Cardiovascular and Neuronal Consequences of Thyroid Hormones Alterations in the Ischemic Stroke

Effects of repetitive transcranial magnetic stimulation on cognitive function and hormone levels in early stroke patients with low thyroid hormone levels

Background

This study aimed to observe the effects of repetitive transcranial magnetic stimulation (rTMS) on cognitive function and thyroid hormone levels in early older stroke patients with low thyroid hormone levels, and to investigate the correlation between the changes in thyroid hormone levels and the improvements in cognitive function after stroke.

Methods

Forty older stroke patients who met the inclusion criteria were recruited and randomized into a magnetic-stimulation group (rTMS group) and a sham-stimulation group (Sham group). The rTMS group received low-frequency true stimulation and the Sham group received low-frequency sham stimulation. Patients' cognitive scores, activity of daily living(ADL) scores, and their levels of triiodothyronine (T3), free triiodothyronine (FT3), thyroxin (T4), free thyroxine (FT4), and thyroid stimulating hormone (TSH) were assessed before the intervention, after the 4-week intervention, and after an additional 4 weeks of follow-up; Repeated measurement analysis of variance was used to compare the changes of each index in the two groups at different times and the correlations between patiens' cognitive function scores and their changing hormone levels were subsequently investigated.

Results

Thirty-one patients were included in this study: 16 patients in rTMS group and 15 patients in the Sham group. Repeated-measures ANOVA showed that patients' T3,FT3 and TSH levels tended to increase at 4-week intervention and at the follow up (p < 0.05), and that the rTMS group had a better effect on improving T3 than the Sham group (Fgroup = 5.319, p = 0.028); The cognitive scale at different time points in both groups showed an upward trend (p < 0.05), and the MoCA, DSF, DSB scores in the rTMS group were statistically higher than those in the Sham group at the end of the 4-week intervention and at the follow-up (p < 0.05); The changes in the levels of T3 before and after 4-week intervention were positively correlated with the changes in the MoCA scores (r = 0.638, p < 0.05). And the difference in T3 level change was positively correlated with the difference in delayed recall, attention and naming score change (r = 0.562, p < 0.05; r = 0.562, p < 0.05; r = 0.531, p < 0.05); and the difference in FT3 level change was positively correlated with the visuospatial and executive function (r = 0.514, p < 0.05).

Conclusion

Repetitive transcranial magnetic stimulation improved cognitive function and elevated T3 levels in older patients with post-stroke cognitive dysfunction who had low thyroid hormone levels. Within the normal range, increases in T3 levels are positively correlated with changes in cognitive function.

Analysis of the finasteride treatment and its withdrawal in the rat hypothalamus and hippocampus at whole-transcriptome level

PURPOSE

As reported in patients treated for androgenetic alopecia with finasteride (i.e., a blocker of the enzyme 5 alpha-reductase) and in an animal model, side effects affecting sexual, psychiatric, neurological, and physical domains, may occur during the treatment and persist with drug suspension. The etiopathogenesis of these side effects has been poorly explored. Therefore, we performed a genome-wide analysis of finasteride effects in the brain of adult male rat.

METHODS

Animals were treated (i.e., for 20 days) with finasteride (1mg/rat/day). 24 h after the last treatment and 1 month after drug suspension, RNA sequencing analysis was performed in hypothalamus and hippocampus. Data were analyzed by differential expression analysis and Gene-Set Enrichment Analyses (GSEA).

RESULTS

Data obtained after finasteride treatment showed that 186 genes (i.e., 171 up- and 15 downregulated) and 19 (i.e., 17 up- and 2 downregulated) were differentially expressed in the hypothalamus and hippocampus, respectively. Differential expression analysis at the drug withdrawal failed to identify dysregulated genes. Several gene-sets were enriched in these brain areas at both time points.

CONCLUSION

Some of the genes reported to be differentially expressed (i.e., TTR, DIO2, CLDN1, CLDN2, SLC4A5, KCNE2, CROT, HCRT, MARCKSL1, VGF, IRF2BPL) and GSEA, suggest a potential link with specific side effects previously observed in patients and in the animal model, such as depression, anxiety, disturbance in memory and attention, and sleep disturbance. These data may provide an important background for future experiments aimed at confirming the pathological role of these genes.

