Acute lung injury: clinical concept and experimental approaches to pathogenesis

Acute lung injury (ALI) was defined recently as a syndrome of inflammation and increased permeability of the lungs that is associated with clinical radiologic, and physiologic abnormalities that can not be explained by left atrial hypertension. ALI has the same clinical spectrum, although in a milder form, as acute respiratory distress syndrome (ARDS). The risk factors, incidence, and prognosis of ALI are described based on the medical literature and data collected at Keio University Hospital. We estimate that 20,000 to 40,000 cases of ALI, half of which also have ARDS, occur annually in Japan. Despite the new diagnostic criteria, the clinical entity of ALI remains to be clarified both physiologically and biochemically because of the lack of direct diagnostic methods. I briefly review the central mediator(s) and their role in the inflammatory cascade of ALI. Experimental studies and pharmacological interventions from our laboratory are also described.

[Roles of inflammatory cells in the pathogenesis of acute lung injury in guinea pigs exposed to heat-killed bacteria]

To study the contribution of polymorphonuclear (PMN) and mononuclear (MN) phagocytes to the development of acute lung injury, we studied lung injury after intratracheal instillation of lipopolysaccharide (0.02 mg/kg) in guinea pigs previously exposed to heat-killed Corynebacterium parvum. In on group, cyclophosphamide was given to deplete peripheral PMNs. In another group, gadolinium chloride (GdCl3) was injected to suppress the function of MNs. Four hours after instillation of lippoly soccharide, the animals were killed, bronchoalveolar lavage was done, and the lungs were examined histopathologically. 125I-labeled albumin was injected to estimate the endothelial damage, and 131I-labeled albumin was injected to correct for blood contamination in the samples. In the group given cyclophosphamide, lung injury was no less than in the control group. In contrast, lung injury was less sever in the group given GdCl3 than in the control group. These findings suggest that MN are important in the pathogenesis of lung injury, especially in individuals who are immunologically primed by infection.

Linear and angular measurements of the mandible during maximal mouth opening

PURPOSE

There are numerous reports of the translatory movement of the condyle in maximal mouth opening; however, the rotatory movement is less well understood. The purpose of this study was to investigate the rotatory condylar movement and the factors associated with it in normal subjects.

PATIENTS AND METHODS

To study the role of facial morphology in maximal mouth opening, linear and angular measurements of the mandible in both the closed and maximal open positions were made by means of cephalometry. Dental students, 29 men and 31 women with no functional disorders of the masticatory system, were investigated.

RESULTS

When the mouth was fully opened, the linear measurement of condylar movement was 20.5 +/- 4.0 mm in men and 18.1 +/- 2.5 mm in women, and the angular measurements of the rotation of the mandibular ramus were 39.1 +/- 5.9 degrees in men and 36.3 +/- 4.3 degrees in women. These differences were statistically significant (P < .01).

CONCLUSIONS

During condylar movement and rotation of the mandible, mandibular length and the inclination of the mandibular ramus in the former, and the inclination of the mandibular ramus, the mandibular angle and the position of the condyle in the latter, were important factors.

Cell-associated IL-8 in human blood monocytes: analysis by flow cytometry

Several cell-associated cytokines, such as interleukin-1 (IL-1) and tumor necrosis factor, exist on the cell surface and are biologically active. Although extracellular IL-8, a potent chemotactic factor for primarily neutrophils, has been studied extensively, cell-associated IL-8 has barely been studied. In this study, we analyzed the intracellular and cell-surface IL-8 in human blood monocytes in vitro by using flow cytometry and predicted the biological activity of the cell-associated IL-8 in vivo. After fixation with paraformaldehyde, mononuclear cells were divided into two subgroups. One subgroup was left untreated to study cell-associated antigens, and the other subgroup was permeabilized with saponin to detect intracellular antigens. In lipopolysaccharide (LPS)-stimulated monocytes, IL-8 was detected solely intracellularly, whereas both the intracellular and cell-surface IL-1 beta was detectable. In a time-course study, the intracellular IL-8 increased in response to LPS stimulation, but the cell-surface IL-8 was undetectable throughout the course. In an LPS-stimulated monocytic cell line, both ELISA and flow cytometry detected the quantitative change of the intracellular IL-8. The dissimilar localization between IL-8 and IL-1 beta within cells was confirmed by the immunohistochemical analysis. In summary, LPS stimulation induced a time-dependent increase in intracellular but not cell-surface IL-8 in monocytes. Thus, it is unlikely that the cell-associated IL-8 is functioning physiologically. The semiquantitative flow cytometric procedure may be useful for simultaneous examination for cell-surface and intracellular cytokines.

