Homocysteine and Hydrogen Sulfide, Two Opposing Aspects in the Pathobiology of Sulfur Compounds in Chronic Renal Failure

Sulfur is an element with a plurality of functions, resulting from its numerous oxidation states in which it exists, which gives the emerging compounds a greatly diverse stability. Among these we have homocysteine, an amino acid, and hydrogen sulfide, an inorganic gas, both present in the human body, the former in increased amounts in chronic kidney disease, the latter is instead decreased.1,2 These compounds epitomize two opposites: homocysteine even if not incorporated into proteins, nonetheless binds to them strongly, while hydrogen sulfide is volatile.