Dr. Kai Wiemer is a specialist in internal medicine and gastroenterology and heads the Medical Clinic II - Clinic for Gastroenterology at the Knappschaft Clinic in Kamen, Westphalia. With his many years of experience in the diagnosis and treatment of diseases of the gastrointestinal tract as well as liver and pancreatic diseases, he has established himself as a respected specialist. He has in-depth knowledge of endoscopy and the treatment of chronic inflammatory bowel diseases as well as bowel cancer screening.
Dr. Wiemer completed his medical training at the Goethe University in Frankfurt am Main, where he acquired a broad range of specialist knowledge. Over the course of his career, he has specialized in interventional endoscopy, endosonography and nutritional medicine. Particularly noteworthy are his skills in performing ERCP (endoscopic retrograde cholangiopancreatography) and cholangioscopy, which have made him a recognized expert in this field due to his precise and successful interventions.
In addition to his clinical work, Dr. Wiemer has also placed a strong focus on medical research and continuing education. He has supervised several research projects and published scientific papers that have contributed to the further development of gastroenterological treatment approaches. In addition, he is actively involved in the training and further education of medical staff and continuously promotes further training measures in gastroenterology.
As co-author of the S1 guideline on functional dyspepsia (“irritable stomach”) of the German Society for Neurogastroenterology and Motility, Dr. Wiemer has made a significant contribution to the further development of guidelines in this specialist field. In his daily work, he pursues a holistic approach that focuses on individual patient care and close collaboration with his team to ensure optimal care. His commitment and passion for gastroenterology make him a recognized expert in his field.
In an interview with Dr. Wiemer, the editors of the Leading Medicine Guide were able to learn more about confocal laser endomicroscopy, an innovative imaging procedure with high-resolution real-time microscopy.
Confocal laser endomicroscopy is an innovative procedure that is becoming increasingly important in gastroenterology. It enables high-resolution, microscopic examination of tissue in real time during an endoscopy. This procedure is used in particular for the diagnosis and monitoring of diseases of the gastrointestinal tract. This includes the early detection of cancer, the examination of chronic inflammatory bowel diseases such as Crohn's disease and ulcerative colitis, as well as the assessment of precancerous changes and polyps. Thanks to the ability to visualize tissue changes at a cellular level, CLE contributes to a more precise diagnosis and more individualized treatment planning.
Confocal laser endomicroscopy is an advanced imaging technique that differs from other methods for diagnosing gastrointestinal diseases primarily due to its exceptional level of detail.
“For the first time, confocal laser endomicroscopy, or CLE for short, enables microscopically accurate tissue diagnostics in real time during an endoscopic examination. In contrast to conventional procedures, in which a biopsy is first taken and the tissue is then examined in the laboratory, CLE allows the direct observation of reactions of the intestinal mucosa - for example to a provocation test with certain nutrients. This makes it possible to immediately visualize changes without having to take samples. One particular area of application is the diagnosis of so-called 'leaky gut' syndrome, i.e. a disturbed intestinal barrier, which was previously often considered controversial. With CLE, this permeability can now be detected objectively and directly,” explains Dr. Wiemer at the beginning of our conversation and adds:
“In practice, this means that patients are admitted to hospital for the test, as delayed reactions can also occur as part of allergological provocations. The examination is carried out as part of a gastroscopy under sedation - so the patient is asleep during the procedure. Dissolved food is introduced into the duodenum, the first section of the small intestine. At the same time, CLE technology is used: a special laser scanner is advanced to the mucous membrane via the endoscope. The reaction of the intestinal mucosa can be observed live through a magnification of up to a thousand times. A fluorescent contrast agent, known as fluorescein, is administered intravenously beforehand. This agent has also been used in ophthalmology for a long time. The aim is to detect whether the contrast agent leaks out of the blood vessels into the surrounding tissue in the event of a disturbed intestinal barrier - a clear sign of a barrier disorder. The first step is to check whether there is a primary disruption of the intestinal barrier. If the barrier is intact, a possible secondary disorder can then be provoked and visualized by administering certain foods - in the sense of a leaky gut, for example. All of this happens in real time and enables highly precise diagnostics directly on the patient."
Leaky gut, also known as “permeable gut”, describes a condition in which the intestinal wall is damaged and no longer properly fulfills its function as a barrier. Normally, the intestinal mucosa prevents harmful substances from entering the bloodstream. With leaky gut, however, the tight connections between the cells of the intestinal wall are loose, allowing toxins, undigested food components and pathogens to enter the body. This can cause inflammation and an overreaction of the immune system, which is associated with various health problems such as digestive disorders, skin conditions and chronic inflammation.
