Bone Marrow Stromal Cells With Exercise and Thyroid Hormone Effect on Post-Stroke Injuries in Middle-aged Mice

What is the impact of acute endocrine and metabolic alterations on long-term ischemic stroke prognosis: a prospective study

BACKGROUND

Post-stroke stress can trigger instant survival but its influence on long-term ischemic stroke outcomes remains controversial. Thus, we sought to explore the associations of acute post-stroke stress evidenced by endocrine and metabolic changes, with long-term ischemic stroke outcomes.

METHODS

Admissions for acute ischemic stroke within seven days of onset were prospectively recruited to determine acute endocrine and metabolic variations measured by thyroid parameters and the stress hyperglycemia ratio (SHR). Long-term ischemic stroke prognoses were followed up for one year, with the primary outcome being a modified Rankin Scale score of 3 to 6.

RESULTS

A total of 887 patients were enrolled, of which 535 reached the final one-year followed up at a poor prognosis rate of 29.3%. Patients with poor outcomes were observed to have lower levels of free triiodothyronine (fT3) and higher levels of SHR on admission. Medium values (fT3, 4.4 mmol/L; SHR, 8 nmol/L) were used to divide patients into four gradient stress degrees. Larger acute endocrine and metabolic variations (fT3 < 4.4 mmol/L and SHR ≥ 8 nmol/L) were independently associated with a poor one-year prognosis (adjusted OR = 4.231, P = 0.001).

CONCLUSIONS

High degrees of acute post-stroke stress may aggravate long-term ischemic stroke prognosis and timely stress-reduced interventions may help promote post-stroke living quality is equally important as survival.

Effects of the combination of bone marrow stromal cells and exercise on corticosterone, BDNF, IGF-1, and anxiety-like behaviour in a rat model of post-traumatic stress disorder: Comparable effects of exercise

AIM

Post-traumatic stress disorder (PTSD) requires more effective treatment options with fewer side effects. Stem cell therapy, as a novel approach, has been investigated in the treatment of various diseases, including brain disorders. This study investigated the effects of bone marrow stromal cells (BMSCs) and the combination of BMSCs with exercise on corticosterone, BDNF and IGF-1, and anxiety-like behaviours in a male rat model of PTSD.

METHODS

Male adult Wistar rats were subjected to PTSD induced by the single prolonged stress (SPS) model. 7 days after SPS, BMSCs were injected intravenously. The exercise started on day 11 and continued for 4 weeks. On day 40th, anxiety behaviour, corticosterone, BDNF, and IGF-1 were tested. p < 0.05 was considered as a significant level.

RESULTS

The study showed that a combination of BMSCs and exercise significantly reduced anxiety-related behaviours, and alterations in BDNF, IGF-1, and corticosterone levels. Also, BMSCs alone significantly reduced some of the PTSD-induced impairments. However, exercise alone showed greater efficiency in comparison with BMSCs alone.

CONCLUSION

According to the results, although combination therapy effectively improved PTSD-related complications, exercise had relatively comparable effects on PTSD. Exercise has the potential to enhance the efficacy of BMSC therapy. Further research is required to determine whether BMSC therapy is sufficiently efficacious and safe in clinical settings.

Thyroid hormones and stroke, the gap between clinical and experimental studies

Despite plenty of human studies on changes in thyroid hormones after stroke and some animal studies that assessed the effects of thyroid hormone administration on stroke, conclusive evidence for clinical application is lacking. This review aimed to determine the consistency of the results between clinical and preclinical studies. This article reviewed the PubMed, Embase, web of Knowledge, and Google Scholar databases up to June 2023 using the MeSH terms "stroke, cerebral ischemia, cerebral infarction, brain ischemia, brain infarction, triiodothyronine (T3), tetraiodothyronine (T4), thyroxine (T4), and thyroid hormone". The results of clinical and preclinical studies related to T3 substantially confirm each other. That is, in most human studies lower T3 was associated with poor outcomes, and in experimental studies, T3 administration also had therapeutic effects. However, the results of experimental studies related to T4 could not support those of clinical studies. There seem to be some conflicts between experimental and human studies, especially regarding changes and effects of T4 after stroke. The gap between experimental and clinical studies may lead to non-applicable results, wasting time and money, and unnecessary killing of animals.

Association between GFAP-positive astrocytes with clinically important parameters including neurological deficits and/or infarct volume in stroke-induced animals

The effect of GFAP-positive astrocytes, as positive or negative factors on stroke complications such as infarct volume and neurological deficits is currently under debate. This review was aimed to evaluate and compare the frequency of studies that showed a positive or negative relationship between astrocyte activation with the improvement of neurological deficits and/or the decrease of infarct volume. In addition, we reviewed two possible causes of differences in results including timepoint of stroke and stroke severity. Time of GFAP assessment was considered as time point and type of stroke induction and duration of stroke as stroke severity. According to our review in the most relevant English-language studies in the PubMed, Web of Science, and Google Scholar databases from 2005 to 2020, the majority of studies (77 vs. 28) showed a negative coincidence or correlation between GFAP-positive cells with neurological improvement as well as between GFAP-positive cells with infarct volume reduction. In most reviewed studies, GFAP expression was reported as a marker related to or coinciding with worse neurological function, or greater infarct volume. However, there were also studies that showed helpful effects of GFAP-positive cells on neurological function or stroke lesion. Although there are some elucidations that the difference in these findings is due to the time point of stroke and stroke severity, our review did not confirm these interpretations.

Thyroid Hormone and Neural Stem Cells: Repair Potential Following Brain and Spinal Cord Injury

Neurodegenerative diseases are characterized by chronic neuronal and/or glial cell loss, while traumatic injury is often accompanied by the acute loss of both. Multipotent neural stem cells (NSCs) in the adult mammalian brain spontaneously proliferate, forming neuronal and glial progenitors that migrate toward lesion sites upon injury. However, they fail to replace neurons and glial cells due to molecular inhibition and the lack of pro-regenerative cues. A major challenge in regenerative biology therefore is to unveil signaling pathways that could override molecular brakes and boost endogenous repair. In physiological conditions, thyroid hormone (TH) acts on NSC commitment in the subventricular zone, and the subgranular zone, the two largest NSC niches in mammals, including humans. Here, we discuss whether TH could have beneficial actions in various pathological contexts too, by evaluating recent data obtained in mammalian models of multiple sclerosis (MS; loss of oligodendroglial cells), Alzheimer’s disease (loss of neuronal cells), stroke and spinal cord injury (neuroglial cell loss). So far, TH has shown promising effects as a stimulator of remyelination in MS models, while its role in NSC-mediated repair in other diseases remains elusive. Disentangling the spatiotemporal aspects of the injury-driven repair response as well as the molecular and cellular mechanisms by which TH acts, could unveil new ways to further exploit its pro-regenerative potential, while TH (ant)agonists with cell type-specific action could provide safer and more target-directed approaches that translate easier to clinical settings.