Alterations In Vascular Permeability Research Articles

Human cerebral endothelium: Isolation and characterization of cells derived from microvessels of non-neoplastic and malignant glial tissue

Human microvessels were isolated and cultured from non-neoplastic cerebral tissue specimens resected for the treatment of seizure disorders and from malignant glial tumors. After 1-2 weeks, cobblestone patterned plaques of cells were isolated and cultured from these microvessels. Cell lines positive for Factor VIII antigen and negative for glial fibrillary acidic protein were designated as endothelium. Endothelium from both tissue sources produced gamma-glutamyl transpeptidase in response to glial cell conditioned media. Tumor derived microvessel endothelium had decreased longevity in culture when compared to normal microvessel endothelium. Tumor derived endothelium also formed less extensive intercellular junctional complexes in vitro. The isolation and characterization of human cerebral microvessel endothelium derived from non-neoplastic tissue and glial tumors may lead to a further understanding of the role of endothelium in tumor growth and vascular permeability alterations.

Vascular permeability and coagulation during Rickettsia riekettsii infection in dogs

SUMMARY The vascular permeability of the ocular fundus, alterations in the coagulation system, and plasma concentrations of thromboxane B2 (txb2) and 6-keto-prostaglandin F1α, (6-keto-pgf1α) were studied in dogs following intradermal inoculation with 5 × 105 tcid50 of Rickettsia rickettsii. Twenty-four to 48 hours after the onset of fever and rickettsemia, multifocal areas of retinal vasculitis were evident, which corresponded to areas of altered vascular permeability demonstrated by fluorescein angiography. The number and intensity of retinal vessels with sodium fluorescein leakage peaked during the second week after inoculation, and retinal vascular permeability remained altered during the third week of infection, well past the phase of clinical and clinicopathologic recovery. Development of retinal vasculitic foci was associated with thrombocytopenia, increased concentrations of circulating fibrinogen, and slight prolongation of activated partial thromboplastin time. Increased concentrations of fibrin/fibrinogen degradation products were detected in 4 of 9 dogs. Despite the degree of vascular endothelial damage evident on fluorescein angiographic and histologic studies in these dogs, plasma txb2 and 6-keto-pgf1α concentrations were not increased.

Biochemical and cytologic alterations in the respiratory tract of rats exposed for 4 hours to hydrogen sulfide

Fischer-344 rats were killed by exsanguination 1, 20, and 44 hr after a single 4-hr exposure to an atmosphere of 0, 10, 200, and 400 ppm of hydrogen sulfide (H 2S). Alterations in the activities of lactate dehydrogenase and alkaline phosphatase, and cytomorphology of epithelial cells in fluids obtained by nasal and bronchoalveolar lavage were used as indicators of cell injury. Changes in the number of leukocytes were used as indicators of inflammatory response, and changes in the concentration of protein were used as indicators of altered vascular permeability. Inhalation of H 2S resulted in 139, 483, and 817% increased cellularity in the nasal cavity of rats exposed to 10, 200, and 400 ppm, respectively. This was due to marked exfoliation of degenerated epithelial cells and exudation of neutrophils. The high dose of H 2S resulted in a moderate increase in lactate dehydrogenase and protein in nasal passages; values returned to baseline levels 20 hr later. Bronchoalveolar cell counts were decreased in rats exposed to 400 ppm and unchanged in those exposed to 10 and 200 ppm. Enzymatic activities in lung lavage fluid were moderately elevated (up to 90%), yet protein concentrations were increased by more than 3000% and remained significantly elevated up to 44 hr after exposure to 400 ppm. It was concluded that inhalation of H 2S has a severe cytotoxic effect on the nasal epithelium and a severe edematogenic effect on lung parenchyma. These results are in agreement with autopsy findings of individuals killed by accidental exposure to H 2S-containing sour gas.

