Kidney transplant in a dog: indications and procedures [veterinarian's recommendations
Kidney transplant in a dog
Transplantology is a relatively new and constantly developing branch of medicine.
The first reports of attempts at transplantation are recorded at the turn of the 19th and 20th centuries, along with the development of surgery, the pioneers of this field began to think about the "replacement " of defective, deformed and non-functioning organs.
It was nephrologists who took the first steps in transplantology. Initially, attempts were made to replace the non-functional kidneys with artificial devices - patients were detained in "dialysis rooms ", where under special conditions, appropriate temperature and humidity of the room, their blood was filtered through kilometers of tubes for many hours.
The devices themselves were loud and inefficient in their work. The first successful kidney transplant was performed on December 23, 1954 in Boston. The donor was the patient's twin, which significantly contributed to the success of the procedure. The first successful kidney transplant in Poland was performed on January 26, 1966.
In veterinary medicine, transplantology, as a form of therapy for sick animals, has so far remained in the area of theoretical considerations.
Yes, corneal transplants are performed all the time when it comes to its complete degeneration and severe ulceration, or skin grafts from other parts of the body, in the case of extensive injuries, burns or severe infections. Moreover, it was animals (mainly dogs and calves) that were tested before surgical interventions on humans.
However, a whole organ transplant is a very controversial issue.
Kidney transplant surgery is quite popular in the United States - most of the available publications on kidney transplants refer to procedures performed in this country. Based on them, it can be concluded that transplants are much more effective in cats and humans than in dogs.
At the time of writing this article, one kidney transplant has been performed and documented in Poland. This treatment touched the community of veterinarians across the country and sparked an emotional discussion regarding ethical and moral doubts as to the rightness of the procedure. In the following article, I will introduce you to a dog kidney transplant.
- Kidney functions
- Indications for kidney transplantation
- The process of selecting an appropriate donor
- Dog kidney transplant preparation for surgery
- How does a kidney transplant run in a dog?
- Recommendations after surgery and care
- Ethical dilemmas
- Is dog kidney transplant treatment of the future??
The kidneys are a very important organ for the proper functioning of the human and animal body. The main function of the kidneys is to filter the blood and remove excess urea, creatinine and waste products from it.
The kidneys also affect the amount of body fluids, remove excess water from the body.
In addition, they perform secretory functions - erythropoietin produced by the kidneys stimulates the production of red blood cells. They are a very important organ that maintains the acid-base balance of the body. Thanks to them, it is possible to maintain a constant, normal blood pressure.
Blood tests can be used to monitor the effectiveness of kidney function - the basic parameters that are used to assess the effectiveness of kidney function are creatinine and urea.
Unfortunately, these parameters are not specific only to the kidneys - they may increase, for example, in the case of cardiological diseases, dehydration, but also strong physical exertion before the examination. Moreover, creatinine increases only when 75% of the kidney parenchyma is destroyed. At a time when most of the organ is not working properly, it is hard to stop the further degeneration of the kidney parenchyma.
The levels of ions - phosphorus, sodium, potassium and calcium are also important in the diagnosis of kidney diseases.
Any disturbances and raising individual parameters are an indication for in-depth diagnostics.
Urinalysis can also provide many answers as to how well your kidneys work. The presence of protein, an impaired protein to creatinine ratio, insufficiently concentrated urine, or the presence of renal epithelia may indicate organ damage.
A relatively new test that allows for early detection of renal failure is SDMA. It is an index of kidney function and correlates with the renal filtration rate. This test is very sensitive, its result is not influenced by non-renal factors (unlike urea and creatinine).
SDMA increases with damage to as much as 25% of the kidney parenchyma, which enables early implementation of appropriate therapy. SDMA testing should be performed in dogs (and cats) at high risk of renal failure. It is worth repeating them once a year as part of monitoring your pet's health.
30-40% of the kidney parenchyma is enough for the proper functioning of the body. Renal failure is when 85% of the organ's parenchyma is destroyed. This means that ¼ of the kidney is enough for most of the biochemical parameters to remain unchanged.
With so many functions important to your health, kidney failure appears to be a problem that makes your life considerably more difficult.
