Hypoplasia of the arcuate nucleus and maternal smoking during pregnancy in sudden unexplained perinatal and infant death

Maternal smoking during pregnancy is the most important risk factor for sudden perinatal and infant death in more industrialized countries. The frequent observation of hypoplasia of the arcuate nucleus in the brainstem of these victims prompted the verification of whether maternal cigarette smoking could be related to defective development of this nucleus during intrauterine life, by affecting the expression of specific genes involved in its developmental process. In serial sections of the brainstem of 54 cases of sudden and unexplained fetal and infant deaths (13 stillbirths, 7 neonatal deaths and 34 sudden infant death syndrome (SIDS) victims), morphological and morphometrical analysis was used to observe the different structural alterations of the arcuate nucleus (bilateral hypoplasia, monolateral hypoplasia, partial hypoplasia, delayed neuronal maturation and decreased neuronal density) detected in 24 cases (44%). Correlating this finding with smoking in pregnancy, a significantly increased incidence of cytoarchitectural alterations of the arcuate nucleus was found in stillborns and SIDS victims with smoker mothers compared to victims with non-smoker mothers. Moreover, the observation of a wide range of developing morphological defects of the arcuate nucleus related to maternal smoking led to the hypothesis that the constituents of the gas phase in cigarette smoke could directly affect the expression of genes involved in the development of this nucleus, such as the homeobox En-2 gene.

Early atherosclerotic lesions of the cardiac conduction system arteries in infants

INTRODUCTION

Although several studies have described initial atherosclerotic lesions of the coronary arteries, already detectable in infancy and even during the intrauterine life, little, if any, attention has been given to the possible involvement of the cardiac conduction system arteries. In particular, to the best of our knowledge, none has considered the lesions of the cardiac conduction arteries as an initial stage of atherosclerosis.

METHODS

The cardiac conduction system of 70 infants dying suddenly and unexpectedly was removed in two blocks for paraffin embedding and serially cut.

RESULTS

The histological study of the cardiac conduction arteries of the 70 cases examined showed a normal structure in 55 cases (78.57%). In 15 cases (21.43%), there was a thickening of the sinoatrial node and/or atrioventricular artery associated with a thickening of varying severity in coronary artery walls. The lesions were marked by thickening and deposits of amorphous material and mainly lipids in the intima, as well as fragmentation of the elastic fiber system. A significant correlation was evident between early atherosclerotic lesions and both formula feeding and parental cigarette smoking (P<.05, chi(2) test).

CONCLUSIONS

The combination of both the considered risk factors seems to increase the early atherogenic effect of each noxa because the coronary lesions were more diffused in formula-fed infants whose parents both smoked.

Severe carotid barochemoreceptor involvement in stroke

BACKGROUND

Physiopathology of barochemoreception is hindered by the scarce information on its morphology in disease. The baroreflex is of major importance for the maintenance of arterial pressure during orthostatic stress. The purpose of this paper was to characterize the morphological alterations of carotid glomus in old patients who died from stroke and suffering obstructive carotid atheromatosis.

METHODS

Bilateral carotid segments were obtained at autopsy from 17 patients (51-89 years old). Specimens were stained with hematoxylin and eosin; Azan trichrome, Grimelius silver stain for catecholamine detection, and were immunophenotyped for CD34 and S-100. Similar segments of both carotid arteries of six patients (62-77 years old) who died by accidents were used as controls.

RESULTS

The carotid glomus of patients who died from stroke presented atrophy and fibrosis (2.59+/-0.5 vs. 1.17+/-0.39 in the control group; p<0.0001). There was a loss of chief cells and of the argyrophilic staining granules. A focal diminution of glomus vascularization was observed in the areas of atrophy and fibrosis (2.73+/-0.45 vs. 1.5+/-0.52 in the control group; p<0.0001). The arterioles to glomus showed severe fibrointimal proliferation, disruption of internal elastic lamina and luminal narrowing, and luminal thrombi.

CONCLUSION

A severe carotid glomic damage does exist in old patients who died from stroke and suffering from carotid atheromatosis, independent from aging, of note, a "culprit" marked narrowing of the corresponding arterioles was observed.

