Albena Alexandrova and Nesho Chipev conceived and designed the study. Plamen Mitov and Lyubomir Kenderov obtained the samples and contributed to data analyses and summaries. Elina Tsvetanova, Almira Georgieva, Madlena Andreeva, Georgi Petrov, and Georgi Pramatarov performed the biochemical analysis and contributed to data analyses and summaries. Albena Alexandrova and Nesho Chipev supervised the data analysis and wrote the manuscript. All authors have read and agreed to the published version of the manuscript.