Dual α-globin and truncated EPO receptor knockin restores hemoglobin production in α-thalassemia-derived red blood cells.

Alpha-thalassemia is an autosomal recessive disease with increasing worldwide prevalence. The molecular basis is due to mutation or deletion of one or more duplicated α-globin genes, and disease severity is directly related to the number of allelic copies compromised. The most severe form, α-thalassemia major (αTM), results from loss of all four copies of α-globin and has historically resulted in fatality in utero. However, in utero transfusions now enable survival to birth. Postnatally, patients face challenges similar to ß-thalassemia, including severe anemia and erythrotoxicity due to imbalance of ß-globin and α-globin chains. While curative, hematopoietic stem cell transplantation (HSCT) is limited by donor availability and potential transplant-related complications. Despite progress in genome editing treatments for ß-thalassemia, there is no analogous curative option for patients suffering from α-thalassemia. To address this, we designed a novel Cas9/AAV6-mediated genome editing strategy that integrates a functional α-globin gene into the ß-globin locus in αTM patient-derived hematopoietic stem and progenitor cells (HSPCs). Incorporation of a truncated erythropoietin receptor transgene into the α-globin integration cassette dramatically increased erythropoietic output from edited HSPCs and led to the most robust production of α-globin, and consequently normal hemoglobin. By directing edited HSPCs toward increased production of clinically relevant RBCs instead of other divergent cell types, this approach has the potential to mitigate the limitations of traditional HSCT for the hemoglobinopathies, including low genome editing and low engraftment rates. These findings support development of a definitive ex vivo autologous genome editing strategy that may be curative for α-thalassemia.

Discordant Timing of Hypoglycemic Agent Screening Causing Delayed Diagnosis of Sulfonylurea-Induced Hypoglycemia.

Background: Oral hypoglycemic agents are a frequent cause of hypoglycemia in nondiabetic people. Here, we report a case of recurrent hypoglycemia caused by glipizide, in which diagnosis was delayed because of a combination of delayed hypoglycemic agent screening and low sensitivity of the hypoglycemic agent screening panel used. Case Report: A 66-year-old woman repeatedly presented with symptomatic hypoglycemia. At the first presentation, the serum glucose level was 40 mg/dL (2.2 mmol/L), C-peptide level was 13.1 ng/mL (0.8-3.1 ng/mL), proinsulin level was 96.9 pmol/L (<18.8 pmol/L), and insulin level was 164 mU/L (<17 mU/L). An initial hypoglycemic agent screening, performed 24 hours after admission, yielded a negative result, leading to prolonged and recurrent hospitalizations for workup and localization of insulinoma. A hypoglycemic agent screening at a subsequent presentation, concordant with hypoglycemia, yielded a positive result for glipizide, which was at a level of 320 ng/mL (reporting limit, 40 ng/mL). An examination of the patient's home medications revealed a container, labeled as benztropine, containing glipizide tablets. After the diagnosis of glipizide-induced hypoglycemia, the patient had no further episodes of hypoglycemia. Discussion: The failure to detect glipizide using the initial hypoglycemia agent assay was likely because of a combination of a delay in the initial screening and low sensitivity of the assay for glipizide compared with that of other available assays. Here, we discuss important considerations for the interpretation of hypoglycemic agent screening in the diagnosis of hypoglycemia, including the timing of collection and reporting, pharmacokinetics of culprit agents, and sensitivity of the hypoglycemic agent panel used. Conclusion: Screening tests for hypoglycemic agents are necessary for the evaluation of hypoglycemia because their biochemical evaluation may be indistinguishable from that of insulinoma.

Teaching in the robotic environment: Use of alternative approaches to guide operative instruction.

BACKGROUND: With the rapid growth of robotic-assisted surgery, surgical educators recognize the need to develop appropriate curriculum for trainees. However, the unique robotic learning environment challenges educators to determine the most appropriate ways to instruct surgical residents. The purpose of this study was to characterize the instructional techniques used in the robotic teaching environment by observing attending surgeon's language and behaviors during resident robotic dissection. STUDY DESIGN: Attending robotic surgeons guided senior residents through robotic dissection of live porcine tissue. Three observers documented the language, gestures and behaviors occurring at three different stations, and at a fourth station, they obtained video and audio recordings of the instructional interaction. Afterwards, instructors and residents met in separate focus groups. The authors used qualitative content analysis to summarize the type and frequency of teaching behaviors and focus group information to clarify the analysis. We compared the frequency of the behaviors to an existing taxonomy of 16 operative teaching behaviors in open and laparoscopic surgery. RESULTS: Robotic instructors used 11 of the 16 behaviors previously described for surgical instruction. Frequency of use differed in the robotic environment due to relevance and application of new techniques. New, unique robotic teaching behaviors involved disengaging the resident from the operative console for either onscreen direction or for gesturing with verbal instruction. Focus group participants highlighted these behaviors as essential. CONCLUSION: Robotic instruction uses a different set of instructional approaches compared to open and laparoscopic surgery. New teaching behaviors emerged driven by physical separation within the robotic environment. Robotic faculty development should emphasize these unique features.

Gut-Resident Lactobacillus Abundance Associates with IDO1 Inhibition and Th17 Dynamics in SIV-Infected Macaques.

Gut microbes can profoundly modulate mucosal barrier-promoting Th17 cells in mammals. A salient feature of HIV/simian immunodeficiency virus (SIV) immunopathogenesis is the loss of Th17 cells, which has been linked to increased activity of the immunomodulatory enzyme, indoleamine 2,3-dioxygenase 1 (IDO 1). The role of gut microbes in this system remains unknown, and the SIV-infected rhesus macaque provides a well-described model for HIV-associated Th17 loss and mucosal immune disruption. We observed a specific depletion of gut-resident Lactobacillus during acute and chronic SIV infection of rhesus macaques, which was also seen in early HIV-infected humans. This depletion in rhesus macaques correlated with increased IDO1 activity and Th17 loss. Macaques supplemented with a Lactobacillus-containing probiotic exhibited decreased IDO1 activity during chronic SIV infection. We propose that Lactobacillus species inhibit mammalian IDO1 and thus may help to preserve Th17 cells during pathogenic SIV infection, providing support for Lactobacillus species as modulators of mucosal immune homeostasis.