Leptin protects brain from ischemia/reperfusion-induced infarction by stabilizing the blood-brain barrier to block brain infiltration by the blood-borne neutrophils.

The cellular and molecular mechanisms underlying leptin-mediated brain protection against cerebral ischemia were investigated at the blood-brain barrier (BBB) and neutrophil level. Through the ischemia/reperfusion (I/R) animal model, we found that leptin expression level was significantly decreased in ischemic hemisphere. Brain injection with leptin (15 µg/kg, intracisternally) could block the I/R-increased BBB permeability, activation of matrix metallopeptidase 9 (MMP-9) and brain infiltration of blood-borne neutrophils to reduce the infarct volume of ischemic brain. The brain expression level of tight junction protein ZO-1 as well as number and motility of neutrophils in blood was all increased by the same injection, indicating BBB stability (rather than reduction in neutrophils) played a major role in the leptin-inhibited brain infiltration of neutrophils. Leptin-mediated protection of BBB was further confirmed in vitro, through a BBB cellular model under the in vitro ischemic condition (G/R: glucose-oxygen-serum deprivation followed by GOS restoration). The results showed that leptin again could block the G/R-increased neutrophil adherence to EC layer as well as BBB permeability, likely by stimulating the endothelial expression of ZO-1 and VE-Cadherin. The study has demonstrated that leptin could protect ischemic brain via multiple ways (other than neuronal protection), by inhibiting the BBB permeability, brain infiltration of the blood-borne neutrophils and neutrophil adherence to vascular ECs. The role of leptin in vascular biology of stroke could further support its therapeutic potential in other neurodegenerative diseases, associated with BBB disorder.

Impact of Frisbee game course on the upper limb motor function of students with intellectual disabilities.

Objectives: Upper limb motor dysfunction often occurs in individuals with intellectual disabilities, affecting their daily self-care abilities and employability. Therefore, enhancing their upper limb motor function could improve the quality of life. This study investigated the impact of Frisbee game course on the upper limb motor function of students with intellectual disabilities. Methods: A self-designed Frisbee game course was made available to 10 senior vocational students with moderate to severe intellectual disabilities in a special school in New Taipei City, Taiwan. The students participated 40 min each time, 4 times a week, for 6 weeks. Pre and post-test functional capacity and Frisbee throwing distance were measured. Descriptive statistics and paired-sample t-test were performed for the data analysis. Results: Frisbee game course improved the lifting capacity, significantly improved the grip strength (dominant hand), upper limb power, hand-eye coordination, and gross and fine hand motor skills of students with intellectual disabilities. Conclusion: Frisbee game course can improve upper limb muscle strength, power, coordination ability, and dexterity. Schools should implement Frisbee game courses and ensure their availability in the health and physical education of students with intellectual disabilities to enhance their upper limb motor function, employability, and vocational adaptability, thus improving their quality of life.

Molecular Mechanisms Responsible for Neuron-Derived Conditioned Medium (NCM)-Mediated Protection of Ischemic Brain.

The protective value of neuron-derived conditioned medium (NCM) in cerebral ischemia and the underlying mechanism(s) responsible for NCM-mediated brain protection against cerebral ischemia were investigated in the study. NCM was first collected from the neuronal culture growing under the in vitro ischemic condition (glucose-, oxygen- and serum-deprivation or GOSD) for 2, 4 or 6 h. Through the focal cerebral ischemia (bilateral CCAO/unilateral MCAO) animal model, we discovered that ischemia/reperfusion (I/R)-induced brain infarction was significantly reduced by NCM, given directly into the cistern magna at the end of 90 min of CCAO/MCAO. Immunoblocking and chemical blocking strategies were applied in the in vitro ischemic studies to show that NCM supplement could protect microglia, astrocytes and neurons from GOSD-induced cell death, in a growth factor (TGFß1, NT-3 and GDNF) and p-ERK dependent manner. Brain injection with TGFß1, NT3, GDNF and ERK agonist (DADS) alone or in combination, therefore also significantly decreased the infarct volume of ischemic brain. Moreover, NCM could inhibit ROS but stimulate IL-1ß release from GOSD-treated microglia and limit the infiltration of IL-ß-positive microglia into the core area of ischemic brain, revealing the anti-oxidant and anti-inflammatory activities of NCM. In overall, NCM-mediated brain protection against cerebral ischemia has been demonstrated for the first time in S.D. rats, due to its anti-apoptotic, anti-oxidant and potentially anti-glutamate activities (NCM-induced IL-1ß can inhibit the glutamate-mediated neurotoxicity) and restriction upon the infiltration of inflammatory microglia into the core area of ischemic brain. The therapeutic potentials of NCM, TGFß1, GDNF, NT-3 and DADS in the control of cerebral ischemia in human therefore have been suggested and require further investigation.

