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97-541: The National Kidney Registry ( NKR ) is a national registry in the United States listing kidney donors and recipients in need of a kidney transplant. NKR facilitates over 450 " Kidney Paired Donation " (KPD) or "Paired Exchange" transplants annually. More than one-third of potential living kidney donors who want to donate their kidney to a friend or family member cannot because of blood type or antibody incompatibility. Historically, these donors would be turned away and

194-408: A 48-year-old attorney from Minneapolis. This swap took two months to complete and involved 26 different transplant centers. The NKR has facilitated 3214 kidney transplants, as of March 17, 2019. The rapid growth of KPD transplants in the United States has been driven by the following key NKR innovations. The NKR's innovations have generated significant media coverage including a front-page story in

291-448: A better matched kidney transplant is correlated with a lower lifetime mortality rate. For compatible pairs, not only does a better match lead to a better outcome, but it also directly helps other patients with incompatible donors find a match and get transplanted. A favorable blood type compatible pair (i.e. O donor with non-O recipient) will facilitate at least one and as many as six additional transplants. Compatible pair participation

388-406: A bridge donor who donated two months later, extending the chain to 5-deep. This chain was broken after the bridge donor reneged following many failed cross matches that required the donor to repeatedly go to the hospital for blood draws. The NKR's second swap started with the shipment of a kidney from Cornell to UCLA School of Medicine . This was the first time a living donor kidney was shipped on

485-471: A commercial airplane. This second chain crossed the country three times, facilitating eight total transplants at UCLA, Cornell, Stanford University School of Medicine , and California Pacific Medical Center . Ultimately, this chain was broken when the bridge donor reneged. Based on these early experiences, many safeguards were implemented to reduce the risk of broken chains, which dropped the frequency of broken chains from 33% in 2008 to 2% in 2015. In 2012,

582-521: A donor donated on behalf of his grandson who may develop kidney failure 10–20 years in the future. Mr. Hil, the founder of the NKR, was the second donor to donate his kidney through this program. In 2015, the National Kidney Registry completed 360 KPD transplants which accounted for 62% of all U.S. KPD transplants and more than the combined volume of all other KPD programs in world. Concerns regarding

679-459: A kidney but does not donate for some period of time (generally 1 week to 3 months). Just like Domino Chains increased KPD transplants, the utilization of bridge donors also dramatically increased KPD transplants because chains could now be organized over several months and avoid the logistical limitations of performing all surgeries on one day. In 2007, the APD completed the first NEAD chain. That same year,

776-474: A living donor kidney from her compatible cousin. Mr. Hil was the first non-physician to start/lead a KPD program and the first KPD leader to donate one of his kidneys, starting a chain that facilitated eight transplants. In 2008, the National Kidney Registry completed its first KPD transplants and implemented the next major innovation, the shipment of kidneys on commercial airlines. This breakthrough in logistics further expanded KPD. The first living donor kidney that

873-499: A pathological diagnosis. A renal pathologist is a physician who has undergone general training in anatomic pathology and additional specially training in the interpretation of renal biopsy specimens. Ideally, multiple core sections are obtained and evaluated for adequacy (presence of glomeruli) intraoperatively. A pathologist/pathology assistant divides the specimen(s) for submission for light microscopy, immunofluorescence microscopy and electron microscopy. The pathologist will examine

970-491: A portion of medulla called a renal pyramid . Between the renal pyramids are projections of cortex called renal columns . The tip, or papilla , of each pyramid empties urine into a minor calyx ; minor calyces empty into major calyces , and major calyces empty into the renal pelvis . This becomes the ureter. At the hilum, the ureter and renal vein exit the kidney and the renal artery enters. Hilar fat and lymphatic tissue with lymph nodes surround these structures. The hilar fat

1067-474: A reciprocal kidney donation to any specific patient. More than one-third of potential living kidney donors who want to donate their kidney to a friend or family member cannot donate due to blood type or antibody incompatibility. Historically, these donors would be turned away and the patient would lose the opportunity to receive a life-saving transplant . KPD overcomes donor–recipient incompatibility by swapping kidneys between multiple donor–recipient pairs. KPD

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1164-652: A tight hairpin configuration of the tubules, water and ion permeability in the descending limb of the loop, water impermeability in the ascending loop, and active ion transport out of most of the ascending limb. In addition, passive countercurrent exchange by the vessels carrying the blood supply to the nephron is essential for enabling this function. The kidney participates in whole-body homeostasis , regulating acid–base balance , electrolyte concentrations, extracellular fluid volume , and blood pressure . The kidney accomplishes these homeostatic functions both independently and in concert with other organs, particularly those of

