Vibroacoustic Disease Research Articles

Involvement of central airways in vibroacoustic disease patients

Introduction. Vibroacoustic disease (VAD) is the whole-body pathology caused by excessive exposure to LFN. For the past 25 years, it has been know that low frequency noise (LFN, <500 Hz, including infrasound) targets the respiratory system. In LFN-exposed rodents, the morphological changes of respiratory tract tissue partially explained some respiratory symptoms reported by VAD patients. However, many questions remain unanswered. Recently, some volunteer VAD patients underwent bronchoscopy in order to ascertain possible damage that could be associated with their respiratory complaints. Methods. Fourteen fully-informed and volunteer VAD patients were submitted to bronchoscopy, and biopsies were removed for analysis. Results. All patients exhibited small submucosal vascular-like lesions near the spurs, consisting of increased collagen and elastin fibres. Histology disclosed cilliary abnormalities, basal membrane hyperplasia, and thickening of vessel walls. In five patients, collagen bundles appeared degenerative and disrupted. No inflammatory process was ever identified, and no differences were seen between smokers and non-smokers. Discussion. Data is in accordance with what was observed in LFN-exposed animal models and also in 8 VAD patients who developed lung tumours. Collagen disruption and degeneration was also observed in electron microscopy images of the respiratory tract of LFN-exposed rodents. Thickened blood and lymphatic vessel walls have been consistently seen in images of VAD patients and of LFN-exposed rodents. During bronchoscopy performed by other reasons, this sort of structural aspects is not frequently seen. Taken together, it is strongly suggested that these findings could be VAD-specific.

Noise-Induced Gastric Lesions: a Light and Scanning Electron Microscopy Study of the Alterations of the Rat Gastric Mucosa Induced by Low Frequency Noise

Exposure to low frequency noise (LFN) can lead to vibroacoustic disease (VAD), recognized as a systemic disease with lesions in a broad spectrum of organs. Although gastrointestinal complaints are common among individuals exposed to noise, only few studies tried to evaluate the digestive lesions. The authors performed this study in order to investigate gastric lesions in an animal model of VAD. Adult Wistar rats were exposed to continuous LFN. After five weeks they were sacrificed. The stomachs were studied by light microscopy and scanning electron microscopy, and compared with stomachs of animals kept in silence. Superficial erosions were present in the noise-exposed animals. Massive cell death of the gastric epithelium was observed, both by light and electron microscopy. The erosions, reflecting cellular degeneration and death, occurred without inflammation, similar to what has been observed in other LFN-exposed organs.

Efeito da exposição prolongada a ruído ocupacional na função respiratória de trabalhadores da indústria têxtil

Vibroacoustic disease is a pathology caused by long occupational exposure to large pressure amplitude and low frequency noise. It is a systemic disease, with evolvement of respiratory structures. The exposure workers to this noise of textile industry may favour alterations in lung function. We studied 28 women working more than ten years in cotton-mill rooms to evaluate their lung function, including Spirometry, forced oscillation technique (I.O.S.) and Diffusion capacity. These results were compared with those of 30 women of similar ages not exposed to similar noise and not presenting respiratory disease.Statistical significance (P<0.05) was found with FEV25, R5 and ∆ Rs5-Rs20. There was a resistance frequency dependence in 36% of the population exposed to noise, not statistically confirmed. Neither restriction nor changes in diffusing capacity where detected.Conclusion: The analysis of global alterations of lung function parameters suggests small airways aggression by noise. However we cannot definitively exclude the influence of cotton dust inhalation in itself which effects could be increased by the loss of ciliated cells and impairment of airways clearance caused by noise.Rev Port Pneumol 2006; XII (1): 45-60

Effects of long term exposure to occupational noise on textile industry workers’ lung function

Vibroacoustic disease is a pathology caused by long occupational exposure to large pressure amplitude and low frequency noise. It is a systemic disease, with evolvement of respiratory structures. The exposure workers to this noise of textile industry may favour alterations in lung function. We studied 28 women working more than ten years in cotton-mill rooms to evaluate their lung function, including Spirometry, forced oscillation technique (I.O.S.) and Diffusion capacity. These results were compared with those of 30 women of similar ages not exposed to similar noise and not presenting respiratory disease.Statistical significance (P<0.05) was found with FEV25, R5 and Δ Rs5-Rs20.There was a resistance frequency dependence in 36% of the population exposed to noise, not statistically confirmed. Neither restriction nor changes in diffusing capacity where detected. ConclusionThe analysis of global alterations of lung function parameters suggests small airways aggression by noise. However we cannot definitively exclude the influence of cotton dust inhalation in itself which effects could be increased by the loss of ciliated cells and impairment of airways clearance caused by noise.

