Purine nucleoside phosphorylase deficiency induces p53-mediated intrinsic apoptosis in human induced pluripotent stem cell-derived neurons.

Purine nucleoside phosphorylase (PNP) is an important enzyme in the purine degradation and salvage pathway. PNP deficiency results in marked T lineage lymphopenia and severe immunodeficiency. Additionally, PNP-deficient patients and mice suffer from diverse non-infectious neurological abnormalities of unknown etiology. To further investigate the cause for these neurologic abnormalities, induced pluripotent stem cells (iPSC) from two PNP-deficient patients were differentiated into neurons. The iPSC-derived PNP-deficient neurons had significantly reduced soma and nuclei volumes. The PNP-deficient neurons demonstrated increased spontaneous and staurosporine-induced apoptosis, measured by cleaved caspase-3 expression, together with decreased mitochondrial membrane potential and increased cleaved caspase-9 expression, indicative of enhanced intrinsic apoptosis. Greater expression of tumor protein p53 was also observed in these neurons, and inhibition of p53 using pifithrin-α prevented the apoptosis. Importantly, treatment of the iPSC-derived PNP-deficient neurons with exogenous PNP enzyme alleviated the apoptosis. Inhibition of ribonucleotide reductase (RNR) in iPSC derived from PNP-proficient neurons with hydroxyurea or with nicotinamide and trichostatin A increased the intrinsic neuronal apoptosis, implicating RNR dysfunction as the potential mechanism for the damage caused by PNP deficiency. The findings presented here establish a potential mechanism for the neurological defects observed in PNP-deficient patients and reinforce the critical role that PNP has for neuronal viability.

The Use of Induced Pluripotent Stem Cells to Study the Effects of Adenosine Deaminase Deficiency on Human Neutrophil Development.

Inherited defects that abrogate the function of the adenosine deaminase (ADA) enzyme and consequently lead to the accumulation of toxic purine metabolites cause profound lymphopenia and severe combined immune deficiency. Additionally, neutropenia and impaired neutrophil function have been reported among ADA-deficient patients. However, due to the rarity of the disorder, the neutrophil developmental abnormalities and the mechanisms contributing to them have not been characterized. Induced pluripotent stem cells (iPSC) generated from two unrelated ADA-deficient patients and from healthy controls were differentiated through embryoid bodies into neutrophils. ADA deficiency led to a significant reduction in the number of all early multipotent hematopoietic progenitors. At later stages of differentiation, ADA deficiency impeded the formation of granulocyte colonies in methylcellulose cultures, leading to a significant decrease in the number of neutrophils generated from ADA-deficient iPSCs. The viability and apoptosis of ADA-deficient neutrophils isolated from methylcellulose cultures were unaffected, suggesting that the abnormal purine homeostasis in this condition interferes with differentiation or proliferation. Additionally, there was a significant increase in the percentage of hyperlobular ADA-deficient neutrophils, and these neutrophils demonstrated significantly reduced ability to phagocytize fluorescent microspheres. Supplementing iPSCs and methylcellulose cultures with exogenous ADA, which can correct adenosine metabolism, reversed all abnormalities, cementing the critical role of ADA in neutrophil development. Moreover, chemical inhibition of the ribonucleotide reductase (RNR) enzyme, using hydroxyurea or a combination of nicotinamide and trichostatin A in iPSCs from healthy controls, led to abnormal neutrophil differentiation similar to that observed in ADA deficiency, implicating RNR inhibition as a potential mechanism for the neutrophil abnormalities. In conclusion, the findings presented here demonstrate the important role of ADA in the development and function of neutrophils while clarifying the mechanisms responsible for the neutrophil abnormalities in ADA-deficient patients.

Assistive robots to improve the independent living of older persons: results from a needs study.

BACKGROUND: More than 70% of elderly people age 80 and older are experiencing problems in personal mobility. Assistive robotics can represent a concrete support providing also a support for caregivers, clinicians and nurses by reducing their burden. METHODS: A total of 20 older people and 34 caregivers (formal and informal) were interviewed in Italy and the Netherlands to investigate and prioritize their needs concerning the personal mobility domains and their attitudes towards assistive robots. The data were analysed from a user point of view by means of thematic content analysis by underlying recurrent topics. RESULTS: The results revealed four categories of needs from the perspective of the older individuals: instrumental needs, rehabilitation needs, personal safety and indoor activities of daily life. Additionally, the results underline how personal mobility issues influence different aspects of daily life. Complementarily, three categories of caregiver needs were also distinguished: instrumental needs, rehabilitation monitoring needs and checkup needs. The highest percentage of participants showed a positive expectation towards assistive robotics. CONCLUSIONS: The results were clustered according to the robot abilities (i.e., motion, interaction, manipulation, decision support and perception abilities) as a list of functional and technical requirements that should be developed to address all the needs related to the personal mobility. Robotic developer teams that work in this context could take advantage of this research. Additionally, this work can be used as a basis for clinicians and nurses working in geriatric units to understand how the robots can support and enhance their work. Implications for rehabilitation The incidence of personal mobility limitations affects 35% of adults age 70 and older and 72% of people over 80 years of age. Assistive robots can support elderly people during daily tasks: they could promote their personal mobility acting as a supporting tool. The results of the needs analysis revealed four categories of needs from the perspective of the older individuals: instrumental needs, rehabilitation needs, personal safety, and indoor activities of daily life. Three categories of caregiver needs were also distinguished: instrumental needs, rehabilitation monitoring needs, and check-up needs.

