Correlation of CT-based bone mineralization with drilling-force measurements in anatomical specimens is suitable to investigate planning of trans-pedicular spine interventions.

This interdisciplinary study examined the relationship between bone density and drilling forces required during trans-pedicular access to the vertebra using fresh-frozen thoraco-lumbar vertebrae from two female body donors (A, B). Before and after biomechanical examination, samples underwent high-resolution CT-quantification of total bone density followed by software-based evaluation and processing. CT density measurements (n = 4818) were calculated as gray values (GV), which were highest in T12 for both subjects (GVmaxA = 3483.24, GVmaxB = 3160.33). Trans-pedicular drilling forces F (Newton N) were highest in L3 (FmaxB = 5.67 N) and L4 (FmaxA = 5.65 N). In 12 out of 13 specimens, GVs significantly (p < 0.001) correlated with force measurements. Among these, Spearman correlations r were poor in two lumbar vertebrae, fair in five specimens, and moderately strong in another five specimens, and highest for T11 (rA = 0.721) and L5 (rB = 0.690). Our results indicate that CT-based analysis of vertebral bone density acquired in anatomical specimens is a promising approach to predict the drilling force appearance as surrogate parameter of its biomechanical properties by e.g., linear regression analysis. The study may be of value as basis for biomechanical investigations to improve planning of the optimal trajectory and to define safety margins for drilling forces during robotic-assisted trans-pedicular interventions on the spine in the future.

Effects of seawater and freshwater challenges on the Gh/Igf system in the saline-tolerant blackchin tilapia (Sarotherodon melanotheron).

Prolactin (Prl) and growth hormone (Gh) as well as insulin-like growth factor 1 (Igf1) are involved in the physiological adaptation of fish to varying salinities. The Igfs have been also ascribed other physiological roles during development, growth, reproduction and immune regulation. However, the main emphasis in the investigation of osmoregulatory responses has been the endocrine, liver-derived Igf1 route and local regulation within the liver and osmoregulatory organs. Few studies have focused on the impact of salinity alterations on the Gh/Igf-system within the neuroendocrine and immune systems and particularly in a salinity-tolerant species, such as the blackchin tilapia Sarotherodon melanotheron. This species is tolerant to hypersalinity and saline variations, but it is confronted by severe climate changes in the Saloum inverse estuary. Here we investigated bidirectional effects of increased salinity followed by its decrease on the gene regulation of prl, gh, igf1, igf2, Gh receptor and the tumor-necrosis factor a. A mixed population of sexually mature 14-month old blackchin tilapia adapted to freshwater were first exposed to seawater for one week and then to fresh water for another week. Brain, pituitary, head kidney and spleen were excised at 4 h, 1, 2, 3 and 7 days after both exposures and revealed differential expression patterns. This investigation should give us a better understanding of the role of the Gh/Igf system within the neuroendocrine and immune organs and the impact of bidirectional saline challenges on fish osmoregulation in non-osmoregulatory organs, notably the complex orchestration of growth factors and cytokines.

CT-based and morphological comparison of glenoid inclination and version angles and mineralisation distribution in human body donors.

