Functieverlies donornier complexer
dan gedacht
Mensen bij wie de nieren niet meer werken
zijn aangewezen op dialyse, waarbij een apparaat de afvalstoffen uit het lichaam zuivert.
Een andere optie is niertransplantatie, waarvoor in Nederland ongeveer 1000 nierpatiënten
op de wachtlijst staan. De wachtlijst is lang, omdat er een gebrek is aan donoren, maar
ook omdat de helft van de getransplanteerde nieren binnen 15 jaar niet meer functioneert.
Deze patiënten komen dan opnieuw op de wachtlijst. Veel donornieren vallen uit omdat de
structuur van het orgaan verandert. Dit wordt chronische transplantaatdisfunctie genoemd.
In een getransplanteerde nier worden bijvoorbeeld de bloedvaten nauwer. Ook ontstaat
littekenweefsel in de nier. Promovenda Heleen Rienstra ontdekte dat vooral cellen uit de
getransplanteerde nier zorgen voor de vernauwing van de bloedvaten. Bij de vorming van het
littekenweefsel in het interstitium spelen echter ook cellen uit de ontvangende patiënt
een grote rol. Door de oorsprong van de cellen te kennen, kunnen in de toekomst nieuwe
therapieën tegen chronische transplantaatdisfunctie worden ontwikkeld. Ook ontdekte
Rienstra in proefdieren dat het bloeddrukverlagende geneesmiddel spironolacton de
bloedvaten in de nier beschermt, maar de vorming van het littekenweefsel elders in de nier
niet tegengaat. Verder onderzoek moet uitwijzen of spironolacton in combinatie met een
ander middel wel beschermt tegen beide structuurveranderingen in de nier.
Nader inzicht in kwaliteit
donornieren bij hersendood
Een niertransplantatie kan de kwaliteit van
leven van een dialysepatiënt aanzienlijk verbeteren. Er is echter een tekort aan
donornieren; gemiddeld staan dialysepatiënten vier jaar op de wachtlijst voordat er een
geschikte nier beschikbaar is. Een deel van de donornieren is afkomstig van hersendode
personen. Eerder onderzoek toonde aan dat door hersendood een ontstekingsreactie optreedt
in donororganen. Dit kan de kwaliteit van de organen verminderen, waardoor de kans op een
succesvolle transplantatie afneemt. Promovenda Lyan Koudstaal onderzocht schade die aan
donornieren kan ontstaan wanneer door hersendood de darm van de donor beschadigd raakt. Ze
beschrijft de ontsteking, de gereguleerde celdood en de verhoogde doorlaatbaarheid van de
darm bij hersendode donoren. Ook laat ze zien dat in de hersendode periode de hoeveelheid
ontstekingsremmend eiwit in het bloed afneemt en de hoeveelheid ontstekingsstimulerend
eiwit toeneemt. Hierdoor treedt een ontstekingsreactie op.
Veel anabolengebruikers lopen rond
met kapotte nieren
De anabolen hebben kennelijk een direct
toxisch effect op de nieren, vermoedt Herlitz. De grotere lichaamsmassa van de
bodybuilders zorgt er toch al voor dat de nieren het zwaar hebben, net als de tijdelijke
verhoging van de bloeddruk door training en het dieet met veel eiwitten.
Link
Operatierobot succesvol ingezet bij
nierdonatie
In het Erasmus MC is voor het eerst in
Nederland een succesvolle niertransplantatie uitgevoerd met de 'Da Vinci'-operatierobot.
De robot biedt nieuwe mogelijkheden om het aantal niertransplantaties in het Erasmus MC
uit te breiden. Het Erasmus MC heeft in Europa één van de grootste programma's voor
nierdonatie bij leven ontwikkeld, met momenteel ruim honderd donorniertransplantaties per
jaar. Het Erasmus MC wil vanaf 2013 230 niertransplantaties per jaar verrichten. Verdere
verbetering van de donatietechniek past in de strategie om het ongemak voor de donor zo
veel mogelijk te beperken, het aantal complicaties terug te dringen en de kosten voor de
gezondheidszorg te beperken. De Da Vinci-robot maakt het voor chirurgen mogelijk om
ingrepen op enige afstand van de patiënt uit te voeren in weefsels die weinig ruimte tot
manoeuvreren bieden. De chirurg die de robot bedient, heeft een zeer scherp
driedimensionaal zicht op het operatieweefsel. De robotarmen die door de chirurg worden
bediend, opereren zonder trillingen. Dit alles maakt zeer nauwkeurig opereren mogelijk.
