Autoregulation of intestinal capillary filtration rate

1982 ◽  
Vol 243 (6) ◽  
pp. G475-G483
Author(s):  
D. N. Granger ◽  
N. A. Mortillaro ◽  
M. A. Perry ◽  
P. R. Kvietys
Keyword(s):  
Arterial Pressure ◽  
Capillary Pressure ◽  
Filtration Rate ◽  
Pressure Range ◽  
Fluid Pressure ◽  
Lymph Flow ◽  
Filtration Coefficient ◽  
Capillary Filtration ◽  
Capillary Filtration Coefficient ◽  
Flow Capillary

To determine whether intestinal capillary filtration rate, capillary pressure, or both are autoregulated in the cat ileum, the following parameters were measured under isovolumetric conditions: lymph flow, capillary pressure, capillary filtration coefficient, and lymph and plasma oncotic pressures. Superior mesenteric arterial pressure was reduced in 25-mmHg steps from 125 to 25 mmHg. As arterial pressure was reduced, lymph flow, capillary pressure, and the transcapillary oncotic pressure gradient decreased while the capillary filtration coefficient increased. Over the arterial pressure range of 75-125 mmHg, capillary pressure decreased in a fashion expected from a rigid system; however, capillary pressure was slightly autoregulated at lower arterial pressures. Lymph flow fell proportionately more than capillary pressure over the entire arterial pressure range. The results of this study indicate that intestinal capillary pressure and capillary filtration rate are poorly autoregulated in the cat when arterial pressure is reduced. Changes in interstitial fluid pressure play a major role in preventing interstitial dehydration in the cat ileum when arterial pressure is reduced.

Sympathetic stimulation and intestinal capillary fluid exchange

1984 ◽  
Vol 247 (3) ◽  
pp. G279-G283 ◽  
Author(s):  
D. N. Granger ◽  
J. A. Barrowman ◽  
S. L. Harper ◽  
P. R. Kvietys ◽  
R. J. Korthuis
Keyword(s):  
Capillary Pressure ◽  
Nerve Stimulation ◽  
Sympathetic Nerve ◽  
Filtration Rate ◽  
Lymph Flow ◽  
Filtration Coefficient ◽  
Fluid Exchange ◽  
Sympathetic Nerve Stimulation ◽  
Capillary Filtration ◽  
Capillary Filtration Coefficient

Sympathetic nerve stimulation is generally considered not to alter intestinal capillary pressure or filtration rate because of appropriate adjustments in the pre-to-postcapillary resistance ratio. To directly assess this possibility, we measured lymph flow, capillary pressure, capillary filtration coefficient, and the transcapillary oncotic pressure gradient in the cat small intestine. Measurements were taken under control conditions and during the steady-state phase of periarterial nerve stimulation, i.e., following completion of the escape phase. Venous outflow pressure was held constant (0 mmHg) during the entire experiment. Nerve stimulation resulted in a significant reduction of lymph flow (by 65%), capillary filtration coefficient (by 75%), and capillary pressure (by 15%). Interstitial fluid pressure, calculated from the measured parameters in the Starling equation, was also reduced (from -0.74 to -2.53 mmHg) by nerve stimulation. The results of this study indicate that intestinal capillary pressure and capillary filtration rate are not "autoregulated" during sympathetic nerve stimulation. Capillary derecruitment appears to be largely responsible for the dramatic reduction in filtration rate associated with adrenergic stimulation.

Evaluation of Starling forces in the equine digit

1988 ◽  
Vol 64 (4) ◽  
pp. 1580-1583 ◽  
Author(s):  
D. Allen ◽  
R. J. Korthuis ◽  
S. Clark
Keyword(s):  
Capillary Pressure ◽  
Interstitial Fluid ◽  
Venous Pressure ◽  
Fluid Pressure ◽  
Calculated Data ◽  
Filtration Coefficient ◽  
Fluid Exchange ◽  
Tissue Pressure ◽  
Capillary Filtration ◽  
Capillary Filtration Coefficient

A pump-perfused extracorporeal digital preparation was used to evaluate blood flow, arterial pressure, venous pressure, isogravimetric capillary filtration coefficient, capillary pressure, and vascular compliance in six normal horses. From these data, pre- and postcapillary resistances and pre- and postcapillary resistance ratios were determined. Vascular and tissue oncotic pressures were estimated from plasma and lymph protein concentrations, respectively. By use of the collected and calculated data, tissue pressure in the digit was calculated using the Starling equation. In the isolated equine digit, isogravimetric capillary pressure averaged 36.7 mmHg, plasma and lymph oncotic pressures averaged aged 19.12 and 6.6 mmHg, respectively, interstitial fluid pressure averaged 25.6 mmHg, and the capillary filtration coefficient averaged 0.0013 ml.min-1.mm-1.100 g-1. Our results indicate that digital capillary pressure in the laterally recumbent horse is much higher than in analogous tissues in other species such as dog and human. However, the potential edemagenic effects of this high digital capillary pressure are opposed by at least two mechanisms: 1) a high tissue pressure and 2) a low microvascular surface area for fluid exchange and/or a low microvascular permeability to filtered fluid.