Leptin and interleukin-1beta modulate neuronal glutamate release and protect against glucose-oxygen-serum deprivation.

Molecular mechanism underlying leptin-mediated neuronal protection against glucose-oxygen-serum deprivation (GOSD) insult was investigated by focusing on the interactions among leptin, Interleukin-1beta (IL-1beta) and glutamate and their impacts on the growth of neurons under GOSD. The trypan blue dye exclusion assay, 4', 6-diamidino-2-phenylindole (DAPI) assay, cytokine antibody array assay, immunocytochemical staining assay, glutamate determination kit, immunoblocking and chemical blocking strategies were applied to serve the study goal. Results showed that in response to 6 h of GOSD, cortical neurons can secrete significant amounts of leptin and IL-1beta to protect neurons from GOSD-induced cell damage. Serine/threonine kinase Akt (Akt) and extracellular signal-related kinase (ERK) inhibitors significantly reversed leptin-mediated neuroprotection. GOSD-induced IL-1beta was further enhanced by leptin in Akt/ERK-dependent manner. Blockade of endogenous leptin with specific antibodies significantly inhibited GOSD-induced IL-1beta expression and increased glutamate release from GOSD neurons. IL-1 blockade with IL-1 receptor antagonist (IL-1ra) on the other hand, inhibited leptin-mediated neuroprotection and suppression of glutamate release from GOSD neurons. Pre-treating GOSD neurons with leptin and IL-1beta in combined significantly increased their survival but decreased their releases of glutamate. The results indicate that leptin may act through Akt and ERK signaling pathways to protect neurons from GOSD insult; the protection was in part IL-1beta dependent and through which the glutamate release from GOSD neurons was inhibited. Therapeutic values of leptin and IL-1beta were suggested in the treatment of cerebral ischemia at early stage.

Molecules involve in the self-protection of neurons against glucose-oxygen-serum deprivation (GOSD)-induced cell damage.

Molecules involved in self-protection of neurons against glucose/oxygen/serum deprivation (GOSD) were investigated. Trypan blue dye exclusion assay, Western blotting, ELISA, cytokine antibody array and chemical blocking assay were applied in the study. Results showed that early induction (at 6h of GOSD) of cyclooxygenase-2 (COX-2), leptin, transforming growth factor-beta1 (TGF-beta1), glial-cell-line-derived neurotrophic factor (GDNF) and neurotrophin-3 (NT-3) all played a compensatory role in the protection of neurons against GOSD. Decline of these molecules and peroxisome proliferators-activated receptor (PPAR)-gamma and -alpha since 12h of GOSD may lead to an irreversible neuronal death. Nitric oxide (NO) and superoxide at low concentrations were neuroprotective whereas at high concentrations were detrimental to neurons. Accumulation of NO and superoxide at late stage of GOSD should therefore be prevented. The study provided a useful platform for screening of potential anti-ischemic drugs and also explained why GOSD neuron derived conditioned medium (NCM) only exerted a time-restricted neuroprotection.

Protection of ischemic brain cells is dependent on astrocyte-derived growth factors and their receptors.

An in vitro ischemia model (oxygen, glucose, and serum deprivation) is used to investigate the possible cellular and molecular mechanisms responsible for cerebral ischemia. We have previously demonstrated that supernatants derived from ischemic microglia can protect ischemic brain cells by releasing GDNF and TGF-beta1. In the present study, we investigate whether products of ischemic astrocytes can also protect ischemic microglia, astrocytes, and neurons in a similar manner. Supernatants from ischemic astrocytes were collected after various periods of ischemia and incubated with microglia, astrocytes, or neurons individually, under in vitro ischemic conditions. The components responsible for the protective effects of astrocyte-derived supernatants were then identified by Western blot, ELISA, trypan blue dye exclusion, and immunoblocking assays. Results showed that under conditions of in vitro ischemia the number of surviving microglia, astrocytes, and neurons was significantly increased by the incorporation of the astrocyte-derived supernatants. Astrocyte supernatant-mediated protection of ischemic microglia was dependent on TGF-beta1 and NT-3, ischemic astrocytes were protected by GDNF, and ischemic neurons were protected by NT-3. In addition, protein expression of TGF-beta1 and NT-3 receptors in microglia, GDNF receptors in astrocytes, and NT-3 receptors in neurons was increased by in vitro ischemia. These results suggest that astrocyte-derived protection of ischemic brain cells is dependent not only on factors released from the ischemic astrocytes, but also on the type of receptor present on the responding cells. Therapeutic potential of TGF-beta1, GDNF, and NT-3 in the control of cerebral ischemia is further suggested.