INFLUENCE OF VITAMIN B6 DEFICIENCY ON RESPIRATION OF LIVER MITOCHONDRIA IN NEW-BORN RATS DURING LACTATION IN CONTEXT OF CARDIOLIPIN COMPOSITION CHANGES

Objectives: Vitamin B6 (VitB6) deficiency during pregnancy translates into a severe VitB6-deficiency (plasma leves decreased by 97 %) in new-born rats. Here, effects of VitB6-deficiency on cardiolipin (CL) composition and oxygen consumption of liver mitochondria are analyzed. Methods: New-born rats (10 per group) from VitB6-deficient (B) and control (C) rats were euthanized at day 14 p.p. (B1,C1) or 28 p.p. (B2,C2) and mitochondria and cardiolipin prepared from liver samples. CL-species were quantified by ESI-MS/MS analysis and mitochondrial respiration measured using a Mitocell MT200/oxygraph. Results: VitB6-deficiency provoked highly significant changes in the CL-composition of liver mitochondria e.g. increased amounts of (C18:1)2/C16:0)2, C22:16/C18:2)3 and oxidized CL or fatty acid contents. These changes are associated with increased state IV respiration and decreased respiratory control ratios in VitB6-deficient rats. Elder rats showed increased oxygen consumption during state III, indicating lower efficacy of OXPHOS and increased ROS generation. Age-dependent changes of CL-composition and mitochondrial respiration seem to exist. Conclusion: VitB6-deficiency leads to substantial changes in CL-composition and mitochondrial respiration. To what extent these mitochondrial alterations contribute to the well-established metabolic changes during VitB6-deficiency remains to be determined in future studies.