ABSTRACT Gastroenterology, hepatology and liver transplant exchanges between the USA and Cuba have mainly consisted of scientific events and short visits. This has facilitated Cuba’s inclusion in recognized scientific organizations, familiarity with Cuba’s biotech products for treatment of liver disease, and access by Cuban professionals to the highest level of scientific information for clinical practice. It has also given health professionals in the US a more accurate picture of Cuba’s health sector. The results of the Global Alcoholic Liver Disease Survey, which included Cuba and was designed and coordinated in the USA, opened doors to joint research and scientific publications. Until now, there have been no protocols for ongoing cooperation to enable bilateral clinical trials or continuing professional development in diagnostic, therapeutic and surgical techniques for hepatology and liver transplantation. There are many mutually beneficial research prospects in these areas. What has been accomplished to date, described in this article, is encouraging and sets the stage for future collaboration.

After the discovery of gammaglutamyltranspeptidase in 1950 by Hanes, the significance of its increased levels in clinical practice has mainly been focused on ethanol toxicity, and also some neoplasms and biliary tract obstruction. More recently, attention has swift to the metabolic functions of this enzyme, as a neutralizer of oxygen free radicals and as a glutathione donor to the cell. High serum levels of gamma-glutamyltranspeptidase is known to occur when oxidative stress is increased, or associated with several vascular risk factors and the insulin resistance syndrome, as an early marker of diabetes. There are also a number of drugs that induce the expression of the tissue enzyme (microsomes) with the result of high serum levels without structural damage to the liver. Because it is a ubiquitous enzyme, a very high number of causes can be involved, that may be difficult to recognize. Finally, because glutathione is necessary to conjugate a number of chemical compounds, from an epidemiological and toxicological perspective, the enzyme might be useful as a biomarker of several ambient toxins. In this review we want to emphasize the increasing clinical and diagnostic significance of this enzyme discovered half a century ago.

Desde su descubrimiento en 1950 por Hanes, la enzima gammaglutamiltranspeptidasa, al menos en medicina clínica, se ha vinculado casi en exclusiva, al valor de su aumento en la toxicidad por etanol y, en menor medida, de la existencia de ciertas neoplasias y de bloqueo de la vía biliar. Más recientemente, menudean trabajos acerca de su papel metabólico, mediando la neutralización de radicales libres de oxígeno y aprovisionando de glutatión a las células. El nivel sérico de gammaglutamiltranspeptidasa es expresivo de estrés oxidativo aumentado y se ha asociado a diversos factores de riesgo cardiovascular y a componentes del síndrome de resistencia a la insulina, de modo que sería un biomarcador precoz para el desarrollo de diabetes. Por otro lado numerosos fármacos inducen la enzima tisular (microsomas) pudiendo dar elevaciones séricas que no suponen daño estructural a nivel hepático. Su ubicuidad anátomo-citológica hace que pueda aumentar en suero en numerosos procesos, siendo por ello en ocasiones dificultoso patentizar su origen. Finalmente, desde un ángulo epidemiológico y toxicológico, siendo que el glutatión es necesario para conjugar diversas sustancias químicas, la enzima resultaría un biomarcador, entre otros, de numerosas sustancias nocivas medioambientales. Se incide en conjunto en este ensanchamiento del significado clínico y diagnóstico de una enzima que se creía suficientemente conocida desde hace medio siglo en que se descubrió.