Introduction. In the eighties the role of the pathologist within the field of safety assessment of food, chemicals and pharmaceutical products became more and more important. In this period, it was recognized that there was a need for specialized pathologists being trained in pathology, toxicology, pharmacology, laboratory animal science and Good Laboratory Practice. For this reason, in 1988 the Dutch Registration Committee for Laboratory Animal Pathologists/Toxicologic Pathologists (CRP/TP: Commissie Registratie Proefdierpathologen/Toxicologisch Pathologen) was founded. This Committee falls under the auspices of the Dutch Society of Pathology (NVvP; Nederlandse Vereniging voor Pathologie) and the Royal Dutch Society for Veterinary Medicine (KNMvD; Koninklijke Nederlandse Maatschappij voor Diergeneeskunde) and is responsible for the registration, the re-registration and the training of new laboratory animal pathologists and toxicologic pathologists.
Toxicologic pathology is a very specialized area covering both pathologic and toxicologic subjects. Therefore, in the Netherlands, the training of toxicologic pathologist is a joint responsibility of Veterinary Pathologists (united in a section of the NVvP) and registered Toxicologic Pathologists (united in a section of the Dutch Society of Toxicology; NVT).
Training of the toxicologic pathologist. Starting from 1989 (after a “de facto” recognition of 18 pathologists working in the field of toxicologic pathology at that time), all newcomers in the field of toxicologic pathology have to follow an extensive training program that is composed, approved and controlled by the CRP/TP. The candidate should be academically educated, preferably as a veterinarian, but medical doctors, or medical biologists may be accepted as trainee based on their pathology- and/or toxicology-related knowledge and experience. The training program comprises at least 4 years and consists partly of courses, but the major part consists of on-the job-training supervised by an experienced Board Certified Toxicologic Pathologist. The training program is additionally monitored by an external tutor. After successful completion of the training program, the candidate will be accredited and registered as Board Certified Toxicologic Pathologist (‘CRP/TP Board Certified Toxicologic Pathologist’). A re-registration procedure every 5 years warrants active participation and abiding proficiency of the registered toxicologic pathologist within his/her profession.
As a Board Certified Toxicologic Pathologist, in about 30 years now, Dr. Thoolen worked (for EU, USA, including China) on many preclinical (sub-) chronic toxicity and carcinogenicity studies which are valid for registration world-wide (see “studies track record”). These studies are valid for all 38 OECD-countries including FDA ( according to the Mutual Acceptance of Data (MAD) Decision).
Dr. Thoolen received is first registration in 1993, and the latest re-registration as Board Certified Toxicologic Pathologist (CRP/TP) was in 2022 (2022-2027).
Digital Pathology, also referred to as Telepathology and Whole Slide Imaging (W.S.I.), is the process of producing high resolution digital images from tissue sections on glass slides, and subsequent evaluation. These glass slides are normally examined under a microscope by a pathologist as part of the diagnostic process. The emergence of digital pathology now means that digital images are stored on secure servers and can be viewed on computer monitors; enabling pathologists to work remotely and to collaborate with other colleagues and/or when second opinions are needed.
Histopathology is conventionally performed by certified pathologists using a light microscope. This histopathological examination is not an exercise in “picture matching” for it represents a careful step by step evaluation of tissue and cellular patterns. This includes assessment of size, shape, staining characteristics and topographical tissue and cell organizations and integration into meaningful biological conclusions, with considerations of the overall macroscopic and microscopic pathology as well as other related medical disciplines. Species specificity, anatomy, artefacts, control references and experience of the study pathologist are considered key factors in this process. Additional semi-quantitative techniques and artificial intelligence (A.I.) can also be valuable additional techniques for research purposes and decision support.
We have been following the developments of Digital Pathology over the recent years, and it seemed good for peer review and/or educational purpose (e.g. Academic Hospitals, large CROs) of limited number of slides, and long-distance tele-communication. In the past, next to conventional light microscopy, also peer review was done faster in a conventional way by reviewing the glass slides. In addition, in the past there were sometimes problems with proper scanning of every slide which was time consuming.
Nowadays, however, the quality of images generated by using Digital Pathology is as good as conventional review of slides for all organ systems using digital pathology. The UMCU Academic hospital in Utrecht, The Netherlands was one of the the first hospitals world-wide going fully digital in pathology with a future-proof complete digital archive (2015).
