Differentiation of human pluripotent stem cells (hPSCs) into functional cell types is IntroductionHuman embryonic stem cells (hESCs) derived from an early embryo can self-renew indefinitely and differentiate into a variety of cell types. 1 It has been reported that the "stemness" of hESCs is likely maintained through the harmonious actions of signaling pathway networks. 2 Basic fibroblast growth factor (bFGF) is essential for maintaining the stemness of hESCs by highly activating mitogen-activated protein kinase (MAPK) extracellular signalregulated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling, which plays an important role in the stemness of hESCs. 3 Stemness of hESCs is also supported by bFGF-mediated regulation of transforming growth factor-␤ (TGF-␤) signaling 4 ; activation of the TGF-␤/activin/nodal signaling pathway is required to maintain stemness in cooperation with the FGF signaling pathway, whereas its inhibition results in differentiation of hESCs. 5,6 The effect of Wnt signaling on stemness of hESCs is still controversial. Activation of the Wnt pathway by 6-bromoindirubin-3-oxmie, a specific inhibitor of glycogen synthase-3, sustains the undifferentiated status of hESCs. 7 However, activation of Wnt signaling is insufficient to maintain the undifferentiated status of hESCs, because a canonical Wnt signaling is highly activated during differentiation. 8 The stemness of human induced pluripotent stem cells (hiPSCs), like that of hESCs, seems to be maintained by coordinated networks of signaling molecules, although few differences are observed in the gene expression profile. 9,10 Thus, the stemness and differentiation of hESCs and hiPSCs is regulated by complex networks of signaling pathways. It is likely that the modulation of these signaling pathways can induce differentiation of hESCs into a specialized cell type. In fact, bone morphogenic protein 2/4 (BMP2/4), a member of the TGF␤ superfamily, could differentiate hESCs into trophoblasts, primitive endoderm cells, and mesodermal cells. [11][12][13] However, it has been reported that BMP4 is required for sustaining stemness of mouse ESCs by blocking neural differentiation. 14 hESCs could be differentiated to definitive endoderm cells by activation of activin/nodal signaling and suppression of phosphoinositide 3-kinase (PI3K) signaling. 15 Dual inhibition of SMAD signaling by treatment with Noggin and SB431542 resulted in differentiation of hESCs and hiPSCs into neural cells. 16 Many studies have tried to isolate specialized cell types from spontaneously differentiated cells via formation of hESC-derived embryoid bodies using antibodies against cell-typespecific surface markers. 17,18 However, spontaneous differentiation remains inefficient, in that hPSCs cannot be guided toward a specialized lineage at the initial commitment step.The hPSCs provide a possibility that degenerative or damaged tissues can be replaced with hPSC-derived functional cells. A paucity of number and activity of endothelial progenitor cells is correla...

Objective Stroke often produces marked physical and cognitive impairments leading to functional dependence, caregiver burden, and poor quality of life. We examined the course of disability during a 1-year follow-up period after stroke among patients who were administered antidepressants for 3 months compared to patients given placebo for 3 months. Methods A total of 83 patients entered a double-blind randomized study of the efficacy of antidepressants to treat depressive disorders and reduce disability after stroke. Patients were assigned to either fluoxetine (N = 32), nortriptyline (N = 22) or placebo (N = 29). Psychiatric assessment included administration of the Present State Examination modified to identify DSM-IV symptoms of depression. The severity of depression was measured using the 17-item Hamilton Depression Rating Scale. The modified Rankin Scale was used to evaluate the disability of patients at initial evaluation and at quarterly follow-up visits for 1 year. Impairment in activities of daily living was assessed by Functional Independence Measure at the same time. Results During the 1-year follow-up period, and after adjusting for critical confounders including age, intensity of rehabilitation therapy, baseline stroke severity, and baseline Hamilton Depression Rating Scale, patients who received fluoxetine or nortriptyline had significantly greater improvement in modified Rankin Scale scores compared to patients who received placebo (t [156] = − 3.17, p = 0.002). Conclusions Patients treated with antidepressants had better recovery from disability by 1-year post stroke (i.e., 9 months after antidepressants were stopped) than patients who did not receive antidepressant therapy. This effect was independent of depression suggesting that antidepressants may facilitate the neural mechanisms of recovery in patients with stroke.

