Toll-like receptor 3 (TLR3) and the development of type 1 diabetes mellitus

Type 1 diabetes mellitus (T1DM) is a chronic, progressive autoimmune disease characterized by metabolic decompensation often leading to dehydration and ketoacidosis. Viral agents seem to play an important role in triggering the autoimmune destruction that leads to the development of T1DM. Among several viral strains investigated so far, the enterovirus family has been consistently associated with the onset of T1DM in humans. One of the mediators of viral damage is the double-stranded RNA (dsRNA) generated during replication and transcription of viral RNA and DNA. The Toll-like receptor 3 (TLR3) gene codes for an endoplasmic receptor of the pattern-recognition receptors (PRRs) family that recognizes dsRNA, plays an important role in the innate immune response triggered by viral infection. Binding of dsRNA to the TLR3 triggers the release of proinflammatory cytokines, such as interferons, which exhibit potent antiviral action; thus, protecting uninfected cells and inducing apoptosis of infected ones. Therefore, the TLR3 gene is a good candidate for the development of T1DM. Within this context, the objective of the present review was to address the role of the TLR3 gene in the development of T1DM. Arch Endocrinol Metab. 2015;59(1):4-12.

Enteroviruses as a possible cause of myocarditis, pericarditis and dilated cardiomyopathy in Belém, Brazil

We attempted to assess the role of enteroviruses in the etiology of myocarditis (MC), pericarditis (PC) and dilated cardiomyopathy (DCM) among 15 in-patients at a public hospital in Belém, Brazil, from November 1992 to December 1993. We obtained stool specimens and throat swabs from each patient (particularly acute cases) and, when possible, acute and convalescent serum samples for both isolation and serological procedures. MC, PC and DCM ocurred in 10, 2 and 3 patients, respectively, mostly in the 0- to 10- year age group. Neutralizing antibody seroconversions were detected as follows: one for Coxsackievirus (Cox) B2 in one patient suffering from MC, and two for Cox B4, in patients with DCM and MC. In addition, antibody titers of 1/320 against Cox B2 and Cox B4 were noted in two other patients, one suffering from PC and the other presenting MC. Isolation of echovirus (ECHO) serotype 1 was recorded ina a patient with MC, without either seroconversion or high antibody levels for Cox B 1 to 6. These results indicate that enteroviruses may be involved in the etiology of MC, PC and DCM in the Amazon region.