Asbestosis

Asbestosis is a serious progressive lung disease caused by the inhalation of asbestos fibres and dust. The disease was first identified in 1928 as type of pneumoconiosis – occupational lung ailment caused by inhaled dusts from mines and agriculture. There is no cure or specific treatment for it and scant literature on evidence-based natural management options, however there is ongoing research into early detection and future medical interventions.

What is asbestos?

Asbestos is a group of 6 naturally-occurring silicate minerals with a long thin crystal structure. Each crystal of asbestos contains microscopic fibres which are easily dispersed during processing. There are 2 main types of asbestos – chryosite and amphilobolite (consisting of amorite, crocidolite, tremolite, actinolite) all of which are considered toxic. However, chryosite is the most common form used in industrial materials.

Asbestos has been used for thousands of years but large-scale industrial use only began in the last 100-150 years. After the Second World War until 1954, there was a booming rate of use, with 52% of houses in NSW made with some form of asbestos. Due to its low cost and durable nature it was used as  common building material.

Up until the 1960’s 25% of new homes in Australia were clad with asbestos-containing cement or fibro as it is commonly called and in Victoria 98% of houses built before 1976 had asbestos.

As of 31 December 2003, asbestos and its products have been banned, so it can no longer be imported, sold, supplied, used or re-used. Materials like glass and cellulose fibres have now replaced it. However, the ban does not extend to building materials used before this date. It is difficult to tell with the naked eye if a building has asbestos-containing materials in it, so laboratory tested is needing to confirm this. Contact National Association of Testing Authorities (NATA) for testing information. If you are not planning to arrange testing and your home was built before 2004, it is safest to assume that the building has some asbestos in it and treat it accordingly.

Symptoms development

Symptoms may take 10 years to develop after significant occupational exposure to asbestos. Asbestos particles stay in the lungs and scar tissue forms around them. The inhaled asbestos fibres are highly reactive when compared to coal dust.

Whereas coal dust must accumulate in large amounts before the body reacts by forming scar tissue or fibrosis, it only takes low concentrations of asbestosis before fibroblasts form scar tissue on the lungs. The scarring gradually grows, causing shortness of breath, impeding oxygen uptake into the blood, oxygen deprivation, reduced quality of life and eventually death. Asbestos is also associated with as immune – system dysregulation, leading asbestosis sufferers more susceptible to auto-immune disease such as systemic lupus erythematosus (SLE) and rheumatoid arthritis.

Symptoms of Asbestosis               

• Difficulty breathing
• Chest tightness
• Crackles in both lungs 
• Secondary auto-immune disease

Risk Factors

• Occupational – miners, quarrymen, millers, workers of asbestos textiles, electricians and insulators are most at risk
• Size of the asbestos fibres - fibres less than 5 mm are unlikely to pose any risk ,  whereas 10 -20mm micrometres long fibres may lead to asbestos-related disease
• Smoking appears to speed progression rate of asbestosis.

Prognosis

Asbestosis progressively worsens and though there is no cure, early detection can improve symptoms and treatment outcomes. Survival rates are between 1-5 years after diagnosis. Treatment can prolong life and improve the quality of it. Deaths caused by asbestosis worldwide is tallied at 3495 but asbestosis can also be a risk factor for developing asbestos-linked cancers. The number of asbestos-linked cancers worldwide according to the World Health Organization and International Labour Organization is much higher – about 107,000-112,000.

Treatment for Asbestosis

There is no specific treatment for asbestosis but the management of asbestos-linked disease revolves around  appropriate vaccinations, treatment of lung infections, quitting smoking and oxygen therapy as needed.

Two chemical messengers in the body called interleukin-1-alpha and interleukin-1-beta regulate lung homeostasis and pathology by binding to a receptor called the Interleukin-1 (IL) receptor.  In a healthy lung, IL-1-alpha keeps fibroblast cell production in check and make prostaglandin E2, which stops fibrosis from forming. 

But when inhaled, asbestos triggers IL-1-beta, it stimulates fibrosis and asbestosis and fibrotic nodules, leading to mesothelioma.

Increased IL- 1 beta has been found in coal workers with pneumoconiosis (or miner’s lung) and in cement mason apprentices.

