Research into treatments for feline kidney disease is
ongoing. Few studies are geared specifically towards cats, but findings
from studies into humans or other species such as mice may eventually have
applications for cats.
It must be emphasised
that much of the research discussed below is in its very early stages, and
may turn out to be either unsuitable generally or for cats (who have
unique physiological needs) in particular; and any treatments that turn
out to be feasible may not be available for many years, if at all,
with stem cell
transplants and the use of pimobendan being the only exception.
Therefore this page is
provided primarily for informational purposes: please do not pin your
hopes on any research described herein. In particular,
if your cat is critically ill, don't bother with this page but instead
please focus on the proven treatments outlined on the
Key Issues page.
A 2004 study
demonstrated that adult stem cells may assist with repairing damaged
kidneys in mice. Adult stem cells were taken from the muscle tissue of
healthy mice and cultured. Following implantation into mice with damaged
kidneys, the cells formed new blood vessels and appeared to improve kidney
function.
A number of cats have now received stem cell treatments
at Colorado State University College of Veterinary Medicine. Both Colorado
State University and The Animal Medical Center in New York City are both currently offering free stem
cell transplants to a small number of suitable recipients. Please see
the
Treatments section for more information on stem cell transplants in
cats, and the
Research Participation Opportunities page for more information on the
criteria for taking part in the research.
If
you would like to help fund stem cell research into feline CKD, Deborah,
human of Frankie, a Siamese cat, has set up a programme at Colorado State
University College of Veterinary Medicine. You can read more about
Frankies Fund here and make a donation
here.
Pimobendan
Pimobendan (Vetmedin)
is a heart medication commonly used in dogs. It belongs to a family
of drugs known as imodilators, and is usually used in conjunction
with other heart medications. It appears to be particularly
effective in cases of
congestive heart failure.
Like many
medications, pimobendan is not licensed for use in cats but has been
widely used off label.
Use of pimobendan in 170 cats (2006-2010)
(2011) MacGregor JM, Rush JE, Laste NJ, Malakoff RL, Cunningham SM,
Aronow N, Hall DJ, Williams J, Price LL Journal of Veterinary
Cardiology13(4) pp251-60 found that pimobendan seemed to be effective
in cats with advanced heart disease and congestive heart disease when used
in conjunction with other heart medications.
Effect of pimobendan on the clinical outcome and
survival of cats with non-taurine responsive dilated cardiomyopathy
(2012) Hambrook LE & Bennett PF Journal of Feline Medicine &
Surgery14(4) pp233-9 found that cats with this type of heart
disease who received pimobendan lived for four times as long as cats not
given pimobendan.
In 2010, a
member of Tanya's CRF Support Group whose cat had both CKD and heart
problems was prescribed pimobendan by a vet school. Her cat did very well
on it.
The Winn Feline Foundation reports on a
new study to investigate the use of pimobendan to help cats with CKD. The
researchers have already found it helpful in previous studies for cats who
developed congestive heart failure following
intravenous fluids.
They found that pimobendan not only helped with the heart problems, but
the cats' kidney values also improved. The new study will be researching
this further in a larger group of cats.
Bone
morphogenetic protein 7 (BMP-7) is a protein used to repair bone in
humans. Recent research in mice indicates that BMP-7 may be able to repair
damaged kidneys and even reverse kidney disease. No research on cats has
taken place to date, but human recombinant BMP-7 was used to treat the
mice in the recent research, with promising results.
BMP-7 is
already approved by the FDA for the treatment of broken bones in humans in
the USA, so these findings should lead to further research into the kidney
angle and may eventually lead to a way of controlling and even curing CKD,
although it is very early days as yet so please do not get your hopes up
too much.
I regularly
hear from people desperate to try BMP-7 on their cats. Unfortunately, this
is not currently an option unless you are a millionaire. When used in
orthopaedic surgery, BMP-7 is distributed in sponge form. However, for
kidney treatment, this form is not usable; instead the pure protein form
of BMP-7, suspended in a carrier liquid, is required, and this is
infinitely more expensive. A couple of people I know looked into obtaining
this form of BMP-7, only to discover it would cost in excess of US$142,000
a month to purchase the amount required for a 10 lb (4.5 kg) cat. The
price may fall as BMP-7 is used for humans with kidney disease, but
unfortunately this may well take some time. Since BMP-7 is a human
product, it is also possible that a cat might develop antibodies to it.
β/activin signaling in renal epithelia (2006)
Lin J, Patel SR, Wang M & Dressler GRMolecular and Cellular Biology 26(12) pp4577-4585
concludes that KCP "may play an important role in mediating the
signalspecificity between competing inputs in the initiation
and progressionof renal disease."
Research is to
be undertaken into what role KCP could play in helping humans with kidney
disease.
