Activation of prorenin by (pro)renin receptor stimulates the tissue renin-angiotensin system and plays a significant role in the development of nephropathy in diabetic animals. This study examined whether (pro)renin receptor blockade inhibits the progression of nephropathy that has already developed in diabetic rats. Seventeen-week-old heminephrectomized streptozotocin-induced diabetic rats with an increased urinary protein excretion and a significant glomerulosclerosis had been treated for 12 wk with the (pro)renin receptor blocker (PRRB), angiotensin-converting enzyme inhibitor (ACEi), or vehicle peptide by using subcutaneously implanted osmotic minipumps. At the end of observation, in diabetic rats that were treated with vehicle, urinary protein excretion was progressively increased and a significant progression of glomerulosclerosis was observed. In diabetic rats that were treated with PRRB, however, no further increase in urinary protein excretion or glomerulosclerosis was observed, but 12-wk treatment with ACEi only attenuated further increases in urinary protein excretion and glomerulosclerosis. The enhanced expression of activated prorenin was observed in the kidneys of diabetic rats that were treated with vehicle, whereas it was markedly suppressed in the kidneys of diabetic rats that were treated with PRRB but not ACEi. These results suggest that (pro)renin receptor blockade does not only inhibit the progression of nephropathy but also reverses the glomerulosclerosis that has already developed in diabetic rats. Prorenin has a prosegment of 43 amino acid residues that are attached to the N terminus of mature (active) renin, and the prosegment folds into the active site cleft of mature renin to prevent catalytically productive interaction with angiotensinogen. When a prorenin-binding protein interacts with the "handle region" of the prorenin prosegment, the prorenin molecule undergoes a conformational change to an enzymatically active state. 1 This phenomenon is called nonproteolytic activation, and recent studies found that such binding proteins include the (pro)renin/renin receptor. 2,3 We recently found that nonproteolytic activation of prorenin plays a pivotal role in the activation of the renal renin-angiotensin system (RAS) and the development of nephropathy in diabetic rats and that the (pro)renin receptor blocker (PRRB; formerly handle region decoy peptide) clearly prevented the development of nephropathy and suppressed an increase of renal angiotensins. 3 However, whether nonproteolytically activated prorenin is also involved in the progression of nephropathy that had already developed in diabetic rats remained undetermined.This study was designed to determine whether PRRB is able to inhibit the progression of nephropathy after its development in diabetic rats. Prorenin prosegment has a tetrameric segment termed "gate region" (GR; S 7 FGR 10 ) that is not accessible by its
Recent studies suggest that organ decellularization is a promising approach to facilitate the clinical application of regenerative therapy by providing a platform for organ engineering. This unique strategy uses native matrices to act as a reservoir for the functional cells which may show therapeutic potential when implanted into the body. Appropriate cell sources for artificial livers have been debated for some time. The desired cell type in artificial livers is primary hepatocytes, but in addition, other supportive cells may facilitate this stem cell technology. In this context, the use of mesenchymal stem cells (MSC) is an option meeting the criteria for therapeutic organ engineering. Ideally, supportive cells are required to (1) reduce the hepatic cell mass needed in an engineered liver by enhancing hepatocyte function, (2) modulate hepatic regeneration in a paracrine fashion or by direct contact, and (3) enhance the preservability of parenchymal cells during storage. Here, we describe enhanced hepatic function achieved using a strategy of sequential infusion of cells and illustrate the advantages of co-cultivating bone marrow-derived MSCs with primary hepatocytes in the engineered whole-liver scaffold. These co-recellularized liver scaffolds colonized by MSCs and hepatocytes were transplanted into live animals. After blood flow was established, we show that expression of adhesion molecules and proangiogenic factors was upregulated in the graft.
A feasible large animal model to evaluate regenerative medicine techniques is vital for developing clinical applications. One such appropriate model could be to use retrorsine (RS) together with partial hepatectomy (PH). Here, we have developed the first porcine model using RS and PH. RS or saline control was administered intraperitoneally to Göttingen miniature pigs twice, two weeks apart. Four weeks after the second dose, animals underwent PH. Initially, we tested different doses of RS and resection of different amounts of liver, and selected 50 mg/kg RS with 60% hepatectomy as our model for further testing. Treated animals were sacrificed 3, 10, 17 or 28 days after PH. Blood samples and resected liver were collected. Serum and liver RS content was determined by Liquid Chromatograph-tandem Mass Spectrometer. Blood analyses demonstrated liver dysfunction after PH. Liver regeneration was significantly inhibited 10 and 17 days after PH in RS-treated animals, to the extent of 20%. Histological examination indicated hepatic injury and regenerative responses after PH. Immunohistochemical staining demonstrated accumulation of Cyclin D1 and suppression of Ki-67 and PCNA in RS-treated animals. We report the development of the first large animal model of sustained liver injury with suppression of hepatic regeneration.
Background Oesophageal cancer has a high metastatic potential and poor prognosis, with a significant risk of recurrence after radical resection. However, resected pancreatic metastasis from oesophageal cancer is rare. Case presentation Eleven years prior, a seventy-year-old woman had been treated with transthoracic radical oesophagectomy for oesophageal squamous cell carcinoma. Four years prior, she had undergone chemotherapy for lymph node recurrence at the splenic hilum and achieved a partial response. She had also received chemoradiotherapy for lymph node recurrence at the splenic hilum 3 years prior; a complete response was achieved. However, routine follow-up with abdominal computed tomography recently revealed a tumour at the pancreatic tail and swollen lymph nodes. The patient underwent distal pancreatectomy on the basis of a pre-operative diagnosis of primary pancreatic cancer, although a histological examination of the surgical specimen revealed metastatic squamous cell carcinoma that was compatible with metachronous pancreatic metastasis from oesophageal squamous cell carcinoma. The patient has been undergoing clinical follow-up without adjuvant therapy and has been disease-free for 24 months after resection of the pancreatic metastasis. Conclusions Resection of pancreatic metastasis may improve prognosis and should be considered when treating patients with solitary metastasis from oesophageal squamous cell carcinoma.
BackgroundSince the concept of intraductal tubulopapillary neoplasm (ITPN) was introduced in the current World Health Organization classification of tumors, the number of reports of ITPN occurrence has increased gradually. However, ITPN is usually located in the main pancreatic duct, with few reports of a branch duct ITPN. As a result, imaging protocols for the diagnosis of a branch duct ITPN have not been established.Case presentationWe report a case of a concurrent presentation of a branch duct ITPN and intraductal papillary mucinous neoplasm (IPMN) in the head of the pancreas, with a superior mesenteric artery (SMA) aneurysm. Initially, the cystic masses in the pancreatic head were diagnosed as branch duct IPMNs, with treatment consisting of a pylorus-preserving pancreaticoduodenectomy, in combination with an aneurysmectomy performed for treatment of the SMA aneurysm. Pathological examination confirmed these cysts were a combination of branch-type ITPN and IPMN. The patient recovered from the treatment without complication, with no evidence of recurrence over a period of 34 months post-surgery.ConclusionThis case report of a synchronous presentation of an ITPN and IPMN indicates the difficulty in differentiating these two types of neoplasms in the branch duct of the pancreatic head.
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