Low triiodothyronine is associated with high risk of malnutrition and poor functional status in subacute stroke patients

BACKGROUND AND AIMS

Stroke patients may exhibit low thyroid hormone (TH) levels and disease-related malnutrition, both potentially affecting clinical status; their relationships remain unexplored. This study aimed to evaluate TH concentrations in subacute stroke patients and investigate the relationships between TH levels, nutritional risk, and functional status.

METHODS AND RESULTS

Early subacute stroke patients admitted to a rehabilitation unit were assessed using various nutritional screening tools (Geriatric Nutritional Risk Index-GNRI, Prognostic Nutritional Index-PNI, and Controlling Nutritional Status-CONUT score) and with the Global Leadership Initiative on Malnutrition (GLIM) criteria. Thyroid-Stimulating Hormone (TSH), free Tetraiodothyronine-Thyroxine (fT4) and free Triiodothyronine (fT3) levels were determined. Functional and cognitive status was evaluated using different scales. Associations between altered THs and nutritional status were examined through univariate/multivariate analyses and ROC analyses. Among 264 patients (age 72.0 ± 10.5 yrs), significant correlations emerged between fT3 and nutritional risk and functional tests (mostly p < 0.001). The prevalence of high nutritional risk determined by GNRI, PNI and CONUT increased from higher to lower fT3 tertiles. Lower fT3 levels were observed in patients at high nutritional risk and with GLIM-based malnutrition. fT3 exhibited reasonable predictive power for high nutritional risk (particularly PNI: AUC 0.769, 95%CI 0.702-0.836, p < 0.001). Multivariate logistic regression identified nutritional risk (p < 0.001) and time from stroke onset as predictors of low fT3 values.

CONCLUSION

Altered fT3 levels in early subacute stroke patients correlate with high nutritional risk and poor functional status. Low fT3 values upon admission for stroke rehabilitation may serve as a further parameter to be considered in patients at high nutritional risk.

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.

The key roles of thyroid hormone in mitochondrial regulation, at interface of human health and disease

Mitochondria are highly plastic and dynamic organelles long known as the powerhouse of cellular bioenergetics, but also endowed with a critical role in stress responses and homeostasis maintenance, supporting and integrating activities across multifaced cellular processes. As a such, mitochondria dysfunctions are leading causes of a wide range of diseases and pathologies. Thyroid hormones (THs) are endocrine regulators of cellular metabolism, regulating intracellular nutrients fueling of sugars, amino acids and fatty acids. For instance, THs regulate the balance between the anabolism and catabolism of all the macro-molecules, influencing energy homeostasis during different nutritional conditions. Noteworthy, not only most of the TH-dependent metabolic modulations act via the mitochondria, but also THs have been proved to regulate the mitochondrial biosynthesis, dynamics and function. The significance of such an interplay is different in the context of specific tissues and strongly impacts on cellular homeostasis. Thus, a comprehensive understanding of THs-dependent mitochondrial functions and dynamics is required to develop more precise strategies for targeting mitochondrial function. Herein, we describe the mechanisms of TH-dependent metabolic regulation with a focus on mitochondrial action, in different tissue contexts, thus providing new insights for targeted modulation of mitochondrial dynamics.

Effects of thyroid hormones in skeletal muscle protein turnover

Thyroid hormones (THs) are critical regulators of muscle metabolism in both healthy and unhealthy conditions. Acting concurrently as powerful anabolic and catabolic factors, THs are endowed with a vital role in muscle mass maintenance. As a result, thyroid dysfunctions are the leading cause of a wide range of muscle pathologies, globally identified as myopathies. Whether muscle wasting is a common feature in patients with hyperthyroidism and is mainly caused by THs-dependent stimulation of muscle proteolysis, also muscle growth is often associated with hyperthyroid conditions, linked to THs-dependent stimulation of muscle protein synthesis. Noteworthy, also hypothyroid status negatively impacts on muscle physiology, causing muscle weakness and fatigue. Most of these symptoms are due to altered balance between muscle protein synthesis and breakdown. Thus, a comprehensive understanding of THs-dependent skeletal muscle protein turnover might facilitate the management of physical discomfort or weakness in conditions of thyroid disease. Herein, we describe the molecular mechanisms underlying the THs-dependent alteration of skeletal muscle structure and function associated with muscle atrophy and hypertrophy, thus providing new insights for targeted modulation of skeletal muscle dynamics.

