Intravenous Thyrotropin Releasing Hormone in Amyotrophic Lateral Sclerosis: Autonomic Effects

New Efforts to Demonstrate the Successful Use of TRH as a Therapeutic Agent

Thyrotropin-releasing hormone (TRH) is a tripeptide that regulates the neuroendocrine thyroid axis. Moreover, its widespread brain distribution has indicated that it is a relevant neuromodulator of behaviors such as feeding, arousal, anxiety, and locomotion. Importantly, it is also a neurotrophic peptide, and thus may halt the development of neurodegenerative diseases and improve mood-related disorders. Its neuroprotective actions on those pathologies and behaviors have been limited due to its poor intestinal and blood-brain barrier permeability, and because it is rapidly degraded by a serum enzyme. As new strategies such as TRH intranasal delivery emerge, a renewed interest in the peptide has arisen. TRH analogs have proven to be safe in animals and humans, while not inducing alterations in thyroid hormones' levels. In this review, we integrate research from different approaches, aiming to demonstrate the therapeutic effects of TRH, and to summarize new efforts to prolong and facilitate the peptide's actions to improve symptoms and the progression of several pathologies.

Autonomic dysfunction in the early stage of ALS with bulbar involvement

Our objective was to assess the autonomic function of ALS patients with and without bulbar signs to characterize dysautonomia in ALS disease. Standard autonomic tests and spectral analysis of heart rate variability (HRV), reflecting changes in the sympathovagal balance, were examined in 33 ALS patients (14 with bulbar signs) and 30 controls. Results showed that in the supine position, ALS patients had significantly lower total power and absolute values of high-frequency power indicating a depressed sinus arrhythmia. Patients with bulbar signs showed more marked autonomic alterations at rest. Tilting did not induce the expected increase in low-frequency and decrease in high-frequency power of HRV in all patients. No correlation was found between autonomic tests and clinical parameters. Our findings suggest an early subclinical involvement of the autonomic system in ALS, particularly affecting parasympathetic cardiac control. Patients with prominent bulbar signs show a more severe autonomic dysfunction under resting conditions.