Terminologia Histologica 10 years on: some disputable terms in need of discussion and recent developments

At first sight, the issue of morphological terminology may seem to be a "closed and unchanging chapter", as many of the structures within the human body have been known for decades or even centuries. However, the exact opposite is true. The initial knowledge of the microscopic structure of the human body has been continuously broadening thanks to the development of new specialized staining techniques, discovery of the electron microscope, or later application of histochemical and immunohistochemical methods into routine tissue examination. Contrary to popular belief, histology has a status of constantly developing scientific discipline, with continuous influx of new knowledge, resulting in an unavoidable necessity to revise the histological nomenclature at regular intervals. The team of experts of the Federative International Programme on Anatomical Terminology, a working group of the International Federation of Associations of Anatomists, published in 2008 the First Edition of Terminologia Histologica. Terminologia Histologica (TH) is the best and most extensive of all the histological nomenclatures ever issued. However, here we suggest that several terms of important histological structures are still missing while several other terms are disputable. First, we present some clinically important terms of cells and tissue structures for inclusion in the next TH and, in a second part, we refer to some new terms in the current edition of the TH which are not yet mentioned in current histology textbooks (e.g., fusocellular connective tissue, bundle bone as the third type of bone tissue, spongy layer of vagina or arteria vaginata from the splenic white pulp). With this article we hope to start a wide scientific discussion which will lead to an inambiguous definition and demonstration of typical examples of all terms in the TH, with the result that the new edition of the Terminologia Histologica will become an internationally accepted communication tool for all practitioners and teachers of histology alike.

Renal impairment induced by prenatal exposure to angiotensin II in male rat offspring

Suboptimal conditions during prenatal ontogeny can impair development of several physiological systems and result in cardiometabolic diseases in adulthood. The kidney has been identified as one of the most sensitive organs for developmental programming, but underlying mechanisms are not fully understood. Therefore, in our study we explored the consequences of prenatally increased angiotensin II (Ang II) on the structural development of the kidney and its damage by infiltrated immune cells under normal diet and after an increased salt intake, as a second insult representing a lifestyle factor in humans. Female rats were implanted with osmotic mini-pumps continuously releasing Ang II of dose 2 µg/kg/h during last two weeks of pregnancy, whereas control females were sham operated. Immunohistological and ultrastructural evaluations of the kidneys and their infiltration with immune cells were performed in mature male progeny kept either on a standard or increased salt (2% NaCl) diet. Glomerular volume decreased and the cortical tubulointerstitial injury increased in the offspring prenatally exposed to Ang II with no additional effect of increased salt. Ultrastructural examination demonstrated degenerative changes in proximal tubules, mainly fewer and shorter microvilli in the brush border, enlarged mitochondria, and an increased number of lysosomes in the epithelial cells in the progeny prenatally exposed to Ang II. Moreover, the treatment resulted in increased infiltration of T-cells and macrophages in the renal cortex compared to controls. These changes paralleled with reduced numbers of cytotoxic T-cells in circulation and higher oxidative burst of neutrophils in the progeny of Ang II-treated mothers compared to controls. Altogether, results suggest that prenatally increased Ang II promoted infiltration of immune cells in the kidney and subsequent oxidative stress, which induced a damage of renal glomerular and tubular system entailing negative consequences on the cardiovascular system.

Impact statement

Suboptimal prenatal conditions can contribute to development of cardiovascular diseases and an altered renin-angiotensin-aldosterone system (RAAS) can be involved in the process. In our study, increased angiotensin II in pregnant female rats resulted in renal cortical interstitial damage, and renal ultrastructural changes in the glomeruli, the brush border of proximal tubules and mitochondria in mature male offspring. The treatment promoted infiltration of T cells and macrophages in the kidneys and primed an oxidative burst of circulating neutrophils, indicating a pro-inflammatory state in the progeny of angiotensin II-treated mothers. Deregulated RAAS of mothers is involved in developmental programming of hypertension in adult male offspring via damaging kidney morphology and function. These findings suggest that preventing the activation of RAAS and oxidative stress during perinatal development might protect against hypertension development in adult male progeny.