BACKGROUND: For optimal prosthetic anchoring in omarthritis surgery, a differentiated knowledge on the mineralisation distribution of the glenoid is important. However, database on the mineralisation of diseased joints and potential relations with glenoid angles is limited. METHODS: Shoulder specimens from ten female and nine male body donors with an average age of 81.5 years were investigated. Using 3D-CT-multiplanar reconstruction, glenoid inclination and retroversion angles were measured, and osteoarthritis signs graded. Computed Tomography-Osteoabsorptiometry (CT-OAM) is an established method to determine the subchondral bone plate mineralisation, which has been demonstrated to serve as marker for the long-term loading history of joints. Based on mineralisation distribution mappings of healthy shoulder specimens, physiological and different CT-OAM patterns were compared with glenoid angles. RESULTS: Osteoarthritis grades were 0-I in 52.6% of the 3D-CT-scans, grades II-III in 34.3%, and grade IV in 13.2%, with in females twice as frequently (45%) higher grades (III, IV) than in males (22%, III). The average inclination angle was 8.4°. In glenoids with inclination ≤10°, mineralisation was predominantly centrally distributed and tended to shift more cranially when the inclination raised to > 10°. The average retroversion angle was - 5.2°. A dorsally enhanced mineralisation distribution was found in glenoids with versions from - 15.9° to + 1.7°. A predominantly centrally distributed mineralisation was accompanied by a narrower range of retroversion angles between - 10° to - 0.4°. CONCLUSIONS: This study is one of the first to combine CT-based analyses of glenoid angles and mineralisation distribution in an elderly population. The data set is limited to 19 individuals, however, indicates that superior inclination between 0° and 10°-15°, and dorsal version ranging between - 9° to - 3° may be predominantly associated with anterior and central mineralisation patterns previously classified as physiological for the shoulder joint. The current basic research findings may serve as basic data set for future studies addressing the glenoid geometry for treatment planning in omarthritis.

CD40 Agonist Monoclonal Antibody-Mediated Hepatitis in TNF-Receptor 1 Gene Knockout Mice.

Tumor necrosis factor-alpha (TNF-α) plays an important role in liver inflammation. CD40-CD40 ligand (CD40-CD40L) is a key receptor-ligand signaling pair involved in the adaptive immune response and pathogenesis of autoimmune diseases. In mice, CD40 activation leads to sickness behavior syndrome (SBS) comprising weight loss, sleep disruption and depression, which can be blocked by administration of the TNF-inhibitor etanercept. In the present study, we assessed the extent of hepatic inflammation in mice devoid of the TNF-receptor 1 (TNFR1)-mediated signaling pathway. The TNFR1-depleted (TNFR1-/-) adult mice and their wild type littermates were given a single intra-peritoneal injection of CD40 agonist monoclonal antibody (mAb) or rat IgG2a isotope control. As described previously, TNFR1-/- mice were protected from SBS upon CD40 mAb treatment. Cd40, tnf and tnfr1 mRNA and Tnf-α peptide were increased in the liver of CD40 mAb-stimulated wild type mice. Serum alanine aminotransferase was elevated in both CD40-activated wild type and TNFR1-/- mice. TNFR1-/- mice showed much less intra-parenchymal infiltrates, hepatocellular necrosis, and perivascular clusters upon CD40 mAb activation than their wild type littermates. A gene expression microarray detected increased activity of metabolic and detoxification pathways and decreased activity of inflammatory pathways. We conclude that immune activation and development of liver inflammation in CD40L interactions depend on TNFR1-mediated signaling pathways and are counteracted by alterations in metabolic pathways.

Micro-CT imaging of Thiel-embalmed and iodine-stained human temporal bone for 3D modeling.

INTRODUCTION: This pilot study explores whether a human Thiel-embalmed temporal bone is suitable for generating an accurate and complete data set with micro-computed tomography (micro-CT) and whether solid iodine-staining improves visualization and facilitates segmentation of middle ear structures. METHODS: A temporal bone was used to verify the accuracy of the imaging by first digitally measuring the stapes on the tomography images and then physically under the microscope after removal from the temporal bone. All measurements were compared with literature values. The contralateral temporal bone was used to evaluate segmentation and three-dimensional (3D) modeling after iodine staining and micro-CT scanning. RESULTS: The digital and physical stapes measurements differed by 0.01-0.17 mm or 1-19%, respectively, but correlated well with the literature values. Soft tissue structures were visible in the unstained scan. However, iodine staining increased the contrast-to-noise ratio by a factor of 3.7 on average. The 3D model depicts all ossicles and soft tissue structures in detail, including the chorda tympani, which was not visible in the unstained scan. CONCLUSIONS: Micro-CT imaging of a Thiel-embalmed temporal bone accurately represented the entire anatomy. Iodine staining considerably increased the contrast of soft tissues, simplified segmentation and enabled detailed 3D modeling of the middle ear.

