Metabolic Changes Associated With Cardiomyocyte Dedifferentiation Enable Adult Mammalian Cardiac Regeneration.

BACKGROUND: Cardiac regeneration after injury is limited by the low proliferative capacity of adult mammalian cardiomyocytes (CMs). However, certain animals readily regenerate lost myocardium through a process involving dedifferentiation, which unlocks their proliferative capacities. METHODS: We bred mice with inducible, CM-specific expression of the Yamanaka factors, enabling adult CM reprogramming and dedifferentiation in vivo. RESULTS: Two days after induction, adult CMs presented a dedifferentiated phenotype and increased proliferation in vivo. Microarray analysis revealed that upregulation of ketogenesis was central to this process. Adeno-associated virus-driven HMGCS2 overexpression induced ketogenesis in adult CMs and recapitulated CM dedifferentiation and proliferation observed during partial reprogramming. This same phenomenon was found to occur after myocardial infarction, specifically in the border zone tissue, and HMGCS2 knockout mice showed impaired cardiac function and response to injury. Finally, we showed that exogenous HMGCS2 rescues cardiac function after ischemic injury. CONCLUSIONS: Our data demonstrate the importance of HMGCS2-induced ketogenesis as a means to regulate metabolic response to CM injury, thus allowing cell dedifferentiation and proliferation as a regenerative response.

[Separation and authentication of tilianin and quality standards of semen of Dracocephalum moldavia].

Tilianin was separated and authenticated from the seeds of Dracocephalum moldavia, a Uygur medicine, by chromatographic technique and spectroscopic method. The purity of tilianin is more than 98% determined by HPLC area normalization method. Thin layer chromatography (TLC) method was used to separate tilianin from D. moldavia by mixture of chloroform-methanol (5: 1) as a developing solvent on high performance silicagel precoated plate (SGF254) and using aluminium trichloride as a chromogenic agent for qualitative identification of D. moldavia. To establish a HPLC method for quantitative analysis of D. moldavia, tilianin was used as a Quantitative marker and separated on a C18 (4.6 mm x 250 mm, 5 µm) column with acetonitrile-01% formic acid (25: 75) as the mobile phase and detected at 330 nm. The calibration curve of tilianin displayed ideal linearity over the range of 0.617 2-123.44 µg x mL(-1) with a regression equation of Y = 33.773X - 0.824 8 (r = 1). The average recovery of tilianin was 101.0% with RSD of 3.7%. The RSD values of intra-day and inter-day precision were less than 2%. The content of tilianin in 4 batches of the authenticated semen of D. Moldavia was between 0.016 and 0.187 mg x g(-1). The qualitative and quantitative method established is suitable for the quality evaluation and assessment of semen of D. Moldavia.