Effects of anesthesia on the blood glucose of C57/BL6J mice were evaluated under conditions commonly used for testing retinal sensitivity with electroretinographic (ERG) recordings. We evaluated the effects of four anesthetics: nembutal (50 mg/kg), pentothal (100 mg/kg), avertin (240 mg/kg), and ketamine/xylazine (100 mg/kg) using saline as control. We measured blood glucose (BG) levels from tail vein blood before and 15 and 60 min following intraperitoneal injections. Fifteen minutes postinjection, all four anesthetics and saline elevated BG with ketamine/xylazine and avertin having substantially greater effects than nembutal, pentothal, and saline. Only the effects of ketamine/xylazine and avertin persisted throughout the test period. Sixty minutes after injecting ketamine/xylazine BG remained elevated at 400 +/- 42 mg/dl, a 167% increase over preinjection levels. Sixty minutes after injecting avertin BG was 288 +/- 10 mg/dl, a 59% increase over preinjection levels. No sustained elevation in BG was detected 60 min following injection of nembutal, pentothal, or saline. Because BG can affect the amplitude of the ERG, caution should be exercised in the use of ketamine/xylazine or avertin. The choice of anesthesia may also be important in diabetes and metabolism research where changes in blood glucose could impact physiological processes.

Summary Induced pluripotent stem cells (iPSCs) are an invaluable resource for the study of human disease. However, there are no standardized methods for differentiation into hematopoietic cells, and there is a lack of robust, direct comparisons of different methodologies. In the current study we improved a feeder-free, serum-free method for generation of hematopoietic cells from iPSCs, and directly compared this with three other commonly used strategies with respect to efficiency, repeatability, hands-on time, and cost. We also investigated their capability and sensitivity to model genetic hematopoietic disorders in cells derived from Down syndrome and β-thalassemia patients. Of these methods, a multistep monolayer-based method incorporating aryl hydrocarbon receptor hyperactivation (“2D-multistep”) was the most efficient, generating significantly higher numbers of CD34 + progenitor cells and functional hematopoietic progenitors, while being the most time- and cost-effective and most accurately recapitulating phenotypes of Down syndrome and β-thalassemia.

Human induced pluripotent stem cells (hiPSCs) generated from patients and the derivative retinal cells enable the investigation of pathological and novel variants in relevant cell populations. Biallelic pathogenic variants in RPE65 cause early-onset severe retinal dystrophy (EOSRD) or Leber congenital amaurosis (LCA). Increasingly, regulatory-approved in vivo RPE65 retinal gene replacement therapy is available for patients with these clinical features, but only if they have biallelic pathological variants and sufficient viable retinal cells. In our cohort of patients, we identified siblings with early-onset severe retinal degeneration where genomic studies revealed compound heterozygous variants in RPE65, one a known pathogenic missense variant and the other a novel synonymous variant of uncertain significance. The synonymous variant was suspected to affect RNA splicing. Since RPE65 is very poorly expressed in all tissues except the retinal pigment epithelium (RPE), we generated hiPSC-derived RPE cells from the parental carrier of the synonymous variant. Sequencing of RNA obtained from hiPSC-RPE cells demonstrated heterozygous skipping of RPE65 exon 2 and the introduction of a premature stop codon in the mRNA. Minigene studies confirmed the splicing aberration. Results from this study led to reclassification of the synonymous variant to a pathogenic variant, providing the affected patients with access to RPE65 gene replacement therapy.