From confluent human iPS cells to self-forming neural retina and retinal pigmented epithelium

Progress in retinal-cell therapy derived from human pluripotent stem cells currently faces technical challenges that require the development of easy and standardized protocols. Here, we developed a simple retinal differentiation method, based on confluent human induced pluripotent stem cells (hiPSC), bypassing embryoid body formation and the use of exogenous molecules, coating, or Matrigel. In 2 wk, we generated both retinal pigmented epithelial cells and self-forming neural retina (NR)-like structures containing retinal progenitor cells (RPCs). We report sequential differentiation from RPCs to the seven neuroretinal cell types in maturated NR-like structures as floating cultures, thereby revealing the multipotency of RPCs generated from integration-free hiPSCs. Furthermore, Notch pathway inhibition boosted the generation of photoreceptor precursor cells, crucial in establishing cell therapy strategies. This innovative process proposed here provides a readily efficient and scalable approach to produce retinal cells for regenerative medicine and for drug-screening purposes, as well as an in vitro model of human retinal development and disease.Irreversible blindness caused by retinal diseases, such as inherited retinopathies, age-related macular degeneration (AMD), or glaucoma, is mainly due to the impairment or loss of function of photoreceptor cells, supporting retinal pigmented epithelium (RPE) or retinal ganglion cells (RGCs). Rescuing the degenerated retina is a major challenge for which specific cell replacement is one of the most promising approaches (1, 2). Pluripotent stem cells, like human embryonic stem cells (hESCs) or induced pluripotent stem cells (hiPSCs), have the ability to be expanded indefinitely in culture and could be used as an unlimited source of retinal cells for the treatment of retinal degenerative diseases (3, 4). Several publications have indicated that hESCs and hiPSCs can be differentiated into RPE cells spontaneously after fibroblast growth factor (FGF) 2 removal (5–7) or by different floating aggregate methods (8–11). Concerning neural retinal cells, a growing body of convergent data has demonstrated the ability of hESCs or hiPSCs to be committed into the neural retinal lineage and further differentiated into cells expressing photoreceptor markers (12–15). Recent innovative approaches using 3D cultures from embryoid bodies (EBs) of hESCs or hiPSCs allowed the self-formation of optic cup (OC) structures (16) or the generation of optic vesicle (OV)-like structures (17), depending on the addition of exogenous molecules and different substrates used. These protocols require multiple steps and trained handling, which are not always compatible with the manufacturing process for therapeutic approach or drug screening that need a large-scale production of cells of interest. Therefore, very simple and reliable approaches minimizing the use of exogenous molecules should be developed to generate hESCs or hiPSC-derived retinal cells.In the present study, we report a new retinal differentiation process using confluent hiPSCs, without cell clumps or EB formation and in the absence of Matrigel or serum. We demonstrate that integration-free hiPSCs derived from adult human dermal fibroblasts (AHDFs) cultured in proneural medium can simultaneously generate RPE cells and self-forming neural retinal (NR)-like structures within 2 wk and that, when switched to floating cultures, structures containing retinal progenitor cells (RPCs) can differentiate into all retinal cell types, including RGCs and precursors of photoreceptors, needed for therapeutic applications.     

Epidemiology,clinical picture and long-term outcomes of FIP1L1-PDGFRA-positive myeloid neoplasm with eosinophilia: Data from 151 patients

FIP1L1-PDGFRA-positive myeloid neoplasm with eosinophilia (F/P+ MN-eo) is a rare disease: robust epidemiological data are lacking and reported issues are scarce, of low sample-size and limited follow-up. Imatinib mesylate (IM) is highly efficient but no predictive factor of relapse after discontinuation has yet been identified. One hundred and fifty-one patients with F/P+ MN-eo (143 males; mean age at diagnosis 49 years; mean annual incidence: 0.18 case per million population) were included in this retrospective nationwide study involving all French laboratories who perform the search of F/P fusion gene (study period: 2003-2019). The main organs involved included the spleen (44%), skin (32%), lungs (30%), heart (19%) and central nervous system (9%). Serum vitamin B12 and tryptase levels were elevated in 74/79 (94%) and 45/57 (79%) patients, respectively, and none of the 31 patients initially treated with corticosteroids achieved complete hematologic remission. All 148 (98%) IM-treated patients achieved complete hematologic and molecular (when tested, n = 84) responses. Forty-six patients eventually discontinued IM, among whom 20 (57%) relapsed. In multivariate analysis, time to IM initiation (continuous HR: 1,01 [0.99-1,03]; P = .05) and duration of IM treatment (continuous HR: 0,97 [0,95-0,99]; P = .004) were independent factors of relapse after discontinuation of IM. After a mean follow-up of 80 (56) months, the 1, 5- and 10-year overall survival rates in IM-treated patients were 99%, 95% and 84% respectively. In F/P+ MN-eo, prompt initiation of IM and longer treatment durations may prevent relapses after discontinuation of IM.     