[K-ras gene mutations in adenomas from familial adenomatous polyposis]

A 18-year-old woman underwent total colectomy for familial adenomatous polyposis. In order to clarify the significance of K-ras mutations in early colorectal carcinogenesis, K-ras mutations were analyzed in multiple adenomas by PCR-SSCP method. A total of 256 adenomas were found throughout the entire colon and rectum, and the distribution was a sparse type. The correlation between K-ras gene and clinicopathological factors was examined in 90 adenomas. There was no correlation among K-ras mutations and anatomical distribution, or morphological classification, but K-ras mutation was more frequent in severe compared with slight atypia. We investigated the correlation between the size of adenoma in the horizontal and vertical directions and K-ras mutation. K-ras mutation was more frequent in the horizontal size greater than 6 mm in diameter, and also more frequent in vertical size greater than 20 mm in height. It was concluded that the adenomas detecting K-ras mutations might have proliferating potential, and would be applied to determine polypectomy.

Therapeutic advantages of angiotensin converting enzyme inhibitors in chronic renal disease

More than other drugs, angiotension converting enzyme (ACE) inhibitors have been shown to provide better control of glomerular hypertension and improved preservation of renal function. Long-term treatment with captopril slows the progression of renal impairment in diabetic nephropathy; however, the data are inconclusive for non-diabetic nephropathies. ACE inhibitors such as captopril, enalapril, alacepril delapril cilazapril, and lisinopril were equally effective in reducing blood pressure in multicenter clinical trials focusing on renal hypertension in Japan. We studied the influence of ambulatory blood pressure (ABP) and the effects of hypertension therapy in 104 patients with chronic renal glomerulonephritis as diagnosed by renal biopsy. Patients were subdivided into hypertensive, normotensive and hypotensive groups according to ABP and ages. Hypotensive subjects showed an improvement, while normotensive subjects showed a slower rate of progression of renal function loss than hypertensive patients. This suggests that the adequate ABP levels were 100 to 125/55 to 75 in those who were less than 40 years old, 100 to 135/60 to 80 mm Hg in patients aged 40 to 60, and 105 to 140/60 to 85 mm Hg in those over 60 years old. The renal protective effects of calcium antagonists and ACE inhibitors were associated with a reduction in blood pressure, but not with the hypotensive action.

[Effects of intravenous 2-chloroadenosine on endotoxin-induced acute lung injury]

To assess the effects of 2-chloroadenosine (2CA) on acute lung injury caused by endotoxin (lipopolysaccharide), guinea pigs were given 2CA intravenously. Three groups were used: saline control, endotoxin control and 2CA+ endotoxin. In the endotoxin and 2CA+ endotoxin groups, neutrophils accumulated in bronchoalveolar lavage fluid and in lung tissue. However, neutrophil accumulation did not differ significantly between the endotoxin and the 2CA+ endotoxin groups. The number of macrophages in bronchoalveolar lavage fluid was significantly higher in the endotoxin group than in the saline control group, but the difference between the saline control and the 2CA+ endotoxin groups was not significant. The lung wet-dry weight ratio and 125I-albumin lung tissue-plasma ratio, which were used to measure acute lung injury, were significantly higher in the endotoxin group than in the 2CA+ endotoxin and the saline control groups. However, these ratios did not differ between the 2CA+ endotoxin and the saline control groups. These results suggest that 2CA attenuated endotoxin induced acute lung injury in guinea pigs.

Augmentation of endotoxin-induced pulmonary responses by mononuclear cell phagocytosis in the reticuloendothelial system

OBJECTIVE

To test the hypothesis that the effects of intravenous injection of latex particles would demonstrate the contribution of phagocytosis by mononuclear phagocytes to the development of Escherichia coli-induced acute lung injury in neutropenic guinea pigs.

