Angiotensin-converting enzyme in sarcoidosis

Serum ACE Level in Sarcoidosis Patients with Typical and Atypical HRCT Manifestation

BACKGROUND

Sarcoidosis is an inflammatory disease that affects multiple organs. Before widespread use of computed tomography (CT), the severity of sarcoidosis was assessed based on chest X-ray abnormalities. HRCT can distinguish between active inflammatory changes and irreversible fibrosis. In this study, we analyzed different ACE levels in 148 patients diagnosed with sarcoidosis.

MATERIAL/METHODS

We categorized these patients based on their HRCT results into four groups: 1) patients diagnosed with chronic disease; 2) patients diagnosed with non-chronic disease; 3) patients who exhibited typical HRCT changes; and 4) patients who exhibited atypical HRCT changes. Afterward the mean ACE level of each group was calculated and compared.

RESULT

The HRCT scans of chronic sarcoidosis patients tended to show more atypical sarcoidosis patterns. Moreover, there was a reverse correlation between chronicity and ACE level (P-value <0.05).

CONCLUSIONS

HRCT is another modality which would be useful when the diagnosis of sarcoidosis is not definite.

Correlation between disease activity, one-year prognosis, and angiotensin-converting enzyme in untreated sarcoidosis

The correlation between S-angiotensin-converting enzyme (SACE) and disease activity was examined in 185 observation periods in 85 untreated sarcoidosis patients. An agreement between SACE and chest roentgenographic changes was found in 42% of the observations, although less frequently in patients with erythema nodosum. The most convenient interval between enzyme measurements seems to be 3 months in patients with active disease, but more frequent check-ups are advised in patients with erythema nodosum. In 24 patients followed for one year after diagnosis, SACE correlated fairly well to the clinical course, and the pattern of enzyme variation may be a prognostic indicator in sarcoidosis.

Relationship between circulating immune complexes and angiotensin-converting enzyme in pulmonary sarcoidosis

The relationship between circulating immune complexes (CIC), serum angiotensin-converting enzyme (SACE) and clinical features was investigated in 119 patients with sarcoidosis. CIC, measured by the C1q-binding test and a polyethylene glycol precipitation test, were detected in 42% of the patients. A significantly higher level of CIC was found in patients with duration of the disease of more than 2 years and in patients in stage II or III on chest X-ray. SACE was increased in 45% of the patients, most frequently in those with active disease and in those in stage II or III on chest X-ray. No positive correlation was found between CIC and elevated levels of SACE.

Angiotensin-converting enzyme in hypercalcaemic disorders

Serum angiotensin-converting enzyme (SACE) was elevated (mean +/- S.D. 55.2 +/- 19.8 U/ml) in 11 patients with hypercalcaemia due to sarcoidosis, whereas it was within the normal limits ((20.0 +/- 5.2 U/ml) in 23 patients with other hypercalcaemic conditions. Among these, 16 had primary hyperparathyroidism and a SACE level of 18.6 +/- 4.7 U/ml, significantly lower than in healthy controls (24.4 +/- 6.2 U/ml). In 7 patients with hypercalcaemia due to malignancies or prolonged immobilization SACE was 21.8 +/- 5.9 U/ml. A weakly positive correlation was found between SACE and S-calcium in hypercalcaemic sarcoidosis patients but not in the other patients or in a control group of 144 consecutive sarcoidosis patients. sarcoidosis with hypercalcaemia seems to be associated with a very high prevalence of elevated SACE. Especially when sarcoidosis is suspected to be the cause of hypercalcaemia, SACE measurement may be useful as a rapid diagnostic guide.

The level of angiotensin-converting enzyme as indicator of 2-year prognosis in untreated pulmonary sarcoidosis without erythema nodosum

In order to evaluate the prognostic significance of elevated serum angiotensin-converting enzyme (SACE) in pulmonary sarcoidosis, the 2-year prognosis was studied in 33 untreated patients without erythema nodosum. Elevated SACE was found in 19 patients among whom total regression or improvement was noted in 42%, against 86% in 14 patients with normal SACE in serial measurements. The groups with and without elevated enzyme levels were not different with respect to sex, age, pulmonary changes, or extrathoracic manifestations. Thus, the findings of elevated SACE in this category of sarcoidosis patients may have some prognostic significance, pointing toward a greater risk of a chronic course.