Biochemical and Cytologic Alterations in the Respiratory Tract of Rats Exposed for 4 Hours to Hydrogen Sulfide

Fischer-344 rats were killed by exsanguination 1, 20, and 44 hr after a single 4-hr exposure to an atmosphere of 0, 10, 200, and 400 ppm of hydrogen sulfide (H2S) Alterations in the activities of lactate dehydrogenase and alkaline phosphatase, and cytomorphology of epithelial cells in fluids obtained by nasal and bronchoalveolar lavage were used as indicators of cell injury. Changes in the number of leukocytes were used as indicators of inflammatory response, and changes in the concentration of protein were used as indicators of altered vascular permeability. Inhalation of H2S resulted in 139, 483, and 817% increased cellularity in the nasal cavity of rats exposed to 10, 200, and 400 ppm, respectively. This was due to marked exfoliation of degenerated epithelial cells and exudation of neutrophils. The high dose of H2S resulted in a moderate increase in lactate dehydrogenase and protein in nasal passages; values returned to baseline levels 20 hr later. Bronchoalveolar cell counts were decreased in rats exposed to 400 ppm and unchanged in those exposed to 10 and 200 ppm. Enzymatic activities in lung lavage fluid were moderately elevated (up to 90%), yet protein concentrations were increased by more than 3000% and remained significantly elevated up to 44 hr after exposure to 400 ppm. It was concluded that inhalation of H2S has a severe cytotoxic effect on the nasal epithelium and a severe edematogenic effect on lung parenchyma. These results are in agreement with autopsy findings of individuals killed by accidental exposure to H2S-containing sour gas.

O2 radicals in arachidonate-induced increased blood-brain barrier permeability to proteins.

We studied the effect of topical application of arachidonate on the brain surface on blood-brain barrier permeability to either 125I-labeled human albumin or to horseradish peroxidase administered intravenously. Arachidonate was applied under a cranial window, and the concentration of albumin was measured in brain after elimination of the blood by perfusion-fixation. Permeability to 125I-labeled albumin was increased in the superficial 4 mm of the cortex but not in the deeper cortical layer 4-6 mm from the surface. This increased permeability to albumin was prevented by simultaneous topical application of superoxide dismutase (60 U/ml) and catalase (40 U/ml). Alterations in vascular permeability to horseradish peroxidase were evaluated in semiquantitative fashion, and they behaved similarly. Extravasated horseradish peroxidase was found in the wall of penetrating arterioles, and to a lesser extent in the wall of intraparenchymal vessels and capillaries, but not in the wall of pial arterioles or veins, although these latter vessels displayed focal endothelial lesions. We conclude that arachidonate increases the blood-brain barrier permeability to proteins. This increase in permeability is mediated by O2 radicals. The increased permeability occurs primarily in penetrating arterioles and not in pial arterioles or veins.

Human Hypersensitivity Angiitis, An Immune Complex Disease

Human hypersensitivity angiitis is an immune complex disease in which patients present with palpable purpuric lesions of the skin and may often have multiple organ involvement. The antigen may be derived from an infectious organism such as the hepatitis virus, streptococcus, or a drug, and complexes with antibody. Under circumstances of vascular turbulence or vessel wall dilatation this complex may become fixed, activating the complement sequence with elaboration of chemotactic factors for neutrophils. These cells release lysosomal enzymes resulting in vessel wall destruction. Red blood cells leak into the tissue producing purpura and the inflammatory infiltrate accounts for the palpability. Although many patients have skin lesions only, others may have involvement of joints, gastrointestinal tract, kidneys, and even the lungs. The central question in the pathogenesis of this disease is why the immune complex is so selective in its site of deposition. Part of the reason must be related to the lattice formation of a particular complex, while other reasons are related to host factors of altered vascular permeability, integrity of clearance mechanisms or even a genetically determined defect of the phagocytic system.

Evidence for a Direct Effect on Vascular Permeability of Platelet-Activating Factor Induced Hemoconcentration in the Guinea Pig

The ability of synthetic platelet-activating factor (PAF) given intravenously to produce loss (extravasation) of protein rich plasma (resulting in hemoconcentration) has been examined using guinea pigs. Hemoconcentration induced by PAF was not prevented by prior administration of inhibitors of thromboxane synthetase (7-(3-pyridyl)heptanoic acid, UK-37,248-01), PGI2, aspirin, indomethacin or antiserum induced thrombocytopenia. Calcium channel blockers (nifedipine, verapamil, diethylamino octyltrimethoxybenzoate, diltiazem), antihistamines (pyrilamine, cimetidine, diphenhydramine), or the elevator of cAMP IBMX were ineffective in blocking PAF-induced hemoconcentration. In contrast, CV-3988, reported to be a specific antagonist to PAF, was 98% inhibitory of PAF extravasation when given i.a. at 3.5 mg/kg. The ED50 was 0.14 mg/kg I.A. and 15 mg/kg p.o. against 75 ng/kg PAF. These data suggest that PAF-induced hemoconcentration involves receptor mediated alterations of vascular permeability that are inhibited by a specific PAF antagonist.

