Increased serum and urinary calcitonin levels in patients with pulmonary disease

Measurement of procalcitonin in saliva of pigs: a pilot study

Background

Procalcitonin (PCT) is a widely used biomarker of sepsis in human medicine and can have potential applications in the veterinary field. This study aimed to explore whether PCT could be measured in the saliva of pigs and whether its concentration changes in sepsis. Therefore, a specific assay was developed and analytically validated, and changes in PCT concentration were evaluated in two conditions: a) in an experimental model of sepsis produced by the administration of lipopolysaccharide (LPS) to pigs (n = 5), that was compared with a model of non-septic inflammation induced by turpentine oil (n = 4), and b) in healthy piglets (n = 11) compared to piglets with meningitis (n = 20), a disease that usually involves sepsis and whose treatment often requires large amounts of antibiotics in farms.

Results

The assay showed coefficients of variation within the recommended limits and adequate linearity after serial sample dilutions. The method's detection limit was set at 68 μg/L, and the lower limit of quantification was 414 μg/L. In the LPS experiment, higher concentrations of PCT were found after 24 h in the animals injected with LPS (mean = 5790 μg/L) compared to those treated with turpentine oil (mean = 2127 μg/L, P = 0.045). Also, animals with meningitis had higher concentrations of PCT (mean = 21515 μg/L) than healthy pigs (mean = 6096 μg/L, P value < 0.0001).

Conclusions

According to these results, this assay could be potentially used as a tool for the non-invasive detection of sepsis in pigs, which is currently a topic of high importance due to antibiotic use restriction.

Serum Immunoreactive Calcitonin in Lung Cancer

Serum immunoreactive calcitonin (iCT) assay was performed in 92 patients suffering from different kinds of cancer of the lung and in 42 healthy control subjects. Gel filtration of serum of patients suffering from microcytoma was carried out on Sephadex G75 to study the forms of circulating iCT. The obtained results (pg/ml M ± SE) were: 1) normal subjects, 73 ± 3; 2) epidermoidal cancer, 105 ± 19; 3) adenocarcinoma, 116 ± 47; 4) anaplastic carcinoma with large cells, 156 ± 74; 5) microcytoma, 354 ± 74; 6) chronic obstructive bronchitis, 38 ± 6. Gel filtration of serum of patients with microcytoma demonstrated the same behavior as in normal subjects. We can conclude that iCT increases significantly in microcytoma with extensive disease (84 % of cases): in this condition, the iCT assay can be useful as a marker in follow-up of disease.

Procalcitonin (PCT) in patients with abdominal sepsis

BACKGROUND

To assess the accuracy of procalcitonin as a measure of severity in patients with septic abdominal illnesses and the sepsis syndrome, to compare measurements with those of other inflammatory mediators, and to predict outcome.

METHODS

We carried out a prospective clinical study from 246 patients with infective or septic episodes confirmed at laparotomy and 66 patients undergoing elective operations who acted as controls. Specimens of blood for measurement of cytokine concentrations determination were obtained daily from septic patients. In the control group specimens were obtained before operation, at the end of operation, and on each of the following days until normal recovery (day 10). Every two weeks up to 3 months for patients with metastases, who were being followed up.

RESULTS

Compared with other cytokines such as tumor necrosis factor alphaa and interleukin 6 procalcitonin was closely related to the development of infective and septic complications. 59 of 246 patients (24%) with sepsis died. Procalcitonin concentrations preoperatively [median 2.05 compared with 4.2 ng/ml (p=0.08)] (Mann-Whitney U-test) did not differ, but those on the days 1,4 and at the end differed significantly [day 1: 4.9 compared with 13.8 ng/ml (p<0.01); day 4: 4.8 compared with 13.0 ng/ml (p<0.01) and 0.4 compared with 13.25 ng/ml (p<0.01) at the end of the study]. In the control group only 7 (1.6%) of all blood samples, were detected outside the normal range (up to 0.8 ng/ml).

CONCLUSIONS

Procalcitonin is a new indicator of infection and sepsis. TNF and IL-6 concentrations always rise after major operations and fall in the absence of infection, indicating operative trauma. Procalcitonin is sensitive in detecting infective complications. Under routine conditions the procalcitonin concentrations seems to be valid, reproducible and detectable.