There is a standard scheme that covers the five most common food allergens: Egg white, soy, milk, yeast, peanut and wheat. This scheme is used both in clinical practice and in studies.
“The test checks whether the patient reacts to one of these food allergens, which leads to fluorescein escaping from the blood vessels and into the intercellular space. This reaction becomes visible and enables a precise diagnosis. After the test, the results can be discussed with the patient and, if necessary, nutritional advice can be offered by qualified staff. An example from practice: a patient was recently examined who had been struggling with irritable bowel symptoms for years without an exact cause being found. Using CLE technology, we were able to clearly determine that she was reacting to wheat, although a gluten intolerance had already been ruled out. This brought her great relief as she finally had a clear cause for her symptoms. It was not the gluten that triggered the reaction, but possibly a sensitivity to certain proteins in wheat, such as amylase trypsin inhibitors (ATI), which can also be found in other gluten-containing grains,” explains Dr. Wiemer.
There is no clear answer to the question of whether the number of people who are allergic to these foods has increased. There is certainly greater health awareness and an increasing willingness to investigate food intolerances more closely. New diagnostic procedures, both serological tests and imaging procedures such as CLE, offer better diagnostic possibilities today than 20 or 30 years ago. Even complaints such as irritable bowel syndrome, which in the past were often only treated by exclusion diagnostics, can now be investigated using more precise methods. “In patients in whom neurological tests are unremarkable and there is no classic IgE-triggered allergy, CLE can help to identify an intestinal barrier disorder (leaky gut) that may be responsible for their symptoms. A major advantage of this method is that the examination can be performed within a gastroscopy lasting around 20 minutes. Such changes are not visible during a normal endoscopy. The CLE technology makes it possible to observe the reactions of the intestinal mucosa in real time and record them on images, which enables precise and reliable diagnostics,” explains Dr. Wiemer.
CLE is a precise diagnostic option that can be used for a large number of patients. In certain cases, however, classic endoscopy is also sufficient, for example when it comes to ruling out or confirming celiac disease.
“In conventional endoscopy, the endoscope is inserted into the stomach and, if celiac disease is suspected, tissue samples are taken from the small intestine for subsequent analysis in the laboratory. During the CLE examination, which is aimed at a more detailed analysis, the patient lies on the examination table, similar to a normal gastroscopy. The endoscope is inserted into the descending part of the small intestine, the duodenum. A laser probe is advanced through the endoscope to examine the mucous membrane in this region. The first step is to check whether the intestinal barrier is intact or whether there are already signs of leaky gut, a disturbed intestinal barrier. In some cases, this barrier can already be disturbed without food provocation, which requires further examinations to find out the exact cause. In such cases, allergological tests may also be necessary,” says Dr. Wiemer and continues:
"However, if the intestinal barrier is intact, the examination is continued with various provocation agents. These are also introduced into the small intestine via the endoscope. We then observe how the mucous membrane reacts to these substances. A positive test is indicated, for example, by the release of fluorescein, a contrast agent, from the blood vessels into the tissue. Cell destruction often occurs in the area of the intestinal mucosa, which is known as “cell shedding”. This causes small cell fragments to detach, which also become visible with the fluorescein. These reactions are typical signs of a disturbed intestinal barrier and confirm the positive test. After the examination, the patient may be referred to the nutritional counseling service, where they will receive comprehensive advice and support to adjust their diet according to the results. This is an important part of the treatment concept, as the right diet plays a central role in the treatment of leaky gut and other intestinal problems."
The nutritional advice that the patient receives following the CLE examination does not offer strict prescriptions, but rather recommendations to help them support their gut and alleviate their symptoms.
“Of course, it is not possible to look after every patient around the clock, and we know from experience, for example when looking after celiac patients or people with chronic inflammatory bowel disease, that mistakes are human. Anyone can slip up and eat something that doesn't quite match the recommendations. However, the decisive advantage is that the patient then at least knows exactly where the symptoms are coming from. For example, if they react to wheat and then treat themselves to a bread roll, they know why they are experiencing symptoms and this can be very relieving. They no longer have to wonder what caused their symptoms. It becomes critical when people look for simple solutions in advertising to alleviate the symptoms of irritable bowel syndrome. Products are advertised that offer probiotics in the form of yoghurt drinks or capsules, which may provide some relief, but they are not miracle cures. Especially in the case of a specific intolerance, such as wheat intolerance, it is not enough to simply consume such a product. It's a complex issue and relying on supplements alone will not solve the cause of the problem,” Dr. Wiemer explains.