Intestinal capillary filtration in acute and chronic portal hypertension

1988 ◽  
Vol 254 (3) ◽  
pp. G339-G345 ◽  
Author(s):  
R. J. Korthuis ◽  
D. A. Kinden ◽  
G. E. Brimer ◽  
K. A. Slattery ◽  
P. Stogsdill ◽  
...  
Keyword(s):  
Blood Flow ◽  
Portal Hypertension ◽  
Capillary Pressure ◽  
Vascular Resistance ◽  
Interstitial Fluid ◽  
Venous Pressure ◽  
Fluid Pressure ◽  
Lymph Flow ◽  
Interstitial Fluid Pressure ◽  
Capillary Filtration

The impact of acute and chronic portal hypertension on the dynamics of intestinal microvascular fluid exchange was examined in anesthetized, fasted, sham-operated control rats with normal portal pressures (CON), during acute elevations in portal pressure (APH) in control rats, and in rats in which chronic portal hypertension (CPH) was produced by calibrated stenosis of the portal vein 10 days prior to the experiments. Although intestinal blood flow and vascular resistance were not altered by APH in control rats, CPH was associated with an increased intestinal blood flow and reduced intestinal vascular resistance when compared with CON and APH. Intestinal capillary pressure and lymph flow were elevated in APH and CPH relative to control values. However, the increase in both variables was greater in CPH. The capillary filtration coefficient was elevated only in CPH. The transcapillary oncotic pressure gradient was not altered by APH or CPH. Interstitial fluid pressure was increased from -1.1 mmHg in CON to 3.9 mmHg during APH and to 5.0 mmHg in CPH. The results of this study indicate that chronic elevations in portal venous pressure produce larger increments in intestinal capillary pressure and filtration rate than do acute elevations in portal venous pressure of the same magnitude. However, the potential edemagenic effects of elevated capillary pressure in both acute and chronic portal hypertension are opposed by increases in lymph flow and interstitial fluid pressure.

Autoregulation of capillary pressure and filtration rate in isolated rat hindquarters

1985 ◽  
Vol 248 (6) ◽  
pp. H835-H842 ◽  
Author(s):  
R. J. Korthuis ◽  
D. N. Granger ◽  
M. I. Townsley ◽  
A. E. Taylor
Keyword(s):  
Skeletal Muscle ◽  
Arterial Pressure ◽  
Capillary Pressure ◽  
Filtration Rate ◽  
Venous Occlusion ◽  
Aortic Pressure ◽  
Capillary Filtration ◽  
Abdominal Aortic ◽  
Capillary Pressures ◽  
Isolated Rat

The hypothesis that skeletal muscle capillary pressure and/or capillary filtration rate are autoregulated was tested in 10 isolated rat hindquarters. Capillary pressure was directly assessed with the venous occlusion technique as abdominal aortic pressure was reduced in 25-mmHg decrements from 125 to 25 mmHg. Capillary pressure was not altered by reduction of arterial pressure from 125 to 100 mmHg, but it decreased progressively when arterial pressure was reduced from 100 to 25 mmHg. As perfusion pressure was reduced, capillary filtration rate decreased progressively, while the capillary filtration coefficient increased. The progressive decrease in capillary pressures was less than that predicted for a totally passive system, implying that capillary pressure was autoregulated to some degree. However, analysis of pre- to postcapillary resistance ratios suggested that the degree of capillary pressure autoregulation was minimal when perfusion pressures varied over a range of 100–25 mmHg. Capillary filtration rate was maintained better than would be predicted from the measured fall in capillary pressure by readjustments of interstitial Starling forces. These results indicate that capillary pressure is poorly autoregulated in rat skeletal muscle but that compensatory readjustments in interstitial Starling forces help maintain fluid balance and prevent excess dehydration of the interstitium of skeletal muscle as arterial pressure is reduced.

scholarly journals Comparative Study of Capillary Filtration Coefficient (Kfc) Determination by a Manual and Automatic Perfusion System. Step by Step Technique Review

2019 ◽  
pp. 901-908
Author(s):  
C.C. Bravo-Reyna ◽  
G. Torres-Villalobos ◽  
N. Aguilar-Blas ◽  
J. Frías-Guillén ◽  
J.R. Guerra-Mora
Keyword(s):  
Arterial Pressure ◽  
Pulmonary Arterial Pressure ◽  
Ischemia Reperfusion ◽  
Venous Pressure ◽  
Filtration Coefficient ◽  
Perfusion System ◽  
Gold Standard Method ◽  
Capillary Filtration ◽  
Capillary Filtration Coefficient ◽  
Pulmonary Arterial