Up-regulation of expression of the ubiquitin carboxyl-terminal hydrolase L1 gene in human airway epithelium of cigarette smokers

Neuroendocrine differentiation is a common feature of lung cancer and increased numbers of neuroendocrine cells and their peptides have been described in chronic smokers. To understand the effects of cigarette smoking on the gene expression profile of neuroendocrine cells, microarray analysis with TaqMan confirmation was used to assess airway epithelial samples obtained by fiberoptic bronchoscopy from 81 individuals [normal nonsmokers, normal smokers, smokers with early chronic obstructive lung disease (COPD), and smokers with established COPD]. Of 11 genes considered to be neuroendocrine cell specific, only ubiquitin carboxyl-terminal hydrolase L1 (UCHL1), a member of the ubiquitin proteasome pathway, was consistently up-regulated in smokers compared with nonsmokers. Up-regulation of UCHL1 at the protein level was observed with immunohistochemical analysis of bronchial biopsies of smokers compared with nonsmokers. UCHL1 expression was evident only in neuroendocrine cells of the airway epithelium in nonsmokers; however, UCHL1 was also expressed in ciliated epithelial cells in smokers. This observation may add further weight to recent observations that ciliated cells are capable of transdifferentiating to other airway epithelial cells. In the context that UCHL1 is involved in the degradation of unwanted, misfolded, or damaged proteins within the cell and is overexpressed in >50% of lung cancers, its overexpression in chronic smokers may represent an early event in the complex transformation from normal epithelium to overt malignancy.

Large cell carcinoma with calcitonin and vasoactive intestinal polypeptide-associated Verner-Morrison syndrome

Verner-Morrison syndrome, characterized by diarrhea, hypokalemia, and hypochlorhydria, is caused most commonly by vasoactive intestinal polypeptide-secreting islet cell tumors of the pancreas. Verner-Morrison syndrome has not been described as a paraneoplastic syndrome in non-small cell lung cancer. We describe a 38-year-old man with metastatic non-small cell lung cancer of large cell carcinoma with neuroendocrine differentiation who presented with bone metastasis and intractable secretory diarrhea that was unresponsive to pharmacological treatment, including octreotide. Laboratory evaluation indicated elevated serum calcitonin and vasoactive intestinal polypeptide levels. Chemotherapy resulted in a transient response in the patient's diarrhea and neuroendocrine markers. The patient did not respond to further therapy and died 5 months after onset of back pain. To our knowledge, this is the first published case of large cell carcinoma with neuroendocrine differentiation associated with treatment-responsive paraneoplastic Verner-Morrison syndrome.

Urine bombesin-like peptide elevation precedes clinical evidence of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of very low birth weight infants, associated with oxygen therapy, barotrauma, and/or infections. Improved medical care has led to a paradoxically increased incidence of BPD due to greater infant survival. Early prediction of BPD has proven challenging. Increased pulmonary neuroendocrine cells containing bombesin-like peptide immunoreactivity occur in infants with BPD. We hypothesized that elevated urine bombesin-like peptide levels precede BPD. One hundred thirty-two infants, 28-weeks gestation or less, were studied. Urine bombesin-like peptide levels, determined by radioimmunoassay, were normalized for creatinine. BPD was defined as oxygen dependence at 36 weeks postmenstrual age. A first urine bombesin-like peptide level greater than 20,000 pg/mg creatinine (12,500 fmol/mg) between postnatal days 1-4 occurred among 54% of the infants who later developed BPD (p < or = 0.001), versus 10% among non-BPD infants (specificity 90%). Multivariable logistic regression analyses revealed that elevated urine bombesin-like peptide levels are associated with BPD (odds ratio 9.9, 95% confidence interval: 3.4, 29) (p < or = 0.001) after adjusting for all confounding factors. Thus, elevated bombesin-like peptide levels in these infants at 1-4 days after birth are associated with a 10-fold increased risk of developing BPD. Utilizing urine bombesin-like peptide for screening might permit early therapeutic interventions to reduce disease progression and could provide a target for new preventive therapies.

Clinical evaluation of a new sensitive calcitonin assay: study of specificity

BACKGROUND

Calcitonin (CT) is the most sensitive marker available for medullary thyroid carcinoma, but it lacks specificity. Procalcitonin is the precursor protein of calcitonin. Infections are known to be associated with elevations of procalcitonin. The aim of this study was to evaluate a new sensitive calcitonin assay in a large population and to study the assay specificity in two particular populations: patients with renal failure and patients hospitalized in intensive care units with a high procalcitonin level.

METHODS

Using two immunometric assays (A and B) to detect only mature calcitonin, we evaluated the calcitonin level in 488 sera (46 stimulation tests) from 340 subjects.

RESULTS

The clinical evaluation showed that the calcitonin concentrations obtained with the two assays were similar for all patients except those with high procalcitonin levels. Among the patients, 12% (n=13) had basal calcitonin concentrations greater than 10 pg/ml with method A and 25.7% (n=25) with kit B. No correlation was found between calcitonin and procalcitonin concentrations.

