment are necessary to establish treatment methods to boost neurogenesis in bedridden patients.

Hindlimb unloading: rodent analog for microgravity

The rodent hindlimb unloading (HU) model was developed in the 1980s to make it possible to study mechanisms, responses, and treatments for the adverse consequences of spaceflight. Decades before development of the HU model, weightlessness was predicted to yield deficits in the principal tissues responsible for structure and movement on Earth, primarily muscle and bone. Indeed, results from early spaceflight and HU experiments confirmed the expected sensitivity of the musculoskeletal system to gravity loading. Results from human and animal spaceflight and HU experiments show that nearly all organ systems and tissues studied display some measurable changes, albeit sometimes minor and of uncertain relevance to astronaut health. The focus of this review is to examine key HU results for various organ systems including those related to stress; the immune, cardiovascular, and nervous systems; vision changes; and wound healing. Analysis of the validity of the HU model is important given its potential value for both hypothesis testing and countermeasure development.

Intermittent application of hypergravity by centrifugation attenuates disruption of rat gait induced by 2 weeks of simulated microgravity

The effects of intermittent hypergravity on gait alterations and hindlimb muscle atrophy in rats induced by 2 weeks of simulated microgravity were investigated. Rats were submitted to hindlimb unloading for 2 weeks (unloading period), followed by 2 weeks of reloading (recovery period). During the unloading period, animals were subjected to the following treatments: (1) free in cages (Control); (2) continuous unloading (UL); (3) released from unloading for 1 hour per day (UL+1G); (4) hypergravity for 1h per day using a centrifuge for small animals (UL+2G). The relative weights of muscles to the whole body weight and kinematics properties of hindlimbs during gait were evaluated. UL rats walked with their hindlimbs overextended, and the oscillation of their limb motion had become narrowed and forward-shifted after the unloading period, and this persisted for at least 2 weeks after the termination of unloading. However, these locomotor alterations were attenuated in rats subjected to UL+2G centrifugation despite minor systematic changes in muscle recovery. These findings indicate hypergravity application could counteract the adverse effects of simulated or actual microgravity environments.

No pain, no gain: lack of exercise obstructs neurogenesis

Bedridden patients develop atrophied muscles, their daily activities greatly reduced, and some display a depressive mood. Patients who are able to receive physical rehabilitation sometimes show surprising clinical improvements, including reduced depression and attenuation of other stress-related behaviors. Regenerative medicine has advanced two major stem cell-based therapies for CNS disorders, namely, transplantation of exogenous stem cells and amplification of endogenous neurogenesis. The latter strategy embraces a natural way of reinnervating the damaged brain and correcting the neurological impairments. In this study, we discussed how immobilization-induced disuse atrophy, using the hindlimb suspension model, affects neurogenesis in rats. The overarching hypothesis is that immobilization suppresses neurogenesis by reducing the circulating growth or trophic factors, such as vascular endothelial growth factor or brain-derived neurotrophic factor. That immobilization alters neurogenesis and stem cell differentiation in the CNS requires characterization of the stem cell microenvironment by examining the trophic and growth factors, as well as stress-related proteins that have been implicated in exercise-induced neurogenesis. Although accumulating evidence has revealed the contribution of "increased" exercise on neurogenesis, the reverse paradigm involving "lack of exercise," which mimics pathological states (e.g., stroke patients are often immobile), remains underexplored. This novel paradigm will enable us to examine the effects on neurogenesis by a nonpermissive stem cell microenvironment likely produced by lack of exercise. BrdU labeling of proliferative cells, biochemical assays of serum, cerebrospinal fluid and brain levels of trophic factors, growth factors, and stress-related proteins are proposed as indices of neurogenesis, while quantitative measurements of spontaneous movements will reveal psychomotor components of immobilization. Studies designed to reveal how in vivo stimulation, or lack thereof, alters the stem cell microenvironment are needed to begin to develop treatment strategies for enhancing neurogenesis in bedridden patients.

Swimming exercise stimulates neuro-genesis in the subventricular zone via increase in synapsin I and nerve growth factor levels

In this study, we investigated the effects of 8-weeks of swimming exercise on neurogenesis in the subventricular zone (SVZ) and on the levels of nerve growth factor (NGF) and synapsin I protein in the olfactory bulb (OB) of adult rats at a series of relevant time points (2 days, 1 week, 2 weeks, 4 weeks, 3 months, and 6 months). Ninety-six male Sprague Dawley rats were divided into 2 groups: (1) a control group (COG; n = 48, n = 8 for each time point) and (2) a swimming exercise group (SEG; total n = 48; n = 8 for each time point). SEG performed swimming exercise for 5 days per week over a period of 8 weeks. We found that the number of 5-bromo-2’-deoxyuridine-5’-monophosphate (BrdU)- and doublecortin (DCX)-positive cells was significantly higher in SEG than in COG at all time points (Day 2, Week 1, Week 2, Week 4, Month 3, and Month 6; p < 0.001). Furthermore, NGF and synapsin I protein levels were significantly higher in SEG on Day 2, and Weeks 1, 2, and 4 than in COG (p < 0.05 for each time point). Our findings suggest that regular swimming exercise in adult rats increases neurogenesis, neuronal survival, and neuronal maintenance in the SVZ; furthermore, swimming exercise increases the levels of NGF and synapsin I in the OB.