The purpose of calculating the capillary filtration coefficient is to experimentally evaluate edema formation in models of pulmonary ischemia-reperfusion injury. For many years, the obtaining of this coefficient implies a series of manual maneuvers during ex-vivo reperfusion of pulmonary arterial pressure, venous pressure and weight, as well as the calculation of the Kfc formula. Through automation, the calculation of capillary filtration coefficient could be easier and more efficient. To describe an automatic method designed in our laboratory to calculating the capillary filtration coefficient and compare with traditional determination of capillary filtration coefficient as gold standard method. An automatic three valve perfusion system was constructed, commanded by a mastery module connected to a graphical user interface. To test its accuracy, cardiopulmonary blocks of Wistar rats were harvested and distributed in manual (n=8) and automated (n=8) capillary filtration coefficient determination groups. Physiological parameters as pulmonary arterial pressure, pulmonary venous pressure, weight and capillary filtration coefficient were obtained. Results: Capillary filtration coefficient, pulmonary arterial pressure, venous arterial pressure shown no statistical significance difference between the groups. The automated perfusion system for obtaining Kfc was standardized and validated, giving reliable results without biases and making the process more efficient in terms of time and personal staff.

Pancreatic circulation: intrinsic regulation

1982 ◽  
Vol 242 (6) ◽  
pp. G596-G602
Author(s):  
P. R. Kvietys ◽  
J. M. McLendon ◽  
G. B. Bulkley ◽  
M. A. Perry ◽  
D. N. Granger
Keyword(s):  
Blood Flow ◽  
Arterial Pressure ◽  
Vascular Resistance ◽  
Venous Pressure ◽  
Filtration Coefficient ◽  
Pancreatic Blood Flow ◽  
Capillary Filtration ◽  
Pressure Elevation ◽  
Capillary Filtration Coefficient ◽  
Intrinsic Regulation

The purpose of the present study was to characterize the intrinsic mechanisms involved in the regulation of blood flow and oxygenation in the totally isolated, perfused canine pancreas. Arterial pressure, venous outflow pressure, blood flow, arteriovenous oxygen difference, and capillary filtration coefficient were measured during graded arterial pressure reductions and venous pressure elevation. Reductions in arterial pressure caused pancreatic blood flow and vascular resistance to decrease, whereas venous pressure elevation resulted in a decreased blood flow and increased vascular resistance. The reductions in blood flow produced by arterial and venous pressure alterations were associated with increases in oxygen extraction and capillary filtration coefficient. During the same pressure perturbations, oxygen uptake remained constant between blood flows of 40-100 ml.min-1.100 g-1, yet decreased progressively as blood flow was reduced below 40 ml.min-1.100 g-1. Arterial occlusion resulted in a postocclusive reactive hyperemia, the magnitude of which was related to the duration of occlusion. The findings of this study suggest that intrinsic regulation of pancreatic blood flow can be attributed to both metabolic and myogenic mechanisms. Resistance and exchange vessels both appear to play a role in the regulation of oxygen delivery to the pancreatic parenchyma.

The effect of posture on the capillary filtration rate in the human forearm

1970 ◽  
Vol 48 (6) ◽  
pp. 405-414 ◽  
Author(s):  
P. D. Newberry ◽  
J. M. McDonald ◽  
E. R. Rowe
Keyword(s):  
Filtration Rate ◽  
Room Temperature ◽  
Venous Pressure ◽  
Filtration Coefficient ◽  
Left Forearm ◽  
Capillary Filtration ◽  
Capillary Filtration Coefficient ◽  
Human Forearm ◽  
Capillary Resistance ◽  
Male Subjects

A water-filled plethysmograph of a new design was used to measure the capillary filtration rate in the left forearm of each of six male subjects at a room temperature of 27 °C, in the supine and the seated positions. The adoption of the seated position resulted in a decrease of the capillary filtration rate by an average of 0.050 ± 0.015 S.E. ml/min∙100 ml (p < 0.02) and in an increase of the average threshold venous pressure for capillary filtration from 14 to 26 mm Hg (p < 0.01). This change was associated with an increase in the post-capillary resistance. Adoption of the seated position caused no significant change in the capillary filtration coefficient.

