The pulmonary neuroendocrine system: the past decade.

The pulmonary neuroendocrine system consists of specialized airway endocrine epithelial cells, associated with nerve fibres. The epithelial cells, the pulmonary neuroendocrine cells (PNEC), can be solitary or clustered to form neuroepithelial bodies (NEB). During the last thirty years, the pulmonary neuroendocrine system has been intensively investigated and much knowledge of its function has been obtained. This text reviews work which dates from the last ten years. In this period, the picture of the pulmonary neuroendocrine system we previously had, has not fundamentally changed. The pulmonary neuroendocrine system is still regarded as an oxygen sensitive chemoreceptor with local and reflex-mediated regulatory functions, and as a regulator of airway growth and development. Continuing research has much more refined this picture. This text reviews several aspects of the pulmonary neuroendocrine system: phylogeny, the amine and peptide content of its epithelial cells, ontogeny and influence on lung development, the influence of hypoxia and nonhypoxic stimuli, immunomodulatory function, innervation and pathology. Among the discoveries of the past decade, three stand out prominently because of their great significance: additional proof that the neural component of the pulmonary neuroendocrine system is sensory, sound experimental evidence that PNEC stimulate airway epithelial cell differentiation and the discovery of a specific membrane oxygen receptor in the PNEC.

Pulmonary neuroepithelial bodies are innervated by vagal afferent nerves: an investigation with in vivo anterograde DiI tracing and confocal microscopy.

The pulmonary airway and alveolar epithelia contain distinctly innervated clusters of basally granulated cells: the neuroepithelial bodies. In the past, morphological criteria and the results of selective vagotomy have led to the interpretation that their innervation is sensory. Consequently, they are regarded as receptor organs. As a further test of this hypothesis, the present investigation set out to label vagal sensory nerve fibres to the lungs by anterograde neural tracing, and to establish the relationship between these fibres and the neuroepithelial bodies. A fluorescent neural tracer was injected unilaterally into the left or right nodose ganglion of adult rats. After suitable survival times, thick frozen sections of lung tissue were studied with laser scan confocal microscopy. Sensory nerve fibres were seen to run in the airway walls and occasionally penetrated the epithelium, where they formed complex terminals. The resulting intraepithelial sensory end organs showed a close morphological resemblance to the neuroepithelial bodies. Subsequently, electron microscopic investigation of such identified structures revealed the typical ultrastructural characteristics of neuroepithelial bodies: corpuscular cells containing dense cored secretory vesicles and contacted by mitochondria-rich nerve endings. We conclude that anterograde tracing of sensory nerves from the nodose ganglion confirms the receptor nature of the pulmonary neuroepithelial bodies, which may correspond to a subpopulation of the irritant and C-fibre receptors.

Lymphocytes and dendritic cells in the normal uterine cervix. An immunohistochemical study.

OBJECTIVE: Assessment of the appearance, distribution and numerical density of immune cell populations in the normal human uterine cervix. SETTING: University Hospital Gasthuisberg. SUBJECTS: 29 healthy women undergoing total hysterectomy for non-cervical benign uterine disease. ANALYSIS: Immunohistochemistry and morphometrical analysis on histological sections containing ectocervix, transformation zone and endocervix, using antibodies against the following antigens: HLA-DR, CD4, CD22, CD1a and CD8. STATISTICAL ANALYSIS: Wilcoxon rank sum test. RESULTS: Lymphocytes in the epithelial and stromal compartments are predominantly T-lymphocytes. Intraepithelial T-lymphocyte and Langerhans' cell densities and their distribution are not influenced by the menstrual cycle and are the same in both ectocervix and transformation zone. CONCLUSION: The wide variation of T lymphocyte subpopulations and Langerhans' cell densities in the normal epithelium of the uterine cervix is stressed. We are the first to present a large and well-defined control series, which is indispensable to study the effect of smoking and other factors on the cervical immune system.

Immunoreactivity for the alpha-subunit of the pituitary glycoprotein hormones in pulmonary neuroendocrine cells of developing human lung and various perinatal diseases.

Infant lung tissue, obtained at autopsy, was studied by immunohistochemistry for the presence of pituitary glycoprotein hormones (PGHs) in the lung. The infants, born at term or preterm, died of various causes. The results provide the first immunological evidence of the presence of the common a-subunit of the pituitary glycoprotein hormones (alphaPGH) in the lung. The immunoreactivity is located in the pulmonary neuroendocrine cells and neuroepithelial bodies. In addition, the cells labelled by alphaPGH antisera (alphaPGH cells) form a subpopulation of the neuroendocrine cells detected by anti-calcitonin immunohistochemistry (CT cells). Moreover, the number of alphaPGH cells appears to increase after neonatal pneumonia or when the number of CT cells is elevated following the development of disease. Also, the weak staining of one of the monoclonal antibodies against the specific b-subunit of thyrotropin (TSH) might, in combination with the increased detectability of a-subunits, indicate that TSH can be endogenously produced in the lung.