Anatomy of the female pelvic nerves: a macroscopic study of the hypogastric plexus and their relations and variations.

The autonomic nerves of the lesser pelvis are particularly prone to iatrogenic lesions due to their exposed position during manifold surgical interventions. Nevertheless, the cause of rectal and urinary incontinence or sexual dysfunctions, for example after rectal cancer resection or hysterectomy, remains largely understudied, particularly with regard to the female pelvic autonomic plexuses. This study focused on the macroscopic description of the superior hypogastric plexus, hypogastric nerves, inferior hypogastric plexus, the parasympathetic pelvic splanchnic nerves and the sympathetic fibres. Their arrangement is described in relation to commonly used surgical landmarks such as the sacral promontory, ureters, uterosacral ligaments, uterine and rectal blood vessels. Thirty-one embalmed female pelvises from 20 formalin-fixed and 11 Thiel-fixed cadavers were prepared. In all cases explored, the superior hypogastric plexus was situated anterior to the bifurcation of the abdominal aorta. In 60% of specimens, it reached the sacral promontory, whereas in 40% of specimens, it continued across the pelvic brim until S1. In about 25% of the subjects, we detected an accessory hypogastric nerve, which has not been systematically described so far. It originated medially from the inferior margin of the superior hypogastric plexus and continued medially into the presacral space. The existence of an accessory hypogastric nerve was confirmed during laparoscopy and by histological examination. The inferior hypogastric plexuses formed fan-shaped plexiform structures at the end of both hypogastric nerves, exactly at the junction of the ureter and the posterior wall of the uterine artery at the uterosacral ligament. In addition to the pelvic splanchnic nerves from S2-S4, which joined the inferior hypogastric plexus, 18% of the specimens in the present study revealed an additional pelvic splanchnic nerve originating from the S1 sacral root. In general, form, breadth and alignment of the autonomic nerves displayed large individual variations, which could also have a clinical impact on the postoperative function of the pelvic organs. The study serves as a basis for future investigations on the autonomic innervation of the female pelvic organs.

Experience from an optional dissection course in a clinically-orientated concept to complement system-based anatomy in a reformed curriculum.

Profound anatomical knowledge is the basis for modern demands in medicine and surgery, but many countries worldwide including Australia and New Zealand have discontinued offering dissection courses to medical and dental students during the past decades. This educational project done in Australia aimed at enhancing basic and advanced anatomy teaching by engaging a sub-group of second-year undergraduate students of a compulsory prosection- and model-based anatomy course (n = 54/170) in an optional multimodal course, which should easily articulate with a vertical curriculum. With topographical cadaver dissections as core, peer student-teams prepared and peer-assessed anatomy lectures based on clinical topics, which were rated highly by the peers and teachers. Anatomical knowledge was tested by quizzes and a multiple-choice examination. Individual dissection skills were self- and teacher-assessed. A final course grade was assigned based on these assessments. The grades in the system-based compulsory course achieved by the attendees of the paralleling dissection course were compared with their peers attending other optional courses. After beginning of the semester, the students in the dissection course performed similar, significantly (P < 0.005) improved during the semester (78.5% vs. 69.9%, 70.1% vs. 64.1%), but in the integrated (including anatomy, biochemistry, physiology) final examination at the end of the year only tended to higher scores. As assessed through interviews and a voluntary questionnaire, all students of the optional dissection course liked these activities, which enhanced their learning experience. Thus, this concept elegantly integrates anatomical dissection with modern teaching demands and is feasible for implementation in modernized curricula. Anat Sci Educ 11: 32-43. © 2017 American Association of Anatomists.

Microglia at center stage: a comprehensive review about the versatile and unique residential macrophages of the central nervous system.

Microglia cells are the unique residential macrophages of the central nervous system (CNS). They have a special origin, as they derive from the embryonic yolk sac and enter the developing CNS at a very early stage. They play an important role during CNS development and adult homeostasis. They have a major contribution to adult neurogenesis and neuroinflammation. Thus, they participate in the pathogenesis of neurodegenerative diseases and contribute to aging. They play an important role in sustaining and breaking the blood-brain barrier. As innate immune cells, they contribute substantially to the immune response against infectious agents affecting the CNS. They play also a major role in the growth of tumours of the CNS. Microglia are consequently the key cell population linking the nervous and the immune system. This review covers all different aspects of microglia biology and pathology in a comprehensive way.