The legacy of Václav Trnka: modern medical education in Slovakia and Hungary in the eighteenth century

A fresh start of higher medical education in Slovakia and Hungary is closely related to Trnava (Nagyszombat). The University of Trnava had originally been established in 1635 but the Faculty of Medicine was added only later, in 1769, when the name of the university was also changed to Royal Hungarian University of Sciences. A fresh graduate, Václav Trnka from Křovice (1739-1791), was appointed as head of the Department of Anatomy. He was not only an anatomist, but a real polymath of the second half of the eighteenth century practicing medicine as well as becoming the Dean, then the Rector of the University. He has lived and acted within several countries of Central Europe, or rather, the Austrio-Hungarian monarchy during the reign of Empress Maria Theresia, then her son Joseph II. Born in Bohemia (now Czech Republic), studied and graduated in Austria, then finally was appointed as the first Professor of Anatomy of a newly established medical faculty in Upper Hungary (now Slovakia). In 1777, the university was moved first to Buda, then to Pest (now parts of the capital of Hungary), and the Faculty of Medicine was not separated from the rest of the faculties before the end of the Second World War. Following several institutional and name changes, this Medical Faculty is considered as the foundation of the present Semmelweis University. Trnka was a proliferous author, publishing more than 20 monographs covering various branches of clinical medicine, however, no anatomical work may be connected to his activity. And as a typical intellectual of the era, he was a keen and talented musician composing several canons.

The histological properties and possible origin of cervical thymus with cysts - A case report and hypotheses about its development

Ectopic accessory thymic tissue usually presents as an asymptomatic neck mass found at any level corresponding to the embryonic descent of the thymus. This tissue may contain smaller or larger cysts. However, the exact pathogenesis of "enigmatic" cervical thymic cysts remains controversial. A 7-year-old boy was referred to our workplace for the evaluation of a cervical mass. An ultrasound suggested a multi-loculated cystic mass, while CT and MRI indicated a left-sided, anteriorly located cervical mass beneath the sternocleidomastoid muscle. Following the radiological findings, surgical excision revealed a cystic mass. The mass of tissue was covered by a capsule. In H&E staining, the cervical mass had the same structure as normal thymus. Additionally, immunohistochemical findings suggest that the cellular microenvironment of cervical thymus also displays a place for development of T-lymphocytes. Within the parenchyma multiple cysts lined with cytokeratin-positive thymic epithelial cells were found. Inside the cysts, there were CD68-positive multinucleated giant cells and cholesterol clefts. A tendency to cystic degeneration inside the thymic tissue occurs more often in cervical thymuses than in normally located ones. The reason for the formation of cysts is unknown. We summarized seven possible histological, embryological and evolutional backgrounds for the development of these thymic cysts.

Distribution and elimination of levamisole in eggs and tissues after oral administration to laying hens, determined by LC-MS/MS

Levamisole was administered to laying hens, and concentrations in eggs and tissues (thigh muscle, breast muscle, liver and kidney) were determined by a newly developed liquid chromatography tandem mass spectrometry method, which allowed trace level quantification of levamisole. The adopted analytical method showed good sensitivity, repeatability and percentage of recovery from spiked matrices. Maximum concentrations of levamisole were found on the first day after the administration (531.1 μg/kg in liver, 164.3 μg/kg in egg yolk, 130.7 μg/kg in kidney, 78.0 μg/kg in breast muscle, 70.7 μg/kg in thigh muscle and 64.0 μg/kg in egg white), after which there is a decline. The compound was rapidly eliminated from eggs, with a half-life of 1.3 days. Elimination appeared to be slower in thigh muscle (3.5 days), breast muscle (3.4 days) and liver (3.3 days). According to this experiment, the levamisole withdrawal periods calculated for eggs, liver, kidney, breast muscle and thigh muscle in laying hens were 14.1, 6.1, >4.0, 14.5 and 13.0 days, respectively. The longest time for levamisole residues to be completely released from tissues was seen in liver samples (37.4 days), followed by thigh muscle, breast muscle and kidney. Elimination from eggs was fastest (16.4 days for levamisole residues to drop below the method quantification limit).