Analysis of the human locus coeruleus in perinatal and infant sudden unexplained deaths. Possible role of the cigarette smoking in the development of this nucleus

We investigated the immunohistochemical expression of the tyrosine hydroxylase (TH) enzyme and the morphometric parameters of the human locus coeruleus (LC) in the brainstems of 32 subjects aged from 17 gestational weeks to 12 postnatal month, died of unknown (sudden unexplained perinatal and infant deaths) and known causes. The goals of this study were: (1) to obtain basic information about the structure and physiology of the LC during the first phases of human nervous system development; (2) to evaluate whether there is altered expression of TH and/or structural alterations of the LC in cases of sudden perinatal and infant death; and (3) to verify if morphological and/or physiological abnormalities of the LC could be related to maternal cigarette smoking. Morphometric analysis showed homogeneous data in cases of sudden perinatal and infant death and in age-matched controls who had died of known aetiology. However, immunohistochemistry demonstrated in a wide subset of sudden and unexplained deaths a negativity or low positivity of TH. High distribution of TH protein were instead detectable in the LC neurons of foetuses aged 17-18 gestational weeks who had died of known causes. Therefore, we postulate the functional importance of the LC in the early phases of central nervous system development. Besides, the observation of a significant correlation between sudden unexplained death, negativity of TH staining and maternal smoking, prompted us to suppose a close relation between smoking in utero and a decrease of the noradrenergic activity of the LC, leading to sudden death in the last part of pregnancy and in the first year of life.

Pathogenesis of early atherosclerotic lesions in infants

High serologic lipid levels, infections, and genetic susceptibility have been proposed as possible etiologic factors of initial atherosclerotic lesions of the coronary arteries in infancy. At a recent WHO annual meeting, it was stated that breast milk substitutes cause irreparable damage in infants. This prompted us to verify whether formula feeding and parental cigarette smoking might play a role in the pathogenesis of early atherosclerotic alterations in infancy. The major epicardial coronary arteries from 36 infants dying suddenly and unexpectedly (sudden infant death syndrome) were embedded in paraffin and serially cut for histologic examination. In 67% of the cases, multifocal coronary early atherosclerotic lesions of varying entities were detected. The alterations ranged from focal plaques with mild myointimal thickening to juvenile soft plaques reducing the arterial lumen. A significant correlation was observed between the early atherosclerotic lesions and the risk factors considered. In particular, we noted different morphologic patterns related to formula feeding and cigarette smoking. Baby formula feeding and parental cigarette smoking might have an atherogenic effect on the coronary walls as from the first months of life. The lesions appear to be larger and more diffuse when both these atherogenic factors are present.

Autoptic examination in sudden infant death syndrome and sudden intrauterine unexpected death: proposal of a national law

The autoptic procedures in sudden infant death syndrome (SIDS) and sudden intrauterine unexpected death (SIUD) victims requires an in-depth examination of the autonomic nervous system, central and peripheral, as well as of the cardiac conduction system. In these pathologies, our studies have identified frequent developmental abnormalities in the brain stem, particularly hypoplasia of the arcuate nucleus, and accessory atrioventricular pathways in the cardiac conduction system. The law 'Post-mortem Investigation on the SIDS and of Unexplained Late Fetal Death' designated the Institute of Pathology of Milan University as the National Reference Center. The objectives of this law include, in article 4, widespread informative and preventive campaigns and continuous formation of programs for medical personnel.

Role of somatostatin and apoptosis in breathing control in sudden perinatal and infant unexplained death

OBJECTIVES

To obtain basic information about the expression of somatostatin in the human central nervous system and, in particular, to evaluate its possible involvement in unexplained perinatal and in sudden infant death syndrome.

MATERIAL

Sixty-seven brainstems from subjects aged from 30 gestational weeks to 12 postnatal months, dying of both known and unknown causes, were selected for this study. The unexplained deaths included 17 sudden intrauterine deaths, 5 sudden neonatal deaths and 28 sudden infant deaths.

METHOD

All brainstems were fixed in 10% phosphate-buffered formalin, processed and embedded in paraffin, according to our protocol available on the web site: http://users.unimi.it/-pathol/sids/riscontro_diagnostico_e.html. The distribution of the somatostatin in the brainstem was studied by immunohistochemistry on serial sections.

RESULTS

We observed an intense somatostatin positivity in many brainstem nuclei prevalently involved in the respiratory activity (parabrachial/Kölliker-Fuse complex, locus coeruleus, hypoglossus nucleus, dorsal vagus motor nucleus, tractus solitarii nucleus, ambiguus nucleus, reticular formation) in stillbirths. In 10 fetuses with unexplained death the neurons of the hypoglossus nucleus were somatostatin-negative. In the postnatal deaths, we observed immunopositivity in the ventrolateral and ventral subnuclei of the tractus solitarii nucleus. Besides, in 15 sudden infant death victims and in 1 control case, somatostatin-positive neurons were also present in the hypoglossus nucleus. In 10 of these 15 cases, a high apoptotic index was also reported.