Distinct presence of the tight junction protein claudin-3 in olfactory bulb and fila olfactoria of the mouse.

The tight junction protein claudin-3 is overexpressed in diverse epithelial tumours and is associated with increased survival, progression and motility of tumour cells. Claudin-3 expression profiles are being increasingly used for diagnostic and prognostic tumour classification. Claudin-3 has been identified as a receptor for Clostridium perfringens enterotoxin, which is under consideration for selective lysis of claudin-3-expressing tumours, particularly brain metastases, and other translational medicine uses. However, the localization of claudin-3 in the brain has not been completely elucidated. While claudin-3 in brain tissue adjacent to claudin-3-expressing metastases had been excluded and low or undetectable levels proposed in the CNS, under physiological conditions, in adult human, rat and mouse brains, claudin-3 was exclusively found in choroid plexus epithelium where it is considered an integral component of the blood-cerebrospinal-fluid barrier. We report here the pronounced presence of claudin-3 not only in the nasal region (as described for rat), but also in the mouse olfactory bulb and nerve using immunohistochemistry and Western blot. Claudin-3 was present in the fila olfactoria from the epithelium to the olfactory nerve and in the main and accessory olfactory bulb. We propose that the abundant presence of claudin-3 in the olfactory system, particularly in nerve fibres and the olfactory bulb cone, which we present here, may play a role at the interface of the central and peripheral nervous system, both as barrier and for axonal growth and communication. Thus, claudin-3 should be considered and further explored with regards to treatment approaches addressing the olfactory bulb and nasal region.

An atypical lateral hernia and concomitant inguinal and umbilical hernias in a patient with polycystic kidney disease and an intracranial aneurysm - a combined approach of clinical and radiological investigation, endoscopic hernia repair, and anatomical cadaver model documentation and a systematic review of the literature.

Atypical hernias are difficult to diagnose due to their rarity and often unspecific symptoms. In the literature there exist hints to peri-inguinal hernias, i.e. direct lateral hernia, but most of them are forms of Spigelian hernias. Since the majority were described during the first half of the past century or even earlier, only very few cases have been documented using modern diagnostic techniques. We report a unique case of a 51 year old patient presenting with an atypical inguinal hernia with concomitant inguinal and umbilical hernias in combination with cystic kidney disease and intracranial aneurysm. The atypical position of the hernia was assumed from clinical inspection, ultrasound and CT scan and verified during pre-peritoneoscopy. Using an anatomical cadaver dissection approach, we followed the unusual position of the hernia through the abdominal wall below the aponeurosis of the external oblique muscle. After a thorough literature search, we assume that the present hernia containing a hernial sac has not been documented before, especially not in such a multidisciplinary approach comprising radiological, surgical and anatomical localisation and endoscopic treatment in a patient with a clinical situation being aggravated by large cystic kidneys leading to dialysis-dependency. Rare hernias have been described as being often associated with concomitant inguinal or other hernias, a predisposition for the male gender and a pathogenic mechanism related to other soft tissue defects such as cystic kidney disease or cranial aneurysm. Thus, we consider this a unique case that has not been documented in this constellation previously, which may increase the awareness for these rare hernias.

Insulin-like growth factor I is expressed in classical and nodular lymphocyte-predominant Hodgkin's lymphoma tumour and microenvironmental cells.

