Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020500 (hyperoxaluria)
 912 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The active transport of conjugated bile acids by the ileum is responsible for the enterohepatic circulation of bile acids, a physiological process that ensures an ample supply to the intestine of these key biological surfactants, irrespective of the rate of their biosynthesis from cholesterol. The ileal bile acid transport system is a high capacity, low affinity secondary active Na+ co-transport system that differs in substrate specificity from that present in the hepatocyte. Ileal transport is homeostatically regulated by feedback inhibition of the bile acids that are transported. The enterohepatic circulation is responsible for the concentration profile present in the intestine--high concentrations in the small intestine and low concentrations in the large intestine. Loss of ileal absorption, when mild, leads to a sequence of events that result in increased concentrations in the large intestine causing diarrhea. Severe bile acid malabsorption causes decreased concentrations in the small intestine which in turn lead to fat maldigestion and fat malabsorption. The increased passage of fatty acids into the colon contributes to diarrhea. Fat maldigestion and malabsorption also causes increased absorption of dietary oxalate from the colon which causes hyperoxaluria and contributes to nephrolithiasis. In cholestatic liver disease, inappropriate upregulation of ileal bile acid transport is likely to cause retention of hepatotoxic endogenous bile acids. In familial hypercholesterolemia, efficient bile acid absorption contributes to downregulation of LDL receptors and the maintenance of elevated plasma cholesterol levels; upregulation of bile acid transport during bile acid sequestrant therapy could diminish its efficacy. Efforts are in progress to develop a suitable bile acid analogue to be administered orally for conditions of bile acid deficiency in the small intestine.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Biological and medical aspects of active ileal transport of bile acids. 206 93

Type I primary hyperoxaluria is an uncommon disease related to alanine glyoxylate aminotransferase (AGT) deficiency, an exclusively hepatic enzyme. AGT deficiency leads to an overproduction of oxalate in the liver and consequent hyperoxalemia and massive hyperoxaluria with renal failure. The diagnosis is confirmed by needle biopsy of the kidney showing the exact nature of the enzyme deficiency. When terminal renal failure has developed there are two therapeutic possibilities: kidney graft or a double liver-kidney graft. Kidney graft alone is often insufficient and carries the risk of recurrent disease in the graft since the liver disorder has not been corrected. Inversely, combined liver-kidney graft can not only replace the destroyed kidneys but also correct the metabolic disorder through the effect of the AGT in the donor liver. Although this approach may be successful, it is a very aggressive procedure with high mortality.
 ...
PMID:[Mechanisms and treatment of primary type I hyperoxaluria]. 869 89

1. Split liver transplantation for a child and an adult recipient is standard today. Living donor liver transplantation for small children should only be necessary in exceptional situations in a country with a well-organized organ donation program. 2. True split liver transplantation for two adults is still not very common. In the United States between April 2000 and May 2001, 89 surgical teams transplanted only 15 left lobes and 13 right lobes. Especially left lobes from deceased donors have a poor outcome; in Europe the ELTR shows a 1-year graft survival of 47%. 3. While in Asia left lobes, right lateral segments, and dual left lateral segments are more frequently used, living donor liver transplantation for adults in Europe and the United States is predominantly performed with right lobes.78 This carries a significant morbidity and mortality risk for the donor. Outcome compared to deceased donor liver transplantation (DDLTx) is similar with a trend towards more short-term and long-term biliary complications. 4. Living donor and split liver transplantation should be used mainly in an elective situation. Candidates are tumor patients, patients with cholestatic liver disease, and elective patients with bile disease. 5. Urgent liver transplantation is not a good option for living donor and split liver transplantation. Hepatic assist devices may change the picture in the future. 6. Living donor liver transplantation for metabolic disorders like Alpha-1-Antitrypsin deficiency, Hyperoxaluria, and others cannot be recommended at present since the genetically related donor and the patient may carry an unknown risk.
 ...
PMID:Live donor/split liver grafts for adult recipients: when should we use them? 1623 27