The effect of pregnancy on endometriosis in baboons (Papio anubis, Papio cynocephalus).

BACKGROUND: This study was performed to test the hypothesis that endometriosis undergoes regression during pregnancy. METHODS: This study was performed on 11 baboons with histologically proven endometriosis, housed at the Institute of Primate Research, Nairobi, Kenya. In each individual baboon paired laparoscopies were performed prior to and during pregnancy (6 during first and 5 during second trimester of gestation) with an interval of 5 +/- 3 months. During each laparoscopy the number, size and type of endometriosis implants were noted in detail on a pelvic map; the endometriosis score and stage were calculated according to the revised American Fertility Society (AFS) classification. In each baboon the observations prior to and during pregnancy were compared and analysed by Wilcoxon signed rank test (two-tailed). RESULTS: No significant change was observed in the AFS score or stage of endometriosis, or in the number, size and type of endometriotic lesions in baboons during gestation when compared to the nonpregnant state. CONCLUSION: In baboons pregnancy had no significant effect on endometriosis during the first or second trimester of gestation.

Elastogenesis is linked to epithelial-stromal interactions in postnatal hamster bronchioles.

In a previous study, direct epithelial-stromal cell contacts via foot processes perforating the basement membrane were investigated in bronchioles of postnatal hamster lungs. In the present study, analogous postnatal epithelial foot processes have been found on stromal cells exhibiting active elastogenesis as determined by morphological criteria. In addition, elastin is prominently present close to the epithelium, but less so in the deeper layers, in the bronchioles of the 14-day-old hamster. The elastin often has an asymmetrical distribution around the subepithelial fibroblast with preference for secretion toward the epithelium. Thus, elastogenesis can now be linked to epithelial-stromal interactions at the temporal, functional, and morphological levels.

The prevalence of spontaneous endometriosis in the baboon (Papio anubis, Papio cynocephalus) increases with the duration of captivity.

BACKGROUND: It is not known whether stress affects the prevalence of endometriosis in women. Baboons with spontaneous endometriosis may be interesting models to study the human disease. For baboons, living in captivity is a period of chronic stress without continuous exposure to pregnancy. This study was done to compare the prevalence of endometriosis between baboons recently captured in the wild and those living in captivity for several years. METHODS: A diagnostic laparoscopy was performed for screening endometriosis and obtaining biopsies in 104 female baboons including animals that had been captured in the wild less than 1 year ago (n=52, Group I), primates that had been living in captivity for one to two years (n=30, Group II) and animals that had been captured for more than two years (n=22, Group III). RESULTS: The prevalence of clinical and biopsy-proven endometriosis in all baboons was 17% and 12%, respectively. Clinical endometriosis was found more frequently in group III (32%) than in group II (17%) or group I (11%). The prevalence of biopsy-proven endometriosis was also significantly higher in group III (27%) than in groups I and II combined (8%, p=0.03). CONCLUSIONS: The results indicate that the prevalence of endometriosis increases with the time spent in captivity. This trend may be explained by more menstrual cycles uninterrupted by pregnancy in captive than in wild baboons, and possibly also by age-related factors or by captivity-associated stress.

Cervical cotinine and macrophage-Langerhans cell density in the normal human uterine cervix.

Cotinine levels in blood and cervical fluid of smokers and non-smokers were analysed using capillary-column gas chromatography. These levels were not related to numerical cell densities of intraepithelial S100-protein- and LN2-positive Langerhans cells or to MAC-387-positive macrophages in the stroma of the transformation zone of normal uterine cervices. A decrease in the number of Langerhans cells was noted in smokers, especially in those using oral contraceptives (OCs). Macrophages were more numerous in the endocervical stroma of smokers, suggesting a local response to smoke constituents. These findings may indicate a synergistic suppression of local cervical immunity by smoking and OCs.

Langerhans' cells and L1 antigen expression in normal and abnormal squamous epithelium of the cervical transformation zone.

