A novel mechanism of capillary growth in the rat pulmonary microcirculation

Wiley - Tập 228 Số 1 - Trang 35-45 - 1990
Peter H. Burri1, Mojmir R. Tarek1
1Institute of Anatomy, Section of Developmental Biology, University of Berne, CH‐3000 Berne 9, Switzerland

Tóm tắt

AbstractPostnatally, the rat lung parenchyma undergoes impressive growth. Within four months of birth, lung volume and alveolar and capillary surface areas increase over 20‐fold and capillary volume 35‐fold. Investigation of methacrylate casts of the pulmonary microvasculature revealed that, with age, lung capillaries were not only growing in surface and volume but also increasing their network density. We proposed that the capillary bed grows by formation of slender intravascular tissue pillars and termed this type of growth intussusceptive microvascular growth (Caduff et al., Anat. Rec., 216:154–164, 1986). The aim of this investigation was to detect the presence and to analyze the ultrastructure of slender tissue posts (diameter 1–2.5 μm) extending across the capillary lumina in serial electron microscopic sections of rat lung parenchyma (age 44 days). Computer‐assisted three‐dimensional reconstruction of the capillary lumen confirmed that tissue posts were matching the holes previously observed in casts. Post ultrastructure varied with size from a simple area of interendothelial contact to tissue pillars with a core of interstitial tissue. Based on the changing morphology of the pillars, a hypothesis for their development can be proposed: phase I, creation of a zone of contact between opposite capillary walls (formation of an interendothelial bridge); phase II, reorganization of the intercellular junctions of the endothelium, with central perforation of the capillary layer; phase III, formation of an interstitial post core, with successive invasion by cytoplasmic extensions of myofibro‐blasts, pericytes, and finally interstitial fibers; and phase IV, growth of the slender pillar to a normal full size capillary mesh. These findings support the new concept of intussusceptive growth of the lung capillary system.

Từ khóa


Tài liệu tham khảo

10.1016/0026-2862(77)90141-8

Brody J. S., 1983, Proliferation of alveolar interstitial cells during postnatal lung growth: Evidence for two distinct populations of pulmonary fibroblasts, Am. Rev. Respir. Dis., 127, 763

Burger P. C., 1984, Scanning electron microscopy of vascular casts in experimental ocular vasoproliferation, Scanning Electron Microsc, 1893

10.1002/ar.1091780405

Buzney S. M., 1977, Aldose reductase in retinal mural cells, Invest. Ophthalmol. Vis. Sci., 16, 392

10.1002/ar.1092160207

10.1001/archopht.1961.00960010368014

10.1111/j.1749-6632.1982.tb25720.x

10.1038/288551a0

10.1126/science.2432664

10.1083/jcb.25.1.157

Furcht L. T., 1986, Critical factors controlling angiogenesis: Cell products, cell matrix, and growth factors, Editorial. Lab. Invest., 55, 505

10.1159/000410083

10.1083/jcb.60.2.375

10.1002/jcp.1041180203

10.1007/BF02810077

10.1083/jcb.17.1.208

10.1016/0040-8166(86)90026-1

Small J. V., 1968, Proceedings of Fourth European Regional Conference on Electron Microscopy, 609

Weibel E. R., 1979, Stereological Methods, Practical Methods for Biological Morphometry, 1

Weibel E. R., 1979, Pulmonary Edema, 1

10.1007/BF00341407

Thông tin
Thông tin xuất bản

Wiley

Tập 228 Số 1

35-45

Thông tin tác giả