Hodgkin's lymphoma (HL) is among the most frequent nodal lymphomas in the Western world and is classified into two disease entities: nodular lymphocyte-predominant Hodgkin's lymphoma (NLPHL) and classical Hodgkin's lymphoma (cHL, 95% of all HL). HL lesions are characterised by a minority of clonal neoplastic cells, namely Hodgkin and Reed-Sternberg (HRS) cells and their variants in cHL and lymphocyte-predominant (LP) cells in NLPHL, both occurring within a microenvironment of, for example, reactive T and B cells, macrophages and granulocytes that are assumed to support the proliferation and maintenance of neoplastic cells through cytokines, chemokines and growth factors. Insulin-like growth factor I (IGF-I) is an important growth factor involved in proliferation, differentiation, apoptosis and cell survival of numerous (including immune) tissues and probably has a role in tumour pathogenesis and maintenance. Although HL is characterised by disturbed cell differentiation and apoptosis mechanisms, with the involvement of the IGF-I receptor (IGF-1R), the distinct location of IGF-I in HL has not yet been defined. We localise IGF-I by double-immunofluorescence in frequent neoplastic cells of all cHL and NLPHL cases investigated. Additionally, IGF-I immunoreactivity is detected in high endothelial venules and various immune cells within the surrounding tissue of cHL including neutrophils and macrophages. IGF-1R immunoreactivity of variable intensity is found in HRS cells and high endothelial venules within the microenvironment in cHL. We assume that autocrine and paracrine IGF-I plays an anti-apoptotic role in tumour pathogenesis and in shaping the tumour microenvironment.

Oestrogen and insulin-like growth factors during the reproduction and growth of the tilapia Oreochromis niloticus and their interactions.

Oestrogens and insulin-like growth factors (Igfs) play both a central role in the regulation of reproduction and growth and can interact especially in species showing a clear-cut sex-linked growth dimorphism (SGD) like in tilapia. Aromatase is essential in ovarian differentiation and oogenesis since it controls oestrogen synthesis. During tilapia sex differentiation, aromatase cyp19a1a expression increases from 9 days post-fertilization (dpf), resulting in high oestradiol level. High temperature, exogenous androgens or aromatase inhibitors override genetic sex differentiation inducing testes development through the suppression of cyp19a1a gene expression and aromatase activity. Supplementation with 17ß-oestradiol (E2) of gonadectomized juveniles induced a sustained and higher E2 plasma level than in intact or gonadectomized controls and both sexes showed reduced growth. Juvenile and mature females treated with the aromatase inhibitor 1,4,6-androstatriene-3,17-dione had 19% lower E2 plasma level compared to controls and they showed a 32% increased growth after 28 days of treatment. Altogether, these data suggest that E2 inhibits female growth leading to the SGD. Regarding Igf-1, mRNA and peptide appeared in liver at ∼ 4 dpf and then in organs involved in growth and metabolism, indicating a role in early growth, metabolism and organogenesis. Gonad igf-1 showed an early expression and the peptide could be detected at ∼ 7 dpf in somatic cells. It appeared in germ cells at the onset of ovarian (29 dpf) and testicular (52 dpf) meiosis. In testis, Igf-1 together with steroids may regulate spermatogenesis whereas in ovary it participates in steroidogenesis regulation. Igf-1 and Igf-2 promote proliferation of follicular cells and oocyte maturation. Igf-3 expression is gonad specific and localized in the ovarian granulosa or testicular interstitial cells. In developing gonads igf-3 is up-regulated in males but down-regulated in females. In contrast, bream Gh injections increased igf-1 mRNA in male and female liver and ovaries but gonadal igf-3 was not affected. Thus, local Igf-1 and Igf-2 may play crucial roles in the formation, development and function of gonads while Igf-3 depending on the species is involved in male and female reproduction. Furthermore, precocious ethynylestradiol (EE) exposure induced lasting effects on growth, through pituitary gh inhibition, local suppression of igf-1 expression and in testis only down-regulation of igf-3 mRNA. In conclusion, SGD in tilapia may be driven through an inhibitory effect due to E2 synthesis in female and involving Igfs regulation.

Developmental oestrogen exposure differentially modulates IGF-I and TNF-α expression levels in immune organs of Yersinia ruckeri-challenged young adult rainbow trout (Oncorhynchus mykiss).