This study evaluates the presence of Langerhans' cells and expression of L1 antigen in squamous epithelium of the normal and dysplastic transformation zone of the cervix uteri and determines the influence of tobacco smoking and pregnancy. Women who smoked and pregnant women showed a decrease of Langerhans' cell counts in normal epithelium. In cervical intraepithelial neoplasia (CIN) 1 lesions, decreased Langerhans' cell counts were noted. L1 antigen expression was significantly less in CIN of all grades. Normal squamous epithelium of smokers showed weaker staining for L1 antigen but total staining scores were not significantly different. These data suggest a decrease in epithelial cell-mediated immune response in smokers, pregnant women and in low-grade CIN. Dysplastic squamous cells probably have intracellular regulatory problems independent of other immune cells.

Morphologic and neuroendocrine features of adenocarcinoma arising in the transition zone and in the peripheral zone of the prostate.

We examined retrospectively 107 step-sectioned radical prostatectomy specimens. The index tumor in each specimen was designated a transition zone carcinoma (TZCa) or a peripheral zone carcinoma (PZCa) based on its location. All tumor sections were immunohistochemically stained with chromogranin A (ChrA). A semiquantitative ChrA score (0 to 3) was assessed. ChrA-positive neuroendocrine cells were found in 83% of the index tumors. The ChrA score was significantly related to the Gleason score, the volume of the tumor, and the pathologic stage. Twenty-two percent of the index tumors were designated TZCas; 75% of these demonstrated neuroendocrine differentiation versus 85% of the PZCas. A high ChrA score of > or = 2 was found in 46% of PZCas and in only 33% of TZCas. Capsular transgression, seminal vesicle involvement, positive surgical margins, and lymph node metastasis were seen in the TZCa group in 33%, 17%, 29%, and 4%, respectively versus 58%, 20%, 48%, and 6% in the PZCa group. These findings were associated with a higher mean tumor volume in the TZCa group compared with the PZCa group. The average Gleason score of 4.5 in the TZCa group was significantly (P < 0.0001) lower than the Gleason score 6.2 in the PZCa group. Multicentricity was found in 62% of TZCas and in 49% of PZCas. Eighty-seven percent of the second tumors in the prostates with a primary TZCa were located in the peripheral zone. We conclude that the frequently occurring neuroendocrine cells population enlarges with tumor progression, especially in PZCas.(ABSTRACT TRUNCATED AT 250 WORDS)

Intrapelvic injection of menstrual endometrium causes endometriosis in baboons (Papio cynocephalus and Papio anubis).

OBJECTIVE: The Sampson hypothesis of retrograde menstruation as a cause of endometriosis was tested by determining the effect of intrapelvic injection of menstrual versus luteal endometrium on the incidence, peritoneal involvement, and stage of endometriosis. STUDY DESIGN: Seventeen baboons were injected retroperitoneally with luteal (n = 6) or menstrual (n = 7) endometrium and intraperitoneally with menstrual endometrium (n = 4). Laparoscopies were performed after 2 months in all animals and after 5 and 12 months in six and five primates injected with luteal and menstrual endometrium, respectively. RESULTS: The peritoneal endometriosis surface area, number of implants, and incidence of typical and red subtle lesions were significantly higher after retroperitoneal injection of menstrual than of luteal endometrium. By use of menstrual endometrium intraperitoneal seeding was more successful in causing endometriosis than was retroperitoneal injection. No significant changes in number or surface area of endometriotic lesions induced with retroperitoneal injection of luteal endometrium after 5 months were observed in the six baboons. At repeat laparoscopy 12 months after intrapelvic injection of menstrual endometrium progression was recorded in three of four regularly cycling animals, whereas regression was evident in one baboon that had become amenorrheic after induction. CONCLUSION: Intrapelvic injection of menstrual endometrium can cause peritoneal endometriosis and offers experimental evidence supporting the Sampson hypothesis.

Peripherally localized benign hyperplastic nodules of the prostate.

Approximately one-half of needle-core biopsy samples performed for palpable and/or ultrasonographically hypoechoic focal lesions of the prostate reveal carcinoma. A fraction of the negative biopsy samples are related to benign hyperplastic nodules, localized in the peripheral zone of the prostate. The present study examines the morphology of this particular lesion in surgical specimens obtained after cystoprostatectomy and radical prostatectomy performed for bladder and (small) prostate cancer, respectively. Peripheral hyperplastic nodules occur in 18.5% of this population and are unifocal in one-half of the cases. The mean diameter is 4 (+/- 1.3) mm. Peripheral hyperplastic nodules are characteristically localized posteriorly in the peripheral zone, between the midline and the lateral border of the prostate and often in the vicinity of the boundary of the transition zone. Histologically, they resemble glandulostromal hyperplastic nodules as observed in classic benign nodular hyperplasia of the transition zone. Cystic transformation may occur. The nodules are sometimes surrounded by condensed stroma and atrophic glands. Atypical adenomatous hyperplasia is rarely noticed in this lesion. No pure stromal (leiomyomatous) nodules without glands are seen. The peripheral hyperplastic nodule should be included in the differential diagnosis of focal lesions of the peripheral zone.

