The PEPaNIC long-term outcome study: Neurocognitive developmental deficit
after critical illness in children: role of modifiable epigenetic changes

Rationale: Even after discharge from the hospital these children often continue
to suffer from morbidity for years, with impaired neurocognitive development
and reduced quality of life as the main problems. This *legacy* of critical
illness carries an enormous burden for the patient, their family, the
healthcare system and society in general. Nutritional support strategies
(tolerating caloric deficits versus aggressive nutritional support in the PICU)
may play a role in this legacy of critical illness. Controlling blood glucose
to fasting normoglycaemia has recently been shown to improve (neurocognitive)
outcome in critically ill children 4 years after ICU admission. This tight
blood glucose control provoked autophagy and a fasting response in the
thyrotropic and somatotropic axes, which related to improved outcome. Caloric
restriction in the acute phase of critical illness by delaying the
administration of parenteral nutrition reduced morbidity in critically ill
adults. We are currently performing a large randomized controlled trial
(Paediatric Early versus Late Parenteral Nutrition in Critical illness -
PEPaNIC: CCMO projectnr: NL38772.000.12) investigating the short term outcome
effects of these different nutritional support strategies. However, metabolism
has recently been involved in the regulation of autophagy and epigenetic
modifications. Whether caloric restriction, a metabolic intervention, has
*carry-over* effects, or metabolic memory by epigenetic changes, leading to a
more beneficiary long-term neurocognitive outcome is unknown.

We hypothesise that, in comparison with the current practice of aggressive
nutritional support, tolerating caloric deficits early during critical illness
in critically ill children has *carry-over* effects, through epigenetic
changes, that improve long-term (neurocognitive) outcomes.
The primary goal of the PEPaNIC long-term outcome study is to determine the
long-term neurocognitive outcome (more specifically the IQ-scores, motor and
executive function) of critical illness and the effect hereon of artificial
nutrition provided during the acute phase of critical illness in children.
The objectives to be reached within the time frame of this follow-up project
are the following:
* Performing a well-designed and sufficiently powered, multi-centre long-term
outcome study to investigate the consequences of early versus late parenteral
nutrition supplementing insufficient enteral feeding on the neurocognitive
outcomes of critically ill children beyond the acute disease course.
* Identifying patient populations that would benefit for long-term outpatient
follow-up and care and are currently not offered long-term follow-up in the
existing traditional follow-up programs.
* Following, in parallel and longitudinally, matched healthy control children
together with the critically ill children to reliably assess the *carry-over*
effects of critical illness in comparison with normal ageing over a similar
time frame in healthy children.
* Characterising the fasting response on the metabolic profile and the
neuro-endocrine axes and mapping the epigenetic modifications in the blood of
critically ill children that underlie the differences in long-term outcomes.
With the PEPaNIC follow-up project we aim to add value to the treatment of
critically ill children by the early diagnosis of and counselling in the legacy
of critical illness. The novel, nutritional strategy of tolerating caloric
deficits could reduce healthcare costs by postponing the administration of
expensive parenteral nutrition and by preventing complications in prolonged
critically ill patients. As the nutritional strategy may improve neurocognitive
development and success in life for critically ill children through epigenetic
changes, tremendous costs for society can be saved.

The primary focus of the PEPaNIC long-term outcome study is neurocognitive
development, and more specifically the IQ scores, motor coordination, attention
and executive function, at 2 and 4 years after inclusion in the study, in
comparison with matched healthy control subjects.

We will compare healthy children with the entire group of children who
participated in PEPaNIC as a whole, being a reflection of a paediatric ICU
population. The PEPaNIC population is very heterogeneous both in diagnosis, age
and in severity of illness, making it representative for a general PICU
population. Also, we will analyse the patients according to their randomisation
allocation of *early parenteral nutrition* with *late parenteral nutrition* in
the PEPaNIC study.

The children will undergo neurocognitive testing (see Table 1 of Protocol), and
together with their parents are asked to fill in Health related Quality of Life
questionnaires.

Additionally, we will continue to take biological samples (blood, hair, buccal
swaps) during these follow-up visits, similar to those that have already been
taken during the clinical PEPaNIC trial. These measurements will focus on
metabolic markers and the key hormones of the thyrotropic and somatotropic
axes. Additionally, the presence of genetic variation, telomere length and
epigenetic modifications (histone modification, DNA methylation, micro-RNAs) in
white blood cells will be examined and validated for functional relevance with
use of mRNA arrays. To investigate the effect on endurance/activity, the
participants will perform a walking test and wear an activity measuring device
at home during several days.

The risk is expected to be futile as it will only entail performing
questionnaires and tests and blood draws (separate consent). The burden is
expected to be moderate as it will entail a half of day of questionnaires and
neuropsychological tests in the outpatient clinic. An additional increase to
this burden are the laboratory tests. Separate consent will be asked at
different time points for the blood draws at 2 and 4 year follow up. For
patients who are already enrolled in clinical follow-up programs the burden
will be less as they are already asked to come to the outpatient clinic and
participate in these tests and blood draws. In contrast to the burden there is
also a benefit. The long-term follow up will be held as part of already
organised follow-up outdoor clinics and which are developed to help children
and their parents to recover physically, emotionally and socially after ICU
admissions. Aside from the scientific role of our follow-up this clear clinical
benefit comes available for all participants, not just those that are
traditionally part of an existing follow-up program. For the healthy matched
controls there is no clear benefit other than a (neuro)psychological and
physical evaluation.