1261-502: A two-year period, these preferences shifted until nearly all recipients would accept shipped kidneys with very few donors willing to travel. By 2010, the option to have a donor travel was phased out and all kidneys that needed to be moved between centers were shipped. After several near misses and with the UNOS reporting that 1–2% of deceased donor kidney lost or mis-routed, the NKR developed the first GPS tracking systems for human organs to monitor

1358-456: Is homologous with the vas deferens of amniotes. However, the situation is not always so simple; in cartilaginous fish and some amphibians, there is also a shorter duct, similar to the amniote ureter, which drains the posterior (metanephric) parts of the kidney, and joins with the archinephric duct at the bladder or cloaca . Indeed, in many cartilaginous fish, the anterior portion of the kidney may degenerate or cease to function altogether in

1455-586: Is also being used to find better donor–recipient matches for compatible pairs who want a lower lifetime mortality and longer lasting transplant. The first paper outlining the concept of paired exchange was authored by FT Rapaport and published in 1986. The first recorded paired exchange transplants were organized in South Korea by Dr. Park beginning in 1991. For nearly a decade, only Park and his team in South Korea utilized this novel approach to facilitate transplants for incompatible donor–recipient pairs. In 1999,

1552-408: Is an adjective meaning “relating to the kidneys”, and its roots are French or late Latin. Whereas according to some opinions, "renal" should be replaced with "kidney" in scientific writings such as "kidney artery", other experts have advocated preserving the use of "renal" as appropriate including in "renal artery". In humans, the kidneys are located high in the abdominal cavity , one on each side of

1649-562: Is contiguous with a fat-filled cavity called the renal sinus . The renal sinus collectively contains the renal pelvis and calyces and separates these structures from the renal medullary tissue. The kidneys possess no overtly moving structures. The kidneys receive blood from the renal arteries , left and right, which branch directly from the abdominal aorta . The kidneys receive approximately 20–25% of cardiac output in adult human. Each renal artery branches into segmental arteries, dividing further into interlobar arteries , which penetrate

1746-402: Is divided into three or more distinct lobes. The lobes consists of several small, irregularly arranged, lobules, each centred on a branch of the ureter. Birds have small glomeruli, but about twice as many nephrons as similarly sized mammals. The human kidney is fairly typical of that of mammals . Distinctive features of the mammalian kidney, in comparison with that of other vertebrates, include

1843-497: Is frequently used to cure renal cell carcinoma . Renal physiology is the study of kidney function . Nephrology is the medical specialty which addresses diseases of kidney function : these include CKD, nephritic and nephrotic syndromes , acute kidney injury , and pyelonephritis . Urology addresses diseases of kidney (and urinary tract) anatomy : these include cancer , renal cysts , kidney stones and ureteral stones , and urinary tract obstruction . The word “ renal ”

1940-526: Is indicated when the glomerular filtration rate has fallen very low or if the renal dysfunction leads to severe symptoms. Dialysis is a treatment that substitutes for the function of normal kidneys. Dialysis may be instituted when approximately 85%–90% of kidney function is lost, as indicated by a glomerular filtration rate (GFR) of less than 15. Dialysis removes metabolic waste products as well as excess water and sodium (thereby contributing to regulating blood pressure); and maintains many chemical levels within

2037-428: Is sensed in the corresponding dermatome . Thus, pain in the flank region may be referred from corresponding kidney. Nephrons , the urine-producing functional structures of the kidney, span the cortex and medulla. The initial filtering portion of a nephron is the renal corpuscle , which is located in the cortex. This is followed by a renal tubule that passes from the cortex deep into the medullary pyramids. Part of

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2134-617: Is shortening the wait times for incompatible pairs with hard to match blood type combinations (e.g. "O" patients with "A" donors) and driving more matches for highly sensitized patients (e.g. cPRAs > 90%). Researchers have also discovered that better HLA matching not only leads to longer lasting transplants, but is also correlated with lower patient mortality rates because better matched kidneys require less immunosuppression and less immunosuppression reduces nephrotoxicity and other negative side effects from post-transplant anti-rejection medications. Equally important, better HLA matching reduces

2231-469: Is slightly lower. The right kidney sits just below the diaphragm and posterior to the liver . The left kidney sits below the diaphragm and posterior to the spleen . On top of each kidney is an adrenal gland . The upper parts of the kidneys are partially protected by the 11th and 12th ribs . Each kidney, with its adrenal gland is surrounded by two layers of fat: the perirenal fat present between renal fascia and renal capsule and pararenal fat superior to

