Quick and effective improvement of leucine enriched dietary supplement on malnutrition in acute stroke patients receiving enteral tube feeding

Transcranial direct-current stimulation confers neuroprotection by regulating isoleucine-dependent signalling after rat cerebral ischemia-reperfusion injury

Isoleucine is a branched chain amino acid. The role of isoleucine in cerebral ischemia-reperfusion injury remains unclear. Here, we show that the concentration of isoleucine is decreased in cerebrospinal fluid in a rat model of cerebral ischemia-reperfusion injury, the rat middle cerebral artery occlusion (MCAO). To our surprise, the level of intraneuronal isoleucine is increased in an in vitro model of cerebral ischemia injury, the oxygen-glucose deprivation (OGD). We found that the increased activity of LAT1, an L-type amino acid transporter 1, leads to the elevation of intraneuronal isoleucine after OGD insult. Reducing the level of intraneuronal isoleucine promotes cell survival after cerebral ischemia-reperfusion injury, but supplementing isoleucine aggravates the neuronal damage. To understand how isoleucine promotes ischemia-induced neuronal death, we reveal that isoleucine acts upstream to reduce the expression of CBFB (core binding factor β, a transcript factor involved in cell development and growth) and that the phosphatase PTEN acts downstream of CBFB to mediate isoleucine-induced neuronal damage after OGD insult. Interestingly, we demonstrate that direct-current stimulation reduces the level of intraneuronal isoleucine in cortical cultures subjected to OGD and that transcranial direct-current stimulation (tDCS) decreases the cerebral infarct volume of MCAO rat through reducing LAT1-depencent increase of intraneuronal isoleucine. Together, these results lead us to conclude that LAT1 over activation-dependent isoleucine-CBFB-PTEN signal transduction pathway may mediate ischemic neuronal injury and that tDCS exerts its neuroprotective effect by suppressing LAT1 over activation-dependent signalling after cerebral ischemia-reperfusion injury.

Insights into Pathogenesis, Nutritional and Drug Approach in Sarcopenia: A Systematic Review

Sarcopenia is a multifactorial condition related to the loss of muscle mass and strength due to aging, eating habits, physical inactivity, or even caused by another disease. Affected individuals have a higher risk of falls and may be associated with heart disease, respiratory diseases, cognitive impairment, and consequently an increased risk of hospitalization, in addition to causing an economic impact due to the high cost of care during the stay in hospitals. The standardization of appropriate treatment for patients with sarcopenia that could help reduce pathology-related morbidity is necessary. For these reasons, this study aimed to perform a systematic review of the role of nutrition and drugs that could ameliorate the health and quality of life of sarcopenic patients and PRISMA guidelines were followed. Lifestyle interventions have shown a profound impact on sarcopenia treatment but using supplements and different drugs can also impact skeletal muscle maintenance. Creatine, leucine, branched-chain amino acids, omega 3, and vitamin D can show benefits. Although with controversial results, medications such as Metformin, GLP-1, losartan, statin, growth hormone, and dipeptidyl peptidase 4 inhibitors have also been considered and can alter the sarcopenic's metabolic parameters, protect against cardiovascular diseases and outcomes, while protecting muscles.

The Effect of Branched Chain Amino Acid Supplementation on Stroke-Related Sarcopenia

Background

Stroke-related sarcopenia is caused by various factors, such as brain damage, systemic catabolic state, skeletal muscle imbalance, and malnutrition. In the long-term care plan after stroke, appropriate rehabilitation strategies to achieve maximum functional improvement and prevent the development of sarcopenia are important. This study has investigated the effect of branched-chain amino acid (BCAA) supplementation on sarcopenia after stroke. We also evaluated the effect of BCAA on functional improvement during the intensive rehabilitation period.

Methods

Patients with subacute stroke with stroke-related disabilities were enrolled and given dietary supplement powder containing BCAAs for 1 month. These BCAAs were supplied through the nutrition team during feeding time. Patients whose age, sex, and stroke lesions were similar to those of the study group were enrolled in the control group through medical record review. Both groups received personalized intensive inpatient rehabilitation therapy in a single-unit rehabilitation center. All patients' target calories were calculated regularly by the nutritional support team in our institution. Sarcopenia status was evaluated using grip strength and the skeletal muscle index (SMI), which was assessed by dual-energy X-ray absorptiometry (DEXA). The functional status associated with stroke was evaluated every month, including activities of daily living, balance, gait, and swallowing.

Results

A total of 54 patients were enrolled, with 27 patients in each of the two groups. The study group showed significantly greater improvement in SMI after intervention than the control group. Both groups improved functionally over time, but the improvement in the study group was significantly greater than that in the control group. Univariate analysis revealed that patients with better functional status had a greater SMI with a combination of BCAA supplementation and intensive rehabilitation therapy.

Conclusion

Our results showed a positive effect of BCAA supplementation on sarcopenia after stroke. We also found that nutritional support helps functional improvement during neurological recovery. These results suggest that comprehensive rehabilitation intervention combined with BCAA supplementation could be a helpful option during the critical period of post-stroke neurological recovery.

Correction to: Quick and effective improvement of leucine enriched dietary supplement on malnutrition in acute stroke patients receiving enteral tube feeding

An amendment to this paper has been published and can be accessed via the original article.