Another topic that often comes up is the difficulty consumers have in choosing the right foods in supermarkets, especially if they have certain intolerances or allergies.
The multitude of ingredients and the often incomprehensible names on labels can be confusing. The industry should become aware of its responsibility and label ingredients more clearly, especially for processed products such as baked goods or ready-made soups, which often contain additives that are difficult for consumers to understand. It would be a step forward if manufacturers were to name these ingredients more clearly. A simpler solution could also be to use fresh, unprocessed food wherever possible, which is always a good choice anyway.
Dr. Wiemer comments: “There is a clear link between diet and the microbiome when it comes to gut health. A varied, seasonal and fresh diet helps to keep the microbiome in balance. However, anyone who severely restricts their diet or relies too much on food supplements risks a reduced diversity of bacteria in the gut. One example of this was a young man who had a very restrictive diet and took a variety of supplements. His microbiome was severely restricted in some areas. The recommendation to eat as varied and seasonal a diet as possible has a positive effect on the microbiome and helps to keep it in balance. Patients who come to us with symptoms similar to those of a leaky gut often find that they have unnecessarily restricted themselves. If they respond to the provocation tests, at least they know that they don't have to give up every food, but that their symptoms could be caused by other factors. This realization can be enormously relieving and help patients regain control over their diet,” and emphasizes:
“For a healthy intestinal flora, it is particularly important to eat fiber-rich foods, especially from plant-based sources. A balanced diet with plenty of fresh vegetables, fruit and wholegrain products is crucial. Even though it is normal for the intestines to have to do more digestive work when processing fiber-rich plant substances, you should not be discouraged if you experience slight discomfort after eating raw foods - it usually goes away. There is a widespread myth that you shouldn't eat green salad in the evening because it is difficult to digest. I think this idea is outdated. As with many other old traditions, such as the wisdom that you shouldn't go into the water after a meal, these are rumors with no scientific basis."
CLE offers significant advantages compared to conventional imaging techniques, particularly when differentiating between active inflammation and scar tissue.
“Laser endomicroscopy in gastroenterological endoscopy has been around in its current form since the early 2000s and I am very pleased that we are able to bring this method more into focus. It is particularly important that patients know that this examination is available to them. It is by no means a private service, but is open to all patients. This is a point that should be emphasized again and again, precisely because this problem, such as irritable bowel syndrome, affects many people. It would be unfortunate if we were to offer this treatment method in the form of two-tier medicine, as this would not be in the spirit of fair healthcare."
Knappschaft Kliniken Kamen offers specialized gastroenterological care with a focus on modern, minimally invasive procedures. The aim of the clinic in Kamen is to replace surgical procedures with innovative treatment methods. Furthermore, the integration of new technologies in medical care is being promoted.
“It is particularly important for me to emphasize that our focus is not exclusively on CLE. This method is only a small part of our work. Our main activity is in gastroenterology, with a particular focus on interventional endoscopy. These are interventions that can replace surgical measures in many cases. Our aim is to avoid major surgical interventions for our patients by using modern endoscopy procedures. This endoscopy goes far beyond the classic gastroscopy and colonoscopy that almost every gastroenterologist offers on an outpatient basis. What sets us apart is endoscopy of the 'third space', i.e. modern resection procedures, for example of tumors within the thin layer of connective tissue beneath the mucous membrane of the gastrointestinal tract. We also work with endosonographic procedures, for example, to puncture neighboring organs in order to obtain tissue samples and create stent connections. This type of 'surgery-replacing' endoscopy is the mainstay of our clinic. We also offer a 24/7 endoscopy on-call service, which means that we are available for emergencies around the clock, all year round. This also includes the ERCP on-call service, which only a few centers in the region can provide. This service is a key service for us and we are proud to be able to offer it in this form,” says Dr. Wiemer, who concludes our conversation by taking a look into the future:
“We would like to be more visible, especially in the region, although we are well connected and strategically located - directly at the Kamener Kreuz, an important traffic axis that connects north, south, east and west. We offer a full range of outpatient and inpatient gastroenterology services, including neurogastroenterology, interventional endoscopy and nutritional medicine, in a very specialized and efficient unit with a great team. In terms of medical progress, we also see great potential for the future in artificial intelligence (AI). We have already integrated AI technologies in endoscopy, particularly in colorectal cancer screening. We are also connected to a major university AI center as part of the Knappschaftsverbund. We are currently in talks about possible joint research projects, both in the field of CLE and endoscopy in general. This AI center is one of the leading ones in Germany, and the collaboration could bring decisive progress for our work and medical care”.
Dr. Wiemer - thank you very much for this informative interview!