DESIGN

Prospective, controlled, experimental study. Intravenously injected the latex particles into 41 guinea pigs to investigate the contribution of the phagocytosis in acute lung injury.

SUBJECTS

Forty-one guinea pigs.

INTERVENTIONS

Forty-one guinea pigs were divided into five experimental groups: a saline group (n=9); an endotoxin group (n=10) receiving 2 mg/kg of intravenous E. coli endotoxin; a latex group (n=7) receiving 2 x 10(9)/kg of intravenous polystyrene latex (mean diameter 3.19 micrometers); an endotoxin + latex group (n=8); and an E. coli group (n=7) receiving 2 x 10(9) live E. coli/kg.

MEASUREMENTS AND MAIN RESULTS

The lung wet/dry ratio was increased in the live E. coli-treated guinea pigs (6.71 +/- 0.16 [SEM], p < .01) as compared with the saline control (5.40 +/- 0.16, whereas the ratio was not increased in the endotoxin (5.52 +/- 0.14) or latex (5.58 +/- 0.20) groups. However, the lung wet/dry ratio was greater in the endotoxin + latex group (6.11 +/- 0.16, p < .05) than in the saline control. The 125I albumin lung tissue/plasma ratio was greater in the E. coli (2.00 +/- 0.29, p < .01) and endotoxin + latex (0.84 +/- 0.12, p < .05) groups than in the saline group (0.18 +/- 0.07), whereas no increases were observed in the endotoxin group (0.22 +/- 0.10) and the latex (0.34 +/- 0.13) group. More than 40% of the injected radiolabeled latex was observed to have accumulated in the reticuloendothelial system (liver and spleen), in both the saline control (40.1 +/- 2.3%, n=4) and endotoxin (57.3 +/- 6.8%, n=5) groups, with 2.6 +/- 1.5% and 3.1 +/- 1.7% in the lungs for the saline control and the endotoxin groups, respectively. The percent deposition of radiolabeled latex in the liver was greater in the endotoxin group (51.7 +/- 3.8%, p < .05) than in the saline group (37.6 +/- 5.9%).

CONCLUSIONS

These findings suggest that, in neutropenic guinea pigs: a) the combination of endotoxin and latex particles induces acute lung injury; and b) the phagocytic properties of mononuclear phagocytes in the reticuloendothelial system augment endotoxin-induced pulmonary responses and may play a role in the development of live E. coli-induced acute lung injury.

Flow cytometric detection of cell-associated cytokines in alveolar macrophages

To elucidate the cytokine-producing capacity of alveolar macrophages (AMs), we have introduced a method of flow cytometry combined with saponin treatment to detect the cell-associated cytokines. We studied bronchoalveolar lavage fluid cells from six patients with sarcoidosis (SAR) and six control (CTL) subjects. Cells were either left uncultured, or cultured with and without lipopolysaccharide (LPS), then treated with paraformaldehyde and saponin and analysed for cell-associated interleukin-1 beta (IL-1 beta) and tumour necrosis factor-alpha (TNF-alpha) by flow cytometry. Cell-associated IL-1 beta and TNF-alpha were also analysed by immunoassays. The flow cytometric cytokine values were correlated with the immunoreactive cell-associated cytokines (IL-1 beta: r = 0.45, p < 0.05; TNF-alpha: r = 0.82, p < 0.001). The histograms of cell-associated IL-1 beta yielded a single peak both in the patients and controls, whereas the histograms of cell-associated TNF-alpha exhibited two peaks in SAR patients, but just a single peak in the CTL subjects. The mean value of the cell-associated TNF-alpha in LPS+ AMs was higher in the SAR patients than in the CTL subjects (p < 0.001). In conclusion, the flow cytometric method can be applied to the semiquantitative detection of cell-associated cytokines in alveolar macrophages at the single cell level.