That's right - dogs suffering from kidney failure, depending on the severity of the disease, have different and varying degrees of clinical symptoms. Starting from decreased appetite, through recurrent bladder infections, hypertension, damage to the heart muscle, fast fatigue, greater thirst, reluctance to exercise, non-regenerative anemia, disturbances in ionogram, convulsions, ending with erosions on mucous membranes, dental or ophthalmic problems - kidney failure affects all organs and the efficiency of the entire body.
Indications for kidney transplantation
Taking into account the numerous functions of the kidneys, one can only imagine how much discomfort an animal suffering from renal failure feels.
The indications for kidney transplant surgery are primarily their advanced insufficiency, i.e. a condition where more than 90-95% of the kidney parenchyma does not work properly.
The candidate must not show any other chronic diseases - he must not have cardiological problems or diabetes. Urea and creatinine levels should be balanced before surgery - animals very often require regular fluid therapy or dialysis to improve their health.
An indication for the transplant procedure may also be congenital malformations of the kidneys.
An example is polycystic kidney disease. This condition is much more common in cats than in dogs, but it doesn't mean that dogs cannot suffer from it.
Renal dysplasia, hypoplasia, or hydronephrosis may also be indications for surgery. Hereditary juvenile kidney failure, caused by collagen defect, is a very common condition in cocker spaniels and may also be an indication for transplant.
Kidney agenesis, i.e. the congenital absence of one kidney, may not show any clinical symptoms for many years of the animal's life - the other kidney takes over its work perfectly. However, when the parenchyma of the only kidney is damaged, any symptoms of failure develop very quickly. Again, the need for a kidney transplant may be considered.
Keepers must be aware that the animal will require regular checks and medication, practically for the rest of the animal's life. The transplanted kidney is at the same risk of damage to the parenchyma and the development of failure.
Caregivers should strictly follow any nutritional recommendations and treat the transplanted dog like a dog with initial organ failure.
The process of selecting an appropriate donor
The chances of receiving a transplant increase when the kidney donor is related to the recipient - ideal when it comes from the same litter. In such cases, the possibility of the transplant being rejected by the recipient's organism is the lowest.
However, it is quite difficult to implement, especially if the recipient is an adopted dog of unknown pedigree.
It is important that the donor has the same blood type as the recipient, confirmed not only by the blood type (DEA 1.1, 1.2, 1.3, 4, 5 and 7), but also testing for the presence of anti-DEA antibodies.
The donor should be of a similar size and build as the recipient.
Before the procedure, the health of the donor should be checked. The dog should have an extended blood test that includes not only blood count and biochemistry, but also:
- determination of coagulation factors,
- extended liver tests,
- determination of the activity of thyroid hormones,
- SDMA mark.
In addition, he should have an abdominal ultrasound, chest X-ray and cardiological examination to make sure that the procedure will be as safe for him as possible.
Any deviations from the norms or noticed disturbances in biochemical parameters (especially urea, creatinine and SDMA) disqualify the donor.
Dog kidney transplant preparation for surgery
Preparing the recipient for the transplant procedure is quite a long process. The dog must be in the best possible condition, so fluid therapy is very often introduced (to reduce the elevated levels of urea and creatinine and to compensate for possible electrolyte disturbances), the doses of drugs lowering the phosphorus level are increased.
The level of urea, creatinine and phosphorus should be regularly controlled and compacted to levels within the recommended standards for the dog of the given breed and age.
The dog should have cardiological examinations - as I mentioned at the beginning, the kidneys also affect the regulation of blood pressure, so their failure can cause significant fluctuations in peripheral pressure. It has an impact on the work of the heart muscle.
If cardiac disturbances are detected, appropriate treatment is needed. In addition, a patient eligible for transplant should have tick-borne disease tests - many of them may survive in the dormant phase for many years and become noticeable when the body is strongly weakened, for example after kidney transplant surgery.
You should also make your pet back and update its vaccinations against infectious diseases, because immunosuppressive drugs taken after the procedure will certainly adversely affect the susceptibility to infectious diseases.
All these procedures are aimed at reducing complications after the surgery, maximum strengthening of the body, bringing the dog to the best condition and thus increasing the chances of receiving a transplant.
Before the kidney transplant procedure, the recipient dog must take not only preparations supporting the kidneys and prescribed cardiological drugs. It is equally important to take medications that will make it easier to accept the transplant.