CONCLUSIONS

We suggest that abnormalities in the distribution of SS in the hypoglossus nucleus before and after birth may contribute to the induction of both fatal breathing in prenatal life and abnormal ventilatory control after birth leading to irreversible apnea.

Glial and neuronal alterations in the nucleus tractus solitarii of sudden infant death syndrome victims

The factors underlying the sudden infant death syndrome (SIDS) are still unknown, but in recent years much attention has been focused on the central cardiorespiratory control system. In the present work we analyzed the nucleus tractus solitarii (nTS) of 23 SIDS victims and 17 age-matched control cases. We studied the functional and morphological alterations of neurons and glial cells to evaluate the results of possible hypoxic-ischemic injury that could have led to sudden death. Morphometric and immunohistochemical analyses were performed on medullary sections. In the nTS of SIDS victims we observed modifications of both neuronal and glial cells. Brain injury triggers the activation of both astrocytes and microglia, which respond to neuronal damage by characteristic changes that could explain our observations in the nTS of SIDS victims. In our investigation of the nTS of SIDS victims we found a significant increase of reactive astrocytes density, a significantly higher percentage of necrotic cells, an increase of reactive microglial cells density, a significantly higher expression of substance P and the presence of NMDA receptors immunoreactivity. Our results support the hypothesis that there is injury of the nTS neurons in SIDS victims, even if the causes of this damage are still unknown. This neuronal damage may explain why adequate ventilation is often not maintained during hypoxia. Such histological findings have never been thought sufficient to explain SIDS, but the tissue findings could be an indication of the impairment of several pathophysiological mechanisms which may underlie brainstem dysfunction, affecting cardiorespiratory control.

Hypoplasia of the Parabrachial/Kölliker-Fuse Complex in Perinatal Death

We report the first observation of perinatal death attributable to morphological alterations of the parabrachial/Kölliker-Fuse complex. In an infant, born at 41 weeks of gestation with severe signs of asphyxia and dead 20 h after delivery, we observed the presence of rare and immature neurons in the brain stem areas of both lateral and medial parabrachial nuclei and the absence of the characteristic neurons of the Kölliker-Fuse nucleus. Such hypoplasia was associated with severe hypoplasia of the arcuate nucleus and pulmonary hypoplasia.

Cytoarchitectural organization of the parabrachial/Kölliker-Fuse complex in man

While the parabrachial/Kölliker-Fuse complex has been described in a variety of animal species it has not been characterized in human brainstem. In the present study we investigated fetal and infant brainstems, focusing particularly on the dorsolateral part of the pontine tegmentum, with the aim of defining the precise cytoarchitecture of the medial parabrachial, lateral parabrachial, and Kölliker-Fuse nuclei in man, and analyzing the developmental stages of this complex. In serial sections of 28 human brainstems of subjects aged between 32 gestational weeks and 1 year we made a morphologic and morphometric analysis of the shape and size of the parabrachial/Kölliker-Fuse complex. We observed a homogeneous morphology in all cases, which enabled us to define the structure of the three nuclei. The features of the parabrachial nuclei are largely consistent with those reported in experimental studies. However, the Kölliker-Fuse nucleus appears to be more developed in human beings than in other animal species, showing a greater extension and a more complex structure. The neuronal maturation of these nuclei was seen to occur between the 35th and the 36th gestational weeks.

Study of the brainstem, particularly the arcuate nucleus, in sudden infant death syndrome (SIDS) and sudden intrauterine unexplained death (SIUD)

Complete examination of the brainstem involves transverse serial 5-microm sections made throughout the entire brainstem. The number of serial sections varies from 360 in sudden intrauterine unexplained death (SIUD) to 600 in term fetuses to over 1400 sections in sudden infant death syndrome (SIDS) victims. The procedure is not applicable in all histopathological laboratories, owing to the need for additional technical personnel. The simplified procedure allows a remarkable reduction of the number of sections. The brainstem is divided into 3 blocks. The first, cranial block, extends from the border between the medulla oblongata and pons up to the upper pole of the olivary nucleus. The second, intermediate block, corresponding to the submedian area of the inferior olivary nucleus, has as reference point the obex and extends 2 to 3 mm above and below the obex itself. The third, caudal block, includes the lower pole of the inferior olivary nucleus and the lower adjacent area of the medulla oblongata. Examinations of the brainstems from 106 SIDS victims, 30 controls, and 51 stillborns underlined a remarkable variability, particularly of the arcuate nucleus. The simplified examination of the brainstem makes it possible to evaluate the structures, examining 3 specific levels, defined by morphologic reference points.

