How latent viruses cause breast cancer: An explanation based on the microcompetition model

Background

Inhaled anesthetic agents, such as isoflurane, are widely used agents in daily anesthesia practice. These agents affecting spatial learning and memory formation have become a hot topic. As shown in the previous studies, inhalation anesthetics have adverse effects on cognition. These adverse effects mostly present in neonatal (newborn), infant and early childhood periods. Although it is thought that free oxygen radicals, cytotoxicity, apoptosis and neuroinflammation are associated with this condition, there is no consensus about exact mechanisms. Isoflurane, the most commonly used inhaled anesthetic in the pediatric population, is one of the agents most likely associated with cognitive dysfunction.

Effects od Aquaporin 4 (AQP4)

Aquaporin 4 (AQP4) is a member of a water channel protein family commonly found in the central nervous system. Mainly, it regulates water content in the brain. In addition to this important function, it has been reported to have effects on neuroinflammation, neuroexitation, astyrocyte migration, spatial learning and memory. In this respect, the relationship between AQP4 and cognition has been studied in the recent years. Previous studies have shown that perivascular AQP4 levels in patients with Alzheimier's disease have decreased. Similarly, in many experimental studies, it has been found that the absence of or a reduction in AQP4 caused cognitive impairment.

What did the researchers find?

In the study published in BJBMS, the authors investigated the effects of long-term isoflurane anesthesia on cognition and AQP4 expression in infant rats. As a result of the study, they observed that isoflurane exposure did not cause neurocognitive impairment in infant rats and increased AQP4 expression in the early period. Enhanced levels of AQP4 decreased over time and normal expression levels were observed in the long-term effect of isoflurane. There are many studies in the literature about the "waste clearance" property of AQP4. However, the authors of this study think that thanks to this feature of AQP4, which increased in the early period in our results, may have decreased apoptosis, neuroinflammation or free oxygen radicals. In order to clarify these mechanisms, they believe that new studies are needed especially with AQP4 knockout experiment groups.

More information:
Serdar Demirgan, Onat Akyol, Zeynep Temel, Aslıhan Şengelen, Murat Pekmez, Recep Demirgan, Mehmet Salih Sevdi, Kerem Erkalp, Ayşin Selcan. Isoflurane exposure in infant rats acutely increases aquaporin 4 and does not cause neurocognitive impairment. Bosn J Basic Med Sci. 2019 Feb 26. doi: 10.17305/bjbms.2019.4116.

Provided by Association of Basic Medical Sciences of FBIH