[Indirect and mixed mechanisms of action in toxic myopathies]

Toxic myopathies are a group of pathologies characterized by a structural and/or functional disturbance of muscles induced by an exogenous agent. The most frequent are those induced by drugs used in clinical practice. Illegal drugs, pesticides, solvents, metals and even physical and gaseous agents can cause this kind of disease and exert toxicity on muscle tissues. Some toxins from animals, plants or micro-organisms are potent myotoxic agents, which can lead to fatal complications. Respiratory arrest and rhabdomyolysis are often referred to as the ultimate complications of these pathologies. Several mechanisms of action can be triggered. Muscles may represent a direct target for exogenous agents by acting on the myocyte components or indirect target by inducing functional disorders. These disorders are triggered by neuromuscular interferences (organophosphates, antipsychotics, curares, etc.) and endocrine (glucocorticoids and ethyl alcohol), immune (d-penicillamine and statins) and hydroelectrolytic system dysfunctions (diuretics, laxatives and toluene). Direct and indirect effects can be induced by the same toxic agent, such as carbon monoxide, glucocorticoids, ethyl alcohol and some toxins from snake venoms.

[Environment and lifestyle: Impacts on male fertility?]

In this last century, an increase of men infertility has been registered. It has been suggested that environmental factors could a negative impact over sperm quality. Among these factors, impact of environmental toxicant has been spread by media. In this review of scientific literature, we identify several environmental factors that could impact men fertility in a negative way. These factors are tobacco, marijuana, weight, body mass index, heat, nutritional state, electromagnetic waves and altitude. For each of these factors, the impact over men fertility, their mechanism, as well their influence over the use of Assisted Reproductive Technics are reported.

[Direct mechanism of action in toxic myopathies]

Toxic myopathies are a large group of disorders generated by surrounding agents and characterized by structural and/or functional disturbances of muscles. The most recurrent are those induced by commonly used medications. Illicit drugs, environmental toxins from animals, vegetables, or produced by micro-organisms as well as chemical products commonly used are significant causes of such disorders. The muscle toxicity results from multiple mechanisms at different biological levels. Many agents can induce myotoxicity through a direct mechanism in which statins, glucocorticoids and ethyl alcohol are the most representative. Diverse mechanisms were highlighted as interaction with macromolecules and induction of metabolic and cellular dysfunctions. Muscle damage can be related to amphiphilic properties of some drugs (chloroquine, hydroxychloroquine, etc.) leading to specific lysosomal disruptions and autophagic dysfunctions. Some agents affect the whole muscle fiber by inducing oxidative stress (ethyl alcohol and some statins) or triggering cell death pathways (apoptosis or necrosis) resulting in extensive alterations. More studies on these mechanisms are needed. They would allow a better knowledge of the intracellular mediators involved in these pathologies in order to develop targeted therapies of high efficiency.