Participation of Mast Cells and Complement in the Immediate Phase of Hematoporphyrin-Induced Phototoxicity

We have investigated the roles of mast cells and the complement system in the immediate phase of hematoporphyrin-induced phototoxicity in guinea pigs. Clinically, i.v. injection of hematoporphyrin, followed by irradiation with a light source containing 400-405 nm wavelength, resulted in the immediate onset of erythema and edema, which subsided partially in 30-60 min. This was followed by the appearance of delayed erythema and edema, which peaked at 6-12 h after irradiation. Histologic examination of the response of the immediate phase, using a 1 micron-thick section, revealed eosinophil infiltration and mast cell degranulation. The immediate phase of the clinical response was further quantitated by the extravasation of intravenously injected [125I]bovine serum albumin. Pretreatment of the guinea pig skin with the intradermal injection of compound 48/80 significantly suppressed the increase in vascular permeability induced by hematoporphyrin and irradiation (p less than 0.05). This hematoporphyrin-induced alteration in vascular permeability was also significantly inhibited by antihistamines, either H1 receptor antagonist alone (p less than 0.05) or a combination of H1 and H2 receptor antagonists (p less than 0.05). Guinea pigs depleted of complement also showed significantly less vascular permeability changes (p less than 0.05). These results indicate that functionally intact mast cells, and the complement system, are required for the full development of the immediate phase of phototoxicity induced by hematoporphyrin.

Modification of the clinical and histopathologic expression of experimental allergic encephalomyelitis by the vasoactive amine antagonist cyproheptadine

Experimental allergic encephalomyelitis (EAE) is an autoimmune syndrome that can be induced in Lewis rats by myelin basic protein (BP) in complete Freund's adjuvant (CFA). Rats that have recovered from a primary episode of EAE display paradoxical long-term resistance to EAE reinduction by BP-CFA. Previous observations indicated, however, that clinical disease could be reinduced in convalescent rats by a concomitant secondary challenge with BP-CFA + Bordetella pertussis extract (PERT). Vascular permeability changes in the central nervous system (CNS) paralleled disease reinduction. To further probe the relationship between disease reinduction and vascular permeability, convalescent rats were treated with the vasoactive amine antagonist cyproheptadine (CYP) prior to a secondary challenge with BP-CFA + PERT. Data presented here indicate that CYP treatment results in substantial protection of convalescent rats from clinical disease reinduction by BP-CFA + PERT. CYP did not, however, prevent the development of new CNS lesions. CYP therapy also altered the clinical course of EAE induced by a primary injection of BP-CFA + PERT. In these rats, there was a delay in the onset of clinical signs as well as in the appearance of CNS lesions. Nevertheless, both CYP-treated and untreated naive rats challenged with BP-CFA + PERT eventually developed severe and usually lethal EAE. The effect of CYP on EAE induced in naive rats without including PERT in the sensitization protocol was also evaluated. In contrast to the mitigating effect of CYP on EAE induced or reinduced by BP-CFA + PERT, CYP treatment did not affect the clinical course or the development of CNS lesions in rats challenged with BP-CFA alone. Likewise, the passive transfer of EAE, mediated by mitogen-stimulated cells obtained from BP-CFA-sensitized donors, was not affected by CYP treatment. Collectively, these data indicate that CYP therapy altered the expression of EAE induced by regimens that included PERT, but did not affect EAE induced without PERT. In view of the opposing effects of PERT and CYP on vascular permeability, these data are consistent with the hypothesis that alterations in vascular permeability may play a crucial role in controlling the expression of autoimmune neurological diseases.

Effect of forskolin on alterations of vascular permeability induced with bradykinin, prostaglandin E 1, adenosine, histamine and carrageenin in rats

The effect of the diterpene forskolin on vascular permeability alone and in combination with bradykinin, prostaglandin E 1, adenosine or histamine has been investigated in rats. Vascular permeability in rat skin was measured using [ 125I]-labelled bovine serum albumin ([ 125I]BSA) as a tracer. In addition, the effect of forskolin on footpad edema induced by the injection of a mixture of 2% carrageenin was determined. Forskolin caused a marked potentiation of the increase in vascular permeability in rat skin elicited by the intradermal injection of histamine or bradykinin. However, forskolin caused a significant suppression of the prostaglandin E 1-induced vascular permeability response and at a low concentration suppressed the response to adenosine. Forskolin greatly potentiated the footpad edema induced with carrageenin in rats. Intravenous administration of the enzyme bromelain, which reduces plasma kininogen levels, inhibited the footpad edema induced with carrageenia or with a mixture of carrageenin and forskolin. Parenteral administration of a prostaglandin synthetase inhibitor, indomethacin, suppressed the footpad edema induced with carrageenin, but did not inhibit the footpad edema induced with a mixture of carrageenin and forskolin. An antihistamine, cyproheptadine, had no effect on carrageenin-induced footpad edema either in the presence or absence of forskolin. These results suggest that both bradykinin and prostaglandins are essential for the development of carrageenin-induced footpad edema and that bradykinin plays an important role in the potentiative effect of forskolin on footpad edema induced with carrageenin in rats.