2328-419: Is the peritoneum , while the posterior (rear) surface is the transversalis fascia . The superior pole of the right kidney is adjacent to the liver. For the left kidney, it is next to the spleen . Both, therefore, move down upon inhalation. A Danish study measured the median renal length to be 11.2 cm ( 4 + 7 ⁄ 16  in) on the left side and 10.9 cm ( 4 + 5 ⁄ 16  in) on

2425-464: Is the fastest growing segment of KPD and holds the promise of facilitating better matches for patients with compatible donors while limiting KPD wait times to less than 12 months for patients that have a cPRA (" Calculated panel reactive antibodies " ) less than 98%. Advanced Donation, which began in 2012 and expanded in 2014 to include Voucher donations and swap saver cases, expanded so rapidly that by 2017, Advanced Donation accounted for nearly half of

2522-450: Is the production of urine . These include the nitrogenous wastes urea , from protein catabolism , and uric acid , from nucleic acid metabolism. The ability of mammals and some birds to concentrate wastes into a volume of urine much smaller than the volume of blood from which the wastes were extracted is dependent on an elaborate countercurrent multiplication mechanism. This requires several independent nephron characteristics to operate:

2619-485: Is the specialty under Surgery that deals with kidney structure abnormalities such as kidney cancer and cysts and problems with urinary tract . Nephrologists are internists , and urologists are surgeons , whereas both are often called "kidney doctors". There are overlapping areas that both nephrologists and urologists can provide care such as kidney stones and kidney related infections . There are many causes of kidney disease . Some causes are acquired over

2716-492: Is the transport of molecules from this ultrafiltrate and into the peritubular capillary network that surrounds the nephron tubules. It is accomplished via selective receptors on the luminal cell membrane. Water is 55% reabsorbed in the proximal tubule. Glucose at normal plasma levels is completely reabsorbed in the proximal tubule. The mechanism for this is the Na /glucose cotransporter. A plasma level of 350 mg/dL will fully saturate

2813-545: The New York Times . and nationally televised interviews by Katie Couric with the CBS Evening News . Diane Sawyer from ABC News, and Byron Pitts at Nightline . Kidney Paired Donation According to a 2019 study, kidney exchanges improve overall transplant quality, which leads to fewer transplant failures. The exchanges also reduce waiting times for patients needing kidney transplants. The study found that

2910-409: The bone marrow . Calcitriol , the activated form of vitamin D , promotes intestinal absorption of calcium and the renal reabsorption of phosphate . Renin is an enzyme which regulates angiotensin and aldosterone levels. Although the kidney cannot directly sense blood, long-term regulation of blood pressure predominantly depends upon the kidney. This primarily occurs through maintenance of

3007-445: The endocrine system . Various endocrine hormones coordinate these endocrine functions; these include renin , angiotensin II , aldosterone , antidiuretic hormone , and atrial natriuretic peptide , among others. Filtration, which takes place at the renal corpuscle , is the process by which cells and large proteins are retained while materials of smaller molecular weights are filtered from

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3104-458: The extracellular fluid compartment, the size of which depends on the plasma sodium concentration. Renin is the first in a series of important chemical messengers that make up the renin–angiotensin system . Changes in renin ultimately alter the output of this system, principally the hormones angiotensin II and aldosterone . Each hormone acts via multiple mechanisms, but both increase the kidney's absorption of sodium chloride , thereby expanding

3201-418: The posterior pituitary gland . An increase in osmolality causes the gland to secrete antidiuretic hormone (ADH), resulting in water reabsorption by the kidney and an increase in urine concentration. The two factors work together to return the plasma osmolality to its normal levels. Various calculations and methods are used to try to measure kidney function. Renal clearance is the volume of plasma from which

3298-451: The renal fascia . The human kidney is a bean-shaped structure with a convex and a concave border. A recessed area on the concave border is the renal hilum , where the renal artery enters the kidney and the renal vein and ureter leave. The kidney is surrounded by tough fibrous tissue, the renal capsule , which is itself surrounded by perirenal fat , renal fascia , and pararenal fat . The anterior (front) surface of these tissues

3395-406: The spine , and lie in a retroperitoneal position at a slightly oblique angle. The asymmetry within the abdominal cavity, caused by the position of the liver , typically results in the right kidney being slightly lower and smaller than the left, and being placed slightly more to the middle than the left kidney. The left kidney is approximately at the vertebral level T12 to L3 , and the right

3492-504: The urinary bladder harbour specialized parasites , monogeneans of the family Polystomatidae. The kidneys of reptiles consist of a number of lobules arranged in a broadly linear pattern. Each lobule contains a single branch of the ureter in its centre, into which the collecting ducts empty. Reptiles have relatively few nephrons compared with other amniotes of a similar size, possibly because of their lower metabolic rate . Birds have relatively large, elongated kidneys, each of which