Presence and possible implications of open-ring centrioles, multiple basal centrioles and basal cilia in neonatal hamster bronchioles.

In studying epithelio-stromal interactions in the neonatal hamster lung, basal centrioles, basal cilia and open-ring centrioles attracted our attention. The same structures are also found in bronchiolar epithelium of a 3-week-old fawn-hooded rat, indicating that they are not specific phenomena of hamster lung. Although cells with basal centrioles are not common, they are more readily observed in a sample of bronchioles at the second postnatal week as compared to the fourth neonatal day. The centrioles may often possess two satellites and function as microtubule organizing centers (MTOC). Open-ring centrioles are mature structures and also serve as MTOC. Apparently, triplets may de novo be added to and/or degraded from an open-ring centriole. The basal cilia and the cilia in the ciliated vacuoles/cysts, have a normal axonemal structure and may have a common origin from the basal centrioles. It is, however, unclear whether or not they are primary-like cilia. In addition, presence of the multiple basal MTOC and some morphologic features point to a high microtubule-associated vesicular transport activity and probably indicate an elevated interaction with the interstitium; thus, the cells have a different polarization then normal ciliated cells.

Tobacco smoking impairs the local immunosurveillance in the uterine cervix. An immunohistochemical study.

Previous reports have supported an association between tobacco smoking and cervical neoplasia. Our observations show an association between smoking and a reduction of the numerical densities of Langerhans cells and of helper/inducer T lymphocytes in the squamous epithelia of the transformation zone of the uterine cervix. This suggests a local impairment of cell-mediated immunity by smoking. This immunosuppressive effect could support the concept that smoking is an independent risk factor for cervical neoplasia.

Morphologic and immunohistochemical changes in prostate cancer after preoperative hormonal therapy. A comparative study of radical prostatectomies.

BACKGROUND: Estramustine phosphate (EMP) and flutamide (FL) were used as reversible preoperative hormonal drugs in the surgical treatment of patients with localized prostate cancer. METHODS: The authors descriptive and quantitatively examined the morphologic and immunohistochemical changes in 40 of 200 step-sectioned radical prostatectomies, obtained after treatment with EMP (25 patients) and with FL (15 patients). Of these, 28 pretreatment needlecore biopsies were available. RESULTS: Every specimen contained adenocarcinoma. Understaging was found in 50% of the cases and a higher Gleason score in 70%. Benign glands underwent atrophy and squamous metaplasia. Treated tumors showed cytoplasmic vacuolization, nuclear pyknosis, fibrosis and lymphocytic infiltrates. The EMP group had an 84% (P < 0.05) higher mean total regression score than the FL group. Estramustine phosphate induced a 56% (P < 0.05) and a 34% decrease in tumoral prostate specific antigen and prostate specific acid phosphatase intensity scores, respectively, versus 29% and 32% after FL. The mean proliferating cell nuclear antigen (PCNA) labeling index and the mean mitotic index of the EMP group were 52% (P < 0.05) and 70% (P < 0.05) lower than those measured in the FL group. Each FL-treated tumor and 92% of EMP-treated tumors expressed chromogranin A (ChrA); ChrA labeling correlated significantly with PCNA labeling. Seventy-six percent of EMP-treated specimens revealed venous thrombosis. CONCLUSIONS: Estramustine phosphate induces important morphologic and immunohistochemical changes in prostate cancer with an apparent decrease of secretory and proliferative activity when compared with FL-treated tumors. These changes represent pitfalls in the diagnosis and grading of treated carcinomas. Nearly every treated adenocarcinoma of the prostate has neuroendocrine differentiation, showing increasing ChrA labeling with higher tumor stage. A significant correlation between tumor proliferation and neuroendocrine differentiation was noticed in this small cohort of patients. There was a high incidence of periprostatic venous thrombosis after EMP treatment.

7B2 expression in intrapulmonary neuroepithelial bodies: immunocytochemical detection and colocalization with serotonin and calcitonin gene-related peptide.