Normal physical activity obliterates the deleterious effects of a high-caloric intake

A high-caloric intake combined with a sedentary lifestyle is an important player in the development of type 2 diabetes mellitus (T2DM). The present study was undertaken to examine if the level of physical activity has impact on the metabolic effects of a high-caloric (+2,000 kcal/day) intake. Therefore, healthy individuals on a high-caloric intake were randomized to either 10,000 or 1,500 steps/day for 14 days. Step number, total energy expenditure, dietary records, neuropsychological tests, maximal oxygen uptake (V̇o2max), whole body dual-energy X-ray absorptiometry (DXA) and abdominal magnetic resonance imaging (MRI) scans, continuous glucose monitoring (CGM), and oral glucose tolerance tests (OGTT) with stable isotopes were performed before and after the intervention. Both study groups gained the same amount of body weight. However, the inactive group accumulated significantly more visceral fat compared with the active group. Following the 2-wk period, the inactive group also experienced a poorer glycemic control, increased endogenous glucose production, decreased hepatic insulin extraction, increased baseline plasma levels of total cholesterol and LDL, and a decreased cognitive function with regard to capacity of attention. In conclusion, we find evidence to support that habitual physical activity may prevent pathophysiological symptoms associated with diet-induced obesity.

Treadmill exercise ameliorates impairment of spatial learning ability through enhancing dopamine expression in hypoxic ischemia brain injury in neonatal rats

Substantia nigra and striatum are vulnerable to hypoxic ischemia brain injury. Physical exercise promotes cell survival and functional recovery after brain injury. However, the effects of treadmill exercise on nigro-striatal dopaminergic neuronal loss induced by hypoxic ischemia brain injury in neonatal stage are largely unknown. We determined the effects of treadmill exercise on survival of dopamine neurons in the substantia nigra and dopaminergic fibers in the striatum after hypoxic ischemia brain injury. On postnatal 7 day, left common carotid artery of the neonatal rats ligated for two hours and the neonatal rats were exposed to hypoxia conditions for one hour. The rat pups in the exercise groups were forced to run on a motorized treadmill for 30 min once a day for 12 weeks, starting 22 days after induction of hypoxic ischemia brain injury. Spatial learning ability in rat pups was determined by Morris water maze test after last treadmill exercise. The viability of dopamine neurons in the substantia nigra and dopamine fibers in the striatum were analyzed using immunohistochemistry. In this study, hypoxic ischemia injury caused loss of dopamine neurons in the substantia nigra and dopaminergic fibers in the striatum. Induction of hypoxic ischemia deteriorated spatial learning ability. Treadmill exercise ameliorated nigro-striatal dopaminergic neuronal loss, resulting in the improvement of spatial learning ability. The present study suggests the possibility that treadmill exercise in early adolescent period may provide a useful strategy for the recovery after neonatal hypoxic ischemia brain injury.

Protective effects of astaxanthin on capillary regression in atrophied soleus muscle of rats

AIM

The capillary regression in skeletal muscles associated with a chronic decrease in activity is related to a dysfunction of endocapillary cells induced by over-expression of oxidative stress. We hypothesized that treatment with astaxanthin, an antioxidant, would attenuate the oxidative stress induced by decreased skeletal muscle use, and that this attenuation would prevent the associated capillary regression. The purpose of the present study was to investigate the antioxidant and preventive effects of astaxanthin on capillary regression in the soleus muscle during hindlimb unloading.

METHODS

Twenty-four adult male Wistar rats were assigned randomly either to a control, control plus astaxanthin treatment, hindlimb unloaded or hindlimb unloaded plus astaxanthin treatment group for 7 days.

RESULTS

Hindlimb unloading resulted in a decrease in mean soleus absolute weight, capillary number, volume and luminal diameter. The accumulation of reactive oxygen species and the over-expression of superoxide dismutase (SOD-1), a decrease in the levels of vascular endothelial growth factor (VEGF) and its receptors, an inhibition of the angiopoietin pathway and an increase of thrombospondin-1 (TSP-1), as an anti-angiogenic factor were showed. Administration of astaxanthin attenuated the changes in SOD-1 and VEGF, up-regulated the angiogenic factors and reduced the capillary regression in the soleus of hindlimb unloaded rats. In addition, the VEGF-to-TSP1 ratio was higher in the astaxanthin treated groups than in the control and HU groups.