[Pneumonia caused by varicella-zoster virus in a patient with rheumatoid arthritis]

A 56-year-old woman suffering from rheumatoid arthritis, was admitted to our hospital for evaluation of fever and dyspnea. A month before admission, she had been given a diagnosis of herpes zoster and was treated with an antiviral agent. However, a perineal eruption persisted. A chest X-ray film and a chest CT scan showed many diffuse nodular shadows in both lung fields. With conservative treatment, the shadows regressed along with the skin eruption and other symptoms. Pneumonia caused by varicella-zoster virus was diagnosed from the clinical course, chest roentgenographic and CT scan findings, and serological data. The risk of mortality in varicella-zoster pneumonia is high in adults, especially in immunosuppressed patients. Early diagnosis and effective treatment are, therefore, essential in the management of this disease. Though varicella-zoster pneumonia is rare, chest roentgenographic and CT scan findings are characteristic and suggestive. This case may serve as a reminder of the features of varicella-zoster pneumonia: many nodular shadows on the chest X-ray film and CT scan.

Local Pseudomonas instillation induces contralateral lung injury and plasma cytokines

We investigated whether local bacterial instillation leads to lung injury in noninstilled lung regions and examined local and systemic cytokine accumulation. Rats were challenged by intrabroncheal instillation of Pseudomonas aeruginosa, 10(7) colony-forming units (CFU) (HD group, n = 11), 4 x 10(6) CFU (LD group, n = 10), or saline (control group, n = 12). 99mTc-labeled macroaggregated albumin was added to the P. aeruginosa or saline solution for later documentation of the instilled area. At 4 h the right lung, including instilled segment, and the left lung were sampled. Lung injury was assessed by lung tissue to plasma 125I-labeled albumin (T/P) and lung wet-dry (W/D) ratios. We measured plasma and bronchoalveolar lavage fluid (BALF) levels of tumor necrosis factor (TNF) and cytokine-induced neutrophil chemoattractant (CINC). HD bacterial instillation induced neutrophil recruitment and TNF and CINC elevation in BALF (p < 0.05) associated with increased T/P (p < 0.005) and W/D (p < 0.05) ratios in both instilled and the noninstilled lungs as compared with the saline-instilled and noninstilled controls. LD bacterial instillation induced neutrophil recruitment and TNF and CINC elevation only in the instilled lung (p < 0.05), and not in the noninstilled lung, and did not increase the T/P or W/D ratio. Plasma levels of TNF and CINC were increased in the HD, but not the LD, group when compared with the saline controls (p < 0.05). These data indicate that, when the dose is high enough to cause an excess inflammatory response, local bacterial instillation leads to neutrophil sequestration, lung injury, and cytokine elevation in the noninstilled lung associated with systemic cytokine release.

[High concentrations of interleukin-8 in bronchoalveolar lavage fluid from a patient with adult respiratory distress syndrome]

A 75-year-old man was admitted to the hospital due to acute onset of a dry cough and dyspnea on exertion. Arterial blood gas analysis showed hypoxemia (PaO2 = 63 Torr) on room air. Chest radiography and computed tomography showed diffuse bilateral infiltrates. Adult respiratory distress syndrome was diagnosed from the findings described above and from the lack of evidence of left heart failure. Diffuse alveolar damage was confirmed at autopsy. During the course of his illness, the patient underwent bronchoalveolar lavage five times. The recovered fluid had high concentrations of interleukin-8 (IL-8), with a maximum of 6260 pg/ml and a minimum of 190 pg/ml, and these values correlated with the number of polymorphonuclear cells in the fluid. Levels of leukotriene B4, another chemotactic factor for PMN, in the lavage fluid were not high. We conclude that IL-8 was a major chemoattractant for PMN in the alveoli of this patient.

Establishment of high- and low-invasion clones derived for a human tongue squamous-cell carcinoma cell line SAS

Distant-organ metastasis and regional lymph node metastasis are still the major cause of mortality of oral-cavity squamous-cell cancer (SCC). However, only a few studies have been undertaken to elucidate the mechanism of invasion and metastasis of oral SCC. In this study, we attempted to establish human oral SCC clones with different invasiveness, defined by endothelial cell monolayer assay, which can be used for the study of invasion and metastasis of oral SCC. We established five clones from the human oral SCC cell line SAS by a limiting-dilution method. Two distinct clones, SAS-L1 with very low invasive potential and SAS-H1 with very high invasive potential, were picked out by rat lung endothelial cell monolayer assay. The number of SAS-H1 that penetrated the rat lung endothelial cell monolayer was six fold higher than the number of SAS-L1. There were no differences of metalloproteinase production and cell adhesiveness to Matrigel of SAS-L1 and SAS-H1. However, SAS-H1 exhibited a higher migration ability than SAS-L1. This pair of clones would be a useful experimental model to help in the study of the invasiveness of human oral SCC.