3589-403: The APD conceived of a critically important innovation called "NEAD Chains" that amplified the matching power of Domino Chains by allowing Bridge Donors to extend chains. Prior to the utilization of Bridge Donors, a chain of transplant surgeries would be completed in one day, which limited the number of transplants that could be performed. A bridge Donor is someone whose paired recipient has received

3686-473: The NEPKE and PDN programs folded due to funding issues and increased regulatory requirements imposed on U.S. KPD programs by CMS and UNOS. During this time, the NKR developed the first donor preselect system that allowed donors to be accepted or declined before a match was offered. This innovation was taken from the brokerage industry, essentially porting the limit order concept to KPD. The preselect concept eliminated

3783-408: The NKR broke the world record for the largest kidney swap by organizing a 30-deep chain involving 60 donors and recipients. This chain was started by Rick Ruzzamenti, a 44-year-old from Riverside, California. The swap took four months to complete and involved 17 different transplant centers across 11 states. Three years later, on March 26, the next record breaking chain was set into motion by Kathy Hart,

3880-520: The NKR initiated the Advanced Donation Program (ADP) which inverted the role of the bridge donor – now donors were donating in advance of their paired recipient transplants which further alleviated scheduling challenges for paired donors. In 2014, the National Kidney Registry set a new record by organizing a swap that included 70 surgeries completing over two months. That same year, the NKR completed its first long term Advanced Donation whereby

3977-518: The U.S. Congress passed the Charlie Norwood Act which clarified that paired exchange was legal. Prior to the passage of this law, many in the U.S. transplant community feared that KPD was unlawful due to the prohibition of "valuable consideration" as articulated in the NOTA laws that govern the U.S. transplant industry. With the passage of the Charlie Norwood Act, many more KPD programs were launched in

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4074-547: The U.S. including the UNOS KPD program which was government sponsored with funding from deceased donor registration fees and charitable contributions. In 2007, Garet and Jan Hil founded the National Kidney Registry (NKR) after their daughter (age 10) lost her kidney function and needed a transplant. Both parents were incompatible and could not donate to their daughter, who later, after an extensive donor search, received

4171-503: The United States, a compatible donor was found. After this transplant ordeal, the Hil family founded the National Kidney Registry to eliminate the problem of incompatible donors, by building a national kidney paired donation (KPD) program. The NKR organized its first swap on Valentine's Day in 2008 at Cornell Medical Center in New York City. This first swap was a 3-deep chain that ended with

4268-416: The United States, into a single registry, and facilitate the transplant process. The NKR was founded in 2007 by the Hil family, after their youngest daughter lost her kidney function at age ten. Both parents were ruled out from donating to their daughter because they were biologically incompatible. After many unsuccessful attempts to find a compatible donor through all of the kidney paired exchange programs in

4365-524: The adult. In the most primitive vertebrates, the hagfish and lampreys , the kidney is unusually simple: it consists of a row of nephrons, each emptying directly into the archinephric duct. Invertebrates may possess excretory organs that are sometimes referred to as "kidneys", but, even in Amphioxus , these are never homologous with the kidneys of vertebrates, and are more accurately referred to by other names, such as nephridia . In amphibians , kidneys and

4462-461: The assessment of renal disease. The role of the renal biopsy is to diagnose renal disease in which the etiology is not clear based upon noninvasive means (clinical history, past medical history, medication history, physical exam, laboratory studies, imaging studies). In general, a renal pathologist will perform a detailed morphological evaluation and integrate the morphologic findings with the clinical history and laboratory data, ultimately arriving at

4559-495: The basis of a detailed medical history , and physical examination . The medical history takes into account present and past symptoms, especially those of kidney disease; recent infections; exposure to substances toxic to the kidney; and family history of kidney disease. Kidney function is tested by using blood tests and urine tests . The most common blood tests are creatinine , urea and electrolytes . Urine tests such as urinalysis can evaluate for pH, protein, glucose, and

4656-484: The blood and move it to the filtrate which helps to increase the pH of the blood. On the basal side of the cell there is a HCO 3 /Cl exchanger and a Cl/K co-transporter (facilitated diffusion). When the reaction is pushed to the left it also increases the HCO 3 concentration in the cell and HCO 3 is then able to move out into the blood which additionally raises the pH. The intercalated B cell responds very similarly, however,