CONCLUSION

These results suggest that astaxanthin may be an effective treatment to counter the detrimental effects of a chronic decrease in skeletal muscle use on the capillary network and associated angiogenic pathways.

Effects of Treadmill Exercise on the Recovery of Dopaminergic Neuron Loss and Muscle Atrophy in the 6-OHDA Lesioned Parkinson's Disease Rat Model

This study was to determine the effect of exercise on the recovery of dopaminergic neuron loss and muscle atrophy in 6-OHDA-induced hemi Parkinson's disease model. Exercise was loaded twice per day for 30 minutes each time, at 5 days after 6-OHDA lesioning and continued for 16 days using a treadmill. Exercise significantly increased the number of tyrosine hydroxylase positive neuron in the lesioned substantia nigra and the expression level of tyrosine hydroxylase in the striatum compared with the control group. To examine which signaling pathways may be involved in the exercise, the phosphorylation of GSK3β and ERK were observed in the striatum. In the control group, basal level of GSK3β phosphorylation was less than in both striatum, but exercise increased it. ERK phosphorylation decreased in the lesioned striatum, but exercise recovered it. These findings suggest that exercise inactivates GSK3β by phosphorylation which may be involved in the neuroprotective effect of exercise on the 6-OHDA-induced cell death. In the exercise group, weight, and Type I and II fiber cross-sectional area of the contralateral soleus significantly recovered and expression of myosin heavy chain and Akt and ERK phosphorylation significantly increased by exercise. These results suggest that exercise recovers Parkinson's disease induced dopaminergic neuron loss and contralateral soleus muscle atrophy.

Evaluation of gene, protein and neurotrophin expression in the brain of mice exposed to space environment for 91 days

Effects of 3-month exposure to microgravity environment on the expression of genes and proteins in mouse brain were studied. Moreover, responses of neurobiological parameters, nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF), were also evaluated in the cerebellum, hippocampus, cortex, and adrenal glands. Spaceflight-related changes in gene and protein expression were observed. Biological processes of the up-regulated genes were related to the immune response, metabolic process, and/or inflammatory response. Changes of cellular components involving in microsome and vesicular fraction were also noted. Molecular function categories were related to various enzyme activities. The biological processes in the down-regulated genes were related to various metabolic and catabolic processes. Cellular components were related to cytoplasm and mitochondrion. The down-regulated molecular functions were related to catalytic and oxidoreductase activities. Up-regulation of 28 proteins was seen following spaceflight vs. those in ground control. These proteins were related to mitochondrial metabolism, synthesis and hydrolysis of ATP, calcium/calmodulin metabolism, nervous system, and transport of proteins and/or amino acids. Down-regulated proteins were related to mitochondrial metabolism. Expression of NGF in hippocampus, cortex, and adrenal gland of wild type animal tended to decrease following spaceflight. As for pleiotrophin transgenic mice, spaceflight-related reduction of NGF occured only in adrenal gland. Consistent trends between various portions of brain and adrenal gland were not observed in the responses of BDNF to spaceflight. Although exposure to real microgravity influenced the expression of a number of genes and proteins in the brain that have been shown to be involved in a wide spectrum of biological function, it is still unclear how the functional properties of brain were influenced by 3-month exposure to microgravity.

Effects of hindlimb unloading on neurogenesis in the hippocampus of newly weaned rats

Effects of hindlimb suspension (HS) and ambulation recovery on hippocampal neurogenesis of newly weaned rats were studied by using immunohistochemical techniques. The number of proliferating cell nuclear antigen-positive (PCNA(+)) cells in the subgranular zone (SGZ) markedly decreased during normal growth. However, neither HS nor subsequent recovery caused additional changes in the number of PCNA(+) cells. The number of doublecortin-positive (DCX(+)) neurons decreased gradually during normal growth. HS resulted in a further decrease in these neurons. However, DCX(+) cell numbers became identical to the levels in age-matched controls after 14 days of recovery. PCNA and DCX-double positive cells in the SGZ were also observed, and their cell numbers were not affected by HS and 14-day ambulation. Thus, HS suppressed the generation of DCX(+) neurons without affecting PCNA(+) cells in the SGZ of weaned rats. Taken together, hippocampal neurogenesis in weaned rats was not severely affected by HS while it decreased significantly as they had grown.

