Comparison of the metabolism of 10 chemicals in human and pig skin explants

Skin metabolism is important to consider when assessing local toxicity and/or penetration of chemicals and their metabolites. If human skin supply is limited, pig skin can be used as an alternative. To identify any species differences, we have investigated the metabolism of 10 chemicals in a pig and human skin explant model. Phase I metabolic pathways in skin from both species included those known to occur via cytochrome P450s, esterases, alcohol dehydrogenases and aldehyde dehydrogenases. Common Phase II pathways were glucuronidation and sulfation but other conjugation pathways were also identified. Chemicals not metabolized by pig skin (caffeine, IQ and 4‐chloroaniline) were also not metabolized by human skin. Six chemicals metabolized by pig skin were metabolized to a similar extent (percentage parent remaining) by human skin. Human skin metabolites were also detected in pig skin incubations, except for one unidentified minor vanillin metabolite. Three cinnamyl alcohol metabolites were unique to pig skin but represented minor metabolites. There were notable species differences in the relative amounts of common metabolites. The difference in the abundance of the sulfate conjugates of resorcinol and 4‐amino‐3‐nitrophenol was in accordance with the known lack of aryl sulfotransferase activity in pigs. In conclusion, while qualitative comparisons of metabolic profiles were consistent between pig and human skin, there were some quantitative differences in the percentage of metabolites formed. This preliminary assessment suggests that pig skin is metabolically competent and could be a useful tool for evaluating potential first‐pass metabolism before testing in human‐derived tissues.

We have investigated the metabolism of 10 chemicals in viable pig and human skin. Phase I and II metabolic pathways were present in skin from both species. Chemicals not metabolized by pig skin were also not metabolized by human skin. Six chemicals metabolized by pig skin were also metabolized to a similar extent by human skin. Pig and human skin produced common metabolites, although some species differences were observed and as their relative amounts differed.

Principles for the safety evaluation of cosmetic powders

Consumer exposure to cosmetic (personal care) products is mostly by dermal contact, however additional considerations with regards to potential inhalation exposure from some cosmetics, such as sprays and powders, may be needed for a robust and reliable safety assessment. To get a deeper understanding of the exposure to airborne particles and droplets during product application, a team of international experts was founded under the umbrella of the European Association of the Cosmetic Industry "Cosmetics Europe" (CE) in Brussels. This expert team has worked out a pragmatic strategy how small and medium sized enterprises (SMEs), but also relevant authorities, could handle the safety evaluation of cosmetic powder products. Sufficient information on the aerodynamic diameter of sprayed droplets and here specifically of airborne particles is essential in addition to knowing the exposure after typical product application. The current article is focused on the determination of inhalation exposure to solids, and the derivation of safe exposure levels for cosmetic powder products found in the market. The principles described herein are very similar to spray products as published earlier and should be applied in a similar way (Steiling et al., 2014). Prediction models for the best estimate of inhalation exposure, developed with data from computer simulation programs, individual real-time measurements or finally by experience from the market were introduced and applied. Safety assessment approaches for exposure from powder spray products were developed and have been already considered in regulatory guidelines like the EC Cosmetics Regulation.

Comparison of protocols measuring diffusion and partition coefficients in the stratum corneum

