The stress hormone COrtisol and the development of MEtabolic Syndrome and Cardiovascular DIseases
Unravelling the cause(s) of hypercortisolism in obesity:
Investigating the influence of the liver, gut and immune system

Over the past decades the number of obese persons has increased dramatically
worldwide. In 2017, 12% of the Dutch population was obese, versus 5% around
1980.. In particular abdominal obesity is often complicated by metabolic
disturbances, e.g. insulin resistance, dyslipidemia and increased blood
pressure, collectively grouped into the term metabolic syndrome (MetS).
According to current knowledge, there are numerous clinical, biochemical,
immunological, microbiological and psychological factors that are involved in
the development of obesity and the metabolic syndrome.
The current study aims to integrate promising targets to help understand the
biological process of obesity and weight loss.

1. The influence of glucocorticoids on obesity and the metabolic syndrome.
Stress leading to the activation of the hypothalamus-pituitary-adrenal (HPA)
axis with the stress hormone cortisol as the main effective end-product, has
been implicated in the development of obesity and MetS. Cushing*s syndrome,
which is characterized by a pathological increase of cortisol levels, causes an
array of symptoms (like weight gain, increase in blood pressure, dyslipidemia,
diabetes mellitus and ultimately CVD) which has a striking resemblance with the
MetS and CVD in the normal population. Interestingly, coinciding with the rise
in obesity, MetS and CVD, the intake of food with high glycemic index and the
level of stress has increased in the population, while on average hours of
sleep decreased(6). These are all factors known to induce an increase in daily
cortisol production.

Previously, we have found that roughly half of the patients with obesity have
increased cortisol levels in scalp hair, a method we recently developed to
measure long-term cortisol levels. Also, cortisol is known to be related to the
metabolic syndrome and cardiovascular diseases. A possible explanation for this
phenomenon could be the occurrence of hepatic steatosis, that may influence
cortisol metabolism ( that mainly takes place in the liver). Other studies
found altered cortisol metabolizing enzymes in the livers of patients with
hepatic steatosis. We hypothesize that alteration of these enzymes may lead to
higher cortisol levels in certain patients with obesity, thereby further
increasing the vicious cycle of obesity, hepatic steatosis and increased
cortisol levels. Also increased bile acids are known to alter cortisol
metabolism.

Patients who undergo LRYGB for clinical care are an excellent population to
obtain liver samples, because they have severe obesity and a high likelihood of
having hepatic steatosis. Furthermore, the liver biopsy poses minimal
additional risk as they already undergo a laparoscopy. Because the surgeon
will have a clear view of the liver, and takes the biopsies before continuing
the operation, it is possible to anticipate on any adverse events that may
occur. Studying the biopsies will be complemented by extensive analysis of
cortisol metabolites in urine, that can be used to study the process of
cortisol clearance, and by hair cortisol analyses, as previously described.

2. Immunological and microbiological factors
Together with the altered cortisol state in obesity, that is described above,
it is known that the immune system and gut microbiome are altered in obesity.
In obesity, low-grade inflammation is seen that is characterized by a
pro-inflammatory immunological pattern and a decline in the biodiversity of the
gut microbiome, that also frequently occur together. It is also known that this
pro-inflammatory phenotype with low gut microbiome diversity improves after
weight loss, either as a consequence of bariatric surgery of after lifestyle
changes. However, not all questions regarding the change in gut microbiome and
immunological profile are answered yet. A recent study demonstrated that
mainly patients with increased trunk fat mass and comorbidities (type 2
diabetes, hypertension and severity) had low gene richness of their microbiome.
Interestingly, we also find this phenotype in hypercortisolism. Possibly, the
'leaky gut' in obesity triggers immune activity and the HPA-axis. Also, we may
speculate that hepatic steatosis develops as a consequence of an altered gut
microbiome, perhaps via portal vein circulation. Altogether, we hypothesize
that in a large proportion of patients with obesity there is a pro-inflammatory
state together with a microbiome with low gene richness, that may partially
explain the hypercortisolism. Furthermore, we expect that all components of
this phenotype alleviate throughout the course of weight loss. Due to the
nature of the intervention, we may see different changes in patients that
undergo LRYGB as compared to a CLI. Both patient groups,of whom in-depth
cortisol phenotyping will be available, provide therefore a unique opportunity
to the interactions between metabolic status, liver function, stress hormones,
the immune status and the gut microbiome.

Primary Objective:
- To investigate the differences between hypercortisolistic patients with
obesity and normocortisolistic patients with obesity, with respect to hepatic
steatosis, immunological factors, and the gut microbioma in order to obtain
insight of the mechanisms underlying hypercortisolism.

Secondary Objective(s):
- To study the differential weight-reducing treatments (1. Bariatric surgery
and 2. Combined lifestyle intervention) on cortisol status, immunological
factors, and gut microbioma

Prospective cohort study

There will be no additional study visit.
The extra burden for patients, will be (besides regular clinical care):
- Questionnaires for 2 follow-up visits ( that take approximately 20 minutes of
extra time)
- Extra blood tubes drawn at a (standard clinical care) planned venipuncture
- One additional venipuncture during a routine clinical follow-up visit where
there is normally no venipuncture
- Stool samples at the day of admission and before 2 routine follow-up visit
- Hair samples during 3 routine outpatient clinic visits
- 24 hour urine collection before admission and at 2 routine follow-up visits
- Peroperative liver and VAT biopsy

Bleeding is a possible adverse event after liver- and VAT biopsy. To minimize
the risk of this unfavorable outcome, these biopsies will be done at the
beginning of the surgical procedure. The surgeon will have a clear view of the
location of the biopsy during the complete procedure and will have the maximal
amount of time to anticipate on a bleeding when it occurs.