Multifocal cardiac Purkinje cell tumor in infancy

Cot death is the commonest form of death among babies in the first year of life. The authors report the unusual case of a 2-month-old female infant dying suddenly and unexpectedly in whom a postmortem histological examination demonstrated a cardiac multifocal Purkinje cell tumor. Necroscopy studies of sudden infant death should always include an accurate histological examination of the cardiac conduction system and brainstem using serial sections.

Preliminary study on the cytoarchitecture of the human parabrachial/Kölliker-fuse complex, with reference to sudden infant death syndrome and sudden intrauterine unexplained death

The parabrachial/Kölliker-Fuse complex has been defined, in different animal species, to lie in the dorsolateral part of the pontine tegmentum and to be subdivided into three well-defined regions: the medial parabrachial nucleus, the lateral parabrachial nucleus, and the Kölliker-Fuse nucleus. Experimental studies have shown that the parabrachial/Kölliker-Fuse complex is involved in a variety of functional activities and above all plays an important role in respiratory modulation. In human brainstem, the cytoarchitecture and physiology of this complex have not yet been fully characterized. The aim of the present study was to examine fetal and infant human brainstems in order to define the precise morphology of the three nuclei of the parabrachial/Kölliker-Fuse complex, and to determine whether this nervous center shows morphologic alterations in sudden infant death syndrome (SIDS) and in sudden intrauterine unexplained death (SIUD). In serial sections of 31 brainstems of subjects aged from 32 gestational wk to 10 months of life, we studied, by morphologic and morphometric analyses, the cytoarchitecture and the extension of the three nuclei of the parabrachial/Kölliker-Fuse complex. All the morphometric parameters were very similar in SIUD and SIDS cases to those of the respective control group, as shown by the absence of significant statistical differences between the two fetus and infant groups. We observed that the features of both the lateral and the medial parabrachial nuclei are largely consistent with those reported in experimental studies. In contrast, the Kölliker-Fuse nucleus appears to be more developed in human beings than in other animal species, showing a greater extension and a more complex structure, as well as subdivision into two subnuclei (compactus and dissipatus).

Sudden unexpected death of a term fetus in an anticardiolipin-positive mother

A term male fetus suddenly and unexpectedly died in utero at the 40th week of gestation. The mother had a regular and unremarkable pregnancy except for an anticardiolipin antibodies positivity. The histological examination of the cardiac conduction system showed islands of conduction tissue in the central fibrous body, known as persistent fetal dispersion. The brainstem examination revealed a severe bilateral hypoplasia of the arcuate nucleus. This morphological finding has been described in more than 35% of our stillborn as well as sudden infant death syndrome (SIDS) cases, independently from the presence of anticardiolipin antibodies. Some authors have given emphasis to the possible lethal association of maternal autoantibodies and QT prolongation. Our findings emphasize the need of an accurate postmortem examination including the study of brainstem and cardiac conduction system in every case of unexpected late intrauterine death, following the same standardized autopsy protocol adopted in SIDS cases.

Involvement of somatostatin in breathing control before and after birth, and in perinatal and infant sudden unexplained death

The distribution of the somatostatin was studied by immunohistochemistry on serial sections of the 56 brain stems from subjects aged from 30 gestational weeks to 12 postnatal months, dying of both known and unknown causes. The unexplained deaths included 13 sudden intrauterine deaths, 4 sudden neonatal deaths and 24 sudden infant deaths. We observed intense somatostatin positivity in the cell bodies and fibres of many brainstem nuclei prevalently involved in the respiratory activity (parabrachial/Kölliker-Fuse complex, locus coeruleus, hypoglossus nucleus, dorsal vagus motor nucleus, tractus solitarii nucleus, ambiguus nucleus, and reticular formation) in stillbirths. Only in 8 foetuses with unexplained death the hypoglossus nucleus was somatostatin-negative. In the postnatal deaths, the immunopositivity was prevalently limited to the ventrolateral and ventral subnuclei of the tractus solitarii nucleus. In 13 sudden infant death victims and in one case of death due to pneumonia, somatostatin-positivity was also present in the hypoglossus nucleus. We concluded that: 1) the somatostatin is an important foetal breathing-inhibitor, but it becomes important for the physiological control of respiration immediately after delivery; 2) functional alterations of the hypoglossal nucleus can occur in both sudden perinatal and infant deaths and contribute to the induction of both fatal breathing movements in foetuses and abnormal ventilatory control in infants leading to irreversible apneic phenomena.

