Notch signaling: a novel regulating differentiation mechanism of human umbilical cord blood-derived mesenchymal stem cells into insulin-producing cells in vitro / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Human umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) could be induced to differentiate into insulin producing cells (IPCs) in vitro, which have good application potential in the cell replacement treatment of type-1 diabetes. However, the mechanisms regulating this differentiation have remained largely unknown. Notch signaling is critical in cell differentiation. This study investigated whether Notch signaling could regulate the IPCs differentiation of human UCB-MSCs.</p><p><b>METHODS</b>Using an interfering Notch signaling protocol in vitro, we studied the role of Notch signaling in differentiation of human UCB-MSCs into IPCs. In a control group the induction took place without interfering Notch signaling.</p><p><b>RESULTS</b>Human UCB-MSCs expressed the genes of Notch receptors (Notch 1 and Notch 2) and ligands (Jagged 1 and Deltalike 1). Human UCB-MSCs with over-expressing Notch signaling in differentiation resulted in the down-regulation of insulin gene level, proinsulin protein expression, and insulin-positive cells percentage compared with the control group. These results showed that over-expressing Notch signaling inhibited IPCs differentiation. Conversely, when Notch signaling was attenuated by receptor inhibitor, the induced cells increased on average by 3.06-fold (n = 4, P < 0.001) in insulin gene level, 2.60-fold (n = 3, P < 0.02) in proinsulin protein expression, and 1.62-fold (n = 6, P < 0.001) in the rate of IPCs compared with the control group. Notch signaling inhibition significantly promoted IPCs differentiation with about 40% of human UCB-MSCs that converted to IPCs, but these IPCs were not responsive to glucose challenge very well both in vitro and in vivo. Hence, further research has to be carried out in the future.</p><p><b>CONCLUSIONS</b>Notch signaling may be an important mechanism regulating IPCs differentiation of human UCB-MSCs in vitro and Notch signaling inhibition may be an efficient way to increase the number of IPCs, which may resolve the shortage of islet of cell replacement treatment of type-1 diabetes.</p>

Extracellular matrix gel is necessary for in vitro cultivation of insulin producing cells from human umbilical cord blood derived mesenchymal stem cells / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Pancreatic islet cell transplantation is an effective approach to treat type 1 diabetes. However, this therapy is not widely used because of the severe shortage of transplantable donor islets. This study investigated whether mesenchymal stem cells (MSCs) derived from human umbilical cord blood (UCB) could be transdifferentiated into insulin producing cells in vitro and the role of extracellular matrix (ECM) gel in this procedure.</p><p><b>METHODS</b>Human UCB samples were collected and MSCs were isolated. MSCs specific marker proteins were analyzed by a flow cytometer. The capacities of osteoblast and adipocyte to differentiate were tested. Differentiation into islet like cell was induced by a 15-day protocol with or without ECM gel. Pancreatic characteristics were evaluated with immunofluorescence, reverse transcription polymerase chain reaction (RT-PCR) and flow cytometry. Insulin content and release in response to glucose stimulation were detected with chemiluminescent immunoassay system.</p><p><b>RESULTS</b>Sixteen MSCs were isolated from 42 term human UCB units (38%). Human UCB-MSCs expressed MSCs specific markers and could be induced in vitro into osteoblast and adipocyte. Islet like cell clusters appeared about 9 days after pancreatic differentiation in the inducing system with ECM gel. The insulin positive cells accounted for (25.2 +/- 3.4)% of the induced cells. The induced cells expressed islet related genes and hormones, but were not very responsive to glucose challenge. When MSCs were induced without ECM gel, clusters formation and secretion of functional islet proteins could not be observed.</p><p><b>CONCLUSIONS</b>Human UCB-MSCs can differentiate into islet like cells in vitro and ECM gel plays an important role in pancreatic endocrine cell maturation and formation of three dimensional structures.</p>

Amniotic membrane transplantation for the managenment of earlier Mooren's ulcer / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To investigate the efficacy and safety of annular conjunctival excision combined with amniotic membrane transplantation for the management of earlier Mooren's ulcer.METHODS: Thirty eyes (24 patients) with earlier Mooren's ulcer were treated with this method, followed-up for 5-30mo. The characteristic of these patients was localized periphery corneal ulcer: the ulcer involved 30-120° corneal limbus with depth of 1/3-1/2 cornealthickness and width of 2-5mm.RESULTS: After surgery, symptoms subsided remarkably and immediately in all patients,and almost disappeared after stitches were removed. Corneal melts were controlled. At postoperative 2-3mo, the corneal thickness of the ulcer area became almost stable, which in some patients recovered normal and in others were still thinner than normal, and the average increase was about 1/3 of the corneal thickness. Corneal transparence and vision were improved. During follow-up, no severe complications or recurrence were noted.CONCLUSION: Conjunctival peritomy combined with amniotic membrane transplantation is an effective and safe method for the treatment of earlier Mooren's ulcer.