[A case report of small cell carcinoma of the esophagus with remarkable response to neoadjuvant chemotherapy]

A 61-year-old male consulted our hospital with complaints of pain in swallowing. The X-ray Barium studies and upper gastrointestinal (UGI) scope revealed an irregular ulcerated lesion in the middle portion of the esophagus. He was diagnosed as having small cell carcinoma of the esophagus by means of biopsy specimens. Three courses of combined chemotherapy with CDDP, etoposide and 5-FU were used before operation. Following the chemotherapy, according to the UGI scope findings, the tumor of the esophagus disappeared. An esophagectomy through a thoracolaparotomy was performed. The chemotherapy resulted in a Grade 2 response, as ascertained by means of pathological findings for the resected specimen. After an additional course of chemotherapy, the patient was discharged from the hospital. Although we performed the curative resection for this patient, extensive recurrences and distant metastasis to the mediastinal lymph nodes and lung were found in less than a year. It is said that this tumor has a poor prognosis, and the one-year survival rate is about 10% following the treatment. It is necessary to combine surgery with effective chemotherapy and irradiation to obtain a good prognosis after resection of small cell carcinoma of the esophagus.

Heat-killed Corynebacterium parvum enhances endotoxin lung injury with increased TNF production in guinea pigs

Corynebacterium parvum (CP) is known to increase susceptibility to endotoxin, which is associated with increased production of tumor necrosis factor (TNF). We investigated the effect of CP-priming on the pathogenesis of acute lung injury caused by intratracheal Escherichia coli endotoxin (lipopolysaccharide [LPS]). Guinea pigs were divided into four groups: (1) control (n=6), (2) CP-alone (n=6), (3) LPS-alone (n=6) and (4) CP + LPS (n=6). A CP dose of 4 mg/kg was injected intraperitoneally 7 d before the study. Animals were observed for 4 h after intratracheal administration of 0.02 mg/kg of LPS. The lung wet-to-dry weight ratio (W/D), [125I] albumin concentration ratio of lung tissue to plasma (T/P) and of bronchoalveolar lavage (BAL) fluid to plasma (B/P) and differential cell count in BAL fluid were examined. In the LPS-alone group, neither excess lung water nor increased albumin leakage was observed. The CP + LPS group showed increased lung water and albumin leakage as compared with the other three groups (p<0.05). We also observed increased cell counts in BAL fluid (p<0.05), in the CP + LPS group. The spleen weight was increased in guinea pigs pretreated with CP, indicating reticuloendothelial system (RES) activation. In the CP + LPS group, the TNF level was increased in both plasma and BAL fluid. We conclude that pretreatment with CP enhances LPS-induced acute lung injury in parallel with increasing TNF production, which suggests that the activation of mononuclear phagocytes contributes to increased susceptibility to intratracheal endotoxin in guinea pigs.

Effects of benidipine, a calcium antagonist, on urinary kallikrein excretion and renal impairment in experimental diabetes

OBJECTIVE

To assess the long-term effects of different antihypertensive agents on urinary protein excretion and kallikrein excretion in diabetic rats with renal impairment.

METHODS

Uninephrectomized streptozotocin diabetic Wistar-Kyoto rats were randomly assigned to receive vehicle, a calcium antagonist (benidipine) or an angiotensin converting enzyme inhibitor (captopril) for up to 12 weeks. Active kallikrein was determined by its kininogenase activity, and generated kinins were measured by radioimmunoassay. Total kallikrein was also determined by measuring kininogenase activity after inactive kallikrein had been activated with trypsin.

