Childhood Kidney Diseases

Korean Society of Pediatric Nephrology (대한소아신장학회)
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Podocytopathy and Morphologic Changes in Focal Segmental Glomerulosclerosis

초점분절사구체경화증에서 발세포병증과 형태 변화

  • Jeong, Hyeon Joo (Department of Pathology, Yonsei University College of Medicine)
  • 정현주 (연세대학교 의과대학 병리학교실)
  • Received : 2012.11.25
  • Accepted : 2012.12.13
  • Published : 2013.04.30
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Abstract

Podocytopathy is glomerular lesions characterized by podocyte injury. It is observed in various glomerular diseases, but minimal change disease and focal segmental glomerulosclerosis (FSGS) are the prototypes. In this review, morphologic features of podocyte injury and subtypes of FSGS will be reviewed briefly. Effacement of podocyte foot processes is the most common feature of podocyte injury. As podocytic injury progresses, intracytoplasmic vacuoles, subpodocytic cyst, detachment of podocytes from the glomerular basement membrane and apoptosis develop. Glomerular capillary loops in epithelium-denuded area undergo capillary collapse. Synechia and hyalinosis may accompany this lesion. To manifest segmental sclerosis, podocyte loss above a threshold level may be required. Injured podocytes can injure neighboring intact podocytes, and thereby spread injury within the same lobule. FSGS can be categorized into five subtypes by morphologic characteristics; not otherwise specified (NOS), perihilar, cellular, tip, and collapsing types. Each subtype has been reported to show different clinical courses and associated conditions, but there are controversies on its significance. With recent progress in the discovery of genetic abnormalities causing FSGS and plasma permeability factors, we expect to unravel pathophysiology of FSGS and to understand histological sequences leading to FSGS in near future.

발세포병증은 발세포의 손상을 특징으로 하는 사구체질환이다. 발세포의 손상은 여러 사구체질환에서 관찰될 수 있으나, 미소변화질환과 FSGS에서 주요 병인으로 작용한다. 이 글에서는 FSGS에서 발세포 손상의 형태 변화와 분절경화의 유형을 설명하고자 한다. 발세포가 손상되면 형태 변화로 발돌기의 소실, 발세포 세포질 내 공포, 발세포하 낭 등이 관찰되며, 심하면 발세포의 탈락 및 자멸사가 관찰된다. 그러나 분절경화가 초래되기까지에는 일정 수준 이상의 발세포의 소실이 있어야 하며, 손상된 발세포는 동일한 사구체 소엽 내 주변 발세포로 손상을 전파하여 병변이 커지게 된다. FSGS는 광학현미경 소견을 기초로 NOS형, perihilar형, cellular형, tip형, collapsing형의 다섯 가지 유형으로 나뉜다. 각 아형에 따라 임상 경과나 스테로이드 치료에 대한 반응이 다르고 흔히 동반되는 임상 조건들도 다르다고 보고되었으나 이에 대하여는 아직도 논란이 있는 실정이다. 앞으로 FSGS 발생에 관여하는 유전 정보와 혈액 내 투과인자의 성분 등 관련된 인자들에 대한 체계적인 연구가 이루어지면 FSGS에서 관찰되는 조직 변화나 병태생리를 더 잘 설명할 수 있을 것으로 기대해 본다.

Keywords

References

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