Intensified aquaculture has strong impact on fish health by stress and infectious diseases and has stimulated the interest in the orchestration of cytokines and growth factors, particularly their influence by environmental factors, however, only scarce data are available on the GH/IGF-system, central physiological system for development and tissue shaping. Most recently, the capability of the host to cope with tissue damage has been postulated as critical for survival. Thus, the present study assessed the combined impacts of estrogens and bacterial infection on the insulin-like growth factors (IGF) and tumor-necrosis factor (TNF)-α. Juvenile rainbow trout were exposed to 2 different concentrations of 17ß-estradiol (E2) and infected with Yersinia ruckeri. Gene expressions of IGF-I, IGF-II and TNF-α were measured in liver, head kidney and spleen and all 4 estrogen receptors (ERα1, ERα2, ERß1 and ERß2) known in rainbow trout were measured in liver. After 5 weeks of E2 treatment, hepatic up-regulation of ERα1 and ERα2, but down-regulation of ERß1 and ERß2 were observed in those groups receiving E2-enriched food. In liver, the results further indicate a suppressive effect of Yersinia-infection regardless of E2-treatment on day 3, but not of E2-treatment on IGF-I whilst TNF-α gene expression was not influenced by Yersinia-infection but was reduced after 5 weeks of E2-treatment. In spleen, the results show a stimulatory effect of Yersinia-infection, but not of E2-treatment on both, IGF-I and TNF-α gene expressions. In head kidney, E2 strongly suppressed both, IGF-I and TNF-α. To summarise, the treatment effects were tissue- and treatment-specific and point to a relevant role of IGF-I in infection.

Interleukin-6 enhances insulin secretion by increasing glucagon-like peptide-1 secretion from L cells and alpha cells.

Exercise, obesity and type 2 diabetes are associated with elevated plasma concentrations of interleukin-6 (IL-6). Glucagon-like peptide-1 (GLP-1) is a hormone that induces insulin secretion. Here we show that administration of IL-6 or elevated IL-6 concentrations in response to exercise stimulate GLP-1 secretion from intestinal L cells and pancreatic alpha cells, improving insulin secretion and glycemia. IL-6 increased GLP-1 production from alpha cells through increased proglucagon (which is encoded by GCG) and prohormone convertase 1/3 expression. In models of type 2 diabetes, the beneficial effects of IL-6 were maintained, and IL-6 neutralization resulted in further elevation of glycemia and reduced pancreatic GLP-1. Hence, IL-6 mediates crosstalk between insulin-sensitive tissues, intestinal L cells and pancreatic islets to adapt to changes in insulin demand. This previously unidentified endocrine loop implicates IL-6 in the regulation of insulin secretion and suggests that drugs modulating this loop may be useful in type 2 diabetes.

Growth hormone (GH) treatment acts on the endocrine and autocrine/paracrine GH/IGF-axis and on TNF-α expression in bony fish pituitary and immune organs.

There exist indications that the growth hormone (GH)/insulin-like growth factor (IGF) axis may play a role in fish immune regulation, and that interactions occur via tumour necrosis factor (TNF)-α at least in mammals, but no systematic data exist on potential changes in GH, IGF-I, IGF-II, GH receptor (GHR) and TNF-α expression after GH treatment. Thus, we investigated in the Nile tilapia the influence of GH injections by real-time qPCR at different levels of the GH/IGF-axis (brain, pituitary, peripheral organs) with special emphasis on the immune organs head kidney and spleen. Endocrine IGF-I served as positive control for GH treatment efficiency. Basal TNF-α gene expression was detected in all organs investigated with the expression being most pronounced in brain. Two consecutive intraperitoneal injections of bream GH elevated liver IGF-I mRNA and plasma IGF-I concentration. Also liver IGF-II mRNA and TNF-α were increased while the GHR was downregulated. In brain, no change occurred in the expression levels of all genes investigated. GH gene expression was exclusively detected in the pituitary where the GH injections elevated both GH and IGF-I gene expression. In the head kidney, GH upregulated IGF-I mRNA to an even higher extent than liver IGF-I while IGF-II and GHR gene expressions were not affected. Also in the spleen, no change occurred in GHR mRNA, however, IGF-I and IGF-II mRNAs were increased. In correlation, in situ hybridisation showed a markedly higher amount of IGF-I mRNA in head kidney and spleen after GH injection. In both immune tissues, TNF-α gene expression showed a trend to decrease after GH treatment. The stimulation of IGF-I and also partially of IGF-II expression in the fish immune organs by GH indicates a local role of the IGFs in immune organ regulation while the differential changes in TNF-α support the in mammals postulated interactions with the GH/IGF-axis which demand for further investigations.