With advancements in the operative techniques, patient survival following liver transplantation (LTx) has increased substantially. This has led to the acceleration of pre-existing kidney disease because of immunosuppressive nephrotoxicity making additional kidney transplantation (KTx) inevitable. On the other hand, in a growing number of patients on the waiting list to receive liver, long waiting time has resulted in adverse effect of decompensated liver on the kidney function. During the last two decades, the transplant community has considered combined liver kidney transplantation (CLKTx) to overcome this problem. The aim of our study is to present an overview of our experience as well as a review of the literature in CLKTx and to discuss the controversy in this regard. All performed CLKTx (n = 22) at our institution as well as all available reported case series focusing on CLKTx are extracted. The references of the manuscripts were cross-checked to implement further articles into the review. The analyzed parameters include demographic data, indication for LTx and KTx, duration on the waiting list, Model for End-Stage Liver Disease (MELD) score, Child-Turcotte-Pugh (CTP) score, immunosuppressive regimen, post-transplant complications, graft and patient survival, and cause of death. From 1988 to 2009, a total of 22 CLKTx were performed at our institution. The median age of the patients at the time of CLKTx was 44.8 (range: 4.5-58.3 yr). The indications for LTx were liver cirrhosis, hyperoxaluria type 1, polycystic liver disease, primary or secondary sclerosing cholangitis, malignant hepatic epithelioid hemangioendothelioma, cystinosis, and congenital biliary fibrosis. The KTx indications were end-stage renal disease of various causes, hyperoxaluria type 1, polycystic kidney disease, and cystinosis. The mean follow-up duration for CLKTx patients were 4.6 +/- 3.5 yr (range: 0.5-12 yr). Overall, the most important encountered complications were sepsis (n = 8), liver failure leading to retransplantation (n = 4), liver rejection (n = 3), and kidney rejection (n = 1). The overall patient survival rate was 80%. Review of the literature showed that from 1984 to 2008, 3536 CLKTx cases were reported. The main indications for CLKTx were oxalosis of both organs, liver cirrhosis and chronic renal failure, polycystic liver and kidney disease, and liver cirrhosis along with hepatorenal syndrome (HRS). The most common encountered complications following CLKTx were infection, bleeding, biliary complications, retransplantation of the liver, acute hepatic artery thrombosis, and retransplantation of the kidney. From the available data regarding the need for post-operative dialysis (n = 673), a total of 175 recipients (26%) required hemodialysis. During the follow-up period, 154 episodes of liver rejection (4.3%) and 113 episodes of kidney rejection (3.2%) occurred. The cumulative 1, 2, 3, and 5 yr survival of both organs were 78.2%, 74.4%, 62.4%, and 60.9%, respectively. Additionally, the cumulative 1, 2, 3, and 5 yr patient survival were 84.9%, 52.8%, 45.4%, and 42.6%, respectively. The total number of reported deaths was 181 of 2808 cases (6.4%), from them the cause of death in 99 (55%) cases was sepsis. It can be concluded that there is still no definitive evidence of better graft and patient survival in CLKTx recipients when compared with LTx alone because of the complexity of the exact definition of irreversible kidney function in LTx candidates. Additionally, CLKTx is better to be performed earlier than isolated LTx and KTx leading to the avoidance of deterioration of clinical status, high rate of graft loss, and mortality. Shorter graft ischemia time and more effective immunosuppressive regimens can reduce the incidence of graft malfunctioning in CLKTx patients. Providing a model to reliably determine the need for CLKTx seems necessary. Such a model can be shaped based upon new and precise markers of renal function, and modification of MELD system.
 ...
PMID:A single center experience of combined liver kidney transplantation. 1993 Mar 23

Liver transplantation (LT) activity started in Spain in 1984 and has exceeded 23,700 interventions, with more than 1000 transplants performed yearly. Every hospital needs official authorization to perform a LT, which implies the obligation to register all patients on the national waiting list. The Spanish National Transplant Organization (ONT) provides essential support for organ procurement, allocation, and management of the waiting list at a national level. Liver allocation is center-oriented as all available organs are referred to the ONT for the whole country. The allocation rules for LT are made according to disease severity after consensus among professionals from every transplant center and ratified by representatives of the regional health authorities. Authorization and location/distribution of transplant centers are regulated by the country (Spain) and by the different regions according to the Real Decreto 1723/2012. For a total population of 47,850,795 inhabitants, there are 24 centers for LT for adults (1 team/2 million people) and 5 for LT for children (1 team/9.5 million people). Nonbiliary cirrhosis, particularly alcohol- and hepatitis C virus-related cirrhosis (60%), and tumors, mainly hepatocellular carcinoma (19%), are the most common indications for LT in Spain. Unusual causes of LT include metabolic diseases like Wilson's disease, familial amyloid polyneuropathy and hyperoxaluria type I, polycystic kidney and liver disease, and some tumors (epithelioid hemangioendothelioma and neuroendocrine tumors). Important efforts are now being undertaken to improve the quality and transplantability of extended criteria livers, in particular those arising from DCD, which represent the greatest opportunity to expand the donor pool. These efforts have to be addressed to adapt the organ preservation procedures, be it through the application of regional perfusion in situ or the use of machine perfusion preservation ex situ. Liver Transplantation 22 1259-1264 2016 AASLD.
 ...
PMID:Liver transplantation in Spain. 2719 47