CONCLUSION

The new sensitive calcitonin assay tested is very efficient especially for the low concentrations. The cross-reaction for high procalcitonin levels exists and is variable according to the kits used. The procalcitonin evaluation can help the interpretation of ambiguous calcitonin levels.

Comparison of procalcitonin, sCD14 and interleukin-6 values in septic patients

The aim of the study was to investigate whether procalcitonin, soluble CD14 and interleukin-6 show advantages in predicting the outcome and specificity for bacterial infection in patients with sepsis in comparison to common C-reactive protein measurement. Laboratory parameters were measured in plasma of patients during 14 days following the diagnosis of sepsis. Patients fulfilling the ACCP/SCCM criteria for sepsis were admitted to an intensive care unit (n=35). Procalcitonin was measured with an immunoluminometric assay, and soluble CD14 and interleukin-6 were analysed by ELISA. C-reactive protein was determined nephelometrically. Measurements were performed on days 0, 1, 2, 3, 4, 7 and 14. Separating the patients into survivors (n=22) and non-survivors (n=13), it was demonstrated that non-survivors mostly exhibited, after the day of admission, increasing procalcitonin concentrations which peaked around days three and four. In contrast, the procalcitonin concentrations of survivors fell continuously to the value of 2.1 ng/ml which was reported to be important for patients prognosis. The difference between procalcitonin median values of survivors (n=22) and non-survivors (n=13) attained the level of statistical significance on day 7 and on day 14 (p=0.05). When comparing the median values of Creactive protein, soluble CD14 and interleukin-6 between survivors and non-survivors, no significant differences were detectable. In this study, plasma concentrations of soluble CD14 and interleukin-6 showed no predictive value for patients' outcome as compared with established laboratory parameters such as C-reactive protein or leukocyte count. Monitoring of procalcitonin seemed to detect severe episodes of sepsis and may improve the laboratory monitoring of septic patients.

Pyrexia, procalcitonin, immune activation and survival in cardiogenic shock: the potential importance of bacterial translocation

AIMS

Exposure to bacterial endotoxin, perhaps due to bowel congestion or ischaemia and altered gut permeability, may result in immune activation that is characteristic for patients with severe heart failure. It is known that blood procalcitonin rises in response to bacterial endotoxin exposure.

METHODS

We measured procalcitonin in a group of 29 patients with acute cardiogenic shock and no sign of infection (all without bacteraemia) and 26 with septic shock. Blood was analysed for procalcitonin, interleukin-6, tumour necrosis factor-alpha (TNF-alpha), c-reactive protein (CRP) and neopterin. Patients were managed conventionally in an intensive care unit with no further experimental procedures.

RESULTS

Three cardiogenic (10%) and seven septic shock patients (27%) survived. Most patients with acute heart failure surviving 12 h or more (18 of 20) developed a pyrexia (738.0 degrees C) of unknown origin in the absence of positive cultures, with a rise in procalcitonin (1.4+/-0.8 to 48.0+/-16.2 ng/ml, P<0.001), CRP (76.5+/-16.4 to 154.7+/-22.9 mg/l, P<0.001) and neopterin (20.7+/-3.5 to 41.2+/-6.7 nmol/l, P<0.001). Patients with septic shock had higher initial levels of cytokines, and higher peak levels. Those with heart failure surviving (n=3) and those dying in the first 12 h (n=9) had no rise in cytokine levels. The patients with high procalcitonin had a higher temperature (38.9+/-0.3 vs. 37.3+/-0.23 degrees C, P<0.05), TNF-alpha (43.95+/-9.64 vs. 16.43+/-4.33 pg/ml; P<0.005) and CRP (146.1+/-18.4 vs. 68.2+/-39.6 mg/ml, P<0.005). Peak procalcitonin levels correlated with peak temperature (r=0.74, P<0.001).

CONCLUSION

Cardiogenic shock causes a pyrexia of unknown origin in patients surviving for 12 h and that is associated with a rise in procalcitonin levels. This lends support to the hypothesis that patients with cardiogenic shock may be being exposed to bacterial endotoxin at a time when bowel wall congestion and or ischaemia is likely to be present.

