Biomimetic activity of soluble, well-defined, aqueous Ti(IV)-citrate species toward adipogenesis. An in vitro study

Metal-organic complexes bearing physiological substrates have been the target of several investigations, probing into the potential of well-defined atoxic metalloforms to influence fundamental cellular processes overcoming insulin resistance in Diabetes mellitus 2. Outstanding cases of such metals include zinc and vanadium, both being the target of intense synthetic and biological studies toward insulin mimesis. Owing to the close proximity in the periodic table, an early transition metal, titanium, emerges as another potential candidate of biologically relevant complexation, reflecting species capable of promoting insulin mimetic activity. Driven by the so far explored aqueous synthetic chemistry of Ti(IV)-hydroxycaboxylato systems, a well-defined Ti(IV)-citrate compound was synthesized under physiological conditions, isolated, and characterized, followed by its introduction in biological assays, targeting adipogenic events linked to glucose uptake and catabolism. The mononuclear Ti(IV)-citrate complex was introduced to 3T3-L1 cells, thereby probing into its biological activity (toxicity, morphology, migration, and adipogenic capacity). The results project an atoxic profile for the Ti(IV)-citrate species, thus justifying further incorporation in cellular differentiation processes, leading to mature adipocytes in a time- and concentration-dependent fashion. The experiments suggest that Ti(IV)-citrate is a competent agent promoting fibroblast differentiation, as evidenced by key adipogenic biomarkers, while concurrently exhibiting synergistic/enhancing action with insulin. The collective results show, for the first time, that an appropriately configured soluble-bioavailable complex Ti(IV) form exhibits a distinctly unique bioprofile, thereby lending credence to the notion that titanium metallopharmaceuticals hold merit as competent agents in adipogenesis and insulin mimesis in Diabetes mellitus.