RESULTS

Urinary protein excretion increased significantly in diabetic rats compared with non-diabetic rats. Urinary active kallikrein excretion was significantly reduced in diabetic rats, whereas urinary total kallikrein excretion was unchanged, resulting in a reduced percentage of active to total kallikrein compared with that in non-diabetic rats. Benidipine and captopril reduced blood pressure and attenuated the development of diabetic renal impairment in a similar manner. However, only benidipine attenuated the decreases in urinary active kallikrein excretion and the ratio of active to total kallikrein in diabetic rats.

CONCLUSIONS

Although pathophysiological relevance of impaired urinary kallikrein activation to the development of diabetic renal impairment remains to be determined, our result might suggest a new mechanism by which calcium antagonists protect the kidney from diabetic renal impairment.

The relationship between maximal jaw opening and size of skeleton: a cephalometric study

The purpose of this study was to investigate the correlation between maximal mouth opening and size of the skeleton. The subjects were dental students at the Dental School of the Health Sciences University of Hokkaido with no functional disorders of the masticatory system. The stature and maximal mouth opening were recorded in 29 males and 31 females. These subjects agreed to have a lateral cephalogram taken at the closed and maximal mouth opening positions. The correlations between the maximal mouth opening and the body height, mandibular length and mandibular angle were significant. The correlation between the maximal mouth opening and the movement of the condyle was also significant.

Cardiomegaly and vasoactive hormones in rats with chronic myocardial infarction: long-term effects of chlorothiazide

1. The effects of prolonged chlorothiazide treatment of left ventricular failure on cardiac hypertrophy, circulating vasoactive hormones and exchangeable body sodium were examined in rats with chronic myocardial infarction induced by left coronary artery ligation. Chlorothiazide therapy commenced either immediately or 2 weeks after infarction. For 4 weeks, the rats were given either chlorothiazide (50 mg day-1 kg-1) in their drinking water or drinking water alone. 2. Cardiac weight increased in untreated rats with infarction in comparison with sham-operated controls, indicating the presence of chronic left ventricular dysfunction, although exchangeable body sodium, plasma renin activity, plasma vasopressin and plasma osmolality remained unchanged. 3. Chlorothiazide raised haematocrit and plasma renin activity equally in rats with and without infarction, although exchangeable body sodium, plasma vasopressin and plasma osmolality were not changed by the treatment. Plasma atrial natriuretic peptide was 2-fold higher in rats with infarction and this response was not affected by chlorothiazide treatment. Chlorothiazide therapy did not prevent or reverse cardiac hypertrophy. 4. Chronic diuretic therapy in this experimental model of heart failure did not reduce extracellular sodium, plasma vasopressin or the extent of ventricular hypertrophy, possibly because the condition was associated with activation of the renin-angiotensin system.

Effect of a specific neutrophil elastase inhibitor, ONO-5046, on endotoxin-induced acute lung injury

Because excessive neutrophil elastase (NE) activity is involved in the pathogenesis of acute lung injury, we speculated that administering anti-NE might prevent lung injury. In a guinea pig model of acute lung injury induced by Escherichia coli endotoxin (lipopolysaccharide [LPS]), we investigated the effect of ONO-5046, a low-molecular-weight and specific inhibitor of NE. ONO-5046 produced concentration-dependent inhibition of guinea pig NE, whereas there were no inhibitory effects on neutrophil chemotaxis or the expression of adhesion molecules in endothelial cells. Detectable NE activity in bronchoalveolar lavage (BAL) fluid was present in the LPS-alone group. No NE activity in BAL fluid was detected in the LPS+ONO-5046 groups. Neutrophil counts in BAL fluid, the lung tissue wet to dry weight ratio, and the lung tissue or BAL fluid to plasma ratio of 125I-albumin were increased in the LPS-alone group as compared with the saline group (p < 0.05). In the LPS+ONO-5046 group, neutrophil counts in BAL fluid, the lung tissue wet to dry weight ratio and BAL fluid to plasma ratio of 125I-albumin were decreased as compared with the LPS-alone group (p < 0.05). These data suggest that ONO-5046 can attenuate LPS-induced acute lung injury.

