FACTORS THAT HAVE MODIFIED THE METABOLISM OF LIVING BEINGS - ENVIRONMENT - 2025

The development of the different industrial, agricultural and urban processes are oriented, in one way or another, towards progress and improving the quality of life. These activities, which are joined by domestic ones, have generated a very serious global environmental pollution.

The vast majority of anthropogenic chemicals used in industrialization alter the environment. As a consequence, factors linked to pollution, such as pesticides and nitrogen dioxide, affect cell metabolism and the environment of living beings.

Environmental pollution. Source: Gabriel Villena from Albacete, Spain

Metabolic processes are associated with the fulfillment of all vital functions, such as respiration, digestion and homeostasis. In these, a set of physical-chemical reactions occur, which are influenced by variations in pH and temperature, among others.

Metabolism participates, among other processes, in the creation and decomposition of body tissues, and in obtaining and reserving energy as a primary source for the functioning of the body.

Factors that have modified the metabolism of living beings and their environment with respect to environmental pollution

Use of pesticides

The development of agricultural activities has resulted in the need for the use of insect control substances, which affect the viability of crops.

Currently very powerful pesticides are used, such as organochlorines, which are stable in the environment. Organophosphates are also used, less stable than the previous ones, but with a high level of toxicity.

Environmental contamination by pesticides is mainly due to their direct application to agricultural crops. It is also due to the inadequate maintenance of the storage tanks and the residues found on the ground, among others.

In this way, toxic particles are incorporated into the air, water and soil, thus modifying their own characteristics. For example, the soil is degraded, causing alterations in its pH, humidity and temperature, among other factors.

Pesticide residues are transferred from the soil to forage, which is consumed by animals. These toxic substances are stored in fat, thus increasing their concentration in milk and meat.

Pesticides are dispersed in the environment, becoming pollutants for the biotic beings that make up the different ecosystems. Thus, metabolic stability is threatened, representing a serious public health danger.

Neurotoxicity

Specialists have conducted research on the effect of organophosphate pesticides on animals. The results show that, even in low concentrations, these toxic substances are endocrine disruptors.

In this way, they could cause alterations in synaptic transmission, as well as they could modify the homeostatic mechanisms of the neuroendocrine system.

The stages of greatest sensitivity to exposure to pesticides are embryonic development and the first years of life, periods in which the processes of cell growth are controlled by hormones.

Any modification in any metabolic process affects the immune system, brain development and organs, such as the thyroid.

The hypothalamus, pituitary, and thyroid axis are sensitive to pesticides. These act by decreasing the production of the hormone thyroxine, due to a low response of TSH to TRH. In this way, there is a dysfunction between the hypothalamus and the pituitary.

When homeostasis is affected by the action of pesticides, the production of thyroid hormone is also impaired. Consequently, the modulation of serotonergic and catecholaminergic functioning, an action carried out by this hormone, modifies the different metabolisms that occur at the brain level.

Dioxins

Dioxins are considered persistent organic pollutants, characterized by a high toxic potential. Once they enter the body, they remain in it for a long time, due to their great chemical stability and their attachment to fatty tissue, where they are stored.

In the environment, they accumulate throughout the food chain, so the higher up the animal is, the more dioxins it may have stored in its body. Another route of transmission is from mother to child, through the placenta and breast milk.

Dioxins are by-products of industrial processes, such as foundry, chlorine bleaching of paper, and herbicide production. They could also occur in forest fires and volcanic eruptions.

The incineration of hospital waste and solids, such as plastic or paper, is usually the main cause of pollution of the environment by this element, because this combustion is incomplete.

This action causes dioxins to be dispersed through the air to ecosystems, having the highest concentration in the soil and sediments. They are also stored in food, such as meat, dairy, seafood, and fish.

Effects on living beings

This toxic compound is considered by the World Health Organization as a “human carcinogen”. In addition, it could affect development and the reproductive, nervous, immune and hormonal systems.

In humans, exposure to dioxins can cause dark spots and chloric acne. It also causes deterioration in the different liver metabolic processes. In high concentrations, it could produce alterations in hormonal levels and glucose metabolism.

In animals it can cause liver damage, weight loss, and endocrine imbalance. Some species present immune problems, thus reducing the ability to fight viruses and bacteria.

Nitrogen dioxide

Recent studies confirm the effects of air pollution on metabolism. According to the WHO, this type of pollution is responsible for more than 5.4% of the deaths of people worldwide.

Nitrogen dioxide is a chemical compound, the main source of which is the combustion of motor vehicles. It is also found in gases emitted by industries. It naturally occurs in volcanic eruptions and forest fires.

Smog is almost exclusively associated with respiratory problems and cardiovascular disorders. Currently, research studies report that people who have been exposed to this pollutant may have a greater risk of suffering from type 2 diabetes.

The scientists established that a higher level of exposure to NO2 increases insulin resistance. In addition, as there is an alteration in the metabolic functions of the β cells, there is a decrease in the secretion of insulin.

It was also shown that when a body is in contact with nitrogen dioxide, there could be an increase in subcutaneous abdominal adipose tissue.

When the fetus is exposed to air pollution with NO2, the baby may experience rapid weight gain at birth. This can lead to increased cardiometabolic risk in middle childhood.

References

1. WHO (2019). Dioxins and their effects on human health. Retrieved from who.int.
2. Françoise Brucker-Davis (2009). Effects of Environmental Synthetic Chemicals on Thyroid Function. Recovered from liebertpub.com.
3. Kim JT, Lee HK. (2014). Metabolic syndrome and the environmental pollutants from mitochondrial perspectives. NCBI. Recovered from ncbi.nlm.nih.gov.
4. Brigitte Le Magueresse-Battistoni, Hubert Vidal, and Danielle Naville (2018). Environmental Pollutants and Metabolic Disorders: The Multi-Exposure Scenario of Life. Recovered from ncbi.nlm.nih.gov.
5. Fiorella, Sarubbi & Palomba, Raffaele, Assunta, Arrichiello & Auriemma, Giuseppe. (2016). Effect of environmental pollution on production and metabolic profile in buffalo cows. Researchgate. Recovered from researchgate.net.
6. Sung Kyun Park (2017). Ambient Air Pollution and Type 2 Diabetes: Do the Metabolic Effects of Air Pollution Start Early in Life ?. American Diabetes Association. Recovered from diabetes.diabetesjournals.org.
7. Yasmin Morales Ovalles, Leticia Miranda de Contreras, María Luisa Di Bernardo Navas (2014). Neurotoxicity of pesticides as endocrine disrupting agents: A review. Recovered from scielo.org.ve.
8. Brian A. Neel1 and Robert M. Sargis (2011). The Paradox of Progress: Environmental Disruption of Metabolism and the Diabetes Epidemic. American Diabetes Association. Recovered from diabetes.diabetesjournals.org.