A case report of a patient with mild asbestosis experienced complete remission with the use of an anti-interleukin-1-beta antibody. Canakinumab is an IL-beta antagonist which is a licensed treatment for auto-inflammatory syndromes an injection under the skin at a dose of 150 mg to be re-injected every 8 weeks. At a routine 1-week follow-up, the body’s markers of inflammation (C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) and markers of auto-immune dysfunction (anti-nuclear antibody (ANA)) were significantly reduced. After 4 months the patient was in clinical remission.  Though the study was too limited to provide treatment information for fibrosis of the lung, it shows canakinumab can be useful for lung and systemic auto-immune symptoms of asbestosis.

IL-beta is also involved in T-cell activation, leading to auto-immune dysfunction. When asbestos is inhaled, the body’s ability to seek out and destroy the foreign matter by impairing body’s anti-tumour cells, hence increasing the risk of asbestos-related cancers.

Antioxidants as a potential treatment

Inhaled fibres of asbestos, silica and other non-cancer forming fibres have been shown to completely deplete the stores of antioxidants glutathione and ascorbate (vitamin C) in the lung tissue. This may indicate a link in the causation of asbestos-related cancers and that antioxidant supplements may have a role in managing asbestos related disease. However, the non-carcinogenic fibres caused the fastest rate of antioxidant depletion, indicating there are other factors in the development of asbestos-related disease. 

Other asbestos diseases

Pleural plaque – taking up to 7 years to show up after asbestos exposure, it is detected by chest X-ray or CT scan.  Pleural plaques are a thickened patch known as fibrosis found in the pleura, the two membranes that line the chest wall and lungs and over and around the diaphragm. They produce no symptoms.

Mesothelioma –  a rare cancer linked to significant and prolonged asbestos exposure. Symptoms may take 25-40 years to develop. Asbestos, when at a high enough level, impairs the body’s natural tumour-fighting cells.
It increases T cell function, also called T -suppressor cells, whose job is to maintain tolerance to foreign body’s that the immune system would otherwise try to get rid of - allowing these mesotheliomas to grow in the membranes lining the lungs, abdomen or heart.

• in the lung lining (or pleura) it is called pleural mesothelioma and its symptoms are as severe chest pain, persistent, dry cough and breathlessness
• in the abdominal lining (or peritoneum) it is called peritoneal mesothelioma and is accompanied by abdominal pain, fever, nausea, vomiting and urinary and bowel issues.
• in the membrane lining the heart (or pericardium) it is called pericardial mesothelioma and causes fluid to pool around the heart bringing on heart palpitations in addition to chest pain, shortness of breath and a persistent cough. ​

Lung cancer – can occur in anyone who has had exposure to asbestos but the risk is increased when the patient is a smoker.  These can be removed completely by surgery if detected early enough.

References

1. https://en.wikipedia.org/wiki/Asbestos
2. Search for biomarkers of asbestos exposure and asbestos-induced cancers in investigations of the immunological effects of asbestos https://www.ncbi.nlm.nih.gov/pubmed/29165150
3. https://en.wikipedia.org/wiki/Regulatory_T_cell
4. http://www.asbestos.vic.gov.au/about-asbestos/health-facts
5. https://www.atsdr.cdc.gov/asbestos/docs/asbestos_factsheet_508.pdf
6. https://www.mesotheliomagroup.com/04-21-17-mesothelioma-early-detection
7. https://www.cancer.org/cancer/cancer-causes/asbestos.html
8. Asbestos fiber length and its relation to disease risk https://www.ncbi.nlm.nih.gov/pubmed/29458304 
9. http://www.asbestoswise.com.au/information-and-resources/asbestos-diseases
10. https://www.mesotheliomaguide.com/mesothelioma/diagnosis/mesothelioma-vs-asbestosis/
11. https://www.medicinenet.com/asbestos-related_disorders/article.htm#asbestos_exposure_diseases_definitions_dangers_and_facts
12. www.asbestoswise.com.au/information-and-resources/asbestosinthehome/
13. Combined effect of silica dust exposure and cigarette smoking on total and cause-specific mortality in iron miners: a cohort study https://www.ncbi.nlm.nih.gov/pubmed/29743082
14. https://bmcmusculoskeletdisord.biomedcentral.com/articles/10.1186/s12891-015-0602-6
15. The proliferative effects of asbestos-exposed peripheral blood mononuclear cells on mesothelial cellshttps://www.spandidos-publications.com/10.3892/ol.2016.4412
16. https://academic.oup.com/annweh/article/44/2/101/167181