Carbon dioxide, an important messenger molecule for small cell lung cancer

Chronic nonneoplastic lung diseases that impair pulmonary oxygenation while increasing the levels of intrapulmonary carbon dioxide (CO2) are a documented risk factor for the development of lung cancer in smokers and nonsmokers. Using established cell lines derived from human small cell lung cancer (SCLC) and non-small cell lung carcinoma, our experiments demonstrated that elevated CO2 concentrations in the range of those found in the diseased lung selectively stimulated the proliferation of SCLC but not adenocarcinoma or squamous cell carcinoma. The proliferative response of SCLC cells involved activation of the mitogen-activated protein kinases ERK-1 and ERK-2, as well as the p70 ribosomal S6 kinase and the stimulation of an autocrine serotonergic loop. Kinase activation was unrelated to changes in intracellular pH. We concluded that CO2 is an important messenger molecule for SCLC which may contribute significantly to the high lung cancer burden observed in individuals with chronic lung disease, by the activation of kinases which play a central role as downstream effectors of many growth factor-stimulated mitogenic pathways.

Pulmonary neuroendocrine cell system in pediatric and adult lung disease

In humans lungs affected by naturally occurring pulmonary disease, the pulmonary neuroendocrine cell system, which is normally arranged in a sparse but even distribution throughout the respiratory tract, increases in size. It is likely that the stimulus for this is pulmonary injury and that its purpose is the paracrine regulation of the restoration of pulmonary tissues to their normal state, an hypothesis supported by studies of animal lungs subjected to experimental injury as well as of the development of human and animal lungs in utero. Initially, this increase involves the development of interrupted rows of neuroendocrine cells. In the later stages, however, development of more disorderly intraepithelial aggregates can occur and the small, locally invasive neuroendocrine cell lesions known as tumourlets may occasionally result. Both of these latter structures often contain secretory products not found in the neuroendocrine cells of normal human lungs, probably indicating a derangement of what appears to be a fundamentally physiological response. It is likely that, in some circumstances, this disorderly change may contribute to pulmonary disease as well as being the result of it.

Pneumonitis-associated hyperprocalcitoninemia

Elevated serum levels of the prohormone of calcitonin (CT), procalcitonin (ProCT), have been documented in illnesses such as inhalational burn injury, in several sepsis syndromes, and in endotoxemia. In this study, we measured and characterized the circulating precursor forms of CT during the course of infectious pneumonitis. The initial (mean +/- SEM) serum total multiform CT level in 12 patients with acute infectious pneumonia was 1,019 +/- 430 pg/mL. In comparison, the mean level of total CT for 19 age-matched control patients without lung disease was 32 +/- 6 pg/mL (P < 0.001). The mean serum total CT level on initial examination was greater in the 6 patients with bacterial isolates, at 1,793 +/- 752 pg/mL, than in those with nonbacterial infectious pneumonia, at 242 +/- 109 pg/mL (P = 0.018). After admission to the hospital, patients' serum total CT progressively declined concomitantly with the clinical resolution of the pneumonia; at discharge, mean serum level was 121 +/- 34 pg/mL. On discharge, the patients who had persistent radiographic abnormalities had significantly higher levels than did those who had complete resolution. Both the mean serum calcium and phosphate were significantly lower at the initial time of study than at discharge (P < 0.002 and P < 0.0004, respectively). Gel filtration chromatography of sera obtained during the acute pneumonitis phase revealed increased levels of precursor forms of CT, including ProCT; these levels diminished with clinical resolution. In an additional three patients, the serum total CT increased very rapidly after aspiration (within 6 to 12 hours); the peak levels were several times greater than the upper limits of normal. In these patients, the principal serum CT components were ProCT and other precursor forms. These results show that both infectious and aspiration pneumonitis are associated with a rapid increase in circulating ProCT and other precursor forms of CT.

Endocrine cells in tumour-bearing lungs

BACKGROUND

When hormones are detected in the serum of patients with bronchial carcinoma they are generally considered to originate from the tumour, but this may be not the only explanation. Pulmonary endocrine cells proliferate in lungs affected by non-neoplastic disease and their products are often demonstrable in the serum. The aim of this study was to examine the pulmonary endocrine systems of a series of tumour-bearing lungs to see whether any changes in them could possibly account for raised levels of pulmonary peptides in the blood.

METHODS

The morphology, number, distribution, and content of pulmonary endocrine cells in 30 pairs of tumour-bearing lungs from patients coming to necropsy with bronchial carcinoma were examined. These features were related to the pathology of the tumour and to other pathological changes present in the lungs, and compared with pulmonary endocrine cells in 10 pairs of control lungs from patients without pulmonary disease.

RESULTS

Increased numbers of endocrine cells, often in the form of large abnormal aggregates, were present in 17 pairs of tumour-bearing lungs where they were associated not with the tumour but with non-tumoral pathology, especially inflammation and changes associated with cardiac failure. Appropriate and inappropriate peptides were identified within them.

