Development Of Interstitial Fibrosis Research Articles

Macrophages, monocyte chemoattractant peptide-1, and TGF-beta 1 in experimental hydronephrosis.

Early cellular and molecular derangements have been evaluated as potential pivotal factors for the late development of interstitial fibrosis after experimental hydronephrosis. In this study, we delineated the kinetics of renal cortical macrophage infiltration as well as the cortical expression of transforming growth factor-beta 1 (TGF-beta 1) and monocyte chemoattractant peptide-1 (MCP-1) at 12, 48, and 96 h after unilateral ureteral obstruction (UUO). Interstitial macrophage number in the obstructed kidney versus the contralateral unobstructed kidney (CUK) significantly increased by 12 (11.1 +/- 0.9 vs. 4.5 +/- 0.6), 48 (27.5 +/- 0.9 vs. 4.0 +/- 0.8), and 96 h (71.4 +/- 4.6 vs. 3.2 +/- 0.4) after UUO. MCP-1 mRNA was detected from 12 to 96 h in the obstructed kidney but was absent in the CUK specimens at all time points. Apical tubular MCP-1 expression, on immunolabeling, was present from 12 through 96 h after UUO in the obstructed kidney but not the CUK specimen. On Northern analysis, there were highly significant 2.6-, 5.8-, and 7.0-fold increments in renal cortical TGF-beta 1 mRNA levels at 12, 48, and 96 h, respectively, in the obstructed kidney versus the CUK specimen. Intracellular TGF-beta 1, on immunolabeling, was detected only in the obstructed kidneys of UUO rats at all three time points and was confined to peritubular cells of the renal interstitium. A significant (P < 0.005) correlation (r = 0.95) between interstitial macrophage number and cortical TGF-beta 1 mRNA levels was noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Cyclosporine A has no direct effect on collagen metabolism by cardiac fibroblasts in vitro.

Cyclosporine A has been implicated in the pathogenesis of myocardial interstitial fibrosis observed in heart transplant recipients. However, other confounding variables such as posttransplantation hypertension and rejection episodes may also be responsible for interstitial fibrosis development and associated abnormalities in ventricular diastolic function. Therefore, we examined whether cyclosporine A directly or indirectly affects fibrillar collagen metabolism by cardiac fibroblasts in vitro. Rat cardiac fibroblasts were isolated by collagenase digestion. Subconfluent cultures were then maintained (24 hours) in serum-containing or serum-free medium before addition of cyclosporine A (50-1,000 ng/mL). After an additional 24 hours, total procollagen synthesis, accumulation, and degradation were analyzed by measuring hydroxyproline content in the cell monolayer and in the ethanol-soluble and ethanol-precipitable fractions of the culture medium. mRNA levels for alpha 1(I) and alpha 1(III) procollagen polypeptides were assessed 2, 6, 12, and 24 hours after cyclosporine A treatment using Northern blot analysis. The results were compared with control cultures maintained in the absence of cyclosporine A. There were no differences in procollagen gene expression, total procollagen synthesis, accumulation, or degradation in cardiac fibroblasts treated directly with cyclosporine A, in concentrations up to 1,000 ng/mL, compared with untreated cells. In additional experiments, we examined whether cyclosporine A might stimulate the production of collagen regulatory substances by cardiac myocytes in culture. However, addition of conditioned media from neonatal myocytes maintained in the presence and absence of cyclosporine A (1,000 ng/mL) also had no effect on collagen deposition by cardiac fibroblasts. We conclude that cyclosporine A has no direct effect on collagen metabolism by cultured cardiac fibroblasts in vitro. In addition, we have excluded a paracrine effect of ventricular myocytes on collagen production in the presence of cyclosporine A. These results suggest that factors other than cyclosporine A are responsible for the interstitial fibrosis observed in cardiac allografts.

Motor neuron syndrome in the arms after radiation treatment.