4753-425: The blood moves through a small network of small veins ( venules ) that converge into interlobular veins . As with the arteriole distribution, the veins follow the same pattern: the interlobular provide blood to the arcuate veins then back to the interlobar veins , which come to form the renal veins which exit the kidney. The kidney and nervous system communicate via the renal plexus , whose fibers course along

4850-407: The blood to make an ultrafiltrate that eventually becomes urine. The adult human kidney generates approximately 180 liters of filtrate a day, most of which is reabsorbed. The normal range for a twenty four hour urine volume collection is 800 to 2,000 milliliters per day. The process is also known as hydrostatic filtration due to the hydrostatic pressure exerted on the capillary walls. Reabsorption

4947-493: The blood volume that enters the kidneys is filtered. Examples of substances reabsorbed are solute-free water , sodium , bicarbonate , glucose , and amino acids . Examples of substances secreted are hydrogen , ammonium , potassium and uric acid . The nephron is the structural and functional unit of the kidney. Each adult human kidney contains around 1 million nephrons, while a mouse kidney contains only about 12,500 nephrons. The kidneys also carry out functions independent of

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5044-426: The body is experiencing acidic conditions. Under acidic conditions, the high concentration of CO 2 in the blood creates a gradient for CO 2 to move into the cell and push the reaction HCO 3 + H ↔ H 2 CO 3 ↔ CO 2 + H 2 O to the left. On the luminal side of the cell there is a H pump and a H/K exchanger. These pumps move H against their gradient and therefore require ATP. These cells will remove H from

5141-554: The body pH to a value of 7.4 by controlling the respiratory rate. When the body is experiencing acidic conditions, it will increase the respiratory rate which in turn drives off CO 2 and decreases the H concentration, therefore increasing the pH. In basic conditions, the respiratory rate will slow down so that the body holds onto more CO 2 and increases the H concentration and decreases the pH. The kidneys have two cells that help to maintain acid-base homeostasis: intercalated A and B cells. The intercalated A cells are stimulated when

5238-412: The body's acid–base balance are the kidneys and lungs. Acid–base homeostasis is the maintenance of pH around a value of 7.4. The lungs are the part of respiratory system which helps to maintain acid–base homeostasis by regulating carbon dioxide (CO 2 ) concentration in the blood. The respiratory system is the first line of defense when the body experiences and acid–base problem. It attempts to return

5335-437: The body. Life expectancy is 5–10 years for those on dialysis; some live up to 30 years. Dialysis can occur via the blood (through a catheter or arteriovenous fistula ), or through the peritoneum ( peritoneal dialysis ) Dialysis is typically administered three times a week for several hours at free-standing dialysis centers, allowing recipients to lead an otherwise essentially normal life. Many renal diseases are diagnosed on

5432-404: The chain starts in the United States. As adoption of Advanced Donation increased, due to the timing advantages that made donation surgery more convenient for the donor, the size and complexity of KPD swaps were reduced, with the logical extension of this trend being the eventual elimination of traditional chain and loop swaps, replaced by 1-deep chains. The following academic publications highlight

5529-544: The course of life, such as diabetic nephropathy whereas others are congenital , such as polycystic kidney disease . Medical terms related to the kidneys commonly use terms such as renal and the prefix nephro- . The adjective renal , meaning related to the kidney, is from the Latin rēnēs , meaning kidneys; the prefix nephro- is from the Ancient Greek word for kidney, nephros (νεφρός) . For example, surgical removal of

5626-504: The extracellular fluid compartment and raising blood pressure. When renin levels are elevated, the concentrations of angiotensin II and aldosterone increase, leading to increased sodium chloride reabsorption, expansion of the extracellular fluid compartment, and an increase in blood pressure. Conversely, when renin levels are low, angiotensin II and aldosterone levels decrease, contracting the extracellular fluid compartment, and decreasing blood pressure. The two organ systems that help regulate

5723-564: The first KPD transplants were performed in Europe followed by the first KPD transplants in the United States in 2000. Over the next ten years the United States would become the most competitive KPD market in the world with more than a dozen KPD programs commencing operations and many KPD programs failing. Outside of the United States, most of the KPD programs have been organized or sponsored by governments which has limited innovation in these programs. Three of

5820-405: The first donor blood cryo-preservation allowing the rapid cross matching of pairs in a swap without requiring fresh blood from donors. This approach accelerates the matching process, reduces swap failure rates and provides the ability to speculatively cross match potential donors for highly sensitized patients, leading to shorter wait times and more transplants for highly sensitized patients. Although