Reporting of randomized factorial trials was frequently inadequate.

OBJECTIVES: Factorial designs can allow efficient evaluation of multiple treatments within a single trial. We evaluated the design, analysis, and reporting in a sample of factorial trials. STUDY DESIGN AND SETTING: Review of 2 × 2 factorial trials evaluating health-related interventions and outcomes in humans. Using Medline, we identified articles published between January 2015 and March 2018. We randomly selected 100 articles for inclusion. RESULTS: Most trials (78%) did not provide a rationale for using a factorial design. Only 63 trials (63%) assessed the interaction for the primary outcome, and 39/63 (62%) made a further assessment for at least one secondary outcome. 12/63 trials (19%) identified a significant interaction for the primary outcome and 16/39 trials (41%) for at least one secondary outcome. Inappropriate methods of analysis to protect against potential negative effects from interactions were common, with 18 trials (18%) choosing the analysis method based on a preliminary test for interaction, and 13% (n = 10/75) of those conducting a factorial analysis including an interaction term in the model. CONCLUSION: Reporting of factorial trials was often suboptimal, and assessment of interactions was poor. Investigators often used inappropriate methods of analysis to try to protect against adverse effects of interactions.

Early Enzyme Replacement Therapy Improves Hearing and Immune Defects in Adenosine Deaminase Deficient-Mice.

Background: Inherited defects in adenosine deaminase (ADA) cause severe immune deficiency, which can be corrected by ADA enzyme replacement therapy (ERT). Additionally, ADA-deficient patients suffer from hearing impairment. We hypothesized that ADA-deficient (-/-) mice also exhibit hearing abnormalities and that ERT from an early age will improve the hearing and immune defects in these mice. Methods: Auditory brainstem evoked responses, organ weights, thymocytes numbers, and subpopulations, lymphocytes in peripheral blood as well as T lymphocytes in spleen were analyzed in ADA-/- and ADA-proficient littermate post-partum (pp). The cochlea was visualized by scanning electron microscopy (SEM). The effects of polyethylene glycol conjugated ADA (PEG-ADA) ERT or 40% oxygen initiated at 7 days pp on the hearing and immune abnormalities were assessed. Results: Markedly abnormal hearing thresholds responses were found in ADA-/- mice at low and medium tone frequencies. SEM demonstrated extensive damage to the cochlear hair cells of ADA-/- mice, which were splayed, short or missing, correlating with the hearing deficits. The hearing defects were not reversed when hypoxia in ADA-/- mice was corrected. Progressive immune abnormalities were detected in ADA-/- mice from 4 days pp, initially affecting the thymus followed by peripheral lymphocytes and T cells in the spleen. ERT initiated at 7 days pp significantly improved the hearing of ADA-/- mice as well as the number of thymocytes and T lymphocytes, although not all normalized. Conclusions: ADA deficiency is associated with hearing deficits and damage to cochlear hair cells. Early initiation of ERT improves the hearing and immune abnormalities.

Most noninferiority trials were not designed to preserve active comparator treatment effects.

OBJECTIVES: To evaluate whether noninferiority trials are designed to adequately preserve the historical treatment effect of their active comparators. STUDY DESIGN AND SETTING: We reviewed 162 noninferiority trials published in high-impact medical journals. We assessed whether trials were designed to ensure that interventions could only be declared noninferior if they preserved at least 50% of the active comparator's historical treatment effect. RESULTS: Only 25 of 162 trials (15%) were designed so that interventions could only be declared noninferior if they preserved at least 50% of the active comparator's historical treatment effect. Most trials did not provide evidence that the active comparator was effective (n = 101), provided inadequate evidence (n = 18), or used a noninferiority margin that was too wide (n = 18). In a subset of 61 noninferiority trials which referenced a prior randomized trial or meta-analysis evaluating the active comparator, only 25 (41%) used a noninferiority margin small enough to preserve at least 50% of the active comparator's treatment effect. Overall, 14 of 162 noninferiority trials (9%) would have allowed the intervention to be declared noninferior even if it was worse than either placebo or another historical control. CONCLUSION: Most noninferiority trials published in major medical journals could allow erroneous declarations of noninferiority.