Endocrine disrupting compounds: can they target the immune system of fish?

Endocrine disruption, in particular disruption by estrogen-active compounds, has been identified as an important ecotoxicological hazard in the aquatic environment. Research on the impact of endocrine disrupting compounds (EDCs) on wildlife has focused on disturbances of the reproductive system. However, there is increasing evidence that EDCs affect a variety of physiological systems other than the reproductive system. Here, we discuss if EDCs may be able to affect the immune system of fish, as this would have direct implications for individual fitness and population growth. Evidence suggesting an immunomodulatory role of estrogens in fish comes from the following findings: (a) estrogen receptors are expressed in piscine immune organs, (b) immune gene expression is modulated by estrogen exposure, and (c) pathogen susceptibility of fish increases under estrogen exposure.

Further insights into the insulin-like growth factor-I system of bony fish pituitary with special emphasis on reproductive phases and social status.

Insulin-like growth factor (IGF)-I, which is crucially involved in fish growth, differentiation, and reproduction, occurs in tilapia pituitary. IGF-I peptide, which is probably produced in hypothalamic perikarya, is present in axons of the neurohypophysis, and IGF-I mRNA and peptide are present in the adenohypophysis in adrenocorticotrophic hormone cells, melanocyte-stimulating hormone cells, with interindividual differences in growth hormone cells, and, starting with puberty, in gonadotrophic hormone (GTH) cells. Subordinate males showed a high IGF-I but a lower beta-luteinizing hormone expression, while in dominant males the opposite was found. IGF-I from the GTH cells may act as auto/paracrine regulators of GTH cell proliferation and enhance GTH synthesis and release during puberty and reproduction, depending on the social status.

Challenge with 17alpha-ethinylestradiol (EE2) during early development persistently impairs growth, differentiation, and local expression of IGF-I and IGF-II in immune organs of tilapia.

The enormous expansion of world-wide aquaculture has led to increasing interest in the regulation of fish immune system. Estrogen has recently been shown to inhibit the endocrine (liver-derived) and autocrine/paracrine local insulin-like growth factor-I system in fish. In order to address the potential actions of estrogen on the IGF system in immune organs, tilapia were fed with 17alpha-ethinylestradiol (EE2)-enriched food from 10 to 40 days post fertilization (DPF) to induce functional feminization, an approach commonly used in aquaculture. EE2-treated and control fish were sampled at 75 and 165 DPF. The expression levels of ER-alpha, IGF-I, IGF-II and growth hormone receptor (GH-R) mRNA in spleen and head kidney were determined by real-time PCR and the expressing sites of IGF-I mRNA identified by in situ hybridisation. Ratios of spleen length and weight to body length and weight were determined. At 165 DPF, the length (4.9% vs. 7.6%) and weight (0.084% vs. 0.132%) ratios were significantly lowered in EE2-treated fish and number and size of the melanomacrophage centres were considerably reduced. At 75 DPF, both in spleen and head kidney of EE2-treated fish the expression levels of IGF-I and IGF-II mRNA were markedly diminished. The suppression was more pronounced for IGF-I (spleen: -12.071-fold; head kidney: -8.413-fold) than for IGF-II (spleen: -4.102-fold; head kidney: -1.342-fold). In agreement, clearly fewer leucocytes and macrophages in head kidney and spleen of EE2-treated fish contained IGF-I mRNA as shown by in situ hybridisation. ER-alpha mRNA expression in spleen was increased at 75 DPF but unchanged in head kidney. GH-R gene expression showed a mild upregulation at 165 DPF in both tissues. Thus, exposure to EE2 during early development affected distinctly the IGF system in tilapia immune organs. It led to lasting impairment of spleen growth and differentiation that can be attributed to an interaction of EE2 with IGF-I and, less pronouncedly, IGF-II. Especially, the impairment of spleen and melanomacrophage centres might interfere with the antigen presentation capacity of the immune system and, thus, alter susceptibility to infection.