5917-457: The focus was only on enrolling incompatible donor–recipient pairs. As paired exchange grew and the process became faster and more reliable, patients with compatible donors that wanted a better match, began enrolling in KPD. Researchers have identified that a better matched kidney is correlated with better outcomes. Specifically a better matched kidney lasts longer and may allow for a lower dosage of post-transplant immunosuppressive medications. Also

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6014-424: The health care cost savings of kidney exchanges are substantial. Swaps of kidneys come in two distinct types: cycles and chains. Cycles only include donors who are paired with a patient so that the donor donates a kidney only if their patient receives a kidney in the swap. Chains are initiated by non-directed donors. These donors, also known as unpaired or altruistic donors, donate a kidney without any expectation of

6111-782: The important early KPD programs in the U.S. were the Hopkins program led by Dr. Montgomery and Dr. Segev, the New England Paired Kidney Exchange (NEPKE) led by Dr. Delmonico and Professor Alvin Roth and the Ohio Organ Consortium which later reorganized as two competing programs, the Paired Donation Network (PDN) led by Dr. Woodle and the Alliance for Paired Exchange (APD) led by Dr. Rees. The Hopkins program, which

6208-408: The improved outcomes from NKR are not driven by a center effect although most of the top U.S. transplant centers participate in KPD via NKR. The improved outcomes from KPD transplants are opening the door for more compatible pair participation in KPD, allowing patient with compatible living donor to essentially trade-up and get a better matched kidney. The increasing enrollment of compatible pairs in KPD

6305-427: The kidney is a nephrectomy , while a reduction in kidney function is called renal dysfunction . Generally, humans can live normally with just one kidney, as one has more functioning renal tissue than is needed to survive. Only when the amount of functioning kidney tissue is greatly diminished does one develop chronic kidney disease . Renal replacement therapy , in the form of dialysis or kidney transplantation ,

6402-463: The kidney with podocin and nephrin expressed in glomeruli, Solute carrier family protein SLC22A8 expressed in proximal tubules, calbindin expressed in distal tubules and aquaporin 2 expressed in the collecting duct cells. The mammalian kidney develops from intermediate mesoderm . Kidney development , also called nephrogenesis , proceeds through a series of three successive developmental phases:

6499-426: The kidney, with only some 50 genes being highly specific for the kidney. Many of the corresponding kidney specific proteins are expressed in the cell membrane and function as transporter proteins. The highest expressed kidney specific protein is uromodulin , the most abundant protein in urine with functions that prevent calcification and growth of bacteria. Specific proteins are expressed in the different compartments of

6596-606: The location of all NKR kidney shipments. The utilization of GPS tracking devices is now mandatory for all NKR shipped kidneys. In 2009, several more key innovations were yielding results at a single center KPD program, the Methodist Transplant Institute, in San Antonio led by Dr. Adam Bingaman. Prior to Dr. Bingaman's work, KPD was built on the notion that the results of a cross match test to determine donor–recipient compatibility are generally predictable and to ensure

6693-487: The management of kidney disease include chemical and microscopic examination of the urine ( urinalysis ), measurement of kidney function by calculating the estimated glomerular filtration rate (eGFR) using the serum creatinine ; and kidney biopsy and CT scan to evaluate for abnormal anatomy. Dialysis and kidney transplantation are used to treat kidney failure ; one (or both sequentially) of these are almost always used when renal function drops below 15%. Nephrectomy

6790-609: The massive complexity and significant impact of these large swaps. Unlike the Hopkins program that was hospital based, NEPKE was launched within the New England Organ Procurement Organization which served several states in the North East. The PDN and APD organizations were founded by transplant surgeons but attempted to create networks of transplant centers that would work together to pool their incompatible pairs, much like NEPKE but without OPO support. In 2006,

6887-444: The membrane proteins are flipped from the intercalated A cells: the proton pumps are on the basal side and the HCO 3 /Cl exchanger and K/Cl co-transporter are on the luminal side. They function the same, but now release protons into the blood to decrease the pH. The kidneys help maintain the water and salt level of the body. Any significant rise in plasma osmolality is detected by the hypothalamus , which communicates directly with

6984-486: The merits of using cryo-preserved donor blood for cross matching were clear, it proved difficult for multi-center KPD programs to implement cryo-preservation due to the complexity of the multi-center environment. The only U.S. multi-center KPD program that successfully implemented cryo-preservation was the National Kidney Registry but only after establishing a central lab and investing three years in software development. The second important innovation implemented in San Antonio

7081-469: The most significant innovations and results in the field of KPD. Kidney In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organs that are a multilobar, multipapillary form of mammalian kidneys , usually without signs of external lobulation. They are located on the left and right in the retroperitoneal space , and in adult humans are about 12 centimetres ( 4 + 1 ⁄ 2 inches) in length. They receive blood from

