Underlying Mechanisms and Treatment of Cellular Senescence-Induced Biological Barrier Interruption and Related Diseases

Given its increasing prevalence, aging is of great concern to researchers worldwide. Cellular senescence is a physiological or pathological cellular state caused by aging and a prominent risk factor for the interruption of the integrity and functionality of human biological barriers. Health barriers play an important role in maintaining microenvironmental homeostasis within the body. The senescence of barrier cells leads to barrier dysfunction and age-related diseases. Cellular senescence has been reported to be a key target for the prevention of age-related barrier diseases, including Alzheimer's disease, Parkinson's disease, age-related macular degeneration, diabetic retinopathy, and preeclampsia. Drugs such as metformin, dasatinib, quercetin, BCL-2 inhibitors, and rapamycin have been shown to intervene in cellular senescence and age-related diseases. In this review, we conclude that cellular senescence is involved in age-related biological barrier impairment. We further outline the cellular pathways and mechanisms underlying barrier impairment caused by cellular senescence and describe age-related barrier diseases associated with senescent cells. Finally, we summarize the currently used anti-senescence pharmacological interventions and discuss their therapeutic potential for preventing age-related barrier diseases.

The anatomic basis for ultrasound in the diagnosis and treatment of styloid process-related diseases

Background

The styloid process (SP), stylohyoid ligament and lesser horn of hyoid bone together form the stylohyoid chain. Differences in the ossification degree and the connection sites of each segment of the stylohyoid chain on both sides lead to variations in the length, orientation, thickness, and straightness of SP. The incidence of elongation of the SP, known as styloid process syndrome (SPS), is around 4%, with only 4% of patients showing elongation show symptoms. Computed tomography (CT) remains the first-choice auxiliary examination for diagnosing SPS, but its performance can be affected by a variety of factors. Ultrasound can reveal the parapharyngeal space and adjacent structures, which offer high consistency with CT findings. Here, we investigated the ultrasonographic features of the SP and its adjacent structures in normal adults and assessed the clinical utility of ultrasound assessment for SP-related diseases.

Methods

With the ramus of mandible, mastoid process, SP, and salivary gland as the anatomical landmarks, ultrasonography was conducted on the parapharyngeal space in 78 healthy adults. The scans were performed along the oblique coronal section of the ramus and the cross-sectional plane between the mastoid process and ramus to visualize the SP and its adjacent structures. The SP length, the shortest distance from the SP tip to the outer edge of tonsil (SP-tonsil distance), and the distance from SP to the internal carotid artery (SP–ICA distance) were measured.

Results

SP and its adjacent structures were successfully visualized on ultrasonography in all 78 subjects. The measured SP length was 2.65±0.48 cm. The SP–tonsil distance was 1.95±0.50 cm. The SP–ICA distance was 0.509±0.231 cm. The SP length and SP–tonsil distance measured by ultrasound were not significantly different from those measured by CT (P=0.071, P=0.053). Furthermore, the SP length and SP–tonsil distance measured by ultrasound were positively correlated with CT measurements (r=0.917, P=0.071; r=0.978, P=0.053, respectively). SP–tonsil distance was negatively correlated with SP length and SP inward deflection angle.

Conclusions

Ultrasound can accurately reveal the shape and size of SP and its adjacent structures and thus will be helpful for the diagnosis of SP-related diseases.

[Asbestos exposure and related diseases among friction products workers (1971-2016)]

Worldwide studies have been published on the mortality of workers employed in asbestos-based materials for the production of clutches and brakes. However no one of these studies is related to Italian cases. Furthermore, not even surveys have been conducted in Italy to characterize the correlation between asbestos exposures and the possible occurring of asbestos-related disease. Our objectives are the following: i) to assess and quantify the asbestos exposure cases, ii) to describe the nature and the frequency of asbestos-related diseases among blue collar employees of an important factory producing brakes and clutches with chrysotile asbestos content from 1971 to 1993 and iii) to provide preliminary data on cumulative asbestos exposure estimated using lung fibre burden analysis. Critical appraisal of airborne asbestos fibre measurements and identification of cases of asbestos-related diseases between the blue collar employees, either notified to the local health authority or recovered from the Italian national Mesothelioma registry was investigated. Lung fibre burden analysis using the lung tissue samples from two deceased blue collar employees was also performed. Airborne asbestos fibre measurements (carried out in 1982) suggested asbestos fibres average concentrations of about 0.3 f/ml, while all 1992 measurements showed results below 0.1 f/ml. Furthermore, since 1988, we identified four cases of pleural plaques, three cases of asbestosis and seven cases of lung cancer. No case of malignant mesothelioma was found. In both lung cancer cases, analysed to measure the lung fibre burden, commercial amphiboles were absent or in limited concentration but chrysotile and, especially, tremolite asbestos were present in noticeable amount. In conclusion, since 1971 and up to early 1980s, exposure to chrysotile asbestos and talc, likely contaminated by tremolite, had been significant and comparable to levels causing asbestosis long-term risk. No case of malignant mesothelioma was found, that is consistent with the absence of amphiboles and with the lower risk of mesothelioma associated with the chrysotile asbestos. However a subset of the blue collar employees, the ones employed later on, could still have not reached the full risk condition, and so being still at risk of developing malignant mesothelioma. In the two lung cancer cases studied, the lung fibre burden was essentially made of chrysotile and tremolite. Lastly, lung cancer occurrence in the population of blue collar employees has been likely underestimated and the correct determination of lung cancer risk should be done through the mortality analysis of this population.