In this study, the occurrence of 7B2, a highly conserved pituitary protein present in many neuroendocrine tissues and tumors, was investigated for the first time in the neuroendocrine cells (NEC) and neuroepithelial bodies (NEB) of hamster, rat and cat lung, as well as its colocalization with serotonin (5-HT) and calcitonin gene-related peptide (CGRP). Bouin fixed and wax embedded lung tissue was serially cut and immunoreactive sites for 7B2, 5-HT and CGRP were demonstrated on adjacent sections with polyclonal rabbit antibodies, using the streptavidin-biotin peroxidase method. 7B2 immunostained NEB were numerous in the intrapulmonary airways and the alveolar parenchyma, always representing a subpopulation of CGRP labelled NEB, but outnumbering those containing 5-HT. NEC, on the other hand, were only immunoreactive for CGRP and 5-HT. Our results suggest that mammalian NEB are storehouses of heterogenous bioactive substances, which may be important components in the development of bronchopulmonary tumors. Moreover, the ubiquitous presence of 7B2 in NEB supports the idea of a pre- and/or post-exocytotic role in the cellular secretory processes while the lack of 7B2 immunoreactivity in NEC might indicate a distinct function for each of both neuroendocrine cell types.

Prenatal ultrasound diagnosis of rhizomelic chondrodysplasia punctata in a primigravida.

Rhizomelic chondrodysplasia punctata (RCDP) is a sublethal autosomal recessive disorder characterized by skeletal dysplasia, microcephaly, mental retardation, congenital cataracts, joint contractures, skin changes, and failure to thrive. Prenatal ultrasound diagnosis has been reported during the second trimester of pregnancy. Prenatal diagnosis is also possible from the first trimester onwards by demonstration of peroxisomal dysfunction in cultured chorionic villous or amniotic fluid cells. In all cases reported hitherto, the prenatal diagnosis was established after the birth of a previous affected child. In contrast to these studies in pregnant multiparous women at risk for RCDP, we report on the first case of prenatal ultrasound diagnosis of RCDP at 19 weeks' gestation in a primigravida. In addition, a complex cardiac malformation associated with hypoplasia of the thymus (DiGeorge anomaly) is described.

Hereditary renal adysplasia: new observations and hypotheses.

Renal agenesis and dysplasia are frequently regarded by pathologists, even pediatric pathologists, as sporadic malformations. We report six fetal autopsy cases of hereditary renal adysplasia (HRA): two pairs of siblings, one case with paternal unilateral renal agenesis, and one case with an autosomal balanced 6p/19q translocation. The main purpose of this paper is to emphasize that nonsyndromal renal agenesis and dysplasia are pathogenetically related and often inherited as an autosomal dominant trait with incomplete penetrance and variable expression. A subsidiary purpose is to present a case of bilateral multicystic dysplasia with a balanced 6p/19q translocation. This observation further supports the assignment of one of the loci for HRA to chromosome 6p.

Kinetics and cellular localisation of putrescine uptake in human lung tissue.

BACKGROUND: The polyamines (putrescine, spermidine, and spermine) are involved in cellular growth, proliferation, and differentiation. In the lungs of various species, polyamines are accumulated by an active uptake system which also mediates the uptake of cystamine and paraquat. In the rat lung putrescine uptake has been shown to be cell-specific, occurring predominantly in the alveolar epithelium. The aim of this study was to characterise the uptake of putrescine in human lung. METHODS: Lung tissue was obtained from 31 patients undergoing surgery for lung cancer. Slices (0.7 mm thick) from non-tumour containing lung parenchyma were incubated for 15-60 minutes in Krebs-Ringer phosphate buffer with various concentrations of putrescine (2.5 to 80 mumol/l) containing 0.1 microCi [1,4-14C]-putrescine. Uptake was assessed from tissue radioactivity. For autoradiographic imaging, slices were incubated for 30 minutes with 2.5 mumol/l putrescine containing 2.5 mCi [1,4n-3H]-putrescine. RESULTS: The accumulation of [14C]-putrescine into slices was time-dependent and energy-dependent, and obeyed saturation kinetics, with mean calculated values for Vmax (maximal rate of uptake) of 414 nmol/g/hour and for Km (medium concentration at which the rate of uptake is half Vmax) of 7.2 mumol/l, with a large interindividual variation. Competitive inhibition was observed on incubation with cystamine, which appears to have a high affinity for the uptake system since its calculated Ki (concentration of inhibitor at which the Km is doubled) was 3.2 mumol/l. Ultrastructural autoradiography showed labelling over both type I and type II cells of the alveolar epithelium, but not over the endothelium or any cells of the interstitium. Alveolar macrophages were also devoid of label. CONCLUSIONS: These results show that the human lung possesses an active uptake system for putrescine, and probably also cystamine, which is located in both cell types of the alveolar epithelium. These findings may be used to develop tests for the assessment of the alveolar epithelium.