7178-545: The need to use supercomputers for match runs because the number of valid one-ways was dramatically reduced. The donor preselect concept developed by the NKR was quickly copied by other major KPD programs and changed the nature of the mathematics needed to support KPD by dramatically reducing the number of one-way match possibilities. In 2012, the National Kidney registry organized the largest swap in history which included 60 surgeries, completed over five months. That same year

7275-428: The negative impact that Cold Ischemic Time (CIT) may have on graft survival, due to the shipment of the kidneys, initially caused concern in the transplant industry and slowed the adoption of KPD. This concern regarding CIT originated from deceased donor transplant experiences where greater CIT is correlated with lower graft survival rates. Prior to KPD, there was no reason to ship living donor kidneys and therefore, there

7372-438: The nephrons. For example, they convert a precursor of vitamin D to its active form, calcitriol ; and synthesize the hormones erythropoietin and renin . Chronic kidney disease (CKD) has been recognized as a leading public health problem worldwide. The global estimated prevalence of CKD is 13.4%, and patients with kidney failure needing renal replacement therapy are estimated between 5 and 7 million. Procedures used in

7469-432: The number of antibodies that a transplant recipient will create making it easier to get a second, third or fourth transplant. This issue is critical for young transplant recipients who have a life expectancy that is longer than the expected graft survival (i.e. how long a transplanted kidney lasts). Deceased donor kidneys typically last 5–15 years and living donor kidneys typically last 10–30 years. When KPD first started,

7566-402: The paired renal arteries ; blood exits into the paired renal veins . Each kidney is attached to a ureter , a tube that carries excreted urine to the bladder . The kidney participates in the control of the volume of various body fluids , fluid osmolality , acid-base balance , various electrolyte concentrations, and removal of toxins . Filtration occurs in the glomerulus : one-fifth of

7663-436: The patient would lose the opportunity to receive a life-saving kidney transplant . KPD overcomes donor-recipient incompatibility by swapping kidneys between multiple donor-recipient pairs, and connecting them in longer chains, as well as taking an altruistic non-directed donor, and start chains of kidney transplants. What the NKR does is consolidate the incompatible pairs of donors and recipients from transplant centers all over

7760-453: The patient's renal disease. In the majority of vertebrates, the mesonephros persists into the adult, albeit usually fused with the more advanced metanephros ; only in amniotes is the mesonephros restricted to the embryo. The kidneys of fish and amphibians are typically narrow, elongated organs, occupying a significant portion of the trunk. The collecting ducts from each cluster of nephrons usually drain into an archinephric duct , which

7857-402: The prediction is accurate, a cross match test must be completed prior to the swap. In 5–10% of the cases, these cross match tests result in an unexpected positive cross match (bad) which causes a swap to fail. These swap failures are costly in terms of wasted time and testing but they are also demoralizing for the patients and donors involved in the cancelled swap. The Methodist program implemented

7954-533: The presence of blood. Microscopic analysis can also identify the presence of urinary casts and crystals. The glomerular filtration rate (GFR) can be directly measured ("measured GFR", or mGFR) but this rarely done in everyday practice. Instead, special equations are used to calculate GFR ("estimated GFR", or eGFR). Renal ultrasonography is essential in the diagnosis and management of kidney-related diseases. Other modalities, such as CT and MRI , should always be considered as supplementary imaging modalities in

8051-467: The presence of the renal pelvis and renal pyramids and a clearly distinguishable cortex and medulla. The latter feature is due to the presence of elongated loops of Henle ; these are much shorter in birds, and not truly present in other vertebrates (although the nephron often has a short intermediate segment between the convoluted tubules). It is only in mammals that the kidney takes on its classical "kidney" shape, although there are some exceptions, such as

8148-399: The pronephros, mesonephros, and metanephros. The metanephros are primordia of the permanent kidney. The kidneys excrete a variety of waste products produced by metabolism into the urine. The microscopic structural and functional unit of the kidney is the nephron . It processes the blood supplied to it via filtration, reabsorption, secretion and excretion; the consequence of those processes

8245-464: The renal arteries to reach each kidney. Input from the sympathetic nervous system triggers vasoconstriction in the kidney, thereby reducing renal blood flow . The kidney also receives input from the parasympathetic nervous system , by way of the renal branches of the vagus nerve ; the function of this is yet unclear. Sensory input from the kidney travels to the T10–11 levels of the spinal cord and