Amniotic membrane transplantation for limbal pathological changes of vernal keratoconjunctivitis / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To evaluate the efficacy and safety of annular bubble conjunctival excision combining with amniotic membrane transplantation(AMT) for vernal keratoconjunctivitis(VKC) with gelatinous swellings(papillae) at the limbus.METHODS: Twenty eyes(10 patients) with VKC, were characterized by gelatinous swellings(papillae) at limbus and were underwent annular bubble conjunctival excision associated with AMT. The follow up ranged 5-21months.RESULTS: After operation, the symptoms were subsided remarkably: itching,discharge and foreign body sensation were almost disappear; photophobia and tearing were obvious in the first week after surgery, but were gradually alleviated, and almost disappear after one month of postoperative.Yellow-brown or filthy red gelatinous protuberances at limbus were cleaned away by operation and did not recur during the follow up. Corneal superficial punctuate keratitis(11 eyes) and corneal ulcers(3 eyes) were healed during the first week after surgery and did not recur. Conjunctival congestion was gradually lessened after surgery, which could not be noted 1months after surgery in 19 eyes, and the conjunctiva around the limbus, where AMT was performed, was whiter than the normal. But conjunctival congestion in 1 eye lasted for about 5mon accompanying with a little of itch, and this eye was treated with eyedrops with improvement but recurrence. No severe complications had been seen during the follow up.CONCLUSION: Annular bubble conjunctival excision combining with amniotic membrane transplantation is an effective and safe method for the treatment of vernal keratoconjunctivitis with gelatinous swellings (papillae) at limbus. But the candidates must be chosen with discretion.

Multilayer amniotic membrane transplantation for the management of corneal perforation associated with ulceration / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To investigate the efficacy, safety and localization of multilayer amniotic membrane transplantation (AMT) for the management of corneal perforation associated with ulceration.METHODS: Six eyes (6 patients) were treated with multilayer AMT for corneal perforation associated with ulceration. The perforation size was 0.5-2mm in diameter. The amniotic membrane (AM) was applied to tamp the perforation, fill the ulcer and cover the surface of ulcer. The follow-up ranged from 5-19 months.RESULTS: The anterior chamber reformed at the first postoperative day in all patients, and kept in normal depth in the follow- up time. The epithelialization of the AM grafts was observed in about 3 weeks after surgery. During the first postoperative month, the corneal thickness at the perforation site gradually increased, and the stromal inflammatory cell invasions surrounding the corneal ulcer were gradually subsided.Two months postoperatively, the ulcer healed with scar with part neovascutarization; the corneal thickness of the ulcer area was stable and recovered almost normal. The vision was not improved in all patients after operation. During-follow up,no severe complications or recurrence of ulceration was noted.CONCLUSION: Multilayer AMT is an effective and safe method for the management of small corneal perforation associated with ulceration, but the ulcer healed with scar.

Amniotic membrane transplantation for corneal perforation associated with ulceration / 眼科

Objective To investigate the efficacy,safety and localization of multilayer amniotic membrane transplantation(AMT) for corneal perforation associated with ulceration.Design A retrospective clinical case series.Participants Nine patients(9 eyes)with corneal perforation secondary to ulceration were enrolled into this study.These were little response to medicine,including bacterial keratitis(4 eyes ),fungal keratitis(2 eyes),fungal and bacterial mixed keratitis( 1 eye),virus keratitis( 1 eye),and Mooren's ulcer ( 1 eye).Size of perforation was 0.5～3.0 mm in diameter.Methods The AMT was applied to tamp the perforation,fill the ulcer and cover the surface of ulcer.After surgery,the medicine was continued to be used to treat the original corneal ulcer.The follow-up ranged from 6～20 months.In the suffering eyes,reformation of anterior chamber,healing of ulcer,complications and recurrence of ulceration were observed.Main Outcome Measures Of the postoperative eyes,reformation of anterior chamber,healing of ulcer,complications and recurrence of ulceration.Results The anterior chamber reformed at the first postoperative day in 9 eyes,and kept in normal depth in the follow-up time.At postoperative 2 months,the ulcer healed with sear and a smooth surface.Corneal thickness of the ulcer area recovered almost to normal.During follow up,no recurrence of ulceration or severe complications was noted.Conclusions Multilayer AMT is a safe and effective method for the management of small corneal perforation associated with ulceration,but the ulcer healed with scar.(Ophthalmol CHN,2008,17:101-103)