Bystin (BYSL) as a possible marker of severe hypoxic-ischemic changes in neuropathological examination of forensic cases

Abstract

Bystin (BYSL) is a 306-amino acid protein encoded in humans by the BYSL gene located on the 6p21.1 chromosome. It is conserved across a wide range of eukaryotes. BYSL was reported to be a sensitive marker for the reactive astrocytes induced by ischemia/reperfusion and chemical hypoxia in vitro and is considered to be one of the common characteristics of astrogliosis. In our study we examined whether BYSL could be used as a marker for hypoxic-ischemic changes in forensic cases. Groups suspected of acute hypoxic-ischemic changes presented strong BYSL expression in the cytoplasm of neocortical neurons especially in layers 3-5, that seemed to be short-lasting. In the hypoxic-ischemic-reperfusion group we did not find BYSL expression. BYSL expression in the cytoplasm of cortical neurons was minimal in the control group (cardiac arrest). BYSL seems to be a promising early marker of severe hypoxic-ischemic changes in neuropathological examination of forensic cases and certainly requires further studies.

Keywords: Brain ischemia; Bystin; Hypoxia-ischemia; Marker.

Fig. 1

Frontal lobes, magnification × 200. H&E and anti-BYSL staining in the 3rd neuronal layer of the neocortex. GFAP marks white matter. a – control group (sudden death), slightly pronounced brain edema; b - control group, normal view of astroglia; c – control group (sudden death), white matter, minimal BYSL expression in neuron cytoplasm; d – HI group - brain edema, ischemic neurons and perineuronal satellitosis; e – HI group, astroglia proliferation and clasmatodendrosis; f – HI group, white matter, statistically significant (comparing to control group) increased BYSL expression in cytoplasm of ischemic neurons; g – HIR group with brain edema, ischemic neurons and severe perineuronal satellitosis; h – HIR group, slightly more pronounced astroglia proliferation and clasmatodendrosis; i – HIR group with no BYSL expression. Inserts b, e, h shows astrocytes in higher magnification

Fig. 2

Case of brain ischemic stroke with duration of over 48 h; magnification ×200. H&E - macrophages infiltration; CD68 - macrophages/phagolytic microglia infiltration (arrows) in the vicinity of blood vessel; GFAP - astrocytes (arrows) in the area of brain ischemic stroke, poor GFAP expression; BYSL - no BYSL expression in the area of brain ischemic stroke