Investigation on the role of thyroid hormones and their derivatives in different physiopathogenetic mechanisms using HPLC-MS/MS

High Performance Liquid Chromatography coupled to Tandem Mass Spectrometry (HPLC-MS/MS) is a versatile analytical technique widely applied in chemistry, biology, laboratory medicine, and biochemistry. This integrated system combines liquid chromatography with tandem mass spectrometry, facilitating the effective separation, identification, and quantification of compounds within complex mixtures. The significance of HPLC-MS/MS extends to various fields, including pharmaceuticals, environmental analysis, and metabolites analysis. This research focused on the application of HPLC-MS/MS for the quantification of thyroid hormones (TH), such as 3,5,3’-triiodothyronine (T3) and thyroxine (T4), along with their metabolites. TH play crucial roles in growth processes, development, and energy metabolism, motivating a comprehensive exploration of their dynamics in different physiological and pathological processes. The study is organized around four investigations utilizing HPLC-MS/MS as a pivotal instrument with unique pre-analytical approaches and analytical methods to explore diverse matrices. Firstly, the research unveiled neurocognitive dynamics in adult-onset hypothyroidism, employing a rodent pharmacological model. Using an HPLC-MS/MS method, we quantified the total fraction of T3 and T4 in serum samples, validating the experimental plan and providing insights into the impact of various replacement strategies on neurocognitive and neurobiological alterations. Secondly, the thesis delved into TH dynamics in diabetic retinopathy, utilizing HPLC-MS/MS to detect and quantify T3 and T4 in plasma and retina samples from a type 2 diabetes mouse model. This shed light on potential mechanisms, including T3-dependent microRNA/gene regulatory circuits and mitochondrial function. Thirdly, the study addressed iodine dynamics and the role of enzyme dehalogenase 1 (DEHAL1), employing a Dehal1 KO mouse model. With an adapted method using a derivatization process, our HPLC-MS/MS analysis was able to quantify precursors MIT and DIT in ...