Various synthetic and natural biomaterials have been used for regeneration of tissues and hollow organs. However, clinical outcome of reconstructive procedures remained challenging due to the lack of appropriate scaffold materials, supporting the needs of various cell types and providing a barrier function required in hollow organs. To address these problems, we have developed a bilayered hybrid scaffold comprising unique traits of polymeric microfibers and naturally derived acellular matrices and tested its potential for hollow organ regeneration in a rat bladder model. Hybrid scaffolds were fabricated by electrospinning of PLGA microfibers directly onto the abluminal surface of a bladder acellular matrix. Stability of this bilayered construct was established using modified spinning technique. The resulting 3-dimensional framework provided good support for growth, attachment and proliferation of primary bladder smooth muscle cells. Histological analysis in vivo at 4 and 8 weeks post implantation, revealed regeneration of bladder tissue structures consisting of urothelium, smooth muscle and collagen rich layers infiltrated with host cells and micro vessels. Furthermore, hybrid scaffolds maintained normal bladder capacity, whereas BAM recipients showed a significant distension of the bladder. These results demonstrate that this adaptable hybrid scaffold supports bladder regeneration and holds potential for engineering of bladder and other hollow organs. AbstractVarious synthetic and natural biomaterials have been used for regeneration of tissues and hollow organs. However, clinical outcome of reconstructive procedures remained challenging due to the lack of appropriate scaffold materials, supporting the needs of various cell types and providing a barrier function required in hollow-organs. To address these problems, we have developed a bilayered hybrid scaffold comprising unique traits of polymeric microfibers and naturally derived acellular matrices and tested its potential for hollow-organ regeneration in a rat bladder model. BAM-recipients showed a significant distension of the bladder. These results demonstrate that this adaptable hybrid scaffold supports bladder regeneration and holds potential for engineering of bladder and other hollow-organs.

Tissue engineering of a construct that will support the contractile properties that allow physiologic voiding is a complex process. The combination of smart scaffolds with controlled topography, the ability to deliver multiple trophic factors and an optimal cell source will allow for the engineering of functional bladder tissues in the near future.

Tension gastrothorax is a life-threatening condition leading to acute and severe respiratory distress. The condition exhibits distinct radiographic features. Emergency decompression of the distended stomach should first be attempted via nasogastric tube. If this maneuver fails, decompression must be achieved either by needle puncture or by chest tube insertion into the stomach.

OBJECTIVE To report our experience of 11 children with pelvi‐ureteric junction obstruction (PUJO) in a duplex kidney and to review previous reports. PATIENTS AND METHODS From 1995 to 2005 the second author (G.H.H.S.) performed 145 pyeloplasties in single‐system kidneys and in 11 children with PUJO in a duplex kidney. Upper and lower pole obstructions were found in both complete and incomplete duplicated systems. Investigations included renal ultrasonography, renal scintigraphy, micturating cystography, cystoscopy and retrograde pyelography. Ten patients had surgery (eight dismembered pyeloplasties, one upper‐pole heminephrectomy, one pyelo‐ureterostomy). RESULTS Three children had obstruction of the upper moiety and eight had obstruction of the lower moiety. Upper and lower pole obstructions were found in both complete and incomplete duplicated systems. CONCLUSION Upper‐pole obstruction in a duplex kidney is rare; the present series suggests that it is more common than previously reported.

Our data suggest a positive effect of prenatal MMC closure on lower urinary tract function. The long-term significance of these results remains unclear. Therefore, continued close monitoring of renal and bladder function are mandatory.

Several congenital disorders can cause end stage bladder disease and possibly renal damage in children. The current gold standard therapy is enterocystoplasty, a bladder augmentation using an intestinal segment. However, the use of bowel tissue is associated with numerous complications such as metabolic disturbance, stone formation, urine leakage, chronic infections, and malignancy. Urinary diversions using engineered bladder tissue would obviate the need for bowel for bladder reconstruction. Despite impressive progress in the field of bladder tissue engineering over the past decades, the successful transfer of the approach into clinical routine still represents a major challenge. In this review, we discuss major achievements and challenges in bladder tissue regeneration with a focus on different strategies to overcome the obstacles and to meet the need for living functional tissue replacements with a good growth potential and a long life span matching the pediatric population.

The object of this study was to investigate the role of scaffold porosity on tissue ingrowth using hybrid scaffolds consisting of bladder acellular matrix and electrospun poly (lactide-co-glycolide) (PLGA) microfibers that mimic the morphological characteristics of the bladder wall in vitro and in vivo. We compared single-spun (SS) PLGA scaffolds with more porous cospun (CS) scaffolds (PLGA and polyethylene glycol). Scaffolds were characterized by scanning electron microscopy. Bladder smooth muscle cells (SMCs) were seeded, and proliferation and histological assays were performed. Sixteen rats were subjected to augmentation cystoplasty with seeded SS or CS scaffolds, morphological, and histological studies were performed 2 and 4 weeks after implantation. The porosities of SS and CS scaffolds were 73.1 ± 2.9% and 80.9 ± 1.5%, respectively. The in vitro evaluation revealed significantly deeper cell migration into CS scaffolds. The in vivo evaluation showed significant shrinkage of SS scaffolds (p = 0.019). The histological analysis revealed a bladder wall-like structure with urothelial lining and SMC infiltration in both groups. The microvessel density was significantly increased in the CS scaffolds (p < 0.001). Increasing the porosity of electrospun hybrid scaffolds is an effective strategy to enhance cell proliferation and distribution in vitro and tissue ingrowth in vivo.

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