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.     

Fetal renin-angiotensin-system blockade syndrome: renal lesions

Background

Fetuses exposed to angiotensin-converting enzyme inhibitors or angiotensin receptor antagonists during the second and/or third trimesters of gestation are at high risk of developing severe complications. They consist in fetal hypotension, and anuria/oligohydramnios leading to Potter sequence, frequently associated with hypocalvaria. Most fetuses die during the pre- or postnatal period, whereas others recover normal or subnormal renal function. However, the secondary occurrence of renal failure or hypertension has been reported in children after apparent complete recovery.

Methods

In this context, we analyzed renal lesions in 14 fetus/neonates who died soon after exposure to renin-angiotensin-system (RAS) blockers. Our objective was to determine the causes for the persistence or the secondary occurrence of renal complications reported in some of the survivors.

Results

As previously described, renal tubular dysgenesis is usually observed. Additional lesions, such as thickening of the muscular wall of arterioles and interlobular arteries, glomerular cysts, and interstitial fibrosis, develop early during fetal life.

Conclusion

We suggest that renal lesions that develop before birth may persist after withdrawal of the causative drugs and normalization of blood and renal perfusion pressure. Their persistence could explain the severe long-term outcome of some of these patients. Long-term study of children exposed to RAS blockers during fetal life is strongly recommended.     

Xpert GBS Assay for Rapid Detection of Group B Streptococcus in Gastric Fluid Samples from Newborns

The Xpert GBS real-time PCR assay was applied to gastric fluid samples from 143 newborns, and it detected group B streptococcus (GBS) within 1 h for 16 (11.2%) cases, while microscopic examination detected only 2 cases. The sensitivity and specificity of the Xpert GBS were 80% and 100%, respectively, with regard to 20 cases of GBS colonization or infection. Concordance of Xpert GBS results versus culture was 92.3%. This test detects in a timely manner newborns at risk for invasive GBS disease.     

One or Several Types of Triptan Overuse Headaches?

Background.— Whereas the clinical features of pure triptan overuse headache (TOH) are well known, there are insufficient data regarding the semiological pattern of headaches when triptan overuse is associated with other types of medication overuse.
Objective.— To investigate and compare the clinical characteristics of patients with pure TOH and those with medication overuse headaches associating triptan and other medication overuses (combined TOH).
Methods.— This cross-sectional, observational study was conducted in 7 tertiary-care headache centers participating in the French Observatory of Migraine and Headaches. From 2004 to 2006, data from 163 patients with TOH were collected in face-to-face structured interviews (according to the International Classification of Headache Disorders, 2nd edition criteria).
Results.— Eighty-two patients fulfilled criteria for pure TOH (pTOH patients) and 81 for combined TOH (cTOH) patients. Continuous headaches were reported in 76% of cTOH patients compared with 32% of pTOH patients. Significantly more frequent and severe headaches and more intense phono-/photophobia between attacks were noted in cTOH patients. More cTOH than pTOH patients reported a history of tension-type headaches and a long-standing history of chronic headaches. Finally, compared with pTOH patients, cTOH patients were characterized by stronger dependence on acute treatments of headaches according to the DSM-IV criteria.
Conclusions.— Combined therapy with analgesics and/or the total number of drug units taken per day may cause a shift from a pattern of clear-cut headache attacks in patients with pTOH toward more severe clinical presentation in patients with cTOH. These patients should receive more intensive prophylactic therapy and specific behavioral management.     

Surgical Management of Benign and Borderline Phyllodes Tumors of the Breast

Phyllodes tumors (PT) are uncommon fibroepithelial breast neoplasms and there is currently no clear consensual treatment for these tumors. The aim of our study was to evaluate the surgical management and outcome of benign and borderline PT. We retrospectively assessed 76 cases of benign or borderline PT managed at the Leon Berard comprehensive cancer center in Lyon, France between July 2003 and December 2013. The mean age at diagnosis was 37.9 years and the median follow‐up was 58 months. Seventy‐five patients (99%), with a mean tumor size of 27 mm, underwent a breast‐conserving procedure. The tumor margins were considered positive (when the tumor was present at the inked surgical section) in seven of 76 cases (9%) and negative in 65 out of 76 cases (86%). We observed the presence of small negative surgical margins <10 mm in 89% and <1 mm in 71% of the patients. Although no re‐excision was performed to increase these margins, we did not see any increase in the local recurrence rate (4%) when compared to recurrence rates reported in the literature. We thus suggest that systematic revision surgery for close or positive surgical margins for benign PT should not be systematically performed. However, as recurrences occur within 2 years of initial excision, we recommend a regular clinical and imaging follow‐up especially during this period for which patient's compliance is essential.