Artificial kidney
Encyclopedia
Artificial kidney is often a synonym
for hemodialysis
, but may also, more generally, refer to renal replacement therapies
(with exclusion of renal transplantation) that are in use and/or in development. This article deals with bioengineered kidney
s/bioartificial kidneys that are grown from renal cell
lines/renal tissue.
drawn from their clinical experiences during the London Blitz
.
is a method for removing waste products such as creatinine and urea, as well as free water from the blood when the kidneys are in renal failure. The mechanical device used to clean the patients blood is called a dialyser, also known as an artificial kidney. Modern dialysers typically consist of a cylindrical rigid casing enclosing hollow fibers cast or extruded from a polymer or copolymer, which is usually a proprietary formulation. The combined area of the hollow fibers is typically between 1-2 square meters. Intensive research has been conducted by many groups to optimize blood and dialysate flows within the dialyser, in order to achieve efficient transfer of wastes from blood to dialysate.
treatment for renal failure, but according to data from the 2005 USRDS 452,000 Americans have end-stage renal disease (ESRD). Intriguing investigations from groups in London, Ontario and Toronto, Ontario have suggested that dialysis treatments lasting two to three times as long as, and delivered more frequently than, conventional thrice weekly treatments may be associated with improved clinical outcomes Implementing six-times weekly, all-night dialysis would overwhelm existing resources in most countries. This, as well as scarcity of donor organs for kidney transplantation has prompted research in developing alternative therapies, including the development of a wearable or implantable device.
However, manufacturing a membrane that mimics the kidney's ability to filter blood and subsequently excrete toxins while reabsorbing water and salt would allow for a wearable and/or implantable artificial kidney. Developing a membrane using microelectromechanical systems (MEMS) technology is a limiting step in creating an implantable, bioartificial kidney.
The BioMEMS and Renal Nanotechnology Laboratories at the Cleveland Clinic's Lerner Research Institute have focused on advancing membrane technology to develop an implantable or wearable therapy for end-stage renal disease (ESRD). Current dialysis cartridges are too large and require superphysiologic pressures for blood circulation, and pores in current polymer membranes have too broad of a size distribution and irregular features. Manufacturing a silicon, nanoporous membrane with narrow pore size distributions improves the membrane's ability to discriminate between filtered and retained molecules. It also increases hydraulic permeability by allowing the mean pore size to approach the desired cutoff of the membrane. Using a batch-fabrication process allows for strict control over pore size distribution and geometry.
In recent studies, human kidney cells were harvested from donated organs unsuitable for transplatation, and grown on these membranes. The cultured cells covered the membranes and appear to retain features of adult kidney cells. The differentiated
growth of renal epithelial cells on MEMS materials suggests that a miniaturized device suitable for implantation may be feasible.
Synonym
Synonyms are different words with almost identical or similar meanings. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. The word comes from Ancient Greek syn and onoma . The words car and automobile are synonyms...
for hemodialysis
Hemodialysis
In medicine, hemodialysis is a method for removing waste products such as creatinine and urea, as well as free water from the blood when the kidneys are in renal failure. Hemodialysis is one of three renal replacement therapies .Hemodialysis can be an outpatient or inpatient therapy...
, but may also, more generally, refer to renal replacement therapies
Renal replacement therapy
Renal replacement therapy is a term used to encompass life-supporting treatments for renal failure.It includes:*hemodialysis,*peritoneal dialysis,*hemofiltration and*renal transplantation.These treatments will not cure chronic kidney disease...
(with exclusion of renal transplantation) that are in use and/or in development. This article deals with bioengineered kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
s/bioartificial kidneys that are grown from renal cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
lines/renal tissue.
Renal Failure
Kidneys are paired vital organs located behind the abdominal cavity, at about the level of the bottom of the ribcage. They perform about a dozen physiologic functions, and are fairly easily damaged. Kidney failure results in the slow accumulation of nitrogenous wastes, salts, water, and disruption of the body's normal pH balance. Until the Second World War, kidney failure generally meant death for the patient. Several insights into renal function and acute renal failure were made during the war, not least of which would be Bywaters and Beall's descriptions of pigment-induced nephropathyNephropathy
Nephropathy refers to damage to or disease of the kidney. An older term for this is nephrosis.-Causes:Causes of nephropathy include administration of analgesics, xanthine oxidase deficiency, and long-term exposure to lead or its salts...
drawn from their clinical experiences during the London Blitz
The Blitz
The Blitz was the sustained strategic bombing of Britain by Nazi Germany between 7 September 1940 and 10 May 1941, during the Second World War. The city of London was bombed by the Luftwaffe for 76 consecutive nights and many towns and cities across the country followed...