Free light chains of immunoglobulins in serum from patients with rheumatoid arthritis, sarcoidosis, chronic infections and pulmonary cancer

Free light chains of immunoglobulins were measured in serum from 181 patients with rheumatoid arthritis (RA), sarcoidosis, pulmonary tuberculosis, pulmonary cancer and chronic bronchitis, i.e. patients with long-term stimulation of the immune system. Increased concentrations of light chains were found in patients with active sarcoidosis, and the light chain level appeared to be a marker of disease activity in sarcoidosis. The mean (+/- S.D.) concentration of kappa plus lambda chains in active sarcoidosis of more than two years' duration was 38.3 +/- 13.7 mg/l, that is twice the concentration of 19.4 +/- 5.5 mg/l found in normals. Some patients with seropositive RA also had increased serum values. The light chain concentrations in seropositive RA were correlated to the severity of the disease measured by clinical staging and laboratory tests. A modest increase in light chains was observed in one patient with tuberculosis, and in two patients each with chronic bronchitis and pulmonary cancer.

End-stage renal disease in sarcoidosis of the kidney

We describe two cases of black women with biopsy-proven sarcoidosis of the kidney who developed end-stage renal disease. Treatment with high-dose glucocorticoids resulted in a good initial response, followed by progressive deterioration of renal function requiring hemodialysis.

In vitro angiotensin-converting enzyme and interleukin-1 production by epithelioid cells isolated from induced rabbit lung granuloma

We attempted in this experiment to culture epithelioid cells isolated from granuloma induced in the lung of female rabbits that had been injected intravenously with Freund's complete adjuvant. The morphologic findings of isolated cells included abundant rough-surfaced endoplasmic reticulum, mitochondria, Golgi complexes, electron-dense lysosomes, and numerous cytoplasmic processes on the cell surface. Enzymatically these cells were positive for acid alpha-naphthyl acetate and beta-galactosidase staining. These findings coincided with the expected morphologic and enzymatic characteristics of epithelioid cells examined in vivo. Cells isolated from this granuloma are thought to be more than 86% epithelioid cells. Additionally, 14.4 +/- 4.3% of the epithelioid cells showed phagocytosis of latex beads, low when compared with the 83.9 +/- 5.2% value of alveolar macrophages obtained from rabbits injected with adjuvant 4 weeks before sacrifice. The isolated epithelioid cells were incubated for 24 h without decrease in cell population. Their culture supernatants showed 1.86 +/- 0.38 units/ml of angiotensin-converting enzyme (ACE) activity, which was inhibited by cycloheximide. The culture supernatants also showed interleukin-1 (IL-1) activity levels of 6411 +/- 914 cpm without lipopolysaccharide (LPS) stimulation. This increased to 21,766 +/- 3026 cpm with LPS stimulation. In view of these results, we believe it is possible to incubate epithelioid cells for up to 24 h during which time they will produce ACE and IL-1 in the culture supernatants.

Posterior mediastinal sarcoidosis

We report two cases of enlargement of the posterior mediastinal lymph nodes due to sarcoidosis. Bilateral hilar enlargement, pulmonary parenchymal involvement, or extrathoracic manifestations of sarcoidosis were absent. A diagnostic thoracotomy had to be performed in both instances.

Angiotensin-converting enzyme and coronary haemodynamics in coronary artery disease

Coronary sinus pacing was performed in 12 patients with and 12 patients without significant coronary artery disease as verified by angiography in order to elucidate a possible link between cardiac exchange of angiotensin-converting enzyme and the coronary circulation. The coronary sinus and arterial blood enzyme activity remained unchanged and were similar in the two groups, both at rest and during pacing, and the activity was not related to pacing-induced changes in oxygen consumption or coronary vascular resistance. Therefore it does not seem that global cardiac formation or depletion of angiotensin-converting enzyme is of regulatory importance in the coronary vascular bed in patients with and without coronary artery disease under these circumstances.