Immune Aspects of Renal Diseases

IMMUNOLOGIC renal injury can be mediated by immune complexes or by free antibody that interacts with native or tissue-bound antigen. RENAL DISEASE MEDIATED BY IMMUNE COMPLEXES The most common mechanism of renal injury involves deposition of immune reactants in the kidney. Circulating immune complexes must have certain physical and biologic properties to be able to localize in tissues and cause injury. Complexes of large size, for example, those at equivalence, are poorly soluble and disposed of by cells of the mononuclear-phagocyte system. Complexes of very small size, formed in extreme antigen excess, are soluble and have limited nephrotoxicity because they do not fix complement. Complexes that are formed in slight antigen excess are both soluble and able to fix complement; such complexes may be nephrotoxic. Whenever appropriate antibodies interact with antigen, the complement system may be activated. Activation of the complement system can lead to alterations in vascular permeability (and

Microscopic study of increased vascular permeability and leucocyte emigration in the chicken wing web

The components of an acute inflammatory response in the chicken were investigated using a combination of histological and colloidal carbon techniques. The experimental model was the inflammatory reaction induced by the subcutaneous injection of turpentine or carrageenin into the wing web. Increased vascular permeability was shown to be mainly venular in origin. There did not appear to be an ordered migration of heterophils and monocytes and the process was unrelated to altered vascular permeability. Special features distinct from acute mammalian inflammation included a basophilic response, giant cell formation and the development of perivascular lymphoid foci.

On the significance of C2, C4, and factor B polymorphisms in disease.

In this review article, recent evidence is presented that some diseases like insulin-dependent diabetes mellitus, multiple sclerosis, and idiopathic membranous nephropathy, which are primarily associated with HLA-D,DR, are also related to the rare C2, C4, and Factor B alleles. Circumstantial evidence is available that at least some of these rare variants may be functionally deficient. Based on the concept of functionally interacting gene clusters, mutant complement genes may lead to impaired effector mechanisms in virus neutralization or lysis of virus-infected cells. Other mechanisms such as alteration of vascular permeability may be involved in the development of proliferative retinopathy and familial hypertension. In lepromatous lepra, an impaired cell-mediated lysis of M. leprae may be related to the hemolytically inactive C4F1 allelic product.

Alteration of vascular permeability due to cytochalasin E

Cytochalasin E increased the vascular permeability of the rat. It induced leakage through the endothelial gaps of the venules and capillaries without affecting the arterioles.

Relationship between inhibition of aortic histamine formation, aortic albumin permeability and atherosclerosis

Effects of partial inhibition of aortic histamine formation on aortic albumin uptake and lipid deposition were examined in male, New Zealand white rabbits maintained on Purina Rabbit Chow containing 0.5% cholesterol for a 2-week period. Aortic histamine synthesis was inhibited by partial inhibition of aortic histidine decarboxylase (HD) through administration of α-hydrazinohistidine (α-HH, MK785, Regis Chemical Co., 25 mg/kg, i.p. at 12-h intervals). Additional rabbits were maintained on either the cholesterol diet or on Purina Rabbit Chow without cholesterol. Results indicate that administration of α-HH for the 2-week period produced a 31% reduction ( P < 0.05) in aortic HD activity in those rabbits maintained on the cholesterol diet, and that concurrently there was a 51% reduction in aorta albumin uptake ( P < 0.025) and a 63% reduction in the extent of oil red O staining. By regression analysis a significant correlation coefficient ( r = 0.71, P < 0.005) was obtained between the aortic albumin uptake and the aortic histamine forming capacity (HFC) in rabbits maintained on this cholesterol diet. These findings indicate that the aortic HD system may be an important enzymatic coupler involved in vascular permeability alterations occurring early in the atherogenic sequence.