Gezond weefsel rondom de nier of tumor of aangedane plek raakt hierbij zo min mogelijk
beschadigd. De houding waarin de chirurg zijn werk verricht, is meer ontspannen en
ergonomisch goed, wat de precisie van werken ten goede kan komen. Sinds dit jaar beschikt
het Erasmus MC over de robot, die behalve door de afdeling Chirurgie ook wordt gebruikt
door de afdelingen Urologie en Verloskunde en Vrouwenziekten.
Nader inzicht in werking nieren en
ontstaan nierziekten
Tienduizenden Nederlanders hebben nieren
die niet goed werken door een aangeboren afwijking, een ontsteking, een nierbeschadiging,
of als gevolg van hoge bloeddruk of diabetes. Sommige nieraandoeningen genezen of kunnen
met succes worden behandeld. Andere nierziekten kunnen nog niet goed worden behandeld.
Wynand Melenhorst verrichtte fundamenteel onderzoek naar de invloed van de genen ADAM17 en
ADAM19 op de werking van de nieren en het ontstaan van nierziekten.
Link
Study Finds Novel Genetic Risk
Factors for Kidney Disease
A team of researchers from the United
States, the Netherlands and Iceland has identified three genes containing common mutations
that are associated with altered kidney disease risk. One of the discovered genes, the
UMOD gene, produces Tamm-Horsfall protein, the most common protein in the urine of healthy
individuals. Although the Tamm-Horsfall protein has been known for almost 60 years, its
functions are not well understood and its relationship to chronic kidney disease risk was
not known previously. The findings are published in the May 10 issue of Nature Genetics.
More than 20 million adults in the United States have chronic kidney disease characterized
by reduced kidney function or kidney damage. The progression of chronic kidney disease can
lead to kidney failure and the need for dialysis or transplantation. In addition, chronic
kidney disease increases the risk of cardiovascular diseases, mortality and medication
side-effects. Known risk factors for chronic kidney disease include hypertension and
diabetes. The research team conducted genome wide association studies of more than 20,000
people enrolled in four large population-based studies of cardiovascular disease risk
factors: Atherosclerosis Risk in Communities (ARIC) Study, the Cardiovascular Health
Study, the Framingham Heart Study and the Rotterdam Study. They further replicated their
findings in another 20,000 participants. Of more than 2,500,000 genetic variants that were
evaluated for each study participant, the researchers found strong statistical evidence
supporting three genes, UMOD, SHROOM3, and STC1 as novel risk genes for reduced kidney
function and chronic kidney disease. “Previous research showed that rare mutations in
the UMOD gene cause hereditary forms of severe kidney disease. Our research indicates that
a common genetic variant with a frequency of 18 percent in populations of European
ancestry is associated with about 25 percent lower risk of chronic kidney disease,”
said the lead author of the study, Anna Kattgen, MD, MPH, a researcher in the Johns
Hopkins Bloomberg School of Public Health’s Department of Epidemiology. Researchers
at Johns Hopkins described another novel genetic variant that increases risk of kidney
disease among African Americans in a separate study last year. “We have known for a
long time that a higher level of proteins, such as albumin, which aren’t usually
present in urine, is a risk factor for kidney disease and its progression. The UMOD
finding suggests that Tamm-Horsfall protein, which is thought to be a normal part of the
urine, deserves attention since its genetic variation relates to risk. For all three genes
the findings are novel and suggest brand new areas for investigation including the need
for developing methods to measure levels in urine or blood,” said Josef Coresh, MD,
PhD, MHS, professor in the Bloomberg School of Public Health departments of Epidemiology
and Biostatistics, and the senior Johns Hopkins author on the study. “The number of
people with chronic kidney disease, including those requiring dialysis or transplantation,
is increasing,” said National Heart, Lung, and Blood Institute (NHLBI) director
Elizabeth G. Nabel, MD.