Biochemical markers in sarcoidosis

The clinical course of sarcoidosis is varying and unpredictable. Once the diagnosis has been made, the clinician needs simple tests to detect and predict remission or progression, to determine whether treatment is effective or not, and to assess the clinical activity of the disease. Sarcoidosis is a multisystem disease, but the lungs are almost always involved. Traditionally, the clinical management has therefore included chest X-rays and lung function studies. Extrapulmonary lesions have been followed in different ways. Sensitive and reproducible biochemical tests would be helpful in evaluating the clinical course of patients with sarcoidosis, if they measure functions related to the granulomatous inflammation. This review will deal with measurements of serum and urinary calcium, and 1,25-dihydroxyvitamin D. The usefulness of single and serial determinations of lysozyme, angiotensin converting enzyme, beta 2-microglobulin, collagenase, carboxypeptidase and glucuronidase in serum, bronchoalveolar lavage fluid, and other biological fluids will be discussed.

Serum angiotensin-converting enzyme in sarcoidosis and psoriasis

Untreated pulmonary sarcoidosis is associated with an increased level of serum angiotensin-converting enzyme (SACE), which is regarded as a valuable method of diagnosing sarcoidosis and measuring the activity of the disease. The level of SACE in cutaneous sarcoidosis or other skin diseases has not been clearly established. We therefore examined SACE in 31 patients with systemic sarcoidosis, including cutaneous manifestations, and 12 patients with isolated cutaneous sarcoidosis. Also, 23 patients with psoriasis were studied. The level of SACE was generally elevated only in patients with untreated systemic sarcoidosis, whereas it was normal in cutaneous sarcoidosis and psoriasis. If the level of SACE is elevated in "isolated" cutaneous sarcoidosis, systemic disease must be strongly suspected.

Angiotensin-converting enzyme: an indicator of bleomycin-induced pulmonary toxicity in humans?

In order to evaluate bleomycin-associated lung damage in humans, lung function parameters and serum levels of the endothelial-bound angiotensin-converting enzyme (ACE) were determined by serial measurements in 11 patients who were treated for testicular cancer. None developed clinical or radiological evidence of pulmonary damage. While the static and dynamic lung function parameters were unchanged, carbon monoxide diffusion capacity (DLCO) decreased significantly (P less than 0.01) during a total of 126 days of pulsed regimen, indicating damage to the alveolar-endothelial membrane. S-ACE was unchanged within each treatment course but increased significantly (P less than 0.05) from the initial value to the last treatment course. Two months after cessation of treatment S-ACE returned to pretreatment values. Although the changes were modest they might mirror treatment-associated endothelial damage.

Determination of serum angiotensin-converting enzyme in sarcoidosis

Serum angiotensin-converting enzyme activity was measured in 72 patients with sarcoidosis and in 50 normal controls by a radiochemical assay. SACE levels were examined with respect to the 'activity' of the disease, based on clinical, radiographic and physiological assessment. SACE activity in 34 patients with clinical sarcoidosis (147 +/- 44.3 nmol/min/ml) was significantly high (p less than 0.001) when compared to that of 38 patients who had recovered from sarcoidosis (113.9 +/- 26.4 nmol/min/ml) and 50 normal subjects (97.8 +/- 21 nmol/min/ml). SACE levels were significantly different (p less than 0.01) between 15 subjects with 'active' disease (173.9 +/- 51.9 nmol/min/ml) and those with 'inactive' disease (126.1 +/- 26.3 nmol/min/ml). It is concluded that there is a strict correlation between SACE levels and 'activity' of sarcoidosis if multiple criteria (clinical, radiographic and physiological) are employed.

Angiotensin-converting enzyme and its clinical significance--a review

There have been considerable advances in understanding the metabolic role of the endothelial lining cells of the blood vessels. Angiotensin-converting enzyme activity is concentrated in these cells, especially those lining the pulmonary circulation. The enzyme exerts control over systemic vascular tone indirectly through the powerful pressor effect of angiotensin II. A number of therapeutic agents are now available which directly inhibit converting enzyme activity and thereby effect a reduction in blood pressure. Macrophages are the source of increased angiotensin-converting enzyme activity commonly found in association with active sarcoidosis. A better understanding of this phenomenon may give fresh insight into this puzzling condition. Pulmonary endothelial metabolism is affected by lung injury and it is likely that in this situation changing activities of serum angiotensin converting enzyme may indicate the extent of damage and the response to therapy. The full clinical significance of serum ACE measurements has yet to be established. However, raised activities have been reported in a number of other conditions and diabetes mellitus and hyperthyroidism are of particular current interest. The numerous methods and reference ranges described in the literature for the measurement of serum ACE activity require further assessment, and there is a clear need for an accepted reference method.

