Depressive disorders in the elderly and dementia: an update / Transtornos depressivos em idosos e demência: uma atualização

ABSTRACT. The relationship between depressive disorders in the elderly and dementia, particularly Alzheimer's disease (AD), is highly complex. While the nature of this relationship is still a matter of debate, differential diagnosis and treatment remain a great clinical challenge. We review recent findings on the conundrum of depressive disorders in the elderly and AD. There is a biological continuum between depressive disorders in the elderly ­ or at least a subgroup of them ­ and AD. While elderly subjects with depression and patients with AD exhibit higher circulating levels of pro-inflammatory molecules and lower BDNF than matched controls, CSF levels of Aß42 can discriminate AD from depressive disorders in the elderly. The role of antidepressant treatment as a strategy to minimize the risk of AD remains to be established.

RESUMO. A relação entre transtornos depressivos em idosos e demência, particularmente a doença de Alzheimer (DA), é altamente complexa. Embora a natureza desse relacionamento ainda seja motivo de debate, o diagnóstico e o tratamento diferenciais continuam sendo um grande desafio clínico. Revisamos descobertas recentes sobre o dilema de transtornos depressivos em idosos e DA. Existe um contínuo biológico entre os transtornos depressivos em idosos ­ ou pelo menos um subgrupo deles ­ e a DA. Enquanto indivíduos idosos com depressão e pacientes com DA exibem níveis circulantes mais altos de moléculas pró-inflamatórias e menor BDNF do que os controles correspondentes, os níveis de Aß42 no LCR podem discriminar a DA de distúrbios depressivos em idosos. O papel do tratamento antidepressivo como estratégia para minimizar o risco de DA ainda precisa ser estabelecido.

MicroRNA-451a, microRNA-34a-5p, and microRNA-221-3p as predictors of response to antidepressant treatment

Aberrant expression of microRNAs (miRNAs) has been shown to be involved in early observations of depression. The aim of this study was to determine if serum levels of miRNA-451a, miRNA-34a-5p, and miRNA-221-3p can serve as indicators of disease progression or therapeutic efficacy in depression. We collected data from 84 depressed patients and 78 control volunteers recruited from the medical staff at the West China Hospital. Depression severity was rated using the 24-item Hamilton Depression Scale (HAMD). Serum miRNA-451a, miRNA-34a-5p, and miRNA-221-3p levels were determined in samples from the depressed patients before and 8 weeks after antidepressant treatment as well as in samples from controls. Compared with the controls, the patients had lower miRNA-451a levels, higher miRNA-34a-5p and miRNA-221-3p levels, and increased HAMD scores whether they underwent antidepressant treatment or not. Eight weeks after antidepressant treatment, the patients exhibited increased miRNA-451a levels, decreased miRNA-34a-5p and miRNA-221-3p levels, and reduced HAMD scores. The serum level of miRNA-451a was negatively correlated with HAMD scores of the patients, while the serum levels of miRNA-34a-5p and miRNA-221-3p were positively correlated with HAMD scores whether the patients underwent antidepressant treatment or not. Paroxetine was markedly effective in 50 patients who also displayed an increased level of miRNA-451a but reduced levels of miRNA-34a-5p and miRNA-221-3p. In contrast, paroxetine was moderately effective or ineffective in 34 patients. In conclusion, depressed patients had lower serum miRNA-451a but higher serum miRNA-34a-5p and miRNA-221-3p, and these miRNAs are potential predictors of the efficacy of antidepressants.