High Phosphorus Linked to Coronary Calcification in Chronic Kidney Disease
For patients with moderate chronic kidney disease (CKD), higher levels of phosphorus in
the blood are associated with increased calcification of the major arteries and heart
valves—which may contribute to the increased risk of cardiovascular disease in
patients with CKD, reports a study in the Journal of the American Society of Nephrology
(JASN). "Previous studies have found that a very high level of phosphorus in the
blood can lead to cardiovascular disease and vascular calcification in dialysis
patients," comments Bryan Kestenbaum, MD, of the University of Washington in Seattle,
Washington, one of the authors of the new study. "We are now recognizing that even a
mild increase in the serum phosphorus level is associated with cardiovascular events in
people with CKD who are not on dialysis."
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Fructose Can Be Dangerous For
Kidneys, Study Finds
Researchers from the University of Florida, led by Michael Gersch, M.D., discovered that
after six weeks, rats on a high-fructose diet (60%) had significantly larger kidneys and
more kidney malfunction than did two other groups of rats -- one fed 60% dextrose and
another fed a standard rat diet (whatever that might be).
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Simple Model Predicts Those at Risk
for Chronic Kidney Disease
Traditionally, doctors have had no clear way to predict which of their patients might be
headed down the road to chronic kidney disease (CKD). Now, researchers at
NewYork-Presbyterian Hospital/Weill Cornell Medical Center and the University of North
Carolina at Chapel Hill have created a simple eight-point risk factor checklist to do just
that. As reported in a special double issue (Dec. 8 and 22) of the Archives of Internal
Medicine, the model accurately stratifies middle-aged and older patients at high risk for
newly diagnosed CKD, which involves a gradual, even fatal loss of kidney function over
time. According to the National Kidney Foundation, 26 million American adults have CKD and
millions of others are at increased risk. "These patients are often battling
concurrent conditions such as diabetes or heart disease, so anything we can do to predict
and then lower their risk for kidney disease will be invaluable," says study senior
author Dr. Phyllis A. August, the Ralph A. Baer Professor of Medical Research at Weill
Cornell Medical College, and an internist and nephrologist at NewYork-Presbyterian
Hospital/Weill Cornell Medical Center.
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Thiamine 'reverses kidney damage'
Doses of vitamin B1 (thiamine) can reverse early kidney disease in people with type 2
diabetes, research shows.
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More kidney stone disease projected
due to global warming, researchers predict
Global warming is likely to increase the proportion of the population affected by kidney
stones by expanding the higher-risk region known as the “kidney-stone belt” into
neighboring states, researchers at UT Southwestern Medical Center and UT Dallas have
found.Dehydration is one of the risk factors linked to kidney-stone disease, and the paper
suggests global warming will exacerbate this effect. The researchers predict that by 2050,
higher temperatures will cause an additional 1.6 million to 2.2 million kidney-stone
cases, representing up to a 30 percent growth in some areas.
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Breakdown of kidney's ability to
clean its own filters likely causes disease
The kidney actively cleans its most selective filter to keep it from clogging with blood
proteins, scientists from Washington University School of Medicine in St. Louis reveal in
a new study. Researchers showed that breakdown of this self-cleaning feature can make
kidneys more vulnerable to dysfunction and disease.
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Male kidneys for men only?
New analysis of the Heidelberg “Collaborative Transplant Study”: Men and Women
benefit from gender specific transplants / Publication in “The Lancet”The gender
of donor and recipient plays a larger role in kidney transplants than previously assumed.
Female donor kidneys do not function as well in men – due to their smaller size.
Women have a higher risk of rejecting a male donor kidney. Therefore, in the future,
gender should be considered more in the allocation of donor kidneys, say researchers from
Basel and Heidelberg.These results are based on an analysis of the “Collaborative
Transplant Study”, the world’s largest database with long-term results of organ
transplants under the leadership of Professor Dr. Gerhard Opelz, Medical Director of the
Department of Transplantation Immunology at the Institute of Immunology of Heidelberg
University Hospital.