Recently Discovered Interstitial Cell Population of Telocytes: Distinguishing Facts from Fiction Regarding Their Role in the Pathogenesis of Diverse Diseases Called "Telocytopathies"

In recent years, the interstitial cells telocytes, formerly known as interstitial Cajal-like cells, have been described in almost all organs of the human body. Although telocytes were previously thought to be localized predominantly in the organs of the digestive system, as of 2018 they have also been described in the lymphoid tissue, skin, respiratory system, urinary system, meninges and the organs of the male and female genital tracts. Since the time of eminent German pathologist Rudolf Virchow, we have known that many pathological processes originate directly from cellular changes. Even though telocytes are not widely accepted by all scientists as an individual and morphologically and functionally distinct cell population, several articles regarding telocytes have already been published in such prestigious journals as Nature and Annals of the New York Academy of Sciences. The telocyte diversity extends beyond their morphology and functions, as they have a potential role in the etiopathogenesis of different diseases. The most commonly described telocyte-associated diseases (which may be best termed "telocytopathies" in the future) are summarized in this critical review. It is difficult to imagine that a single cell population could be involved in the pathogenesis of such a wide spectrum of pathological conditions as extragastrointestinal stromal tumors ("telocytomas"), liver fibrosis, preeclampsia during pregnancy, tubal infertility, heart failure and psoriasis. In any case, future functional studies of telocytes in vivo will help to understand the mechanism by which telocytes contribute to tissue homeostasis in health and disease.

Effects of Cornelian Cherry on Atherosclerosis and Its Risk Factors

Functional food represents an important alternative management of atherosclerosis, its risk factors, and clinical complications. Atherosclerosis is characterized by microinflammation, formation of atheromatous lipoprotein-rich plaques, and protrombogenic status. Cornelian cherry (Cornus mas L., CC) contains polyphenols influencing all three components of atherosclerosis. Its high antioxidant potential, verified in experimental studies, exhibited a pronounced decrease of inflammatory markers. CC treatment demonstrated a favourable effect on lipid spectrum (comparable with statins), decrease of glycemia, and increase of insulin (comparable with glibenclamide). Polyphenols identified in CC exhibited both direct antiplatelet effects and reduction of platelet hyper-reactivity mediated via attenuation of oxidative stress. The first clinical trials confirmed a clinically relevant decrease of total and low-density lipoprotein cholesterol, triacylglycerols, lipoproteins, amelioration of inflammatory activity, and insulin secretion improvement after the treatment with CC polyphenolic compounds. However, the limitation of published studies is the use of undefined cultivars of CC, their experimental nature, small scale, and missing longitudinal trials. Nevertheless, biochemical properties of CC, hitherto described, predispose its products for the adjuvant management of atherosclerosis.

Surgical treatment for breast tumors in children

Introduction/Objective. Fibroadenoma, often called ?breast mice tumors? due to their mobility, are the most common breast tumors in pediatric population. Considering that some tumors have a potential for rapid growth, breast tissue damage, and that an ideal diagnostic tool has yet to be found, complete mass extirpation might be the treatment of choice. The aim of the study was to present our clinical experience in treating children with breast masses. Methods. A retrospective review (2011?2018) of patients treated for breast tumors at the Institute for Child and Youth Health Care of Vojvodina in Novi Sad was conducted. Results. In this study 29 girls (mean age 15.8 ? 1.8) were included. The majority of masses were located in the upper outer (27.6%) or lower inner (24.1%) breast quadrant. The mean mass diameter was 39.7 mm. It has been observed that the mean mass diameter in the group of girls with positive family history for breast diseases was significantly lower (p < 0.05) than in those with negative family history (27.5 vs. 43.2 mm). There were no proven malignant tumors and all tumors have been completely extirpated. The mean postoperative stay was 1.5 ? 1.02 days. Conclusion. An appropriate radical operative technique dependent on mass size and localization is still the ?gold standard? for treating breast masses in pediatric patients. Cooperation with experts in the field of oncologic breast surgery enables implementing these operative techniques in clinical practice of pediatric surgeons.

Cardiac telocytes as principal interstitial cells for myocardial reparation and regeneration after infarction - our hope

According to our knowledge, this is the first research experiment that focuses on the study of the distribution of c-kit positive cells at the sites of myocardial infarction in human hearts (Fig. 3, Ref. 16).

