Apart from being involved in the formation and maintenance of skeletal muscles, bones and the placenta, cell-to-cell fusion plays an important role in numerous other biological processes like fertilization. It has also been implicated in the initiation and progression of cancer and as a driving force in evolution. Moreover, cell-to-cell fusion has been of great value to establish the chromosomal location of specific genes, can be used to induce cellular reprogramming and is indispensable for Oligomycin A generating hybridomas. The involvement of cell-to-cell fusion in a large variety of biological processes and its diverse biotechnological applications have prompted investigations into the mechanisms of cell fusion and the contribution of specific factors to this process. Instrumental to this research is the availability of robust assays to determine cell fusion kinetics and extent. However, most of the existing quantitative cell fusion assays do not allow consecutive analysis of the same cells/tissue. Accordingly, in this paper a new quantitative assay is presented to monitor cell-to-cell fusion. This assay is based on the activation of a latent GpLuc gene after fusion of cells containing this latent reporter gene with cells encoding a recombinase that activates the dormant GpLuc gene. The extent of cell-to-cell fusion is subsequently quantified by simply measuring the enzymatic activity of the luciferase molecules secreted by the cellular fusion products. To the best of our knowledge this is the first assay that allows quantification of cell fusion activity by medium sampling. To validate the new cell fusion assay it was used to monitor the formation of myotubes/sacs in cultures of serum-deprived human myoblasts. In these experiments, several parameters were varied including the acceptor-to-donor cell ratio and the sample regimen of the cell culture medium. Increased serum levels of reactive carbonyl species, such as methylglyoxal, are present in several pathologies and cause complications in severe conditions and diseases, like diabetes mellitus, cardiovascular diseases, atherosclerosis, hypertension, metabolic syndrome, obesity, psoriasis, aging Alzheimer’s disease , dementias, and other neurobiological diseases. Methylglyoxal is a highly reactive a-oxoaldehyde with strong oxidant and glycation properties. Its immediate elimination by detoxification systems is crucial. Accumulated methylglyoxal reacts with proteins, DNA and other biomolecules causing inhibition of enzyme activity, transcriptional activation, apoptosis. The end products of the reactions between methylgyoxal and free amino groups of molecules are insoluble protease-resistant polymers . Methylglyoxal triggers carbonyl and oxidative stress and activates a series of inflammatory responses leading to accelerated vascular endothelial damage. Based on data obtained on peripheral endothelial cells, which forms the blood-brain barrier was also investigated. A concentration-dependent cell toxicity and barrier dysfunction was recently described on a brain endothelial cell line.