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A closed-loop system imitating the function of pancreatic cells, connected to microneedles (MNs) that automatically “release” insulin in response to the blood glucose (BG) levels would be highly satisfactory for improving the quality of life and health for diabetes patients. This paper describes an easy, fast and simple technique of coating a porous polymer layer on stainless steel (SS) MNs that release insulin in a glucose-responsive fashion. It was fabricated by sealing insulin, sodium bicarbonate (a pH-sensitive element [NaHCO3]) and glucose oxidase (glucose-specific enzymes [GOx]) into the pores of a porous polymer coating. Glucose can passively diffuse into the pores and become oxidized to gluconic acid by GOx, thereby causing a decrease in local pH. The subsequent reaction of protons with NaHCO3 forms carbon dioxide (CO2) which creates pressure inside the pores, thereby rupturing the thin polymer film and releasing the encapsulated insulin. Field emission scanning electron microscopy (FE-SEM) images displayed that upon the exposure of MNs to glucose-free phosphate buffer saline (PBS) with pH 7.4, the pores of the porous MNs were closed, while in MNs exposed to a hyperglycemic glucose level, the pores were opened and the thin film burst. These MNs demonstrated both in vitro (in porcine skin and PBS) and in vivo (in diabetic rats) glucose-mediated insulin release under hyperglycemic conditions with rapid responsiveness. This study validated that the release of insulin from porous MNs was effectively correlated with glucose concentration.

There is a need for effective wound healing through rapid wound closure, reduction of scar formation, and acceleration of angiogenesis. Hydrogel is widely used in tissue engineering, but it is not an ideal solution because of its low vascularization capability and poor mechanical properties. In this study, gelatin methacrylate (GelMA) was tested as a viable option with tunable physical properties. GelMA hydrogel incorporating a vascular endothelial growth factor (VEGF) mimicking peptide was successfully printed using a three-dimensional (3D) bio-printer owing to the shear-thinning properties of hydrogel inks. The 3D structure of the hydrogel patch had high porosity and water absorption properties. Furthermore, the bioactive characterization was confirmed by cell culture with mouse fibroblasts cell lines (NIH 3T3) and human umbilical vein endothelial cells. VEGF peptide, which is slowly released from hydrogel patches, can promote cell viability, proliferation, and tubular structure formation. In addition, a pig skin wound model was used to evaluate the wound-healing efficacy of GelMA-VEGF hydrogel patches; the results suggest that the GelMA-VEGF hydrogel patch can be used for wound dressing.

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This study examined the efficacy of antidepressant treatment for preventing the onset of generalized anxiety disorder (GAD) among patients with recent stroke. Of 799 patients assessed, 176 were randomized, and 149 patients without evidence of GAD at the initial visit were included in this double-blind treatment with escitalopram (N=47) or placebo (N=49) or non-blinded problem-solving therapy (PST; 12 total sessions; N=53). Participants given placebo over 12 months were 4.95 times more likely to develop GAD than patients given escitalopram and 4.00 times more likely to develop GAD than patients given PST. Although these results should be considered preliminary, the authors found that both escitalopram and PST were effective in preventing new onset of post-stroke GAD.

Embryonic stem cells (ESCs) maintain unique epigenetic states to maintain their pluripotency. Differentiation of ESCs into specialized cell types requires changes in these epigenetic states. However, the dynamics of epigenetic marks found in hESCs during differentiation are poorly understood. Here, we report the variation in the dynamics of epigenetic modifications associated with the expression of lineage-specific genes during differentiation of hESCs to hepatocytes in vitro. The promoter regions of pluripotency marker genes characterized by permissive histone marks such as trimethylation of H3 at lysine 4 (H3K4me3) and acetylation of H3 at lysine 9 (H3K9ac) in hESCs were instead enriched with repressive histone marks such as dimethylation of H3 at lysine 9 (H3K9me2), trimethylation of H3 at lysine 9 (H3K9me3) and trimethylation of H3 at lysine 27 (H3K27me3) during differentiation to hepatocytes. Interestingly, expression of definitive endoderm marker genes containing bivalent and non-bivalent domains may be modulated by a marked reduction in H3K27me3 and a significant enhancement of permissive marks such as H3K4me3 and H3K9ac during hESC differentiation. Expression of hepatocyte marker genes regulated by histone modifications was similar to that of pluripotency marker genes. Our findings provide insight into the epigenetic mechanisms regulating expression of developmental genes. Of particular interest, they may be differentially regulated either in a bivalent or non-bivalent domain manner during hESC differentiation.