Delayed neuronal maturation of the medullary arcuate nucleus in sudden infant death syndrome

Recently, quantitative abnormalities in neuronal populations derived from the rhombic lip (inferior olive nucleus of the brain stem and external granular layer of the cerebellum) have been reported in victims of the sudden infant death syndrome (SIDS). In this study we examined the arcuate nucleus (ARCn) of 35 SIDS victims and 25 controls, to determine neuronal abnormalities involving this nucleus in SIDS. Computer-assisted cell evaluation was made on sections stained with hematoxylin and eosin to study the neuronal dimensions (nuclear and cytoplasmic area, nuclear/cytoplasmic ratio), the form factor and the density of reactive astrocytes. There was a significant reduction of the neuronal area (nuclear and cytoplasmic) in SIDS victims compared with controls. The neuronal populations of SIDS victims had a significantly higher form factor, index of immaturity. The SIDS victims were divided into two groups on the basis of ARCn development: 18 SIDS-A cases with a well-developed ARCn and 17 SIDS-B cases with severe bilateral hypoplasia. The results of our research indicate that the developmental defect is characterized by a reduction in size of the ARC neurons and by neuronal depletion. In SIDS the ARCn has the histomorphological features of neuronal immaturity, and there is a marked reduction of all quantitative cell parameters and lower astrocytes density with respect to controls. On the basis of the morphometric results of the arcuate neuronal populations, we hypothesize that infants whose neurons have failed to reach full maturity are at risk for SIDS because they are unable to develop appropriate cardioventilatory control.

Atherosclerotic plaque rupture and intraplaque hemorrhage do not correlate with symptoms in carotid artery stenosis

OBJECTIVE

Previously we failed to demonstrate a correlation between plaque type and symptoms in 165 carotid endarterectomy specimens. The purpose of this study was to analyze the relation between the anatomy of the carotid plaques and the presence of symptoms in 281 carotid endarterectomy specimens.

METHODS

The patients were 213 men (mean age, 68 years) and 68 women (mean age, 68.7 years), with symptomatic disease (n = 133) or asymptomatic disease (n = 148). Specimens were processed for histologic analysis and immunohistochemistry.

RESULTS

Plaques were categorized as complicated or noncomplicated, and ruptured or nonruptured. Risk factors could not be correlated with any pathologic or immunohistochemical findings or between plaque type and clinical symptoms.

CONCLUSIONS

Almost 70% of plaque specimens demonstrated thrombus, intraplaque hemorrhage, or both. Thrombosis was observed in one fourth of specimens, and intraplaque hemorrhage in almost two thirds of specimens. Sixty four percent of plaques demonstrated neovascularization. It was not possible to demonstrate that complicated plaques (plaque rupture, thrombosis, intraplaque hemorrhage) are associated with symptoms, and it appears that such plaques may occur at any time, irrespective of symptoms.

Expression of c-fos, p53 and PCNA in the unstable atherosclerotic carotid plaque

BACKGROUND

The process by which a fibrofatty plaque evolves into a fibrotic lesion or into an unstable, lipid-rich plaque is poorly understood. In this study our aim is to deepen the knowledge of the cellular proliferation mechanisms that characterize the initial phases of destabilization of the unstable carotid plaque.

METHODS

32 specimens from carotid endarterectomies were employed to assess by immunohistochemical methods, either in stable (n=10) or unstable (n=22) atherosclerotic plaques, the proliferating cell nuclear antigen (PCNA), the proto-oncogene c-fos, and the oncoprotein p53.

RESULTS

18/32 atherosclerotic plaques (all unstable), showed c-fos immunopositivity (P<0.0001). Ten lesions, three stable and seven unstable, were PCNA+, while 13 cases were positive for p53 (three stable and 10 unstable plaques). When comparing symptomatic vs. asymptomatic patients, the most striking finding was the coincidence between c-fos, PCNA and p53 protein positivity observed only in unstable plaques of seven out of eight patients, all with previous episodes of stroke or transient ischemic attacks. On the other hand, none of the above mentioned positivity was detected in the 24 asymptomatic patients (P<0.0001).