Renalase
It has long been known that the kidneys regulate blood
pressure by producing a hormone called renin. Recent research,
Renalase is a novel, soluble monoamine oxidase that
regulates cardiac function and blood pressure (2005) Xu J, Li
G, Wang P, Velazquez H, Yao X, Li Y, Wu Y, Peixoto A, Crowley S, Desir GV
The Journal of Clinical Investigation115(5) pp1275-80, has
discovered renalase, a monoamine oxidase that breaks down catecholamines,
such as adrenaline and dopamine, and which therefore appears to have a
role in regulating heart contraction and blood pressure.
Renalase is
secreted by the kidneys and circulates in the blood. Patients with kidney
disease have been found to have very low levels of renalase, presumably
because the kidneys can no longer produce it efficiently. In human
patients with
end stage renal
disease (ESRD), this probably plays a role in the build up of
adrenaline, which in turn may then lead to heart disease, a common cause
of death in humans with ESRD.
It is therefore hypothesised that injecting renalase
might help those with kidney disease by replacing the missing renalase.
Researchers compared this to giving
erythropoiesis stimulating
agents such as Epogen
to severely anaemic patients whose kidneys can no longer produce
erythropoietin. It is possible that
Renalase might also be of use in treating heart disease.
L-arginine is an
amino acid which is used to make
nitrous oxide in the kidneys. It is thought that nitrous oxide plays a
critical role in regulating blood flow through the kidneys, and it is
known that the amount of blood flowing through the kidneys can affect
kidney function. L-arginine levels are often very low in CKD cats, so it
is possible that supplementing this might increase nitrous oxide levels
and thus help kidney function.
Telomeres are specialised
protective structures locatedat the ends of
chromosomes. The DNA component of telomeresgradually shortens with age and eventually becomes too short to
allowprotective structures to form and signal
the cell to stop dividing. This process is called cell senescence.
In a study sponsored by the Morris Animal Foundation, researchers
at Colorado State University are going to
investigate the role of cell senescence in the development of feline CKD. Using aseries of tests, they will compare measurements of cell senescence
in deceased CKD catsand deceased cats who did
not have CKD.
They hope this may help lead to further treatment options for CKD.
This research requires the bodies of deceased cats, so,
although this is a difficult thing to
contemplate, some people might like to consider donating their
cat's body to Colorado State University.
This would allow them to take a few small
samples afterdeath to help learn more about
kidney disease. The ashes of the deceased cat would be returned to owners
about a week later. See the
Research Participation Opportunities page for more information.
Implantable
Artificial Kidney
UCSF
unveilsmodelforimplantable
artificialkidneytoreplacedialysis
is a report on a new artificial kidney for humans developed by the
University of California San Francisco. It is currently too large to be
implanted, but it is hoped the implantable version will be ready for
clinical trials in 2015-2017.
Bardoxolone (RTA402)
A drug called bardoxolone methyl, an
antioxidant, has been found to reverse the decline of kidney function
commonly seen in diabetics. In a trial of 227 human patients,
Bardoxolone methyl and kidney function in CKD with
type 2 diabetes
(2011) Pergola PE, Raskin P, Toto RD, Meyer
CJ, Huff JW, Grossman EB, Krauth M, Ruiz S, Audhya P, Christ-Schmidt H,
Wittes J & Warnock DG New England Journal of Medicine365(4)
pp327-36, it appeared to improve kidney function by about 30% over
a year.
Neutrophil Gelatinase-Associated
Lipocalin (Ngal) or Siderocalin
Research on mice indicates that a protein called
neutrophil gelatinase-associated lipocalin (Ngal) may be of use against
acute kidney
injury (AKI). Large amounts of Ngal are found in blood, urine and
kidney tissue at the onset of AKI, which means it could be
helpful for diagnosing AKI at an early stage.
It is thought that Ngal is produced by the body during
AKI in an attempt to protect the kidneys, but in many cases it is produced
too late to prevent damage. If Ngal were to be injected earlier, it
might also be able to prevent damage from occurring. It is expected that human
trials of Ngal will begin shortly.
Overview of biomarkers in acute kidney injury
(2012) Segev G Presentation to the Advanced Renal Therapies
Symposium, NYC, reports on using Ngal and other markers to detect
AKI more quickly (go to page 12).
Studies indicate that a drug called fenoldopam may
be of some use in treating cats with
acute kidney
injury (AKI). Cats suffering from AKI may exhibit oliguria (limited
urine output). Dogs and humans with this problem are usually treated with
a drug called dopamine, but this has not been particularly effective in
cats because they have fewer receptors for this drug.
Diuretic effects of fenoldopam in healthy cats
(2006) Simmons JP, Wohl JS, Schwartz DD, Edwards HG & Wright JC Journal
of Veterinary Emergency and Critical Care16(2), pp96–103,
found that fenoldopam
, which is normally used to treat severe
hypertension in humans, appears to increase blood flow and urine output in
healthy cats. Further studies are needed to see if it has the same effect
on cats suffering from AKI.
If
you would like to help fund stem cell research into feline CKD, Deborah,
human of Frankie, a Siamese cat, has set up a programme at Colorado State
University College of Veterinary Medicine. You can read more about