Intestinal capillary filtration in experimental diabetes mellitus

1987 ◽  
Vol 253 (1) ◽  
pp. G20-G25
Author(s):  
R. J. Korthuis ◽  
V. H. Pitts ◽  
D. N. Granger
Keyword(s):  
Diabetes Mellitus ◽  
Reflection Coefficient ◽  
Capillary Pressure ◽  
Experimental Diabetes ◽  
Lymph Flow ◽  
Experimental Diabetes Mellitus ◽  
Capillary Filtration ◽  
Solute Exchange ◽  
Capillary Filtration Coefficient ◽  
Osmotic Reflection Coefficient

There is indirect evidence that indicates that intestinal transcapillary fluid and solute exchange is significantly altered in diabetes mellitus. To directly assess the dynamics of microvascular fluid and solute exchange in the small intestine (jejunum-ileum), we measured lymph flow, capillary pressure, capillary filtration coefficient, plasma and lymph oncotic pressures, and the osmotic reflection coefficient in anesthetized, fasted control rats and in rats in which diabetes was induced by a single injection of streptozotocin (65 mg/kg ip) 4 wk before the experiments. Diabetes was associated with an increase in lymph flow (by 120%), capillary pressure (by 34%), and capillary filtration coefficient (by 75%) when compared with values from control rats. The transcapillary oncotic pressure gradient was not altered by diabetes. Interstitial fluid pressure, calculated from the measured parameters in the Starling equation, was increased from -1.6 mmHg in control rats to +2.5 mmHg in diabetic animals. Analysis of lymph-to-plasma protein concentration ratios at various lymph flows suggests that the osmotic reflection coefficient in the diabetic intestine is comparable to that obtained in control animals. The results of this study indicate that experimental diabetes mellitus is associated with increases in intestinal capillary pressure and capillary filtration rate but that intestinal capillary permeability is not altered in this disorder.

Effect of histamine on microvasculature of isolated dog gracilis muscle

1975 ◽  
Vol 229 (1) ◽  
pp. 119-125 ◽  
Author(s):  
JE McNamee ◽  
FS Grodins
Keyword(s):  
Reflection Coefficient ◽  
Capillary Pressure ◽  
Plasma Protein ◽  
Protein Concentration ◽  
Gracilis Muscle ◽  
Filtration Coefficient ◽  
Plasma Protein Concentration ◽  
Capillary Filtration ◽  
Average Decrease ◽  
Capillary Filtration Coefficient

Isogravimetric capillary pressure (Pci), capillary filtration coefficient (CFC), and plasma protein concentration were measured before and during adminisistration of histamine in an isolated, independently perfused canine gracilis muscle. Histamine produced an average decrease in Pci of 14.1 mmHg, an increase in CFC of 36-fold, and an increased rate of plasma protein escape of at least 24-fold. These results suggest that histamine reduces the reflection coefficient for protein at the capillary wall and are consistent with predictions of the theory of restricted diffusion assuming that 1-2.5% of available pores increase in radious from 40 to 240 A.

PO2 modulation of paraquat-induced microvascular injury in isolated dog lungs

1990 ◽  
Vol 68 (5) ◽  
pp. 2119-2127 ◽  
Author(s):  
T. Shibamoto ◽  
A. E. Taylor ◽  
J. C. Parker
Keyword(s):  
Latent Period ◽  
Capillary Pressure ◽  
Microvascular Permeability ◽  
Filtration Coefficient ◽  
Base Line ◽  
Capillary Filtration ◽  
Microvascular Injury ◽  
Capillary Filtration Coefficient

We determined the effects of paraquat (PQ) concentrations ranging from 10(-3) to 10(-2) M and three levels of venous PO2 [hypoxia (41 +/- 3 Torr), normoxia (147 +/- 8 Torr), and hyperoxia (444 +/- 17 Torr)] in the presence of 4 x 10(-3) M PQ on microvascular permeability in isolated blood-perfused dog lungs. Capillary filtration coefficient (Kf,c) increased and isogravimetric capillary pressure (Pc,i) decreased 3 h after perfusion with 10(-2) M PQ (n = 7) and 5 h after perfusion with 4 x 10(-3) M PQ (n = 6) but not with 10(-3) M PQ (n = 4). In hyperoxic lungs perfused with 4 x 10(-3) M PQ, Kf,c increased to nine times the base-line value 5 h after PQ [0.15 +/- 0.01 to 1.35 +/- 0.25 (SE) ml.min-1.cmH2O-1.100 g-1]. Pc,i significantly decreased from a base-line value of 9.4 +/- 0.2 to 7.1 +/- 0.4 cmH2O at 3 h. In hypoxic lungs perfused with 4 x 10(-3) M PQ (n = 5), Pc,i and Kf,c changes were not significantly different from those in normoxic lungs treated with PQ. Thus both hyperoxia and an increased dose of PQ shortened the latent period and increased the severity of the PQ-induced microvascular permeability lesion, but hypoxia failed to prevent the PQ damage.

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