The pathophysiologic sequelae of both acute and chronic experimental unilateral ureteral obstruction (UUO) in the rat are the result of a variety of complex humoral and cellular interactions. The development of interstitial fibrosis is dependent on the tightly coupled regulation of synthesis and degradation of extracellular matrix proteins. This laboratory, among others, has shown an up-regulated expression of renal cortical transforming growth factor (TGF)-beta 1 within hours of the onset of UUO. Because a potential contribution of TGF-beta to fibrosis may be its ability to increase the expression of proteinase inhibitors such as members of the tissue inhibitor of metalloproteinase (TIMP) family, this laboratory now sought to delineate the kinetics of TIMP-1, TIMP-2, and TIMP-3 mRNA expression in the renal cortex after UUO. There was a marked elevation of TIMP-1 mRNA expression after UUO, which was first noted at 12 h after ureteral ligation. By 96 h after UUO; there was a 30-fold increment in TIMP-1 mRNA in the obstructed kidneys compared with the contralateral unobstructed kidney or sham-operated rat specimens. In contradistinction to TIMP-1, a decrease in TIMP-3 mRNA levels was noted at 12 h after ureteral obstruction and persisted at the 24-, 48-, and 96-h time intervals. TIMP-2 gene expression remained at a relatively constant level during the entire study. It is proposed that the increased expression of TGF-beta 1 post-UUO induces a profibrogenic state and initiates a cascade of dysregulatory events including the up-regulation of TIMP-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchoalveolar Lavage in Liquid Paraffin Pneumonitis

We evaluated cells and lipids recovered in the bronchoalveolar lavage fluid from seven patients with liquid paraffin pneumonitis. For each patient, the BALF was whitish with oil droplets on the surface. Alveolar macrophages contained numerous, large vacuoles that did not react with May-Grunwald-Giemsa, Papanicolaou, or periodic acid-Schiff but were stained in black with Sudan B, orange with Sudan III and red with oil Red O. Liquid paraffin was identified on thin layer chromatography of BALF-extracted lipids as a very hydrophobic compound migrating on the solvent front as control liquid paraffin. This abnormal spot was definitely identified as liquid paraffin by infrared spectroscopy and gas liquid chromatography for the first patient. The number and percentage of AMs were largely decreased in the BALF of each patient, whereas the number of neutrophils, eosinophils and lymphocytes was increased. These findings suggest that this cell-mediated inflammatory response plays a role in the development of interstitial fibrosis at late stages of liquid paraffin pneumonitis.

Bronchoalveolar lavage in patients with mild and severe rheumatoid lung disease.

The reported prevalence of interstitial lung disease in patients with rheumatoid arthritis has varied from 10% to 50%, yet less than 5% of patients with arthritis develop severe fibrosing interstitial lung disease. This suggests that subclinical disease may not always presage progressive disease. Bronchoalveolar lavage fluid from patients with rheumatoid arthritis and either clinically evident interstitial lung disease or subclinical disease was examined for the presence of factors with a putative role in the development of interstitial fibrosis. Patients with subclinical disease were identified by prospective radiographic and lung function screening of 93 patients with rheumatoid arthritis. Fourteen patients were identified in this manner and an association between subclinical disease and smoking history was noted. Eleven patients with established interstitial lung disease had increased neutrophils (p less than 0.05), collagenase, and type III procollagen N terminal peptide levels (p less than 0.01) in the bronchoalveolar lavage fluid. Preliminary characterisation of the bronchoalveolar lavage collagenase suggested that it originated from neutrophils. Ten patients with subclinical interstitial lung disease underwent bronchoalveolar lavage. Of these, one had increased neutrophils and two had increased collagenase concentrations--abnormalities associated with advanced interstitial lung disease and a poor prognosis. These results suggest that in arthritis patients with evidence of subclinical pulmonary interstitial disease bronchoalveolar lavage might be useful in identifying those who may require careful monitoring in the hope that early treatment will prevent severe fibrosis.

Inhibition of lung damage caused by paraquat with lymphokines or cytokines

Gramoxone, containing paraquat as an active ingredient can cause severe lung injury in both humans and experimental animals. Biologically active fibroblast-stimulating factors produced by lymphocytes and macrophages may be of importance in the development of interstitial fibrosis. In our present study we have attempted to inhibit the process of paraquat induced lung fibrosis by lymphokine-enriched supernatants from concanavalin A stimulated spleen cell cultures. It was found that adequate supernatant treatment significantly reduced PQ-induced lung injury and its associated inflammatory response.