MECHANOTRANSDUCTION IN PERICARDIAL TISSUE OF VIBROACOUSTIC DISEASE PATIENTS

PURPOSE: Mechanical signalling among cells and tissues has been shown to be an important, albeit lesser known, form of transducing pathological stimuli. Cytoskeletal (CSK) structures are organized in accordance with tensegrity architecture and, as such, can bear mechanical loads. Vibroacoustic disease (VAD) is a systemic pathology characterized by the abnormal proliferation of extra-cellular matrices (ECM) in the absence of an inflammatory process. The goal of this report is to qualitatively analyse the images obtained from vibroacoustic disease (VAD) pericardial fragments within the context of tensegrity structures.

THE NEW PERICARDIAL STRUCTURE IN VIBROACOUSTIC DISEASE

PURPOSE: The anatomical study of the pericardium in vibroacoustic disease (VAD) patients was prompted by the echo-imaging results obtained initially in aircraft technicians. With informed consent of VAD patients, submitted to cardiac surgery for other reasons, pericardial fragments were removed for study in order to determine the nature of this abnormal thickening.

O ruído e o aparelho respiratório

Noise-induced pulmonary pathology is still an issue that is regarded with much suspicion despite the significant body of evidence demonstrating that acoustic phenomena target the respiratory tract. The goal of this review paper is threefold: a) to describe acoustic phenomena as an agent of disease, and the inadequacies of current legislation regarding noise-induced, non-auditory pathology; b) to trace how the interest in noise-induced pulmonary pathology emerged within the scope of studies on vibroacoustic disease; and c) to bring to light other studies denouncing noise as an agent of disease that impinges on the respiratory tract. As concluding remarks, future perspectives in LFN-related research will be discussed. The need for animal models will be emphasized.

Morphological Changes in the Respiratory System of Vibroacoustic Disease Patient

PURPOSE: Vibroacoustic disease (VAD) is caused by long-term exposure (years) to low frequency noise (LFN) [≤500 Hz, including infrasound]. In LFN-exposed animal models, the respiratory system was shown to be a target for this acoustic aggressor. Simultaneously, all respiratory tract tumors observed in VAD patients were of a single type of cellularity: squamous cell carcinomas. In this report, fragments of trachea, lung parenchyma and pleura of VAD patients are studied through light and electron microscopy.

120 超・低周波音の知覚と苦情発生状況に関する一考察

120 超・低周波音の知覚と苦情発生状況に関する一考察

Pericardial Morphology in Vibroacoustic Diseas

PURPOSE: Pericardial thickening in the absence of an inflammatory process and with no diastolic dysfunction is the hallmark of vibroacoustic disease (VAD): a whole-body pathology caused by long-term (years) exposure to low frequency noise (LFN) (≤500 Hz, including infrasound). This study explores the morphological features of the human pericardial response to LFN exposure.

In utero and postnatal exposure of Wistar rats to low frequency/high intensity noise depletes the tracheal epithelium of ciliated cells.

Chronic exposure of men or rodents to low frequency/high intensity (LFHI) noise causes a number of systemic changes that make up the so-called vibroacoustic disease (VAD), a disorder that includes alterations of the respiratory system, namely, of its epithelial layer. We have investigated here the susceptibility of the tracheal epithelium of Wistar rats to in utero and postnatal exposure to LFHI noise by comparing its ultrastructure with that of the tracheal epithelium of control rats and of animals exposed to LFHI noise only after reaching adulthood (8 weeks of age). Scanning electron microscopy (SEM) of the inner surface of rat trachea was used to determine the relative areas covered by ciliated and non-ciliated cells. In rats that were exposed in utero and postnatally to LFHI noise, we observed that out of 100 microm(2) of tracheal epithelium only 31 +/- 14 microm(2) were covered by cilia, whereas in control rats; ciliated cells occupied an average of 60 +/- 18 microm(2) out of 100 microm(2) of the epithelium; this difference between the two groups was statistically significant (p <0.05). In rats that were exposed to LFHI noise only after reaching adulthood, cilia covered 55 +/- 22 microm(2) out of 100 microm(2) of the luminal surface of the trachea, a value that, although lower than that of controls, was not found to be statistically different. We conclude that (1) the tracheal ciliated cells are damaged by exposure of rats to LFHI noise if the animals are kept under this environmental aggression during in utero and postnatal periods; (2) tracheal ciliated cells from adult rats are more resistant to the deleterious effects of LFHI noise than pleura or lung alveolar cells that were shown before to undergo marked changes upon chronic exposure of rats to LFHI noise. These findings suggest a note of caution regarding pregnant women and young children: they should be prevented from areas where LFHI noise occurs, namely, in aircraft and textile industries where this type of environmental hazard is often present.