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Pioglitazone lowers cardiovascular
risk in diabetic patients with kidney disease
A new study confirms that chronic kidney disease increases the already-high risk of
serious cardiovascular events in diabetic patients with damage to the large blood vessels
and suggests that treatment with the antidiabetic drug pioglitazone may help to lower this
risk, reports the January Journal of the American Society of Nephrology.
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Link between chronic kidney disease
and oxygen-deprived tissue
Researchers at the University of Pennsylvania School of Medicine have discovered how
low-oxygen conditions can worsen chronic kidney disease. The key player is a protein
called hypoxia-inducible-factor that, as its name suggests, is active when the kidney does
not get enough oxygen, a condition known as hypoxia.
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Receptor protein appears to be key
in breakdown of kidney filtration
Massachusetts General Hospital researchers have identified a new molecular pathway that
appears to be involved in urinary protein loss, an early-stage kidney disease thet affects
100 million people around the world, and is caused by a breakdown in the kidney's
filtering structures.
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Kidney function discovery sheds
light on genetic complexity of disease
To find a cure for cancer, haemophilia and other diseases, researchers need to be looking
for complex, interacting genetic factors, according to the authors of a new study. A new
study, published in the Journal of Clinical Investigation by researchers at the Centenary
Institute, Royal Prince Alfred Hospital (RPA) and The Australian National University
(ANU), has exposed a greater level of genetic complexity for diseases than was originally
thought. The researchers looked at two disorders of kidney function - iminoglycinuria and
hyperglycinuria. These disorders, first described 50 years ago, are conditions where large
amounts of individual amino acids (the building blocks of proteins in our body) are wasted
by the kidney. Professor John Rasko, Head, Gene and Stem Cell Therapy program at Centenary
Institute and Cell and Molecular Therapies at RPA, says although up to one in every
thousand babies has this disorder at birth, it usually resolves in the first year of life.
For those individuals in whom it continues to occur, it is generally thought not to cause
medical problems but previous cases have been linked to high blood pressure, kidney
stones, deafness and problems in the brain. "Iminoglycinuria was observed to occur in
families and the pattern of inheritance suggested that the cause might be due to an
inherited abnormality of a specific pump on the surface of kidney cells," Professor
Rasko explains.
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Early indicator of kidney disease may
also predict risk of pre-diabetes
A blood component called cystatin C, used to test for early-stage kidney impairment, also
may be a very early marker for those at risk of developing a condition known as
pre-diabetes, a study conducted by researchers at the University at Buffalo has shown.
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Kidney disease test may also mark
diabetes
U.S. medical scientists have found a blood marker used to predict early kidney impairment
might also mark a condition known as pre-diabetes.
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A gene that protects from kidney disease
Researchers from the European Molecular Biology Laboratory and the University of Michigan
have discovered a gene that protects us against a serious kidney disease. In the current
online issue of Nature Genetics they report that mutations in the gene cause
nephronopthisis (NPHP) in humans and mice. NPHP is a disease marked by kidney degeneration
during childhood that leads to kidney failure requiring organ transplantation. The
insights might help develop effective, noninvasive therapies.
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Combination therapy stops loss of kidney
function in rare genetic disease
A combination of two types of blood pressure-lowering drugs -- an angiotensin-converting
enzyme inhibitor (ACEI) plus an angiotensin-receptor blocker (ARB), added to enzyme
replacement therapy (ERT) with agalsidase-beta (Fabrazyme, Genzyme Corporation, Cambridge,
Mass.) -- is the first treatment shown to stop progressive loss of kidney function in
patients with severe kidney involvement due to the rare genetic disorder Fabry disease,
reports a study in the September Journal of the American Society of Nephrology.
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Fish oil may help kidney disease
sufferers
A new study by the Queensland University of Technology in Brisbane, Australia, is
investigating if fish oil can help kidney disease sufferers and decrease the inflammation
often associated with dialysis.
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Chinese medicinal compound stops
formation of cysts in polycystic kidney disease in lab
Using a compound from a centuries-old Chinese traditional medicine, Yale University
researcher Dr. Craig Crews has been able to prevent the formation of kidney-destroying
cysts in a mouse model of polycystic kidney disease.
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