During and after this time, scan speed, resolution and quality of scans from glass slides (W.S.I.) have been markedly improved. In recent years, substantial increased amount of W.S.I. validation literature is published on this subject. For both in clinical pathology (human) and pre-clinical veterinary pathology practices, things have improved significantly with demonstration of excellent diagnostic concordance between W.S.I. and conventional microscopy. Nowadays, the application of Digital Pathology, when well performed, can match equally with conventional light microscopy in toxicologic pathology for the safety evaluation in toxicology studies in the development of new vaccines, medicines and chemicals.
As part of GPS continuing commitment to enable our clients to reach their development goals, we are now excited, next to conventional histopathology using the light microscope, to also deliver innovative GLP validated Digital Pathology; Full Histopathology Evaluations and Peer Review solutions from preclinical toxicology studies on a Global scale. This option (Digital Pathology) can now also be performed from scans of histology slides from a large number of whole slide image formats (e.g. Hamamatsu, 3DHistech, Olympus, Aperio/Leica, Ventana/Roche, Philips, Zeiss scanners etc. ).
For more information: bob.thoolen@gpstoxpath. +31 (0)70 3142404
Since 1985 Prof Dr. Ruitenberg developed 4-years curriculum in order to harmonize international education requirements, recognition and registration of this profession. The commission registration laboratory animal pathologists was then established. In 1990 this initiative was further expanded by Prof. Dr. J Vos in 1990 in cooperation with the former committee members. Currently the education has two directions, with the final purpose registration as laboratory Animal Pathologist (consider pathology reseach in animal models of human deseases), or Toxicologic Pathologist. The education curriculum for Toxicologic Pathologists is internationally considered to be one of the better educations for the profession (Version Curriculum1996: “Regulations on Education and Registration/Training programme, Committee for the registration of laboratory Animal/Toxicological Pathologists (CRP/TP) in The Netherlands”).
Currently, every 5 years the Committee for the registration of laboratory Animal/Toxicological Pathologists (CRP/TP) checks the registration status of all Board Certified Pathologists for re-registration. Re-registration will occur every 5 years and will be approved if the Toxicologic Pathologist has remained active in the field during these 5 years. Requirements for approval besides the daily activities within the field (can also include management activity in the pathology field) are courses, post-academic education, slide seminars, congresses and other meetings, publications or presentations.
Dr. R.J.M.M. Thoolen was Board Certified since 1993. On June 15th, 2022 he received his re-registration as Toxicologic Pathologist for the next 5 years.
Ukraine is under attack just to feed "the Ego" of some. It is time that they gain insight into the "non-sense" of war. In this turmoil, Global Pathology Support (GPS) is ploughing on to guard the safety of vaccines, medicines, and chemicals. We just finished full read evaluations of two large projects on carcinogenicity (OECD 453) and histopathology and neuropathology evaluations of one extended one generation toxicity/neurotoxicity study (OECD 443).
A chapter on liver, gallbladder, and pancreas for CRC Press/Francis-Taylor Publishers to publish in a book titled “Toxicologic Pathology: An Atlas “has been finished recently and which will be published in 2022.
GPS is also considering applying Digital Pathology, as recent developments in this area has opened doors, for not only peer review or educational pathology, but also for routine histopathology evaluations. Many publications have shown reliable assessment for different organs systems as compared to conventional (toxicologic) pathology. At the same time pragmatic gain has been established over the years in the speed, logistics and resolution of images generated by digital scanning. Many good systems are on the market like: Hamamatsu, 3DHistech, Aperio (Leica), Sectra and last but not least Phillips. Quality, inter-activity and flexibility are paramount for GPS for the use of such system as it has to match the conventional pathology assessment as close as possible in every aspect and meet the GLP-guidelines.
Other services by GPS to our clients that has already been implemented, is the histology preparation of slides from wet tissues in combination with histopathology evaluation.
Keeping up the good spirit for everyone around the world for a better and safer world, GPS keeps on contributing to our clients in the best possible ways in order to produce safe vaccines, pharmaceuticals and chemicals on a global scale.
For more information call +31 70 3142404.
Following the announcement of 02 September, 2021, I am pleased to announce that we have again gained our new GLP-Compliance from the Dutch Authorities.
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