CONCLUSION

The possibility is raised that, in some subjects with bronchial carcinoma who have raised serum hormone levels, the source of these substances might be the endocrine cells in the diseased lung around the tumour.

Late pulmonary sequela following burns: persistence of hyperprocalcitonemia using a 1-57 amino acid N-terminal flanking peptide assay

Seven patients were evaluated at a mean duration of 8.4 yr after sustaining inhalational injury associated with burns. At the time of re-examination, the patients were asymptomatic and had normal chest X-rays, and arterial blood gases. Three of the seven patients had abnormally elevated serum calcitonin levels. The spirometry (FEV1) measurements showed an inverse trend to that of the serum calcitonin levels. The elevated calcitonin levels had an abnormal predominance of the procalcitonin component as assessed by several region specific antisera. The serum calcitonin also showed a significant correlation with the hormone level which had been obtained at the time of prior discharge from the hospital (r = 0.91). Although there appears to be no or minimal chronic pulmonary sequela to inhalational injury in burns by pulmonary testing, we speculate that the hyperprocalcitonemia in some of the patients may reflect a long-term hyperplastic response of the bronchio-epithelial pulmonary neuroendocrine cells. The potential significance of this and other lung-associated endocrine markers is discussed.

Effects of bombesin and gastrin-releasing peptide on human bronchial epithelial cells from a series of donors: individual variation and modulation by bombesin analogs

Human pulmonary neuroendocrine cells produce a variety of hormones, including mammalian bombesin (BN) or gastrin-releasing peptide (GRP). Neuroendocrine cell hyperplasia and increased release of BN-like peptides occur in several diseases of the airways, including chronic obstructive pulmonary disease (COPD) and bronchopulmonary dysplasia. Growth stimulation of human bronchial epithelial cells by BN, as measured in a colony-forming assay, has been reported previously (Willey et al.:Exp. Cell Res. 153:245-248, 1984). In a follow-up to this report, we examined the response of human bronchial epithelial (HBE) cells to BN or GRP in a similar system, using cells derived from 13 human tissue donors. A stimulatory response (increased colony-forming efficiency) was found in cultures from 8 donors, including 3 with COPD. Statistical significance was found for the data from 5 of these 8 donors. The other 5 donors, 1 normal and 4 lung cancer patients, showed inhibition of colony formation by BN or GRP. Statistical significance was found for 3 of these donors. The ability of BN analogs to modulate BN stimulation was examined in cells from a donor with COPD. [psi Leu13,Leu14] BN(1-14), a BN antagonist, blocked the stimulation induced by BN. [D-Cpa6,psi Leu13,Phe14] BN(6-14), a mixed agonist-antagonist, showed partial agonist activity in HBE cells. [D-Phe1,Leu8,9] Litorin, an agonist, also showed agonist activity in a colony-forming assay with cells from these donors. These results indicate that responsiveness to BN/GRP may vary widely in the human population. Responsiveness may be heightened in disease states involving a proliferation of neuroendocrine cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Heterogeneity studies of hamster calcitonin following acute exposure to cigarette smoke: evidence for monomeric secretion

Various acute stimuli, including cigarette smoke, induce hypercalcitonemia in man and hamsters. We have shown that this occurs also in thyroidectomized subjects. In the present study we have further explored this phenomenon of secretion from the lungs by studying, simultaneously, the HPLC characteristics of pulmonary tissue and serum in control hamsters and in animals immediately following short-term exposure to cigarette smoke. In addition, we have studied the immunoheterogeneity of lung calcitonin 24 hours following the acute exposure. Control lungs contained monomeric immunoreactive calcitonin (M-iCT), high molecular mass iCT (H-iCT), and CT fragments. Immediately following smoke exposure, there was an acute decrease of lung iCT by radioimmunoassay (RIA) which consisted primarily of a decrease in M-iCT by HPLC. Simultaneously, the iCT increase in the serum by RIA was shown by HPLC to involve M-iCT. Twenty-four hours after smoke inhalation, the lung iCT by RIA and M-iCT by HPLC had returned towards control levels. These findings document the molecular characteristics of lung iCT following acute cigarette smoke stimulation, and suggest that under certain circumstances M-iCT may be actively secreted by the lung. It remains to be determined whether this type of secretion reflects hemocrine or paracrine release and what the physiological role for such a secretion may be.

