Volatile Anesthetic Protection Of Renal transplants 1

Despite many achievements in transplantation the persistent shortage of
deceased donors has remained a major problem. Especially in the Netherlands, in
contrast to some other countries in Europe, the number of donor kidneys
retrieved from deceased donors has remained very low forcing transplant teams
to nowadays accept kidneys from living donors and on the other hand from older,
more marginal and non heart beating donors. As result, it is imperative that
every transplanted donor kidney ought to be treated optimally to achieve the
best possible function. During the procedure of organ donation and
transplantation a number of potentially harmful processes will occur that
affect the viability of the transplanted kidney. Both, donor and recipient are
subjected to anaesthesia and surgery, which will produce a sequence of systemic
and local changes including a significant pro-inflammatory and pro-coagulatory
response. The donor organ is by definition exposed to a period of ischaemia
which lasts until the kidney is re-connected to the circulation of the
recipient. This latter process results in a cascade causing renal damage and
associated with the phenomenon of ischemia-reperfusion injury (IR-injury).
While living donors are selected and injury will be hopefully rather small, in
deceased kidney donation significant additional injuries will occur even before
kidney removal. The inflammatory systemic and local renal response to brain
death (in the case of heart-beating donors) and the variable and often extended
period of warm ischemia and hypoxia (in the case of non heart-beating donors)
result in further impairments reducing post-transplant graft function and
survival (1)

During anaesthesia a wide range of drugs can be used during the donor and
recipient procedure. It is likely that some anaesthetic agents will modulate
some of the harmful processes described above. It is the goal of our group to
determine the optimal choice of anaesthetic agents to possibly reduce kidney
injury and thus improve post-transplant renal function and graft survival.
The systemic changes that occur in deceased donors are multiple and complex.
For this reason we will first study the influence of two common anaesthetic
regimens on IR injury in living-donor kidney transplantation (LDKT) to
establish a baseline which can be used as a best standard since living donors
of a kidney are healthy individuals selected on the basis of absence of any
disease. During the donor operation a kidney will be removed, flushed and
transplanted after a short period of preservation in a pre-selected recipient.
We consider the living donor kidney donation and transplantation as the ideal
first step as it is a standardized, controlled, procedure with reproducible
cold and warm ischemic periods, the possibility to precondition both the donor
and the recipient with volatile anaesthetics, and the absence of profound
systemic changes found in (non-) heart beating brain dead donors. The rate of
failure for this procedure defined as delayed graft function with a temporary
need for dialysis is low (<5% ref S. Feng AJT or Transplantation) compared to
kidney transplantation from brain dead heart-beating (15-25%%) and non-heart
beating donors (40-80%) since IR-injury in LDKT is limited. In LDKT the donor
procedure is assumed to be optimal with only a very short warm and cold
ischemic period and a limited inflammatory response compared with brain dead or
asystolic donors (1).
We therefore consider this study as a proof of principle and our main outcome
will define the baseline for markers of kidney injury at a molecular and
cellular level against the background of kidney function after induction of
anaesthesia and during as well as after operation and transplantation.

The primary goal of this first study is to investigate whether there is a
difference in renal protective effect against IR-injury of two representative
methods of anaesthesia in LDKT.
One group (donor and recipient) will receive a combination of the volatile
anaesthetic agent sevoflurane with intravenous opioid remifentanil or
sufentanil while the other group will receive a total intravenous anaesthesia
(TIVA) technique with the anaesthetic agent propofol and intravenous opioid
remifentanil or sufentanil.

Current evidence suggests that sevoflurane may attenuate IR injury. If our data
confirm a greater renal protective effect of sevoflurane compared to propofol,
then the results will be of interest to a wide variety of clinicians, since it
is likely that this protective effect would apply to other procedures in which
the kidneys are exposed to hypoperfusion and IR-injury (e.g. abdominal aortic
aneurysm repair and major hepatic resection).

In addition, once we have determined the influence of sevoflurane on molecular
and cellular function markers, we will then study the impact of the choice of
anaesthetic agent in (non-) heart beating deceased donation with subsequent
kidney transplantation. In that context, the information from the current study
will provide a crucial *baseline* knowledge and help with the interpretation of
changes found in more complex donation and transplantation situations.


