Expression of TNF-α, VEGF-A and Microvessel Density in Cerebral Alveolar Echinococcosis and Their Correlation with Perilesional Brain Edema.

Alveolar echinococcosis (AE) is an infrequent zoonosis caused by Echinococcus multilocularis with a high degree of disability and mortality. Metastatic cerebral alveolar echinococcosis (CAE) is very rare and the lesions could lead to severe perilesional brain edema (PLBE) and subsequent uncontrollable intracranial hypertension. In this study, we sought to determine the expression of edema-associated factors in CAE lesions and their associations with PLBE. We retrospectively evaluated the clinical data of 18 CAE patients who received craniotomy. Severity of PLBE was described by edema index (EI). Archived specimens were processed for immunohistochemistry to detect tumor necrosis factor alpha (TNF-α), vascular endothelial growth factor A (VEGF-A) and microvessel density (MVD) in CAE lesions. Expression intensity of CAE lesions was quantified by integral optical density (IOD) or count and was compared to the control group. The results showed TNF-α and VEGF-A were significantly expressed in CAE lesions (p < 0.001), their levels were positively correlated with PLBE (TNF-α: r = 0.701, p = 0.001; VEGF-A: r = 0.803, p < 0.001). The MVD of CAE lesions had a similar expression with normal brain tissue, and it was positively correlated with PLBE and VEGF-A (PLBE: r = 0.849, p < 0.001; VEGF-A: r = 0.687, p = 0.002). In conclusion, we speculated the upregulation of TNF-α and VEGF-A induced the formation of PLBE. Besides, though there was no extra increase of MVD, it was still regulated by VEGF-A and provided a better anatomical basis for the formation of PLBE and further promoted it.