These are immunosuppressive drugs. They must be used so that the body does not reject the kidney as foreign tissue.
The main drug used before the procedure is methylprednisolone or prednisolone. The dose during the procedure and before it is much higher than the dose after the procedure, so as to saturate the body with the preparation and reduce the chance of rejection. Other drugs that can be used are cyclosporine and azathioprine, in various combinations and schedules, selected by the doctor, based on the patient's health status analysis.
Before the procedure, it is also important to properly hydrate the dog and to compensate for any disturbances in the ionogram. The most commonly used are lactated Ringer's or multi-electrolyte fluid, depending on the results of your blood test. Adequate hydration is also conducive to the acceptance of the transplant, it ensures a better chance for the optimal functioning of the transplanted kidney.
How does a kidney transplant run in a dog?How does a kidney transplant run in a dog?
After all procedures to prepare both dogs for surgery, all renal parameters of both animals are checked on the day of surgery, just before the surgery. Both patients, the donor and recipient, must be fasting, and water is withdrawn a few hours before the procedure.
The first stage of the procedure is the collection of a kidney from a donor. Nephrectomy is performed after administering an appropriate dose of mannitol (to lower blood pressure and reduce the possibility of hemorrhage during the procedure).
Immediately after removing the kidney, the organ is transferred to a sterile solution of cold, heparinized physiological fluid.
The vessels are also gently and carefully rinsed with heparinized physiological fluid until the donor's blood is completely rinsed out. The kidney vessels are closed end-to-end for dogs weighing less than 10 kilograms. In larger animals, closure of the renal artery to the aorta and the renal vein to the caudal vena cava are used.
It is very important to properly secure the delicate ureter from the removed kidney.
Kidney implantation for the recipient is an equally complicated process. Before organ transplantation, the kidney is gently and carefully warmed up. It is implanted slightly more caudally. Failed kidneys are not removed! Make sure that the vessels are properly sealed and ensure blood flow at the same time. The transplanted kidney should start working just minutes after blood flow begins.
After the procedure, both patients should be adequately protected against pain. Sources say it's best to start administering the right measures before making the first cut, to avoid even pain and discomfort.
Morphine, fentanyl and methadone are recommended in doses adjusted to the body weight of patients, either by continuous infusion or at appropriate intervals. Medicines cannot stop working - the pain after kidney removal and transplantation is very strong.
Recommendations after surgery and care
Immediately after the dog's kidney transplant surgery, the amount and quality of urine should be monitored. Both patients should have a urine test every day, as well as urea and ionogram determinations, to quickly spot any anomalies that indicate post-treatment complications.
Both patients should have their blood pressure, heart rate, respiration, and neurological reflexes monitored regularly.
When it comes to medications used after the procedure, both patients should first of all have properly selected painkillers. It is worth considering the use of antibiotics, especially in the recipient - immunosuppressive drugs may weaken the natural immunity of the animal and increase the susceptibility of the weakened organism to possible infections.
Food intake should be monitored and, in the event of a strong aversion to food, insertion of an oesophageal or gastric tube should be considered to enable feeding patients. The regular administration of immunosuppressants in the recipient of the organ should also be followed.
As I mentioned, the recipient dog (as well as the donor dog) requires regular check-ups after the procedure - initially every day, then once a week, once every two weeks. They must not be neglected in order to catch any deviation from the norm at the earliest level.
What's more, you should follow the administration of drugs prescribed before the kidney transplant procedure - preparations that lower phosphorus levels, and drugs recommended by a cardiologist.
Both the donor and recipient should go on a low-protein diet so as not to overburden the kidneys.
Transplantology has always aroused great emotions, not only among doctors, fascinated with new methods of treatment, but also among ethics. Where is the border between saving lives and improving functioning, and persistent therapy? How much this limit can be exceeded if the animal's life is saved?
The basic dilemma faced by the team of doctors and the caregiver is the donor's "consent".
Human transplantation uses organs taken with the consent of the donor, or in the event of death, with the consent of the family or an authorized person. But how to get approval in the case of an animal?
The animal is not aware that it is saving another life, it is unable to understand the suffering after surgery, discomfort due to stitches, convalescence in the name of saving another life. Isn't it sacrificing one animal for the sake of another?