Background:
The oldest and strongest evidence of an influence of choice of anaesthetic
agent on IR injury comes from studies of IR in the heart, where volatile agents
have been shown to have a protective effect similar to that achieved with
ischemic preconditioning (IPC).

Ischemic preconditioning:
Experimental data have demonstrated that subjecting the myocardium to brief
periods of ischemia, followed by reperfusion, protects the myocardium during a
subsequent period of ischemia. resulting in 75% (2). This phenomenon, called
ischemic preconditioning (IPC), results in significantly lower troponin T
levels and a 75% reduction of infarct size. It is associated with two phases of
protection, an early phase immediately after IPC and lasting for approximately
2 hours and a later window of protection starting 24 hours after IPC and
lasting for 3 days. Various kinds of non-ischaemic stimuli can produce a
similar tolerance to a prolonged period of ischaemia by molecular mechanisms
similar to those of IPC.

Anaesthetic preconditioning:
Experimental data have demonstrated that volatile anaesthetics, such as
sevoflurane, isoflurane and desflurane, also protect against
ischemia-reperfusion (IR) injury during cardiac surgery (3,4). This phenomenon
is called anaesthetic preconditioning (APC) and has been demonstrated in vitro
and in vivo in different animal species and in humans. A recent meta-analysis
(5) showed that in patients undergoing cardiac surgery volatile anaesthetic
agents were associated with better outcomes than with intravenous agents. These
outcome measures included cardiac index, troponin serum concentrations,
inotrope requirements, duration of mechanical ventilation and a length of
hospital-stay.

Anaesthetic preconditioning in other organs:
APC with volatile anaesthetics has also been described for other organs such as
blood vessels, lung, liver, brain and kidney (6-18) - both in vivo and in vitro
and in different animal species. Recently Beck-Schimmer et al (19) showed
significant hepatic protection with sevoflurane (compared with propofol, a
widely used intravenous anaesthetic agent) during liver resections in humans.
Clinical outcomes, such as complication rates were decreased by more than 50%
leading the authors to speculate that sevoflurane may confer potent systemic
anti-inflammatory effects.

Anaesthetic preconditioning of the kidney:
So far, the evidence for APC of the kidney is either indirect or restricted to
animal work. Ko et al (20) studied the influence of anaesthetic agent choice on
a variety of renal and hepatic function markers in patients undergoing
hemi-hepatectomy. Typically, during this procedure very conservative fluid
administration regimes are used. While this may achieve the aim of limiting
peroperative bleeding, it also jeopardises renal function if significant renal
hypoperfusion and ischemia occur. In this study, patients who received
desflurane had significantly better creatinin and glomerular filtration rate
values on the first day after surgery than those patients who had received
propofol.

In rats, Lee et al (13) showed that clinically relevant concentrations (1 MAC)
of volatile anaesthetics (sevoflurane and isoflurane) administered both during
and after renal ischemia conferred profound protection against renal IR-injury,
resulting in dramatically lower plasma creatinin levels and reduced renal
necrosis 24-72 h after injury compared with rats that received the intravenous
agents pentobarbital or ketamine.

Summarizing, these early findings suggest that volatile anaesthetic agents may
indeed protect against the IR injury that is inevitably part of organ donation
and thus that their use may improve post-transplant function in kidney
allografts.

Possible Mechanism:
Lee et al demonstrated in vitro in cultured humane renal tubule cells that
sevoflurane directly induced the phosphorylation of the cytoprotective kinases
(ERK and Akt), upregulated the cytoprotective 70-kDa heat shock protein
(HSP70), and attenuated nuclear translocation of the proinflammatory
transcription factor NF- B. They also showed that sevoflurane increases the
release of transforming growth factor-β1 (TGF-β1) in human proximal tubule
(HK-2) cells via externalization of plasma membrane phosphatidylserine (PS),
and this increase in TGF-β1 protected HK-2 cells against hydrogen
peroxide-mediated necrosis (22).

Post Conditioning
Recently, the concept of postconditioning, whereby ischemia or volatile
anaesthetics are introduced immediately upon reperfusion in an effort to
attenuate IR injury has gained increased attention (23-25,27).
Deyhimy et al (28) demonstrated that sevoflurane postconditioning, administered
when reperfusion of the myocardium starts, is as effective as preconditioning
in protecting myocardial function after global ischemia in rats. The
combination of sevoflurane preconditioning and postconditioning offered no
additional benefit over either intervention alone. Similar studies have been
performed with mixed results, Obal et al (26) were able to show an additive
benefit by combining anaesthetic pre- and postconditioning in rats.