[Pathophysiology and Diagnosis of the acute respiratory distress syndrome]

We studied methods for diagnosing the acute respiratory distress syndrome (ARDS) based on its characteristic abnormalities. A gamma-ray external counting method with Tc-99m human serum albumin revealed that pulmonary microvascular permeability was abnormally high in patients with ARDS. With this method, ARDS could be distinguished from cardiogenic pulmonary edema. Levels of interleukin-8 in bronchoalveolar fluid from patients with septic ARDS, reexpansion pulmonary edema, and inhalation burn injury were abnormally high. In 21 patients with acute lung injury, 15 of whom had ARDS, plasma concentrations of three inflammatory markers were measured: thiobarbituric acid reactive material which reflects cell membrane lipid peroxidation; 7S collagen, a component of basement membrane; and the soluble form of P-selectin, an adhesion molecule. Levels of all three were abnormally high in patients with ARDS, and correlated with the degree of lung injury and with the outcome in these patients. We conclude that these measurements in plasma or bronchoalveolar lavage fluid may enable us to assess the severity of ARDS.

Cardiovascular and renal protective effects of losartan in spontaneously hypertensive rats with diabetes mellitus

1. Cardiovascular and renal benefits of a specific angiotensin II (AII) receptor antagonist, losartan (LOS), were assessed in diabetic rats with renal impairment. 2. Uninephrectomized SHR made diabetic by streptozotocin administration were given LOS (5 mg/kg per day, i.p.) alone, captopril (CAP) (50 mg/kg per day, i.p.) alone, or a combination of CAP and LOS via osmotic minipumps for 8 weeks. 3. Both CAP alone and LOS alone completely blocked the development of hypertension in diabetic SHR in the same manner. CAP + LOS did not enhance the antihypertensive effects of LOS alone or CAP alone. 4. CAP + LOS, LOS alone and CAP alone significantly decreased urinary protein excretion and serum creatinine to the same extent. 5. These results indicate that both LOS and CAP exert antihypertensive and renoprotective effects in this model: these actions are mainly through inhibition of AII production.

[Interstitial lung disease in patients with connective tissue diseases]

Interstitial lung disease is a significant prognostic factor in connective tissue diseases. To further clarify clinical and immunological features of interstitial lung disease, we studied 894 consecutive patients with connective tissue diseases first evaluated between 1970 and 1993. Interstitial lung disease was found in 101 of 181 (56%) patients with systemic sclerosis, 92 of 183 (50%) with overlap syndrome, 35 of 76 (46%) with polymyositis/dermatomyositis, and 13 of 444 (3%) with systemic lupus erythematosus (p < 0.05, systemic lupus erythematosus vs. other connective tissue diseases). The presence of interstitial lung disease correlated with decreased survival in systemic sclerosis and in polymyositis/dermatomyositis, but not in overlap syndrome or in systemic lupus erythematosus. Interstitial lung disease in patients with connective tissue diseases was classified into two types: acute (n = 8) and chronic (n = 233). Among the 8 patients with acute disease, 4 (all with dermatomyositis) died of respiratory failure and 3 (all with systemic lupus erythematosus) responded to corticosteroids. Among the 233 patients with chronic interstitial lung disease, 20 had polymyositis/dermatomyositis with anti-aminoacyl tRNA synthetase antibodies and 40 had overlap syndrome with anti-U1 RNP antibodies. Respiratory failure in these patients was not frequent and occurred late in the course of the disease. As a cause of death, respiratory failure was associated with autoantibodies to topoisomerase I and aminoacyl tRNA synthetase but not anti-U1 RNP. Autoantibodies to aminoacyl tRNA synthetases were detected before the development of interstitial lung disease in 9 patients with polymyositis/dermatomyositis. We conclude that the clinical features of interstitial lung disease associated with connective tissue diseases vary with the type of connective tissue disease, and that analysis of autoantibodies can be useful in establishing a diagnosis and in forecasting the course and outcome.

Kinin and angiotensin II receptor antagonists in rats with chronic renal failure: chronic effects on cardio- and renoprotection of angiotensin converting enzyme inhibitors

OBJECTIVE

To assess the potential of the kallikrein-kinin and renin-angiotensin systems in mediating the cardio- and renoprotective effects of angiotensin converting enzyme (ACE) inhibitors in rats with chronic renal failure.