Further life of the donor
Another dilemma that must be faced is the future of the donor's life.
What if the donor left behind, the only kidney will cease to fulfill its functions?
Under physiological conditions, one fully functional kidney is enough to maintain the good quality of the animal's functioning, as I mentioned at the beginning of the article, efficiently functioning 25% of the kidney parenchyma is enough for the body to function properly. However, a donor animal that does not voluntarily have only one kidney may be doomed to a developing failure, resulting in numerous systemic diseases, examples of which are listed above.
"Return " the kidney is out of the question if it serves the recipient efficiently, saving his life. However, whether the donor should become the recipient? Should a decision be made to search for a donor or implement palliative therapy and wait for the end of the animal's life??
Who should take care of the donor animal?
In publications from the United States, I found information that when performing the kidney transplant procedure, the caretakers of the recipient dog sign a commitment (under penalty of a fine) to care for the donor dog for life.
The kidney transplant procedure in a dog, carried out in Poland, which I mentioned at the beginning of the article, resulted in a discussion about animals living in shelters for homeless animals. The donor was then adopted from the shelter, some time after the adoption, a kidney transplant was performed.
There were voices saying that one kidney is a small price to pay for a loving home.
However, is it ethical? It is ethical to adopt or buy an animal just to donate a kidney to a pet? Is it ethically and morally permissible to adopt or buy an animal that is tissue compatible with your pet??
This leads to the conclusion that shelters for homeless animals could be used as a kind of replacement organ farms, or shops where you can choose a "new " dog to be "compatible " with a pet suffering from kidney failure and became an emergency organ storage.
What if the kidney obtained during the transplantation ceases to fulfill its function?
It happens that despite the use of appropriate care, regular use of medications and diet, the kidney function gradually weakens, and the transplant may be rejected, which is quite common in dogs. Failure may then develop again.
Should re-kidney transplantation or rather palliative therapy be considered in such a situation?? Who should make such a decision - the caregiver, the treating physician or the team performing the kidney transplant procedure?
Who should decide about the feasibility of the procedure?
It is known that renal failure can take many stages and the boundary between them is not strictly and clearly defined. Should we wait for the development of stage IV failure, or is it better to start looking for a donor in the early stages? When should no other treatments be considered effective and the patient is eligible for a transplant? Should it be performed immediately after diagnosis of an incurable disease??
These are also difficult topics to deal with when considering the issue of kidney transplantation.
What about organs removed after the animal's death?
Who should decide whether or not tissue should be harvested this way? Won't these considerations push the more determined caregivers to decide on adoption and subsequent euthanasia of the animal in order to obtain a kidney for their beloved pet? It is known that a dog is a family member, not just an animal, so many caregivers are able to bear all the difficulties and costs just to save or extend the life of a beloved pet.
As you can see for yourself, there are many dilemmas about kidney transplant surgery. Unfortunately, there are no clear answers to the questions I asked above, but every caregiver and doctor should think about it before deciding to look for a dog kidney transplant.
Is dog kidney transplant treatment of the future??
As I mentioned at the beginning of this article, most kidney transplant procedures are performed in the United States and most of the publications available on kidney transplantation come from this country.
Kidney transplantation is very common in humans and has a good chance of success in cats. However, doctors are arguing whether this is an appropriate method of therapy for dogs - it carries a high risk of failure.
In 2011, an analysis of 26 cases of dogs whose owners decided to transplant a kidney for their pet was carried out.
40% of patients survived one month after the procedure. Only one dog lived 9 years after the transplant.
The most common cause of dog death after kidney transplant surgery was blockage caused by blood flow disorders.
6 dogs died from severe infection after treatment. It is a very difficult complication to treat - in order to control the infection, immunosuppressants should be discontinued, which in turn increases the risk of transplant rejection.
Another 3 dogs failed the kidney transplant for unknown reasons.
The publication I mentioned does not include any data on donor dogs.
The data on the survival of cats after kidney transplantation look much better and more optimistic - as many as 65% of patients survive six months after the surgical intervention.
Considering the risk, any moral dilemmas and the high frequency of failure, it is worth considering whether a kidney transplant should be used as a therapy method for dogs with renal insufficiency.
Sources used >>