High serum procalcitonin concentrations in patients with sepsis and infection

High concentrations of calcitonin-like immunoreactivity have been found in the blood of patients with various extrathyroid diseases. By means of a monoclonal immunoradiometric assay for calcitonin precursors, we have measured serum concentrations of procalcitonin in patients with various bacterial and viral infections. 79 children (newborn to age 12 years) in hospital with suspected infections were investigated prospectively. 19 patients with severe bacterial infections had very high serum concentrations of procalcitonin at diagnosis (range 6-53 ng/mL) in comparison with 21 children found to have no signs of infection (baseline concentrations < 0.1 ng/mL). Serum procalcitonin values decreased rapidly during antibiotic therapy. 11 patients with peripheral bacterial colonisation or local infections without invasive sepsis and 18 (86%) of 21 patients with viral infections had concentrations within or slightly above the normal range (0.1-1.5 ng/mL). Among 9 severely burned patients studied in an intensive care unit, the post-traumatic course of procalcitonin concentrations (range 0.1-120 ng/mL) was closely related to infectious complications and acute septic episodes. Concentrations of mature calcitonin were normal in all subjects, whatever procalcitonin concentrations were found. Concentrations of a substance immunologically identical to procalcitonin are raised during septic conditions. Serum concentrations seem to be correlated with the severity of microbial invasion.

Pulmonary endocrine cells in infancy and childhood

Lung sections from 22 infants and children who died of noncardiopulmonary diseases (control) and from 12 infants with hyaline membrane disease/bronchopulmonary dysplasia (HMD/BPD) were immunostained for bombesin (BOM), calcitonin (CT), calcitonin gene-related peptide (CGRP), leu-enkephalin (ENK), and serotonin (5HT). The numbers of immunoreactive cells per millimeter airway epithelial length were counted and determined by morphometry. In lungs from the control group, BOM-immunoreactive (IR) solitary cells (SCs) were numerous at the bronchiolar level, and remained so for 4 to 7 months after birth. The number of CT-IR SCs increased markedly around term. At the bronchial level these cells continued to increase postnatally apparently in inverse proportion to the number of BOM-IR SCs in later childhood. The number of CGRP-IR SCs was high only during the neonatal period. 5HT-IR SCs were relatively few and showed no clear developmental change in number. No unequivocal ENK-IR SCs were observed in any case. BOM-IR neuroepithelial bodies (NEBs) were observed more frequently than any other type of NEBs and remained relatively numerous throughout childhood. In lungs of infants with HMD/BPD, endocrine cells of all types except for ENK-IR cells were markedly increased in number during periods of regeneration, to the chronic stage. It is concluded that each of these types of pulmonary endocrine cell demonstrates a characteristic developmental pattern in distribution and frequency during infancy and childhood, probably reflecting the various functional roles of these cells in early life. In HMD/BPD, there is alteration in the number and/or peptide and serotonin content of pulmonary endocrine cells, possibly a result of acute hypoxia, oxygen administration, and epithelial regenerative activity.

Cholinergic regulation of hamster pulmonary neuroendocrine cell calcitonin

The lung content of the peptide hormone calcitonin (iCT) has been localized to discrete and clustered pulmonary neuroendocrine cells. We have undertaken a study of the effect of the autonomic ganglionic agent nicotine on the iCT of hamster lung. The acute subcutaneous administration of nicotine raised serum iCT, while lung tissue concentration of the hormone changed reciprocally to that of the serum. One week following right-sided vagotomy, total (left plus right side) iCT levels decreased following nicotine; the concentration of iCT on the denervated right lung was more markedly decreased than that from the left lung. Hamster serum levels of iCT were significantly reduced following thyroid ablation. As in the intact animals, the subsequent subcutaneous injection of nicotine to these animals raised serum iCT. Further pharmacological evaluations revealed that subcutaneously administered nicotinic cholinergic antagonists, but not muscarinic cholinergic antagonists, prevented the nicotine-evoked increase in serum iCT. Furthermore, the subcutaneous injection of acetylcholine was found to mimic the effect noted for nicotine; this was also abolished by prior administration of a nicotinic antagonist, but not by a muscarinic antagonist. The present study suggests that the nicotinic effect on pulmonary iCT secretion is ganglionically mediated, presumably via vagal innervation of the pulmonary neuroendocrine cells.

