Engineering of a Functional Pancreatic Acinus with Reprogrammed Cancer Cells by Induced PTF1a Expression

A pancreatic acinus is a functional unit of the exocrine pancreas producing digest enzymes. Its pathobiology is crucial to pancreatic diseases including pancreatitis and pancreatic cancer, which can initiate from...

Pancreatic secretion and pressure biomechanics in pancreatic acinus

The article highlights the mechanism of the mathematical model of acinus, the components of the formation of pressure in its cavity and the formation of pancreatic juice. It has been established that the mechanism for creating pressure in the acinus cavity is similar to the intraductal one. In this case, the question remains open about the causes of such high pressure, which is measured in several hundred millimeters of a mercury column, especially since, as histologically established, the pancreas and its ducts do not have muscle structures, and those rudiments of myofibrils, which are noted in some places of the flow system, of course, cannot ensure the development of such pressure. The increase in pressure in the cavity of the acinus is associated with the phenomenon of osmosis in its cells. Since cell membranes have the property of conductivity, as a result of osmosis, water through the membrane first passes from the blood to the cell, then from the cell through the membrane into the acinus cavity. In addition to the mechanism of osmosis through the membrane, in the cells of the acinus epithelium, there is a filtering mechanism through the pores of the layer of connective tissue to the lymph channel. It has now been established that, together with simple osmosis, the phenomenon of electroosmosis takes place in secreting cells and organs of excretion, not only accelerates the transfer of substances, but also increases the pressure on the other side of the membrane against the gradient by almost several first-order units. Thus, the outflow of fluid from the acinus cavity proceeds continuously, but only with a change in the speed of movement, it is determined by the pressure drop in the acinus – tubule – excretory duct system, the opening of the Oddi sphincter and the pulse of the cardiovascular wave, which creates dynamic pressure in the capillary. This whole mechanism, as a result, leads to the filling of the cavity of the acinus and the creation of a certain pressure in it.

Differential filipin labeling of the luminal membranes lining the pancreatic acinus.

The cytochemical labeling of cholesterol by filipin in plasma membranes of the exocrine pancreas has shown a difference in the reactivity to filipin between the acinar and centro-acinar cells. The acinar cell has a poorly labeled luminal membrane but numerous filipin-cholesterol complexes on the basolateral membrane. In contrast, the centro-acinar cell shows a comparable degree of filipin labeling on both luminal and basolateral membrane. This difference in the distribution of filipin labeling suggests underlying differences in the organization of the respective membranes, probably related to their specific functions.