Insulin-like growth factor I messenger RNA and protein are expressed in the human lymph node and distinctly confined to subtypes of macrophages, antigen-presenting cells, lymphocytes and endothelial cells.

Insulin-like growth factor I (IGF-I) is a potent hormone that stimulates growth and differentiation and inhibits apoptosis in numerous tissues. Preliminary evidence suggests that IGF-I exerts differentiating, mitogenic and restoring activities in the immune system but the sites of synthesis of local IGF-I are unknown. Identification of these sites would allow the functional role of local IGF-I to be clarified. The presence of IGF-I in non-immune cells suggests that it acts as a trophic factor, while its occurrence in subtypes of lymphocytes or antigen-presenting cells indicates paracrine/autocrine direct regulatory involvement of IGF-I in the human immune response. The present study investigated the location of IGF-I messenger RNA and protein on archival human lymph node samples by in situ hybridization, immunohistochemistry and double immunofluorescence staining using an IGF-I probe and antisera specific for human IGF-I and CD3 (T lymphocytes), CD20 (B lymphocytes), CD68 (macrophages), CD21 (follicular dendritic cells), S100 (interdigitating dendritic cells) and podoplanin (fibroblastic reticular cells). Numerous cells within the B- and T-cell compartments expressed the IGF-I gene, and the majority of these cells were identified as macrophages. Solitary follicular dendritic cells exhibited IGF-I. A few T lymphocytes, and no B lymphocytes, contained IGF-I immunoreactive material. Furthermore, IGF-I immunoreactive cells outside the follicles that did not react with CD3, CD20, S100 or podoplanin markers were identified as high-endothelial venule (HEV) cells. From this we conclude that the main task of IGF-I in human non-tumoral lymph node may be autocrine and paracrine regulation of the differentiation, stimulation and survival of lymphocytes, antigen-presenting cells and macrophages and the differentiation and maintenance of HEV cells.

Surface marker-defined head kidney granulocytes and B lymphocytes of rainbow trout express benzo[a]pyrene-inducible cytochrome P4501A protein.

Polycyclic aromatic hydrocarbons (PAHs) such as benzo[a]pyrene (BaP) are immunotoxic to fish. Metabolism of PAHs in immune cells has been implicated in PAH immunotoxicity in mammals, but for fish the presence of metabolic enzymes in immune cells is less clear. The objective of this study was to examine localization and induction of the BaP-metabolizing biotransformation enzyme, cytochrome P4501A (CYP1A), in head kidney immune cells of rainbow trout (Oncorhynchus mykiss). In the first step, we measured induction of CYP1A-dependent 7-ethoxyresorufin-O-deethylase (EROD) activity and CYP1A protein in head kidney of rainbow trout treated with a single intraperitoneal (ip) injection of 25 mg BaP/kg body weight. From days 3 to 10 postinjection, the BaP treatment led to a significant elevation of EROD and CYP1A protein in head kidney and liver, with CYP1A expression levels in the head kidney being much lower than in the liver. Next, we examined the cellular localization of CYP1A protein in the head kidney cell types: vascular endothelial, endocrine and lymphoid cells. CYP1A immunoreactivity was detectable only in BaP-treated trout, where it was localized in endothelial and lymphoid cells. Finally, we aimed to clarify which of the hematopoietic cell types possess CYP1A protein. Using double immunostaining for CYP1A and surface markers of rainbow trout immune cells, we identified B lymphocytes and granulocytes expressing inducible CYP1A protein and being the likely sites of BaP metabolism in the head kidney.