Metabolic activation and biological effects of nitrosamines in the mammalian lung

Nitrosamines and their precursors are among the most common contaminants of our environment, and many of them are highly carcinogenic. Nitrosamines are believed to require metabolic activation in the host organism, and many of them demonstrate a pronounced organ and cell type specificity. This review summarizes recent in vivo and in vitro experiments which focus on the mechanisms of nitrosamine-induced lung carcinogenesis. Currently available in vivo and in vitro data suggest that nitrosamines may be metabolized by cytochrome P-450, prostaglandin endoperoxide synthetase, or monoamine oxidases. The presence of one or the other of these enzyme systems may be partially responsible for the cell type-specific effects of this class of chemicals. Moreover, evidence in vitro suggests selective uptake of nitrosamines by cell type-specific receptors, a phenomenon which offers a more logical explanation than previously published theories for the selectivity of biological effects exerted by nitrosamines.

Increased levels of bombesin-like peptides in the lower respiratory tract of asymptomatic cigarette smokers

Bombesin-related peptides are growth factors for a variety of cells, including normal human bronchial epithelial cells. An ELISA for bombesin-like peptides (BLP) has been devised using the MAb BBC353, which is specific for the biologically active carboxy-terminal fragment shared by all known BLP. Using this ELISA, we measured bronchoalveolar lavage (BAL) fluid levels of BLP in normal cigarette smokers (n = 15) and normal nonsmokers (n = 18). Smokers' BAL fluid contained increased levels of BLP, whether expressed in terms of BAL fluid volume (P = 0.0001) or protein content (P less than 0.05). BLP levels did not correlate with any cellular constituent in the BAL fluid but immunostaining of lung tissue with BBC353 revealed an intense specific staining of neuroendocrine cells, implying these as a potential source. Two peaks of bombesin-like immunoreactivity were purified using sequential reverse phase and gel filtration HPLC. Both BLP have apparent molecular weights similar to gastrin-releasing peptide on gel filtration HPLC analysis. However, the amino acid composition of these BLP is different from that of gastrin-releasing peptide or neuromedin B, the only known mammalian forms of BLP, suggesting either incomplete purification or novel peptides. Sequence analysis could not be performed due to blocking groups at the amino terminus of these peptides. Our data demonstrate that cigarette smoking is associated with increased levels of pulmonary BLP and imply a potential role for these neuropeptides in the lung's response to tobacco smoke.

Pulmonary endocrine cells in chronic bronchitis and emphysema

Pulmonary endocrine cells have been studied according to their immunoreactivity for neuron-specific enolase, gastrin-releasing peptide (GRP), calcitonin, leucine-enkephalin, and serotonin in the lungs of subjects with chronic bronchitis and emphysema. The overall population was significantly greater in comparison with matched controls. The change was most marked in lobes affected by pneumonic consolidation, and did not affect equally the sub-populations of cells as identified by their content of peptide; the difference was much greater for calcitonin-containing cells than for those immunoreactive for GRP. This change may be the basis of the hypercalcitoninaemia and hypercalcitoninuria which have been reported in patients with inflammatory pulmonary disease.

Evidence for cigarette smoke-induced calcitonin secretion from lungs of man and hamster

In hamsters, acute cigarette smoke inhalation increased serum levels of the hormone calcitonin; and, in humans, smoking of two high-nicotine content cigarettes increased serum and urine levels of this hormone. The source of this immunoreactive calcitonin (iCT) does not appear to be the thyroid gland, since previously thyroidectomized patients demonstrated a similar response. In the hamster, the increased serum iCT levels were accompanied by a decreased lung tissue iCT content and hypocalcemia. It is suggested that the source of the cigarette smoke-induced hypercalcitonemia is the lung, possibly from the iCT-containing pulmonary neuroendocrine (PNE) cells. Moreover, this response appears to be dependent on the nicotine content of the cigarettes.

Vertebral compression fractures and mineral metabolism in chronic obstructive lung disease

Chronic obstructive lung disease has been reported as a cause of osteoporosis, though whether this association is due to the disease itself or to corticosteroid treatment has not been elucidated. We studied 44 male patients with chronic obstructive lung disease (mean (SD) FEV1 39% (14%) of predicted normal) who were not having long term corticosteroids. No differences in a vertebral deformity score or in metacarpal index were found between them and a control group of similar age. Indices of bone formation (serum osteocalcin) and bone resorption (urinary hydroxyproline) were normal and parathyroid hormone and 1,25-dihydroxyvitamin D were also normal. Serum 25-hydroxyvitamin D was decreased, indicating depleted vitamin D. Calcitonin concentrations were higher in the patient than in the control group of the same age. There was no increase in the prevalence of osteoporosis in patients with chronic obstructive lung disease who had not received long term corticosteroid treatment. Increased concentrations of calcitonin may protect the skeleton from the detrimental effect of hypovitaminosis D.