Collapsin response‐mediator protein 5 (CRMP5) phosphorylation at threonine 516 regulates neurite outgrowth inhibition

The collapsin response‐mediator proteins (CRMPs) are multifunctional proteins highly expressed during brain development but down‐regulated in the adult brain. They are involved in axon guidance and neurite outgrowth signalling. Among these, the intensively studied CRMP2 has been identified as an important actor in axon outgrowth, this activity being correlated with the reorganisation of cytoskeletal proteins via the phosphorylation state of CRMP2. Another member, CRMP5, restricts the growth‐promotional effects of CRMP2 by inhibiting dendrite outgrowth at early developmental stages. This inhibition occurs when CRMP5 binds to tubulin and the microtubule‐associated protein MAP2, but the role of CRMP5 phosphorylation is still unknown. Here, we have studied the role of CRMP5 phosphorylation by mutational analysis. Using non‐phosphorylatable truncated constructs of CRMP5 we have demonstrated that, among the four previously identified CRMP5 phosphorylation sites (T509, T514, T516 and S534), only the phosphorylation at T516 residue was needed for neurite outgrowth inhibition in PC12 cells and in cultured C57BL/6J mouse hippocampal neurons. Indeed, the expression of the CRMP5 non‐phosphorylated form induced a loss of function of CRMP5 and the mutant mimicking the phosphorylated form induced the growth inhibition function seen in wildtype CRMP5. The T516 phosphorylation was achieved by the glycogen synthase kinase‐3β (GSK‐3β), which can phosphorylate the wildtype protein but not the non‐phosphorylatable mutant. Furthermore, we have shown that T516 phosphorylation is essential for the tubulin‐binding property of CRMP5. Therefore, CRMP5‐induced growth inhibition is dependent on T516 phosphorylation through the GSK‐3β pathway. The findings provide new insights into the mechanisms underlying neurite outgrowth.     

Quality of life in overweight and obese children and adolescents: a literature review

Purpose

The purpose of the study is to present a literature review on quality-of-life (QOL) assessment in overweight or obese children and adolescents in order to identify the most affected dimensions and better understand associated factors.

Methods

The ERIC, FRANCIS, MEDLINE, PsycARTICLES, PsycINFO, and Academic Search Premier databases were searched for articles reporting cross-sectional QOL studies in obese children and adolescents published in English before January 2013. The reference lists of retained articles were also screened.

Results

Among the 34 articles retained for the analysis, only three did not report lower QOL among obese youth. Clinical populations appeared to be more affected than the general population. Several variables were associated with QOL such as self-image, bullying, bodily pain, quality of food intake, physical activity, screen time, parents’ educational level, and weight status.

Conclusions

Identifying variables associated with lower QOL in obese children and adolescents offers new perspectives for prevention and care. Further research is needed to better elucidate these findings. Better understanding QOL is a key element essential for the treatment for childhood and adolescent obesity.     

Factors associated with the designation of a health care proxy and writing advance directives for patients suffering from haematological malignancies

Background

During the last few decades, patients’ rights have been reinforced in many countries by acts of law. Measures now include health care proxies to uphold the doctor-patient relationship and advance directives for end-of-life patients. These could be relevant tools as early as the initial diagnosis of haematological malignancies because of the uncertain disease course. The aim of this research was to assess the factors associated with the designation of a proxy and writing advance directives by patients in a haematology department in France.

Methods

After a specific programme to encourage discussions about end-of-life preferences, we conducted a mixed-methods study comprising retrospective analysis of a random sample of 200 patients’ medical records, crossed with a qualitative analysis of the content of advance directives. Statistical analysis was performed by the RKward V 0.6.1 software with 0.05 denoting significance. The study was performed and presented in accordance with the STROBE guidelines. A thematic analysis of the advance directives was performed by two researchers.

Results

A total of 197 medical records were evaluable. The mean age of the patients was 66 years (range: 18–91). Nearly 2/3 of them (64.5%) designated a proxy, 6.1% wrote advance directives, and 8.1% and 4.6% expressed a wish to meet a religious representative or a volunteer, respectively. The 2-year survival rate was 78.4% [95%CI: 68.2-90.2]. Patients who wrote advance directives were statistically older (p <0.00025). Patients who wrote an advance directive were more likely to have expressed a wish to meet a religious representative (p <0.001) or a volunteer (p = 0.003). Marital status was a significant factor in appointing a proxy (p = 0.04).

Conclusions

To the best of our knowledge, this is the first paper to identify influencing factors for proxies and advance directives in a homogenous population of patients with haematological malignancies. Most patients chose a proxy. However, despite several training programmes for the carers and a care planning programme, few patients wrote advance directives. Our findings suggest that influencing factors are advanced age and a wish to see a religious representative. This study highlights the importance of oral communication about end-of-life issues between carers, patients and their relatives.