Structural and functional alterations in the hippocampus due to hypothyroidism

Area of Science:

• Neuroscience
• Endocrinology
• Developmental Biology

Background:

• Thyroid hormones (THs) are vital for central nervous system (CNS) development and function.
• Hypothyroidism, particularly during critical developmental periods, can lead to significant neurodevelopmental deficits, including cognitive impairment.
• The hippocampus is a key brain structure involved in learning and memory, highly sensitive to thyroid hormone levels.

Purpose of the Study:

• To review the current understanding of how fetal-, neonatal-, and adult-onset hypothyroidism impact hippocampal structure and function.
• To elucidate the neurobiological mechanisms underlying hypothyroidism-induced cognitive and neurobehavioral dysfunction.
• To consolidate knowledge on genomic and proteomic alterations in the hippocampus due to thyroid dysfunction.

Main Methods:

• Literature review of studies investigating thyroid hormone effects on the CNS.
• Analysis of research on hippocampal development and function in hypothyroid models.
• Synthesis of data on neurodevelopmental changes, synaptic plasticity, myelination, and neurotransmitter systems.

Main Results:

• THs deficiency during development causes impaired neural growth, reduced synaptic connectivity, delayed myelination, and altered neuronal migration.
• Adult-onset hypothyroidism is associated with neurological and behavioral abnormalities, suggesting ongoing effects on the adult brain.
• Both developmental and adult hypothyroidism induce genomic and proteomic changes within the hippocampus.

Conclusions:

• Hypothyroidism, irrespective of onset timing, profoundly affects hippocampal development and function.
• Understanding these hippocampal alterations is crucial for addressing hypothyroidism-induced cognitive deficits and neurobehavioral issues.
• Further research into the molecular mechanisms can inform therapeutic strategies for thyroid-related neurological disorders.