MT-ND6 and Insulin resistance: However, a significant correlation between preop ND6 levels and HgbA1c and ND6 levels and insulin resistance (HOMA-IR) at 2 weeks post-op suggests that one of the potential drivers of insulin resistance may be short cf-mtDNA fragments such as ND6. These findings, along with the presence of long cf-mtDNA fragments, may underlie the clinical importance of cf-mtDNA as a mechanism explaining the effects of bariatric surgery on the improvement of insulin sensitivity.