.
Artificial Kidney
HemodialysisHemodialysis
In medicine, hemodialysis is a method for removing waste products such as creatinine and urea, as well as free water from the blood when the kidneys are in renal failure. Hemodialysis is one of three renal replacement therapies .Hemodialysis can be an outpatient or inpatient therapy...
is a method for removing waste products such as creatinine and urea, as well as free water from the blood when the kidneys are in renal failure. The mechanical device used to clean the patients blood is called a dialyser, also known as an artificial kidney. Modern dialysers typically consist of a cylindrical rigid casing enclosing hollow fibers cast or extruded from a polymer or copolymer, which is usually a proprietary formulation. The combined area of the hollow fibers is typically between 1-2 square meters. Intensive research has been conducted by many groups to optimize blood and dialysate flows within the dialyser, in order to achieve efficient transfer of wastes from blood to dialysate.
Need for a bioartificial kidney
Over 300,000 Americans are dependent on hemodialysis astreatment for renal failure, but according to data from the 2005 USRDS 452,000 Americans have end-stage renal disease (ESRD). Intriguing investigations from groups in London, Ontario and Toronto, Ontario have suggested that dialysis treatments lasting two to three times as long as, and delivered more frequently than, conventional thrice weekly treatments may be associated with improved clinical outcomes Implementing six-times weekly, all-night dialysis would overwhelm existing resources in most countries. This, as well as scarcity of donor organs for kidney transplantation has prompted research in developing alternative therapies, including the development of a wearable or implantable device.
Bioengineered kidneys
Currently, no viable bioengineered kidneys exist. Although a great deal of research is underway, numerous barriers exist to their creation.However, manufacturing a membrane that mimics the kidney's ability to filter blood and subsequently excrete toxins while reabsorbing water and salt would allow for a wearable and/or implantable artificial kidney. Developing a membrane using microelectromechanical systems (MEMS) technology is a limiting step in creating an implantable, bioartificial kidney.
The BioMEMS and Renal Nanotechnology Laboratories at the Cleveland Clinic's Lerner Research Institute have focused on advancing membrane technology to develop an implantable or wearable therapy for end-stage renal disease (ESRD). Current dialysis cartridges are too large and require superphysiologic pressures for blood circulation, and pores in current polymer membranes have too broad of a size distribution and irregular features. Manufacturing a silicon, nanoporous membrane with narrow pore size distributions improves the membrane's ability to discriminate between filtered and retained molecules. It also increases hydraulic permeability by allowing the mean pore size to approach the desired cutoff of the membrane. Using a batch-fabrication process allows for strict control over pore size distribution and geometry.
In recent studies, human kidney cells were harvested from donated organs unsuitable for transplatation, and grown on these membranes. The cultured cells covered the membranes and appear to retain features of adult kidney cells. The differentiated
growth of renal epithelial cells on MEMS materials suggests that a miniaturized device suitable for implantation may be feasible.
See also
- Artificial organArtificial organAn artificial organ is a man-made device that is implanted or integrated into a human to replace a natural organ, for the purpose of restoring a specific function or a group of related functions so the patient may return to as normal a life as possible...
- KidneyKidneyThe kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
- DialysisDialysisIn medicine, dialysis is a process for removing waste and excess water from the blood, and is primarily used to provide an artificial replacement for lost kidney function in people with renal failure...
- Tissue engineeringTissue engineeringTissue engineering is the use of a combination of cells, engineering and materials methods, and suitable biochemical and physio-chemical factors to improve or replace biological functions...
- Wearable artificial kidney
- Microelectromechanical SystemsMicroelectromechanical systemsMicroelectromechanical systems is the technology of very small mechanical devices driven by electricity; it merges at the nano-scale into nanoelectromechanical systems and nanotechnology...
- NanotechnologyNanotechnologyNanotechnology is the study of manipulating matter on an atomic and molecular scale. Generally, nanotechnology deals with developing materials, devices, or other structures possessing at least one dimension sized from 1 to 100 nanometres...
- HemodialysisHemodialysisIn medicine, hemodialysis is a method for removing waste products such as creatinine and urea, as well as free water from the blood when the kidneys are in renal failure. Hemodialysis is one of three renal replacement therapies .Hemodialysis can be an outpatient or inpatient therapy...
External links
- Tissue engineering and kidneys - umich.edu.
- BioMEMS & Nanotechnology -lerner.ccf.org/bme/mems/