Thyroid Hormone and Tissue Repair: New Tricks for an Old Hormone?

Abstract

Although the role of thyroid hormone during embryonic development has long been recognized, its role later in adult life remains largely unknown. However, several lines of evidence show that thyroid hormone is crucial to the response to stress and to poststress recovery and repair. Along this line, TH administration in almost every tissue resulted in tissue repair after various injuries including ischemia, chemical insults, induction of inflammation, or exposure to radiation. This novel action may be of therapeutic relevance, and thyroid hormone may constitute a paradigm for pharmacologic-induced tissue repair/regeneration.

Causal role of oxidative stress in unfolded protein response development in the hyperthyroid state

“…In agreement with the upregulation of positive APPs, T 3 led to a decrease in the serum levels of albumin, a negative APP that under acute stress conditions is downregulated to achieve a redistribution of liver protein pools [56,57]. Considering that the UPR confers rapid adaptation to the increase in unfolded proteins in the ER lumen by expanding its protein-folding capacity, T 3 -induced liver UPR may represent a favorable mechanism against deleterious stimuli [5,6,9,29] in addition to those studied in experimental models (Fig. 4).…”

“…4). These mechanisms are effective in protecting the liver against IRI [5,6], the beneficial actions of thyroid hormones being also observed in ischemic injury of the heart [26], kidney [27], and brain [28] or in the repair of organs subjected to several types of injury other than IRI [29]. Data presented indicate that a protocol comprising the administration of single daily doses of 0.1 mg T 3 /kg to rats on three consecutive days underlies an enhanced liver ROS generation coupled to T 3 -induced increase in oxygen consumption as a result of the calorigenic effect achieved, leading to significant lipid peroxidation and protein oxidation responses and concomitant GSH depletion.…”

Thyroid hormones and deiodinase activities in plasma and tissues from East Greenland polar bears (Ursus maritimus) during winter season

“…Thus, D2-produced T3 is thought to be more important locally in tissues where D2 is abundant (Bianco et al 2002;Zoeller et al 2007;Gereben et al 2008). In this manner, TH levels can be regulated locally in response to, e.g., specific development periods (Gereben et al 2008), local tissue damage (Mourouzis et al 2013) or metabolic and thermogenic needs (Bianco and Kim 2006;Arrojo e Drigo et al 2013).…”

Levothyroxine improves Paraoxonase (PON-1) serum levels in patients with primary hypothyroidism: Case–control study

“…Recently, a significant association between hypothyroidism and augmentation of free radical productions are occurring leading to the detrimental effects on the endogenous antioxidant enzymes, which is not same in different tissues. [ 5 6 ] Human body antioxidant defence mechanisms against oxidative stress include non-enzymatic and enzymatic pathways. Paraoxonase-1 (PON-1) is one of the enzymatic pathways that found on high-density lipoprotein (HDL) which concerned with hydrolysis of oxidized lipoproteins.…”