Resveratrol improves hippocampal atrophy in chronic fatigue mice by enhancing neurogenesis and inhibiting apoptosis of granular cells

Neuroimaging evidence showed structural and/or functional abnormalities existing in the central nervous system, especially the hippocampus, in chronic fatigue syndrome (CFS) patients. However, its pathophysiologic mechanisms are unclear in part due to the lack of an applicable animal model. We established a chronic fatigue murine model by six repeated injections of Brucella abortus antigen to mice, which was manifested as reduced daily running activity and hippocampal atrophy. Thereafter, resveratrol, a polyphenolic activator of sirtuin 1, was used for treatment in this model. Daily running activity was increased by more than 20%, and the hippocampus was enlarged after 4-week resveratrol therapy. Furthermore, resveratrol inhibited neuronal apoptosis and expression of hippocampal acetylated p53 in the fatigue mice. Resveratrol also improved neurogenesis and expression of brain-derived neurotrophic factor mRNA in the hippocampus. We concluded that repeated injection of B. abortus antigen could induce hypoactivity and hippocampal atrophy in mice. Resveratrol may be effective for improving fatigue symptoms and enlarging the atrophic hippocampus by repressing apoptosis and promoting neurogenesis.

Physical exercise as a preventive or disease-modifying treatment of dementia and brain aging

A rapidly growing literature strongly suggests that exercise, specifically aerobic exercise, may attenuate cognitive impairment and reduce dementia risk. We used PubMed (keywords exercise and cognition) and manuscript bibliographies to examine the published evidence of a cognitive neuroprotective effect of exercise. Meta-analyses of prospective studies documented a significantly reduced risk of dementia associated with midlife exercise; similarly, midlife exercise significantly reduced later risks of mild cognitive impairment in several studies. Among patients with dementia or mild cognitive impairment, randomized controlled trials (RCTs) documented better cognitive scores after 6 to 12 months of exercise compared with sedentary controls. Meta-analyses of RCTs of aerobic exercise in healthy adults were also associated with significantly improved cognitive scores. One year of aerobic exercise in a large RCT of seniors was associated with significantly larger hippocampal volumes and better spatial memory; other RCTs in seniors documented attenuation of age-related gray matter volume loss with aerobic exercise. Cross-sectional studies similarly reported significantly larger hippocampal or gray matter volumes among physically fit seniors compared with unfit seniors. Brain cognitive networks studied with functional magnetic resonance imaging display improved connectivity after 6 to 12 months of exercise. Animal studies indicate that exercise facilitates neuroplasticity via a variety of biomechanisms, with improved learning outcomes. Induction of brain neurotrophic factors by exercise has been confirmed in multiple animal studies, with indirect evidence for this process in humans. Besides a brain neuroprotective effect, physical exercise may also attenuate cognitive decline via mitigation of cerebrovascular risk, including the contribution of small vessel disease to dementia. Exercise should not be overlooked as an important therapeutic strategy.

Induction of striatal neurogenesis enhances functional recovery in an adult animal model of neonatal hypoxic-ischemic brain injury

While intraventricular administration of epidermal growth factor (EGF) expands the proliferation of neural stem/progenitor cells in the subventricular zone (SVZ), overexpression of brain-derived neurotrophic factor (BDNF) is particularly effective in enhancing striatal neurogenesis. We assessed the induction of striatal neurogenesis and consequent functional recovery after chronic infusion of BDNF and EGF in an adult animal model of neonatal hypoxic-ischemic (HI) brain injury. Permanent brain damage was induced in CD-1 (ICR) mice (P7) by applying the ligation of unilateral carotid artery and hypoxic condition. At 6 weeks of age, the mice were randomly assigned to groups receiving a continuous 2-week infusion of one of the following treatments into the ventricle: BDNF, EGF, BDNF/EGF, or phosphate buffered saline (PBS). Two weeks after treatment, immunohistochemical analysis revealed an increase in the number of BrdU(+) cells in the SVZ and striata of BDNF/EGF-treated mice. The number of new neurons co-stained with BrdU and betaIII-tubulin was also significantly increased in the neostriata of BDNF/EGF-treated mice, compared with PBS group. In addition, the newly generated cells were expressed as migrating neuroblasts labeled with PSA-NCAM or doublecortin in the SVZ and the ventricular side of neostriata. The new striatal neurons were also differentiated as mature neurons co-labeled with BrdU(+)/NeuN(+). When evaluated post-surgical 8 weeks, BDNF/EGF-treated mice exhibited significantly longer rotarod latencies at constant speed (48 rpm) and under accelerating condition (4-80 rpm), relative to PBS and untreated controls. In the forelimb-use asymmetry test, BDNF/EGF-treated mice showed significant improvement in the use of the contralateral forelimb. In contrast, this BDNF/EGF-associated functional recovery was abolished in mice receiving a co-infusion of 2% cytosine-b-d-arabinofuranoside (Ara-C), a mitotic inhibitor. Induction of striatal neurogenesis by the intraventricular administration of BDNF and EGF promoted functional recovery in an adult animal model of neonatal HI brain injury. The effect of Ara-C to completely block functional recovery indicates that the effect may be the result of newly generated neurons. Therefore, this treatment may offer a promising strategy for the restoration of motor function for adults with cerebral palsy (CP).