Monocyte-derived growth factors in asbestos-induced interstitial fibrosis

Asbestos-induced pulmonary fibrosis is thought to result from a series of cellular interactions involving the alveolar macrophage and the lung fibroblast. Although a dose-response relation has been established between asbestos exposure and the development of interstitial fibrosis, the majority of workers exposed even to high concentrations of asbestos do not develop radiographically evident interstitial fibrosis. As a means of understanding the pathogenesis of asbestos-induced fibrosis and the differential host response to the asbestos fiber, we studied the production of monocyte-derived growth factors in subjects with asbestosis (N = 5) and normal exposure-matched controls (N = 5). Under unstimulated culture conditions, the conditioned medium (CM) from monocytes from control subjects had a greater proliferative effect on fibroblasts than monocyte CM from patients with asbestosis. With CM from concanavalin A-stimulated monocytes, the proliferative response of the fibroblast was similar in those with asbestosis and control subjects. Freshly isolated monocytes from both normal subjects and patients with asbestosis did not express the gene for the B chain of platelet-derived growth factor (PDGF) as evaluated by hybridization with a PDGF-specific human cDNA probe. After 20 hr of culture in concanavalin A, monocytes from normal subjects expressed the gene for the B chain of PDGF while, under the same culture conditions, none of the monocyte preparations from patients with asbestosis produced mRNA for this growth factor. These data indicate that peripheral blood monocytes from patients with asbestosis compared to exposure-matched controls have a reduced capacity to produce growth factor activity as measured by mitogenic activity and mRNA levels for the B chain of PDGF. These results suggest that peripheral blood monocytes from patients with asbestosis may comprise a less mature population of cells compared to exposure-matched controls.

Experimental chronic pancreatitis in the pig.

Chronic pancreatitis was induced in 22 piglets by dividing all pancreatic attachments to the duodenum; five sham-operated piglets served as controls. Two piglets died of postoperative complications. The animals were autopsied 2, 4, or 6 weeks postoperatively. All operated animals developed chronic pancreatitis. Concomitant with the development of interstitial fibrosis, an increasing progressive atrophy of the exocrine parenchyma occurred, with preservation of the islets of Langerhans. This atrophy and fibrosis were considerable already after 2 weeks. In one piglet only there was some acute inflammation and fat necrosis, whereas all showed at least moderate chronic inflammation, which did not change with time. The growth of the piglets stopped, and all had diarrhoea, which was thought to reflect exocrine insufficiency. Two animals (9%) developed a large pancreatic pseudocyst, and all animals had wide pancreatic ducts. The endocrine function was undisturbed. Intravenous glucose tolerance tests showed that the animals did not become diabetic. This model is appropriate for the study of experimental pancreatitis.

Pulmonary responses to bleomycin-induced injury: an immunomorphologic and electron microscopic study

Intratracheal injection of a small dose of bleomycin in rats induced early alveolar epithelial cell injury and a pneumonitis which subsequently evolved to pulmonary fibrosis. Hydropic degeneration of type I pneumocytes was apparent at 3 days after treatment. Marked interstitial and intra-alveolar pneumonitis developed at 7 days after treatment and was accompanied by hypertrophy and hyperplasia of type II pneumocytes. The inflammatory cell population consisted predominantly of cells with the morphology of large lymphocytes together with a number of eosinophils. Examination by immunoperoxidase and histochemical staining of frozen sections revealed that the lymphoid cells stained positively with the monoclonal antibodies W3/13 and W3/25 but not with other markers. Thus these cells appeared to be helper T lymphocytes. The later development of interstitial fibrosis was accompanied by alveolar microcollapse which contributed to the thickening of alveolar septa observed by light microscopy. The possible role of immunologic and other mechanisms in the pathogenesis of bleomycin-induced pulmonary fibrosis is discussed.

Radiation Injury in Rat Lung: IV. Modification by D-Penicillamine

To determine whether D-penicillamine, known to reduce fibrosis in irradiated rat lung (W. F. Ward, A. Shih - Hoellwarth , and R. D. Tuttle , Radiology 146, 533-537, 1983), also ameliorates radiation injury in the pulmonary endothelium, we measured angiotensin-converting enzyme (ACE) activity, plasminogen activator (PLA) activity, and prostacyclin (PGI2) production in the lungs of penicillamine-treated (10 mg/day, po, continuous after irradiation) and untreated rats from 2 weeks to 6 months after a single dose of 25 Gy of 60Co gamma rays to the right hemithorax. Both ACE and PLA activity in the irradiated right lung of untreated rats decreased dramatically between the 1st and 2nd months after exposure, then reached a plateau through 6 months at approximately 25 and 50% of the normal level, respectively. For the first 2 months after irradiation, penicillamine-treated animals exhibited significantly (P less than 0.05) higher activities of both ACE and PLA than did untreated rats. From 3 to 6 months after irradiation, however, the only significant drug effect on these enzymes was a 25% increase in PLA activity at 6 months. PGI2 production by the irradiated lung of untreated rats increased continuously, and at 6 months was approximately 10 times higher than normal. Penicillamine significantly (P less than 0.05) reduced this hypersecretion, and at 6 months after irradiation, PGI2 production by the lungs of drug-treated rats was only half that of untreated animals. In contrast, the drug had no significant effect on enzyme activities in the lungs of sham-irradiated rats. Thus the antifibrotic agent D-penicillamine delays the onset of radiation-induced enzyme dysfunction in the pulmonary endothelium. In addition at 6 months after irradiation, the lungs of penicillamine-treated rats exhibit 25% more PLA activity and only half as severe a hypersecretion of PGI2 as do the lungs of untreated animals. The drug is most effective in ameliorating endothelial damage during the first 2 months after irradiation, preceding the development of interstitial fibrosis. However, the effect of this penicillamine regimen on pulmonary endothelial function is not as large as its effect on collagen accumulation in irradiated rat lung.

