Animals play varied and important roles in society. In times of crisis, like those we are living through now, their influence is more relevant and noticeable than ever. We are witnessing how eggs and poultry meat are flying off the shelves and how on average, meat consumption has skyrocketed. On the other hand, the lockdown has prompted many people to get a dog or a cat. Shelters are empty in the US, Europe and many other countries. Companionship in times of lockdown is more valuable than ever.
Fig 1: Meat sales evolution in the US at the start of the lockdown
Beyond food and companionship, there are many other roles animals play for us: from the guard dog to the therapy horse or the experimentation to find new drugs or vaccines. However, there is also another contribution that they make that often goes unnoticed.
Animals have been at the very origin of many lives-saving humans medicines and medical procedures. For example, there are many active ingredients which have been discovered in animals: snake venom was the source of hypertension treatments based on a compound called caprotil while a treatment for diabetes is based on the active principle exanetide, which was found in the saliva of the Gila monster lizard.
Fig 2: The snake Bothrops Jararaca whose venom served as the origin of an hypertension treatment
Other examples are: Hog heart valves used for transplants, natural silk used to manufacture suture medicine and leeches used in some surgical procedures (FDA approved). Horses also produce life-saving antibodies that can be used to treat tetanus or diphtheria while millions of embryoned poultry eggs used in the manufacture of human vaccines.
Fig 3: Eggs used to replicate virus and manufacture vaccines
One of the most exciting and little known examples of life-saving human medicines that come from animals is the compound Heparin. This drug saves the lives of 100 million people every year, through its use in heart surgeries, kidney dialysis treatments and to treat blood clots.
Heparin is a natural occurring compound that was isolated in 1916 by Jay McLean, a young student of medicine at John Hopkins University in Baltimore, U.S., from the liver of some animals. It is considered an essential drug by the World Health Organization
Heparin is a natural occurring compound that was isolated in 1916 by Jay McLean, a young student of medicine at John Hopkins University in Baltimore, from the liver of some animals. It is considered an essential drug by the World Health Organization (the list of essential medicines contain the minimum medicine needs for a basic health‐care system, listing the most efficacious, safe and cost‐effective medicines for priority conditions).
Fig 4: Heparin structure
The role of Heparin in the cells is not fully understood, but when administered intravenously it acts as a blood thinner. It is the most commonly used anti-coagulant in thrombosis prevention and treatment. According to data from the International Society on Thrombosis and Haemostasis, which are contributing factors to 25% of human deaths every year.
Heparin is found in the mucosa of different organs. Particularly rich are the lungs of ruminants and the intestines of pigs. Since the mad cow disease crisis Heparin from ruminants is not used today, so the main source is the mucosa from the small intestine of pigs.
Fig 5: Heparin is found in pig’s small intestine
In order to supply the global needs of Heparin, we need to harvest it from 800 M pigs yearly. The main producer is China, although other countries such as Spain are also producers. While it is possible to make synthetic Heparin, it is not possible to produce it commercially, so the only current source is the swine industry.
The potential of the Heparin molecule and its derivatives to develop new drugs is enormous. Currently, new applications related to antitumor, anti-inflammatory and antiviral activity are being studied.
During this Covid-19 crisis, many of us have paused to reflect on the important role of protein and pets in our lives. It is also a good opportunity to understand and appreciate the contribution of animals beyond food and companionship. In the case of Heparin, pigs allow us to have a miracle cure for several threatening diseases thanks to a compound found in their intestine. Thanks to Heparin, millions of people can recover from devastating conditions and have longer, healthier lives.
Just another example of how human health and wellbeing is indebted to the service of animals.
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For some additional reading:
- van der Meer JY, Kellenbach E, van den Bos LJ. From Farm to Pharma: An Overview of Industrial Heparin Manufacturing Methods. Molecules. 2017 Jun 21;22(6):1025. doi: 10.3390/molecules22061025. PMID: 28635655; PMCID: PMC6152658.
- Giangiacomo Torri et al. Heparin centenary – an ever-young life-saving drug. International Journal of Cardiology. Volume 212, Supplement 1, June 2016