The Structural Basis of Altered Vascular Permeability Following Intraocular Inflammation

An immunogenic uveitis was produced in rabbits by the intravitreal injection of bovine gamma-globulin. Four to six months later, an alteration in vascular permeability was determined by greater accumulation of iodinated I 125 serum albumin in the previously inflamed eye than in the normal eye. An altered vascular permeability was found only in eyes with profound structural changes. Possible sites of extravascular protein leakage were: (1) proliferated blood vessels in the posterior chamber and vitreous; and (2) leakage through the disrupted and scarred ciliary epithelium. In eyes without evidence of altered vascular permeability, a persistent chronic inflammation was observed, and gliosis and chorioretinal scarring was prominent.

Vascular permeability alterations to horseradish peroxidase in experimental brain injury

Protein uptake and transport within the brain stem vasculature of mechanically brain injured cats was studied by means of both light and electron microscopy utilizing intravenously injected horseradish peroxidase as the protein tracer. In animals sustaining low grade head injuries not of sufficient intensity to elicit either microscopic, intraparenchymal hemorrhages or subtle, neuropathological responses, peroxidase extravasation was noted both in the vascular walls and in the surrounding parenchyma of the ventromedial aspect of the brain stem. At the ultrastructural level as early as 3 min after brain injury, occasional arterioles, venules and capillaries displayed peroxidase leakage. In serial sections large endothelial segments of these vessels revealed the peroxidase reaction product within numerous vesicles which often shared continuity with tubular and vacuolar profiles. Such vesicular activity apparently moved the peroxidase from the luminal surface to extrude it into the basal lamina. From the perivascular basal lamina, the reaction product flooded the interstices of the surrounding brain stem parenchyma where occasional neural, glial and pericytic elements incorporated the peroxidase within coated invaginations, vesicles, tubules and vacuoles. In that protein leakage was consistently observed despite the apparent integrity of both the endothelial tight junctions and their cell membranes, it is concluded that the vesicular transport of horseradish peroxidase across the endothelia of the brain stem vasculature represents a possible mechanism of blood-brain barrier dysfunction in mechanical brain injury.

Morphological changes of labyrinthine blood vessels following metal poisoning.

Metal intoxication (mercury and arsenic) in guinea pigs may cause damage to labyrinthine blood vessels by swelling of the endothelial cells, mitochondrial disintegration and sometimes protrusion of endothelial cell cytoplasm herniating into the blood vessel lumen. Chronic mercury intoxication resulted in distorted endothelial cells with an increase in the density of their cytoplasm. An altered vascular permeability is likely to occur as the result of the morphological changes.

Perifoveal vascular leakage and macular oedema after intracapsular cataract extraction.

Perifoveal capillary leakage of fluorescein was demonstrated in 60 per cent of 50 eyes when angiography was performed two weeks after cataract extraction. Repeat angiography six weeks postoperatively in 17 eyes demonstrated persistence of already established leakage in 11 of 12 eyes and no new leakage in five eyes previously negative. Cystoid macular oedema with visual acuity of less than 20/40 six weeks postoperatively occurred in five eyes (10 per cent). Eyes of patients with vascular disease and those patients of 60 years or older were found to have altered vascular permeability significantly more frequently. Inflammation was no more severe or prevalent in those patients who demonstrated leakage and no inflammation was clinically apparent in 10 of 11 eyes demonstrating dye leakage six weeks postoperatively. We conclude that the constitutional factors of age and vascular disease are of prime importance in causing altered vascular permeability in the early postoperative period after cataract extraction; factors causing sustained leakage with reduction of visual acuity were not demonstrated.

Circulating immune complexes. Effects on ocular vascular permeability in the rabbit.

Sudden transient, alteration in vascular permeability is producible in rabbit eyes by intravenous injection of large quantities of antigen, bovine gamma-globulin (BGG), into immunized animals or by intravenous injection of large amounts of antigen-antibody complexes (BGG-antiBGG) prepared in antigen excess (20 to 25times) in normal rabbits. Change is measured by ocular accumulation of iodinated I125 serum albumin, relative to that in heart blood, in intact eyes and separate anatomical compartments, in aqueous, in the anterior eye including (lens plus vitreous), and in the posterior segment. Primarily affected are vessels in the iridial portion of ciliary processess; edema is the primary finding. The same vessels are affected by intravenous injection of bacterial endotoxin, but compared with endotoxin, altered vascular permeability is short-lived and is not associated with formation of platelet plugs and intravenous fibrin strands.