Diagnostic performance of VEGF-D for lymphangioleiomyomatosis: a meta-analysis / Desempenho diagnóstico do VEGF-D para linfangioleiomiomatose: meta-análise

ABSTRACT Objective: VEGF-D is a potential biomarker for lymphangioleiomyomatosis (LAM); however, its diagnostic performance has yet to be systematically studied. Methods: We searched PubMed, EMBASE, Scopus, Web of Science, and Cochrane Library to identify primary studies on VEGF-D in relation to the diagnosis of LAM. The quality of the studies was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2). Summary estimates of diagnostic accuracy were pooled using a bivariate random effects model. Subgroup and sensitivity analyses were performed to explore possible heterogeneity. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) was applied to rate the quality of evidence and indicate the strength of recommendations. Results: Ten studies involving 945 patients were of high risk in quality, as assessed using the QUADAS-2. The pooled diagnostic parameters were indicated as follows: sensitivity = 0.82 (95% CI, 0.71-0.90); specificity = 0.98 (95% CI, 0.94-0.99); and diagnostic OR = 197 (95% CI, 66-587). The AUC of summary ROC analysis was 0.98. The subgroup and sensitivity analyses revealed that the overall performance was not substantially affected by the composition of the control group, prespecified cutoff value, the country of origin, or different cutoff values (p > 0.05 for all). A strong recommendation for serum VEGF-D determination to aid in the diagnosis of LAM was made according to the GRADE. Conclusions: VEGF-D seems to have great potential implications for the diagnosis of LAM in clinical practice due to its excellent specificity and suboptimal sensitivity.

RESUMO Objetivo: O VEGF-D é um potencial biomarcador para linfangioleiomiomatose (LAM); entretanto, seu desempenho diagnóstico ainda não foi sistematicamente estudado. Métodos: Foram realizadas buscas nos bancos de dados PubMed, EMBASE, Scopus, Web of Science e Cochrane Library para identificar estudos primários sobre o VEGF-D com relação ao diagnóstico de LAM. A qualidade dos estudos foi avaliada por meio da ferramenta Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2). As estimativas sumárias de acurácia diagnóstica foram combinadas utilizando um modelo bivariado de efeitos aleatórios. Análises de subgrupo e de sensibilidade foram realizadas para explorar possíveis heterogeneidades. O sistema Grading of Recommendations Assessment, Development, and Evaluation (GRADE) foi aplicado para avaliar a qualidade das evidências e indicar a força das recomendações. Resultados: Dez estudos envolvendo 945 pacientes eram de alto risco em qualidade, segundo a ferramenta QUADAS-2. Os parâmetros diagnósticos combinados foram indicados da seguinte forma: sensibilidade = 0,82 (IC95%: 0,71-0,90); especificidade = 0,98 (IC95%: 0,94-0,99); e OR diagnóstica = 197 (IC95%: 66-587). A ASC da análise summary ROC foi de 0,98. As análises de subgrupo e de sensibilidade revelaram que o desempenho global não foi substancialmente afetado pela composição do grupo controle, valor de corte pré-especificado, país de origem ou diferentes valores de corte (p > 0,05 para todos). Uma forte recomendação para a dosagem de VEGF-D sérico para auxiliar no diagnóstico de LAM foi feita de acordo com o sistema GRADE. Conclusões: O VEGF-D parece ter grandes implicações potenciais para o diagnóstico de LAM na prática clínica em virtude da excelente especificidade e sensibilidade subótima.

The TLR7 agonist Imiquimod promote the immunogenicity of msenchymal stem cells

BACKGROUND: Mesenchymal stem cells (MSCs) are considered the best candidate in stem cells therapy due to their multipotent differentiation ability, low expression of co-stimulatory molecules (CD80, CD86, CD34 and HLA-II) and immunosuppression effects on in vivo immune responses. MSCs were now widely used in clinical trials but received no encourage results. The major problem was the fate of engrafted MSCs in vivo could not be defined. Some studies indicated that MSCs could induce immune response and result in the damage and rejection of MSCs. As toll like receptors (TLRs) are important in inducing of immune responses, in this study we study the role of TLR7 in mediating the immune status of MSCs isolated from umbilical cord. RESULTS: Our results indicated that TLR7 agonist Imiquimod could increase the proliferation of PBMC isolated from healthy human volunteers and release of lactate dehydrogenase (LDH) in supernatant from PBMC-UCMSCs co-culture system. Flow cytometry and quantitative PCR also confirmed the regulated expression of surface co-stimulatory molecules and pro-inflammatory genes (IL-6, IL-8, IL-12, TGF-β and TNF-α). And the down-regulation expression of stem cell markers also confirmed the loss of stemness of UCMSCs. We also found that the osteo-differentiation ability of UCMSCs was enhanced in the presence of Imiquimod. CONCLUSION: To our knowledge, this is the first report that activation of TLR7 pathway increases the immunogenicity of UCMSCs. Extensive researches have now been conducted to study whether the change of immune status will be help in tumor rejection based on the tumor-tropism of MSCs.