Lymphatic lacunae of the mucosal folds of human uterine tubes - A rediscovery of forgotten structures and their possible role in reproduction

The mucosa of uterine tube forms multiple and branched longitudinal mucosal folds and takes part in many reproduction events, such as oocyte pick-up, gamete transport, sperm capacitation, fertilization, and early embryonic development. In the habilitation thesis of German physician Paul Kroemer (1904) was the first to describe the lymphatic lacunae inside the tubal folds (by injection of Indian ink), which the author named the öLymphbahnen" (ölymphatic channels"). Despite the fact that this first description has existed for 110 years, there is no mention of these lacunae in most of the current literature. In this article we present a rediscovery of completely overlooked morphological structures of uterine tubes - the lymphatic lacunae in their mucosal folds. The specimens from the uterine tubes were taken from 72 women (mean age 46.25 years) who underwent transabdominal or laparoscopic salpingectomy. The tissue samples from anatomically different parts of the uterine tubes were used for hematoxylin and eosin staining and for immunohistochemistry. Primary antibodies were used to label and detect podoplanin D2-40, a selective marker of lymphatic endothelia, CD34 antigen, and von Willebrand factor (Factor VIII). In the histological slides of the uterine tubes, there were noticeable slits or gaps within the loose connective tissue of the lamina propria of the mucosal folds. They were lined with one layer of squamous endothelial cells. These öempty spaces" were most prominent in the fimbriae, but were still well recognizable in mucosal folds of the ampulla. They always run through the central part of the fold. As a results of immunohistochemistry, we confirmed that in the centre of every mucosal fold, as well as in the fimbriae of the uterine tubes, dilated lymphatic spaces were situated and were lined with a simple layer of lymphatic endothelial cells (positive for podoplanin and CD34, and negative for Factor VIII). As there is no mention on them in the current Terminologia Histologica, we proposed the term ölymphatic lacunae of tubal mucosal folds and fimbriae" in English and ölacunae lymphaticae plicae mucosae et fimbriae" in Latin. According to our hypothesis, these lymphatic lacunae may be responsible for the thickening of the fimbriae during the oocyte pick-up and the maintenance of the tubal fluid.

The Terminologia Histologica after 10years: Inconsistencies, mistakes, and new proposals

This article details our experience with the Terminologia Histologica (TH) and its utility in the teaching of histology, cytology, and clinical medicine (e.g., pathology and hematology). Latin histological nomenclature has been used for 43years, and the latest version of the TH has been in use for 15years (although it was only issued publicly within the past 10years). The following findings and ensuing proposals allow us to discuss key points pertaining to the TH and make important suggestions for potential changes to the TH (such as the exclusion and inclusion of various terms). We classify these changes into six groups: 1.) mistakes in the TH, 2.) discrepancies among various Terminologiae, 3.) discrepancies within the TH, 4.) the repetition of terms, 5.) synonyms in the TH, and 6.) missing terms in the TH. Surprisingly, unlike the anatomical nomenclature, the histological nomenclature has been neglected in the literature. This article addresses this problem by reviewing and summarizing the state of this field, pointing out key discrepancies, offering solutions, and highlighting topics for further discussion.

The Non-cardiomyocyte Cells of the Heart. Their Possible Roles in Exercise-Induced Cardiac Regeneration and Remodeling

The non-cardiomyocyte cellular microenvironment of the heart includes diverse types of cells of mesenchymal origin. During development, the majority of these cells derive from the epicardium, while a subset derives from the endothelium/endocardium and neural crest derived mesenchyme. This subset includes cardiac fibroblasts and telocytes, the latter of which are a controversial type of "connecting cell" that support resident cardiac progenitors in the postnatal heart. Smooth muscle cells, pericytes, and endothelial cells are also present, in addition to adipocytes, which accumulate as epicardial adipose connective tissue. Furthermore, the heart harbors many cells of hematopoietic origin, such as mast cells, macrophages, and other immune cell populations. Most of these control immune reactions and inflammation. All of the above-mentioned non-cardiomyocyte cells of the heart contribute to this organ's well-orchestrated physiology. These cells also contribute to regeneration as a result of injury or age, in addition to tissue remodeling triggered by chronic disease or increased physical activity (exercise-induced cardiac growth). These processes in the heart, the most important vital organ in the human body, are not only fascinating from a scientific standpoint, but they are also clinically important. It is well-known that regular exercise can help prevent many cardiovascular diseases. However, the precise mechanisms underpinning myocardial remodeling triggered by physical activity are still unknown. Surprisingly, exercise-induced adaptation mechanisms are often identical or very similar to tissue remodeling caused by pathological conditions, such as hypertension, cardiac hypertrophy, and cardiac fibrosis. This review provides a summary of our current knowledge regarding the cardiac cellular microenvironment, focusing on the clinical applications this information to the study of heart remodeling during regular physical exercise.