MATERIALS AND METHODS

Spontaneously hypertensive rats (SHR) and normotensive control Wistar-Kyoto (WKY) rats subjected to five-sixths nephrectomy were randomly assigned to treatment with vehicle, a kinin antagonist (Hoe 140) or an ACE inhibitor (cilazapril) or both drugs, intraperitoneally via osmotic minipumps for 4 weeks. In addition, the effects of a chronic infusion of a specific angiotensin receptor antagonist (losartan) alone or in combination with an ACE inhibitor (enalapril) were also investigated in nephrectomized SHR for 2 weeks.

RESULTS

In nephrectomized SHR and WKY rats, cilazapril alone significantly reduced systolic blood pressure, urinary protein excretion, heart weight and serum creatinine. In nephrectomized SHR, Hoe 140 alone or cilazapril in combination with Hoe 140 (7 or 70 mu g/kg per day) induced no changes in these parameters, other than those associated with the effects of cilazapril alone. In nephrectomized WKY rats, cilazapril in combination with Hoe 140 (70 mu g/kg per day) slightly, but not significantly, attenuated the antihypertensive effect of cilazapril but did not affect the other parameters. These results were confirmed by morphological analysis of kidneys. All the drug regimens provided effective protection against an increase in focal glomerular sclerosis. Enalapril did not modify the antihypertensive and renoprotective effects of losartan in nephrectomized SHR.

CONCLUSIONS

The present results indicate that the kallikrein-kinin system might not be a major factor in the cardio- and renoprotective effects of ACE inhibitors in rats with chronic renal failure.

Do kinins mediate cardioprotective and renoprotective effects of cilazapril in spontaneously hypertensive rats with renal ablation?

1. We assessed the potential of the kallikrein-kinin system in mediating the cardioprotective and renoprotective effects of an angiotensin-converting enzyme inhibitor (ACEI), cilazapril (CIL) in rats with renal ablation. 2. Eight week old spontaneously hypertensive rats (SHR) were subjected to 5/6 nephrectomy. One week after the operation, the rats were divided into 5 groups: (i) vehicle; (ii) CIL 1 mg/kg per day per os (p.o.); (iii) Hoe140 (HOE) 70 mu g/kg per day given intraperitoneally (i.p.); (iv) CIL 1 mg/kg per day p.o. plus HOE 7 mu g/kg per day i.p.; (v) CIL 1 mg/kg per day p.o. plus HOE 70 mu g/kg per day i.p. The treatment lasted for 4 weeks. 3. CIL alone significantly reduced systolic blood pressure, urinary protein excretion, heart weight and serum creatinine level. HOE alone did not induce any significant changes in these parameters. CIL in combination with HOE (7 or 70 mu g/kg per day) did not induce any changes in these parameters, in addition to those associated with the effects of CIL alone. 4. These results indicate that the kallikrein-kinin system might not play a major role in the cardioprotective and renoprotective effects of ACE inhibitors in the rat remnant kidney model of chronic renal failure.

Effects of recombinant human erythropoietin on blood pressure and renal function in SHR with chronic renal failure

1. The effects of chronic administration of erythropoietin (EPO) on blood pressure and renal function in rats with ablation of renal mass were assessed. 2. Spontaneously hypertensive rat were subjected to 5/6 nephrectomy (5/6Nx). Four weeks after the operation, the rats were randomly allocated to vehicle, EPO 20IU/kg i.p., or EPO 100 IU/kg i.p. (both given twice a week) for 4 weeks. 3. Marked anaemia was noted in SHR-5/6Nx. EPO caused a significant increase in haematocrit at a high dose but not at a low dose. A dose dependent relationship was noted in the EPO-induced rise in the systolic blood pressure. 4. EPO dose-dependently increased urinary protein excretion. It also increased blood urea nitrogen and serum creatinine levels. 5. These results suggest that EPO ameliorates anaemia and severely accelerates renal failure in SHR-5/6Nx. They also suggest that anaemia can be a haemodynamically favorable adaptation to chronic renal disease and that its correction may have adverse renal haemodynamic and structural consequences.