8342-440: The renal capsule and extend through the renal columns between the renal pyramids. The interlobar arteries then supply blood to the arcuate arteries that run through the boundary of the cortex and the medulla. Each arcuate artery supplies several interlobular arteries that feed into the afferent arterioles that supply the glomeruli. Blood drains from the kidneys, ultimately into the inferior vena cava . After filtration occurs,

8439-561: The renal cortex, a medullary ray is a collection of renal tubules that drain into a single collecting duct . Renal histology is the study of the microscopic structure of the kidney. The adult human kidney contains at least 26 distinct cell types , including epithelial, endothelial, stromal and smooth muscle cells. Distinct cell types include: In humans, about 20,000 protein coding genes are expressed in human cells and almost 70% of these genes are expressed in normal, adult kidneys. Just over 300 genes are more specifically expressed in

8536-412: The reverse of reabsorption: molecules are transported from the peritubular capillary through the interstitial fluid, then through the renal tubular cell and into the ultrafiltrate. The last step in the processing of the ultrafiltrate is excretion : the ultrafiltrate passes out of the nephron and travels through a tube called the collecting duct , which is part of the collecting duct system , and then to

8633-476: The right side in adults. Median renal volumes were 146 cm ( 8 + 15 ⁄ 16  cu in) on the left and 134 cm ( 8 + 3 ⁄ 16  cu in) on the right. The functional substance, or parenchyma , of the human kidney is divided into two major structures: the outer renal cortex and the inner renal medulla . Grossly, these structures take the shape of eight to 18 cone-shaped renal lobes , each containing renal cortex surrounding

8730-471: The specimen using light microscopy with multiple staining techniques (hematoxylin and eosin/H&E, PAS, trichrome, silver stain) on multiple level sections. Multiple immunofluorescence stains are performed to evaluate for antibody, protein and complement deposition. Finally, ultra-structural examination is performed with electron microscopy and may reveal the presence of electron-dense deposits or other characteristic abnormalities that may suggest an etiology for

8827-598: The substance is completely cleared from the blood per unit time. The filtration fraction is the amount of plasma that is actually filtered through the kidney. This can be defined using the equation. The kidney is a very complex organ and mathematical modelling has been used to better understand kidney function at several scales, including fluid uptake and secretion. Nephrology is the subspeciality under Internal Medicine that deals with kidney function and disease states related to renal malfunction and their management including dialysis and kidney transplantation . Urology

8924-399: The transporters and glucose will be lost in the urine. A plasma glucose level of approximately 160 is sufficient to allow glucosuria, which is an important clinical clue to diabetes mellitus. Amino acids are reabsorbed by sodium dependent transporters in the proximal tubule. Hartnup disease is a deficiency of the tryptophan amino acid transporter, which results in pellagra . Secretion is

9021-427: The ureters where it is renamed urine . In addition to transporting the ultrafiltrate, the collecting duct also takes part in reabsorption. The kidneys secrete a variety of hormones , including erythropoietin , calcitriol , and renin . Erythropoietin is released in response to hypoxia (low levels of oxygen at tissue level) in the renal circulation. It stimulates erythropoiesis (production of red blood cells) in

9118-518: Was based out of the Johns Hopkins Hospital , led the industry in early innovations including the critical "domino chain" breakthrough which allowed Good Samaritan donors to start chains, dramatically increasing the number of pairs that could be matched in a swap compared to the loop approach that was used previously. Once the Hopkins team began organizing Domino Chains, these swaps became larger and began attracting national media attention due to

9215-656: Was no understanding of the impact of CIT on outcomes. This concern proved to be unfounded as more living donor kidneys were shipped and the research demonstrated that CIT had no negative impact on KPD outcomes. After completing over 1,000 KPD transplants, it was discovered that NKR's graft survival rates were actually better than the graft survival rates of the typical U.S. non-KPD living donor transplants. Researchers are working to better understand why NKR KPD transplants have superior outcomes and believe it may be driven by better HLA and donor age matching and/or better avoidance of recipient antibodies. Researchers have determined that

9312-446: Was shipped on a commercial airline went from New York to Los Angeles and started NKR's second chain, which facilitated eight transplants using several bridge donors. Initially, NKR provided donors with the option of traveling to the matched recipient's hospital or donating locally and having their kidney shipped. Recipients could also choose if they would accept a shipped kidney or require the donor to travel to their center to donate. Over

9409-424: Was the re-engineering of the donor/patient intake process to educate and enroll compatible pairs in KPD so that the compatible recipient can get a better matched donor kidney. The development of cryo-preservation based cross matching and the systematic enrollment of compatible pairs has helped make San Antonio one of the leading KPD centers in the U.S. By 2010, the UNOS KPD program had completed its first swap, while

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