Association between histological alterations in the thymus and sudden infant death syndrome

INTRODUCTION

Sudden infant death syndrome (SIDS) involves the death of an infant during the first year of life and it is among the leading causes of infant mortality worldwide. One hypothesis regarding the pathogenesis of SIDS is that it results from a combination of three independent factors: endogenous vulnerability, a critical time window during postnatal development, and exogenous stressors. This hypothesis is known as the "triple-risk model".

METHODS

In this study, we used an immunohistological approach to compare the cellular microenvironments of thymuses from 19 infants whose sudden death was classified as SIDS and a control group, which consisted of thymuses from age-matched children undergoing surgery for various congenital heart defects. We hypothesized that morphological signs of stress-related thymic involution would be present.

RESULTS

Based on our observations, we found evidence that the proliferation and maturation of T-lymphocytes in the thymuses of infants with SIDS were suppressed. We observed enhanced macrophage activity, suggesting an increase in the apoptosis of lymphocytes and decrease in number of thymic dendritic cells and myoid cells. Significant apoptosis of thymic lymphocytes without cell regeneration typically leads to atrophy of the thymus. All cellular events we observed resemble the initial stage of stress-related thymic involution.

CONCLUSION

These results support the "triple-risk model," suggesting that certain exogenous stressors might be involved in the pathogenesis of SIDS. This was probably not recognized during the autopsies of infants who died suddenly.

What happens to an acellular dermal matrix after implantation in the human body? A histological and electron microscopic study

Acellular matrices are used for various purposes and they have been studied extensively for their potential roles in regenerating tissues or organs. The acellular matrix generates physiological cues that mimic the native tissue microenvironment. Acellular dermal matrix (ADM) is a soft connective tissue graft generated by a decellularization process that preserves the intact extracellular skin matrix. Upon implantation, this structure serves as a scaffold for donor-side cells to facilitate subsequent incorporation and revascularization. In breast reconstruction, ADM is used mainly for lower pole coverage and the shaping of a new breast. It helps control the positioning of the implant in the inframammary fold, and prevents the formation of contractile pseudocapsule around the breast implant. In this study, we provide a comprehensive histological description of ADM used for human breast reconstruction over the course of several months following implementation. Using immunohistochemical methods (a panel of 12 antibodies) coupled with optical and transmission electron microscopy, we confirmed that the original acellular dermal matrix became recolonized by fibroblasts and myofibroblasts, and also by various other free cells of the connective tissue (lymphocytes, macrophages and multinucleated giant cells, granulocytes, mast cells) after implantation into the patient’s body. Within the implanted ADM, there was a relatively rapid ingrowth of blood vessels. Lymphatic vessels were only detected in one case 9 months after the implantation of the ADM. These results suggest that lymphangiogenesis is a longer process than angiogenesis.

The end-stage failing human myocardium - Where changes in ultrastructure of human cardiac muscle cells do not appear to dictate clinical outcomes

Heart failure is the end stage of cardiovascular abnormalities. Studies have primarily focused on the functional changes of cardiomyocytes in the failing heart from different animal models with very little information in the human condition. In addition little is known about the ultrastructural changes that proceed in cardiomyocytes in route to failure. The aim of this study was to examine the ultrastructural changes in the myocardium of human with end-stage heart failure. Left ventricular myocardial tissue samples from 7 patients with end-stage heart failure were examined with transmission and scanning electron microscopy. All heart failure patients were of New York Heart Association (NYHA) class III-IV. The data indicated normal three-dimensional arrangement of cardiac muscle cells in failing myocardium. The various organelles in cardiomyocytes including the nucleus, mitochondria, myofibrils, T-tubules and intercalated discs did not exhibit any remarkable morphological changes. We did observe the appearance of small membrane bound vesicles which appear to be associated with the intercalated discs. The nearly normal ultrastructure and arrangement of cardiomyocytes was remarkable in contrast to the dramatic clinical status of these patients in heart failure. These observations support the hypothesis, that there are no dramatic changes in the ultrastructure or three-dimensional architecture of cardiomyocytes in end-stage failing human myocardium.