The concept of ischemic and anaesthetic postconditioning is also demonstrated
in vitro in other organs like brain, liver and kidney.

Data of Lee et al (29) suggests that isoflurane administration during
reperfusion after an ischemic period of the brain provides neuroprotection in
rats. Recently Serviddio et al (30) demonstrated that ischemic postconditioning
significantly reduced renal functional injury and reduces mitochondria
respiratory chain impairment and protein damage in rats kidney.

In organ transplantation sometimes organs are harvested from NHB patients. In
this case the patient will receive no general anesthesia during the harvesting
procedure in contrast to HB and living donors. Furthermore harvesting
procedures often take place in other centres than the centre where the actual
transplantation is performed so factors in the pre-harvesting and ischemic
period are difficult to control by the transplant team. On the other hand
factors at the time of reperfusion like anaesthetic post conditioning can be
controlled. In this study we will also look at the concept of post conditioning
and will compare it with the combination of pre and post conditioning.

To compare the renal protective properties of two currently used anaesthetic
techniques - a sevoflurane-remifentanil/sufentanil combination with a
propofol-remifentanil/sufentanil combination for anaesthesia in patients
undergoing living donor kidney donation/transplantation. An additional third
group is added to study the level of protection when the volatile agent is
administered only during reperfusion. This reflects the actual setting of a
renal transplantation with a kidney derived from a NHB deceased donor. In this
third group the donor will receive a propofol-remifentanil/sufentanil
combination. The recipient will receive a sevoflurane-remifenatanil/sufentanil
combination.

Current evidence suggests that sevoflurane may attenuate IR injury. If our data
confirm a greater renal protective effect of sevoflurane compared to propofol,
then the results will be of interest to a wide variety of clinicians, since it
is likely that this protective effect would apply to other procedures in which
the kidneys are exposed to hypoperfusion and IR-injury (e.g. abdominal aortic
aneurysm repair and major hepatic resection).

In addition, once we have determined the influence of sevoflurane on molecular
and cellular function markers, we will then study the impact of the choice of
anaesthetic agent in (non- ) heart beating deceased donation with subsequent
kidney transplantation. In that context, the information from the current study
will provide a crucial *baseline* knowledge and help with the interpretation of
changes found in more complex donation and transplantation situations.

prospective, single blind, randomized controlled study

Donor-recipient couples are randomly allocated to
sevoflurane-remifentanil/sufentanil anaesthesia,
propofol-remifentanil/sufentanil anaesthesia or a combionation of both in which
the donor receives propofol-remifentanil/sufentanil and the recipient receives
sevoflurane-remifentanil/sufentanil. All anaesthetics regimens are being used
as standard of care for general anaesthesia. There is no experimental
intervention as such since both anaesthetic protocols are routinely used in
donor nephrectomy and LDKT.

For the purpose of this study donor and recipient couples will be asked written
informed consent together for the blood and urine samples as well as the kidney
biopsies.

the donor ; ten blood ( 100 ml total) and 10 urine ( 150ml total) samples will
be collected at different time points.

the recipient; nineteen blood (190 ml total) and 13 urine (195 ml total)
samples will be collected at different time points.

There are no significant additional risks or burden for both the donor and the
recipient. Both anaesthetic techniques are standard of care clinically applied
during living donor kidney transplantation.
The total volume of blood sampling has no clinical impact. In the donor five
ten blood samples will be drawn from the arterial line so no additional
puncture will be made. and five of the blood samples will be taken with a
routine IV puncture. These blood samples will be combined with our the routine
daily blood samples taken routinely after each kidney transplantation in our
hospital. In the recipient nine blood samples will be drawn from the arterial
line so no additional puncture will be made and ten blood samples will be taken
with a routine IV puncture. These blood samples will be combined with our the
routine daily blood samples taken routinely after each kidney transplantation
in our hospital. The extra study blood samples will thus have no additional
burden for the patient. Urine sampling has no burden or risk for both donor and
recipient and is part of the routine postoperative care for the renal
transplant patient.