Therapeutic efficacy and pharmacological mechanism of Yindan Xinnaotong soft capsule on acute ischemic stroke: a meta-analysis and network pharmacology analysis

Yindan Xinnaotong soft capsule (YDXNT), a traditional Chinese medicine preparation, has shown a promising effect in the treatment of acute ischemic stroke (AIS). The goal of this study was to investigate the therapeutic effects and pharmacological mechanisms of YDXNT on AIS. Randomized controlled trials were searched and screened. Review Manager 5.4 was used for a meta-analysis. Active ingredients and targets of YDXNT were extracted from the Traditional Chinese Medicine Systems Pharmacology Database, Bioinformatics Analysis Tool for Molecular mechANism of Traditional Chinese Medicine, and Encyclopaedia of Traditional Chinese Medicine. AIS-related targets were retrieved from GeneCards, OMIM, and DrugBank databases. We constructed PPI and ingredient-target networks, performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses, and conducted molecular docking. The YDXNT group had a higher total effective rate and a higher Barthel Index score. YDXNT reduced the low-density lipoprotein cholesterol and the whole blood viscosity at high and shear rates. Our study identified 313 ingredients and 1196 common targets. The key ingredients were mainly quercetin, neocryptotanshinone II, miltionone I, neotanshinone C, and tanshiquinone B, and the key targets were mainly SRC, MAPK3, AKT1, MAPK1, and JUN. GO analysis showed that the core targets mainly involved in atherosclerosis and neural apoptosis. The core pathways were lipid and atherosclerosis, PI3K-Akt, MAPK, and other pathways. Key ingredients exhibited robust binding interactions with core targets. YDXNT could effectively improve the total effective rate, ability of daily life, blood lipids, and blood viscosity. Antiatherosclerotic and neuroprotective effects are the main pharmacological mechanisms.Registration number: CRD42023400127.

Exploring the causal factor effects of hypothyroidism on ischemic stroke: a two-sample Mendelian randomization study

Background

Observational studies have suggested a possible association between hypothyroidism and increased risk of ischemic stroke. However, a causal relationship remains unclear.

Methods

Data on single nucleotide polymorphisms (SNPs) associated with hypothyroidism and ischemic stroke were sourced from the FinnGens database and the UK Biobank of European descent. Both databases underwent separate two-sample Mendelian randomization (MR) analyses. A subsequent meta-analysis of MR results using a random-effects model was conducted to determine the causal relationship between hypothyroidism and ischemic stroke.

Results

All five analyses indicated a positive causal relationship between hypothyroidism and ischemic stroke. MR analysis of the association between hypothyroidism and ischemic stroke yielded a result of the inverse variance weighted (IVW) method at 4.7411 (1.3598-16.5308), p = 0.0146. The analysis of ischemic stroke (without excluding controls) yielded a result of the IVW method of 4.5713 (1.3570-15.3986), p = 0.0142. MR analysis with cerebral infarction yielded a result of the IVW method at 1.0110 (1.0006-1.0215), p = 0.0373. The MR analysis with cerebrovascular disease sequelae yielded an IVW method result of 2.4556 (1.0291-5.8595), p = 0.0429. Analysis for the sequelae of cerebrovascular disease (without excluding controls) yielded an IVW method result of 2.4217 (1.0217-5.7402), p = 0.0446. No evidence of heterogeneity or horizontal pleiotropy was found. The meta-analysis of the five MR results was 2.24 (1.18-4.26), p = 0.025.

Conclusion

Our two-sample Mendelian randomization study suggested a causal relationship between hypothyroidism and ischemic stroke, indicating that hypothyroidism could be a risk factor for ischemic stroke. However, further studies are required to elucidate the underlying biological mechanisms.