Formation of Asbestos Bodies under the Influence of Parenteral Iron Overload

The effect of parenteral administration of iron (dextran) on the number of asbestos fibers in the lungs, formation of asbestos bodies and the development of interstitial fibrosis was studied in guinea pigs exposed intratracheally to anthophyllite dust. The treatment did not accelerate, either qualitatively or quantitatively, the formation of asbestos bodies or retard the development of interstitial fibrosis. The number of naked asbestos fibers was also similar in anthophyllite-inoculated animals to those similarly inoculated, but having had, additionally, a previous saturation with iron.

Evolution of experimental pneumocystis pneumonia

Pneumocystis carinii pneumonitis was induced in 8 adult Wistar rats by treatment with parenteral cortisone acetate to activate latent endogenous Pneumocystis organisms. Four additional rats served as controls. In the earliest phase isolated pneumocysts were seen intimately related to the alveolar epithelium of otherwise histologically normal lung. The organisms then formed focal mural monolayers, and later, multilayering of cysts occurred, leading to a progressive intra-alveolar accumulation of organisms, together with foamy material and alveolar macrophages. Hyaline membranes were seen in the later stages and there were perivascular lymphoplasmacytic infiltrates. The normally attenuated alveolar epithelium was replaced by cuboidal cells containing fine vacuoles and, occasionally, mitotic figures, suggesting proliferation of type II pneumocytes in response to type I epithelial injury. Interstitial reticulin fibres were increased focally by 49 days of cortisone administration, and by 63 days focal fibrosis was present, in some areas appearing to be related to organization and mural incorporation of hyaline membranes. The development of interstitial fibrosis following pneumocystis pneumonia has previously been recorded in man, but most of the patients had also been exposed to other pulmonary fibrogenic agents such as radiotherapy, cytotoxic drugs, oxygen therapy, and bacterial, fungal or viral infections. The present study suggests that pulmonary pneumocystosis may lead to interstitial fibrosis in some instances.

Radiation Nephritis: A Review

Radiation nephritis is a process of necrosis, atrophy and sclerosis that follows exposure of the kidney to ionizing radiation. Experimental studies with electron microscopy demonstrate that this process begins as degeneration of the glomerular endothelium and the tubular epithelium, and their basement membranes, leading to collapse of these structures and the development of interstitial fibrosis. Rather late and complicating events are necrosis and thrombosis of arteries and arterioles, contributing to the destruction of the renal parenchyma. The process is the same with large doses (5,000 to 10,000 rads) and with medium doses (1,000 to 3,000 rads), the only differences being the extent and the speed with which the lesions develop and the frequency of arterial necrosis.

Diffuse Interstitial Pulmonary Calcification

Diffuse interstitial pulmonary calcification (DIPC)—an unusual complication of several diseases including sarcoidosis, varicella, carcinomatosis, multiple myeloma, primary hyperparathyroidism, chronic renal disease with uremia, the milk-alkali syndrome—develops by either metastatic or dystrophic calcification. Metastatic calcification occurs in most hypercalcemic states, and the calcium deposits in normal visceral tissues, such as the lungs, kidneys, stomach, heart, and blood vessels. Dystrophic calcification, on the other hand, develops at normal serum calcium concentrations, and the calcium deposits in pathologic tissues, possibly by the phenomenon of calciphylaxis. The symptoms and signs of DIPC are completely nonspecific and vary depending on the stage and progression of the disease. Once induced, the calcium continues to deposit in the alveolar septa of the lung and frequently incites the development of interstitial fibrosis. This may lead to restrictive lung dysfunction and mechanically stiff lungs. The clinical expressions of DIPC are frequently masked by the manifestations of the primary disease,