With the improvement of tissue matching technology, improved organ preservation technology, skillful transplantation surgery, combined clinical application of new immunosuppressive agents, and rich experience in postoperative management, kidney transplantation has become the most successful and fundamental clinical treatment for end-stage renal disease today. However, the shortage of donor kidneys is still the main obstacle to kidney transplantation, and many patients with end-stage renal disease die while waiting for transplantation, so increasing the source of donor organs is a hot issue of common concern.
I. Review and status of living relative donor kidney transplantation
Since December 23, 1954, Murray et al. performed the first successful kidney transplant between a pair of identical twin brothers, pioneering the first major non-therapeutic procedure performed on a healthy individual in medical history. Currently, living relative donor kidney transplantation occupies a considerable importance in Europe and the United States, and the transplantation results are superior to those of cadaveric kidney transplantation. According to the United States National Network Organ Allocation Center (UNOS) from January to November 2005, 15,209 kidney transplants were performed in the United States, of which 6,021 were living transplants, accounting for 39.6% of the total number of transplants. China’s relative living donor kidney transplantation started late and developed slowly. According to the Chinese Journal of Organ Transplantation Registry, from 1972 to the end of 2005, a total of 539 cases of living relative donor kidney transplantation were performed nationwide, which is less than 1% of the total number of kidney transplantation. In recent years, domestic scholars have done a lot of work on living relative donor kidney transplantation, and the number of living relative donor kidney transplantation has been increasing year by year.
The advantages of living relative donor kidney transplantation
Living donor kidneys are mostly derived from relatives or spouses who are related to the recipient within three generations, and living donor kidney transplantation has the following advantages.
1. elective surgery is possible: adequate preoperative preparation and shorter waiting time for kidney donation
2. shorter heat and cold ischemia time for living donor kidneys compared to cadaveric donor kidneys
3, good transplantation results: most living donors have good histocompatibility of HLA mating due to blood relationship, low incidence of postoperative rejection, less dosage of immunosuppressive agents after transplantation than after cadaveric transplantation, and less cost required for treatment.
4. Pre-operative induction of donor-specific immune tolerance in the recipient: if pre-transplant pretreatment can be given to the recipient, such as immunosuppressants, donor-specific antigen infusion to the recipient (blood transfusion, bone marrow cell transfusion or hematopoietic stem cell transfusion), it is more conducive to long-term high-quality survival.
III. Evidence-based medical evidence for the safety of a healthy donor kidney donor on one side
There are approximately 1.7 to 2.4 million kidney units on both sides of the kidney in a normal human. Clinically, renal failure and obvious symptoms occur when glomerular damage reaches 60% or more. Physiologically speaking, a normal healthy person donating one kidney is equivalent to a reduction of about 50% of kidney units, and the donor still has 10% reserve and emergency capacity, which is theoretically safe. Clinical practice shows that.
1. a large number of patients with end-stage renal disease have normal long-term transplanted kidney function after kidney transplantation, while patients with congenital isolated kidney have normal long-term kidney function, which proves that one kidney is fully capable of meeting normal physiological needs.
2. Long-term clinical observation of bulk cases of removal of one kidney due to renal tumor, traumatic renal rupture, complex renal stone, polycystic kidney, etc. shows that the incidence of renal failure and mortality are not higher than those of normal control population.
IV. Ethical principles of living relative donor kidney transplantation
In living donor kidney transplantation, there are seven principles that must be observed in order to ensure the results: the principle of “no choice but to do so”; the principle of informed consent; the principle of absolute voluntariness; the principle of life autonomy; the principle of “no harm from above”; the principle of benefit; and the principle of mutual benefit. The most important of them are the principle of absolute voluntariness and the principle of life autonomy. The donor should be a citizen over 18 years of age with full autonomy and free from persuasion and pressure from within or outside the family to make the final decision to donate voluntarily. Doctors should consider the selection of donors and recipients from an immunogenetic perspective: identical twins are preferred, followed by siblings, parents and children with two HLA haplogroups, followed by siblings with one HLA haplogroup, followed by siblings with no HLA haplogroup, and followed by those who are distantly related. In China, the current stress is to promote “self-help within the family” program, not to promote non-relative living donor, the reasons are.
1. Given the current situation in China, non-relative living organ donation can easily give way to organ trading and crime.
2. Medical institutions do not have enough human resources to examine, detect and track the identity and true motives of non-relative living donors.
3. The health insurance and social welfare systems are inadequate to systematically protect the long-term health and interests of non-relative living, voluntary, non-remunerated donors. In other words, non-relative living organ donation cannot be carried out before the health benefit protection mechanism of donors is sound. For a very small number of long-term strong requests should be strictly approved by the relevant medical ethics committee to ensure that the strong will of the non-relative living donor can be realized.
V. Assessment of the kidney donor.
Including clinical medicine and psychology, the clinical aspects include the general health status of the donor, routine transplantation examination, renal function and imaging, especially bilateral renal arteriovenous examination is crucial for the selection of the donor kidney, the design of the vascularization for kidney transplantation and the reduction of the risk of kidney donor surgery. Multi-layer spiral CT vascular 3D imaging and magnetic resonance angiography (MRA) are more advantageous than invasive renal artery angiography or digital subtraction angiography (DSA). As for the selection principle of right and left kidneys, it is based on isotope renal dynamic examination to assess the glomerular filtration rate of both donor kidneys, and the better kidney will be reserved for the donor.
VI. Immunosuppressive regimen
As with cadaveric kidney transplantation, the majority of transplant centers still use a triple therapy based on the calcium phosphatase inhibitor cyclosporine A or tacrolimus + enzyme phenolate + prednisone. Due to the immunological advantage of the relative donor kidney, the dose of most centers or Fk506 is lower than in the regimen of cadaveric kidney transplantation.
VII. Enhancing long-term donor follow-up
Most of the long-term follow-up data abroad are currently incomplete, but the reported data show a low risk of deterioration of renal function associated with donor kidney removal. We have not yet seen any literature reports in this regard. Although the recent recovery of living relative donors has been smooth, strengthening long-term follow-up is both responsible for the donor and can accumulate scientific data information in our country in terms of long-term observation of the donor’s renal function, hypertension, and proteinuria.