Demonstration of calcitonin and calmodulin by immunoperoxidase in the cystic fibrosis lung

In this investigation, the presence of calcitonin and calmodulin has been demonstrated in immunoperoxidase formalin-fixed, paraffin-embedded sections of lung from autopsy tissues of four patients who died as a result of complications resulting from their cystic fibrosis disease. Immunoreactive calcitonin has been stained and quantitated in solitary endocrine cells which are increased in number and staining intensity in cystic fibrosis lung when compared to COPD and normal lungs. Immunoreactive calmodulin has been demonstrated to be increased in cystic fibrosis lung when compared to COPD and normal lungs. Previously, increased calcitonin and calmodulin were identified in sputum from cystic fibrosis patients utilizing radioimmunoassay. The calcitonin and calmodulin may be associated with increased calcium in pulmonary secretions leading to selective colonization of the lung by a limited number of pathogenic bacteria and enhanced pulmonary infection.

Widespread distribution of bronchopulmonary endocrine cells immunoreactive for calcitonin in the lung of the normal adult rat

The nature and distribution of bronchopulmonary endocrine cells immunoreactive for calcitonin was studied in normal adult Wistar albino rats by immunoenzyme histochemistry with the peroxidase-antiperoxidase technique. A widespread distribution of both solitary endocrine cells and neuroepithelial bodies immunoreactive for calcitonin was found. Many, but not all, were also immunoreactive for neurone specific enolase. Although both classes of cells were present in airways and parenchyma, most of the solitary cells were found in alveolar ducts and alveoli whereas most of the neuroepithelial bodies were located in bronchi and bronchioles. Bronchopulmonary endocrine cells are generally regarded as being sparse in the adult rat. It is suggested that this may be a consequence of the use of inadequate methods in attempting to identify them. So far as is known, this is the first time that calcitonin has been demonstrated by immunohistochemical methods in the lungs of rats.

Racial differences in calcitonin and katacalcin

Profound racial differences exist in the incidence of osteoporosis, particularly in women. To investigate possible underlying reasons for this, we have measured the circulating levels of calcitonin (iCT), a bone-protecting hormone, and its flanking peptide, katacalcin (iKC), in black Gambian and white British populations. Whilst sex differences in both peptides were observed, with males having higher levels than females, the most striking finding was that white women have the lowest iCT levels. This important observation may explain, at least in part, why osteoporosis is particularly a disease of white, postmenopausal women.

Biological markers in human lung carcinoma: an immunopathological study of six antigens

Immunohistological methods were used to investigate the presence of calcitonin, thyrotrophin, carcinoembryonic antigen, beta pregnancy specific glycoprotein, human placental lactogen, and the beta subunit of human chorionic gonadotrophin in formalin fixed lung tumour tissue sections. Carcinoembryonic antigen was observed in 71% of 101 tumours studied (70%), beta 1 pregnancy specific glycoprotein in 66 of 97 tumours (68%), beta subunit of human chorionic gonadotrophin in 35 of 97 (36%), human placental lactogen in 19 of 97 (20%), calcitonin in 10 of 71 (14%), and thyrotrophin in one of 27 lung tumours studied. There appeared to be no direct association between the presence of any given marker and the presence of any other. Similarly, the association between the presence of a tumour marker and histological type was poor. This study shows that the presence of tumour markers is relatively common in human lung tumours.

Hypothesis: the bronchial Kulchitsky (K) cell as a source of humoral biologic activity

The bronchial Kulchitsky cells are scattered specific cells which lie close to the basement membrane of the bronchi and bronchioles. Electron microscopy reveals that they contain electron-dense granules similar to that seen in cells with a known endocrine function. In addition, experimentally induced degranulation of the K cell suggestive of a secretory process, and the likelihood that these cells are precursors of small cell lung carcinoma (which often elaborates humoral substances) has led to the postulate that this bronchial cell serves a humoral role of either a paracrine or endocrine nature. We have found that the bronchial K cell of man contains a calcitonin-like polypeptide which, immunologically and chemically, is not dissimilar to the hormone produced by the C cells of human thyroid. This finding may help explain the persistence of serum immunoreactive calcitonin (iCT) after total thyroidectomy, the fact that thyroidectomized man does not manifest any profound alteration of calcium metabolism, and why small cell cancer of the lung is frequently associated with hypercalcitonemia. In addition, the finding of K cell hyperplasia in chronic bronchitis and emphysema may explain the occurrence of hypercalcitonemia in patients with these diseases and some lung cancers of cell types other than the small cell variety. Further studies are needed to elucidate the role of K cell iCT, and to determine what other hormones might also be elaborated by this diffuse system of bronchial cells.