Angiotensin-converting enzyme in acute myocardial infarction and angina pectoris

Serum activity of angiotensin-converting enzyme was measured by serial analysis in 19 patients with acute myocardial infarction and in eight patients with angina pectoris. As a rule no changes in enzyme activity occurred during 6 days observations. However, two patients with infarction exhibited a pronounced fall of enzyme activity which could not be related to clinical events. The analysis seems to have no place in the diagnosis and management of patients with myocardial infarction.

[Angiotensin-converting enzyme (ACE). Increased serum activities in patients with dermatological diseases (author's transl)]

Serum activities of ACE were investigated in 40 patients with dermatological disease and in nine patients with sarcoidosis. The method of Cushman and Cheung, modified according to Lieberman, was used. Both sarcoidosis patients and patients with dermatological diseases showed marked elevations of ACE-activity. The increase in ACE-activity might result from inflammation and immunological events.

Angiotensin-converting enzyme and its association with outcome in lung cancer

Serum angiotensin-converting enzyme (SACE) in 141 patients with newly detected primary lung cincer was 22.1 +/- 6.1 nmol/ml/min (mean +/- s.d.); lower than in healthy controls (24.4 +/- 6.2 nmol/ml/min, P less than 0.02). No correlation was found between SACE and sex, age, site of cancer, histological type, or lung function. After subdivision of the patients according to increasing SACE levels: less than 16.0 (mean SACE of lung cancer--s.d.), 16.0-22.0, 22.1-28.2 and greater than 28.2 nmol/ml/min (mean SACE of lung cancer + s.d.) there was a strong association (P less than 0.001) between SACE level and the proportion of patients who were radically operated without relapse during 8-22 months follow-up. None of 23 patients within the lowest SACE range were cured, even though 7 were referred for operation after preoperative examination. In contrast, 10/25 patients (40%) within the highest SACE range were cured. The results suggest that low SACE is associated with poor prognosis in lung cancer, even in patients who are judged as being operable on preoperative evaluation; and measurement of preoperative SACE in lug cancer may be a useful prognostic indicator in this disorder.

Histiocytosis X. VI. Angiotensin-converting enzyme activity

The activity of the endothelial and macrophage derived angiotensin-converting enzyme in blood was within normal range in 12 patients with histiocytosis X, independent of extent and activity of the disease. In contrast to sarcoidosis and Gaucher's disease, histiocytosis X is not associated with elevated levels of angiotensin-converting enzyme.

Serum angiotensin-converting enzyme in malignant lymphomas, leukaemia and multiple myeloma

Serum angiotensin-converting enzyme (SACE) was analysed in 27 patients with Hodgkin's disease, 25 with non-Hodgkin lymphoma, 14 with acute leukaemia, 15 with chronic leukaemia, and 15 with multiple myeloma. SACE was depressed in these patients as a whole, with a mean level of 19.9 mu/ml, compared with 116 healthy controls (mean 24.4 mu/ml, P < 0.001). This depression was greatest in chronic leukaemia and multiple myeloma. In Hodgkin's disease no relationship was found between enzyme activity and stage, activity, histopathology, treatment, mediastinal involvement or prognosis. In non-Hodgkin patients a poor prognosis was generally associated with low SACE activity. The low SACE activity was not related to recent corticosteroid treatment, and the cause and pathophysiological significance is unexplained. Since SACE is high in the granulomatous disorder sarcoidosis (which can mimic malignant lymphnode and blood diseases) SACE analysis can be valuable in evaluating patients with mediastinal lymphadenopathy and those in whom non-caseating epitheliod granulomas are found.

Angiotensin-converting enzyme in uveitis and sarcoidosis

Serum angiotensin-converting enzyme (SACE) was studied in a group of 29 sarcoidosis patients (among whom five had uveitis) and in 22 patients with non-sarcoid uveitis. SACE was normal in all non-sarcoid patients and elevated in 62 per cent of the patients with sarcoidosis. Thus an elevated SACE is closely linked to sarcoidosis and may be a valuable tool in evaluating patients with uveitis in search of a sarcoid origin.