CONCLUSIONS

These findings indicate an important role of these biomarkers in vascular biology. A series of molecular pathways of disease development and progression common both to atherosclerosis and cancer, support that the world's two most common diseases are more closely aligned than previously believed.

Identification of neurons responding to hypoxia in sudden infant death syndrome

The pathogenesis of sudden infant death syndrome (SIDS) is still not understood, although one of the most credited current hypotheses is the respiratory theory. Considerable evidence has been assembled suggesting that hypoxia in human infants produces an initial increase in ventilation, after which respiration is rapidly inhibited. We investigated the expression of the c-fos proto-oncogene, a marker of activated neurons, particularly by hypoxia, in the medulla oblongata nuclei involved in breathing after birth, with special reference to SIDS. We utilized c-fos protein immunohistochemistry on serial transverse sections of medulla oblongata from 22 SIDS victims. In 60% of the analyzed cases, we observed numerous positive c-fos neurons in the dorsal motor nucleus of the vagal nerve. In control cases, the immunohistochemical labeling was negative or very low. The c-fos protein was expressed in the rostral-intermediate portion of the dorsal motor vagal nucleus, where motoneurons with respiratory-related activity are located. The positive c-fos immunoreactivity observed in SIDS suggests that the neurons of the dorsal motor vagal nucleus involved in the regulation of breathing are able to yield an intense, immediate ventilatory response to hypoxia. Our results support the respiratory theory of SIDS.

Crib death: further support for the concept of fatal cardiac electrical instability as the final common pathway

This work intends to be a review of the current status of knowledge on the cardiac conduction system in the crib death as well as remaining challenges, including reflections upon authors' personal works as well as many studies by others. The cardiac conduction system findings of resorptive degeneration, His bundle dispersion, Mahaim fibers, cartilaginous meta-hyperplasia, persistent fetal dispersion, left sided His bundle, hemorrhage of the atrio-ventricular junction, septation of the bifurcation, atrio-ventricular node dispersion, sinus node hypoplasia, Zahn node, His bundle hypoplasia, atrio-ventricular node and His bundle dualism are hereby discussed by the authors. The cardiac hypotheses postulating that crib death could be due to lethal cardiac arrhythmias or heart block were considered of great interest in the 1970s. After a general abandon of the conduction studies in crib death, the cardiac concept of crib death is gathering a renewed interest, as well as the occurrence of infantile junctional tachycardia. Both the morphological and functional derangement underlying crib death remain poorly understood, assuring that it remains to be a major medical and social problem. Despite the non-specificity of most of the cardiac conduction findings in crib death, we believe that they, in association with altered neurovegetative stimuli, could underlie potentially malignant arrhythmias, providing a morphologic support for the cardiac concept of crib death.

Intimal preatherosclerotic thickening of the coronary arteries in human fetuses of smoker mothers

BACKGROUND

Many studies have described the development of preatherosclerotic coronary artery lesions in infancy. The observations reported in the literature regarding the fetal origin of coronary artery lesions are rare and controversial.

OBJECTIVES

To identify the features of preatherosclerotic coronary artery lesions in late fetal stillborns and the possible atherogenic role of maternal cigarette smoking. METHODS; We examined 22 stillborns (13 males and nine females), all of whom had died sine causa after the 32nd week of gestation. All underwent autopsy. Twelve of the mothers smoked over five cigarettes per day before and during the pregnancy. The four major epicardial coronary arteries were isolated along their whole length, embedded in paraffin and serially cut for histologic examination and immunohistochemical studies, particularly searching for the proliferating cell nuclear antigen and c-Fos expression. Alterations of chromosome 7 were also investigated by the fluorescence in situ hybridization technique.

RESULTS

In over 50% of the fetuses, almost all from smoker mothers, multifocal structural alterations of coronary walls were evident. The smooth muscle cells (SMCs) presented loss of polarity, forming columns perpendicular to the axis of the media and infiltrating the subendothelial connective tissue. Increased amounts of mucoid ground substance were also observed in the subendothelial connective tissue. In all the cases with coronary alterations, study of the biological markers showed intense c-Fos positivity of the SMCs.

CONCLUSIONS

Preatherosclerotic intimal alterations of the coronary arteries are already detectable in the prenatal period and are significantly associated with maternal cigarette smoking.