Toll-Like Receptors in Stem/Progenitor Cells.

One of the bridges that control the cross-talk between the innate and adaptive immune systems is toll-like receptors (TLRs). TLRs interact with molecules shared and maintained by the source pathogens, but also with endogenous molecules derived from injured tissues (damage/danger-associated molecular patterns - DAMPs). This is likely why some kinds of stem/progenitor cells (SCs) have been found to express TLRs. The role of TLRs in regulating basal motility, proliferation, processes of differentiation, self-renewal, and immunomodulation has been demonstrated in these cells. In this book chapter, we will discuss the many different functions assumed by the TLRs in SCs, pointing out that, depending on the context and the type of ligands they perceive, they may have different effects. In addition, the role of TLR in SC's response to specific tissue damage and in reparative processes will be addressed, as well as how the discovery of molecules mediating TLR signaling's differential function may be decisive for the development of new therapeutic strategies. Given the available studies on TLRs in SCs, the significance of TLRs in sensing an injury to stem/progenitor cells and evaluating their action and reparative activity, which depends on the circumstances, will be discussed here. It could also be possible that SCs used in therapy could theoretically be exposed to TLR ligands, which could modulate their in vivo therapeutic potential. In this context, we need to better understand the mechanisms of action of TLRs on SCs and learn how to regulate these receptors and their downstream pathways in a precise way in order to modulate SC proliferation, survival, migration, and differentiation in the pathological environment. In this way, cell therapy may be strengthened and made safer in the future.

Involvement of vascular endothelial growth factor in schizophrenia.

Vascular endothelial growth factor (VEGF), which acts as an angiogenic and neurotrophic factor, is involved the regulation of cerebral blood volume and flow in Schizophrenia (SCZ). Several evidence indicates that modification of brain blood circulation due to alterations in the VEGF system affects cognitive performance and brain function in patients with SCZ. The aim of this study is: 1) To analyze the literature data concerning the role of VEGF in modulating the angiogenic response in SCZ. These data are controversial because some studies found elevated VEGF serum levels of VEGF in patients with SCZ, whereas others demonstrated no significant differences between SCZ patients and controls. 2)To analyze the role of VEGF as a predictive factor on the effects of antipsychotics agents used in the treatment of SCZ. In this context, high VEGF levels, associated to better responses to antipsychotics, might be predictive of the use of first generation antipsycotic drugs, whereas low VEGF levels, expression of resistance to therapy, might be predictive for the use of second generation antipsycotic drugs.

Levothyroxine requirement in congenital hypothyroidism: a 12-year longitudinal study.

The aim of the replacement therapy with levothyroxine in congenital hypothyroidism (CH) is to correct hypothyroidism and ensure normal growth and neuropsychological development. Few data are available about the appropriate dose during childhood and early adolescence; therefore, we performed a multicenter observational study in a large population of patients with CH to assess the required levothyroxine dose to obtain euthyroidism. We recruited 216 patients with permanent CH classified into three groups (agenesia, ectopia, and in situ gland) on the basis of the thyroid imaging. The levothyroxine dose was recorded at 6 and 12 months and then yearly until 12 years of age. The daily levothyroxine requirement progressively decreased during the follow-up, irrespective of etiology. It was significantly lower in patients with in situ gland than in patients with athyreosis during the entire study period and with ectopic gland from the age of 1 year. The levothyroxine requirement at 6 months of age was correlated with the requirement at each later time-point. The daily dose was modified less frequently in patients with in situ thyroid (36 %) than in patients with ectopic gland (41.4 %) or with athyreosis (43.6 %). Patients with in situ gland required a lower dose than the other two subgroups. The dose at 6 months seems predictive of the requirement until 12 years of age. Euthyroidism may be achieved in pre-school and in-school patients by 3-4 and 2-3 µg/kg/day (70-90 and 60-80 µg/m(2)/day) of levothyroxine, respectively.