Capillary Basal Lamina Thickness Research Articles

Demonstration of uniform capillary basal lamina thickness by computer technology

Blood capillaries are assumed to be circular cylinders composed of an inner layer of endothelial cells surrounded by an acellular uniformly thick basal lamina. The capillary basal lamina is the structural and functional interface between the capillary endothelial cells and the adjacent extracellular matrix, important in growth and control mechanisms of the endothelial cell. Capillaries examined in electron micrographs are cut randomly and a projected image of a capillary other than perpendicular to its long axis will produce artifactual thickening of the assumed uniformly thick basal lamina. We have developed an interactive computer program to determine the thickness of the capillary basal lamina that corrects the thickness resulting from the sectioning artifact. We have applied this methodology to demonstrate that the basal lamina of the pancreatic capillaries of the rat are uniformly thick.

Reduplicated Basal Lamina of Small Venules and Mesothelium of Human Parietal Peritoneum: Ultrastructural Changes of Reduplicated Peritoneal Basement Membrane

We examined under the electron microscope samples of parietal peritoneum obtained from nine nondiabetic chronic uremics -six of them on maintenance intermittent peritoneal dialysis, ranging in age from 52 to 82 years -mean 64.4 ± 8.1 years and of nine non-uremic, non-diabetic patients -mean age 40.7 ± 12.2 years. Postcapillary venules and small venules showed areas with several layers of reduplicated basal lamina. Some microvessels showed gaps in basallamina with and/or without focal reduplication. Reduplicated submesothelial basal lamina was found in only one patient. These changes were not observed in the nine non-uremic, non-diabetic controls. To the best of our knowledge, this is the first description in humans of such alterations in the aforementioned locations, which may well be secondary to aging and/or to the intense mesothelial renewal observed in I.P.D. patients. We need to determine the possible influence of these ultrastructural changes on transperitoneal transfer of water and solutes during peritoneal dialysis. The basal lamina of blood vessels may not be of uniform thickness. Human non-diabetic adults show significant increase in capillary basal lamina thickness as one moves from head to foot (1). Those regional variations may be related to differences in venous hydrostatic pressure effective on the capillary bed (1). This paper decribes the first observations of reduplicated basal lamina of microvessels in the parietal peritoneum and of that subjacent to mesothelial cells in elderly, non-diabetic uremic patients.

Basal lamina of abdominal skeletal muscle capillaries in diabetics and nondiabetics.

In a "blind" study, skeletal muscle biopsies were obtained from the trunk of 13 nondiabetics, eight chemical diabetics, and four overt diabetics of comparable age. On electron micrographs of 20 capillaries from each case, the areas of various components of the capillary structure were measured with a planimeter. The area of the basal lamina was expressed as a percentage of the total vessel area. This method for measuring objectively the relative thickness of capillary basal lamina considered the vessel size, plane of sectioning, and the function state of the vessel. The theoretical validity of the method is discussed. The widths of the basal lamina of the capillaries of the trunk skeletal muscles of both diabetics and nondiabetics were identical. Morphological differences between the two groups were not present. The discrepancies in results of investigations concerned with the quantity of basal lamina in capillaries of skeletal muscle may be due to naturally occurring regional differences, or because capillary beds of different organs or tissues may be affected differently in diabetes mellitus.