Partition (K) and diffusion (D) coefficients are important to measure for the modelling of skin penetration of chemicals through the stratum corneum (SC). We compared the feasibility of three protocols for the testing of 50 chemicals in our main studies, using three cosmetics-relevant model chemicals with a wide range of logP values. Protocol 1: SC concentration-depth profile using tape-stripping (measures KSC/v and DSC /HSC2 , where HSC is the SC thickness); Protocol 2A: incubation of isolated SC with chemical (direct measurement of KSC/v only) and Protocol 2B: diffusion through isolated SC mounted on a Franz cell (measures KSC/v and DSC /HSC2 , and is based on Fick's laws). KSC/v values for caffeine and resorcinol using Protocol 1 and 2B were within 30% of each other, values using Protocol 2A were ~two-fold higher, and all values were within 10-fold of each other. Only indirect determination of KSC/v by Protocol 2B was different from the direct measurement of KSC/v by Protocol 2A and Protocol 1 for 7-EC. The variability of KSC/v for all three chemicals using Protocol 2B was higher compared to Protocol 1 and 2A. DSC /HSC2 values for the three chemicals were of the same order of magnitude using all three protocols. Additionally, using Protocol 1, there was very little difference between parameters measured in pig and human SC. In conclusion, KSC/v, and DSC values were comparable using different methods. Pig skin might be a good surrogate for human skin for the three chemicals tested. Copyright © 2017 The Authors Journal of Applied Toxicology published by John Wiley & Sons Ltd.

[Lymph node metastases in ypT1/2 rectal cancer after neoadjuvant chemoradiotherapy : The Achilles heel of organ-preserving operative procedures?]

BACKGROUND

For patients with rectal cancer and complete remission (ypT0) or with good response and residual tumor restricted only to the bowel wall (ypT1-2) after neoadjuvant chemoradiotherapy (CRT), local excision has been suggested as an alternative to avoid the significant morbidity and functional deficits associated with total mesorectal excision (TME). The aim of this investigation was to investigate the incidence, distribution and tumor-related localization of mesorectal lymph node (LN) metastases in TME specimens with complete remission (ypT0), intramural (ypT1-2) and extramural (ypT3-4) residual tumor tissue.

PATIENTS AND METHODS

Specimens of TME from 81 patients with locally advanced rectal cancer (UICC II-III) undergoing neoadjuvant CRT within the phase III German rectal cancer trial CAO/ARO/AIO-04 were prospectively evaluated. The entire mesorectal compartment was microscopically screened after complete paraffin embedding. The number and localization of all detectable LN metastases were documented in relation to the primary tumor.

RESULTS

Whereas 50 patients (62 %) had ypT3-4 rectal cancer after neoadjuvant CRT, 20 patients (25 %) presented with residual tumor within the bowel wall (ypT1-2), 11 patients (14 %) had pathological complete remission (ypT0), an average of 28 ± 13.7 LN were detected per specimen and 25 patients (31 %) had residual LN metastases after CRT. Although the incidence of LN metastases was higher in the ypT3-4 group (40 %), 25 % of patients in the ypT1-2 group with intramural residual tumor had a mean number of 2.2 residual LN metastases of which 55 % were located far from the primary lesion in the proximal mesorectum. None of the patients with ypT0 status (complete response) had residual LN metastases.

CONCLUSION

Even in patients with good response and post-CRT tumor tissue restricted only to the bowel wall (ypT1-2), there is still a considerable risk for residual LN metastases. Local excision of residual rectal cancer was accompanied by a higher rate of local failure and radical surgery with TME should remain the standard treatment in these patients. To date, valid selection criteria for patients eligible for organ-sparing surgery are still lacking.

Cervical Strip Biopsy for High-Grade Cervical Intraepithelial Lesions: a Valid Alternative to Conventional Punch Technique

Introduction: To evaluate, if targeted strip biopsies decrease trauma/pain perception while maintaining diagnostic accuracy in patients with the diagnosis of high-grade squamous intraepithelial lesions of the uterine cervix. Patients and Methods: Between July 1st and December 31st 2014 we performed colposcopically directed strip biopsies in 102 patients with colposcopic suspicion of high-grade squamous intraepithelial lesions of the uterine cervix. We used a 3 mm curette for harvesting tissue samples under VITOM® videocolposcopy. So far, 60 patients underwent additional loop excision. Histologic examination of strip biopsies and loop specimens included routine hematoxylin and eosin staining as well as immunohistochemical staining for p16, Ki 67 and stathmin-1. Results: 55 patients (53 %), were histologically diagnosed with cervical intraepithelial neoplasia grade 3 on strip biopsies. Adenocarcinoma in situ was diagnosed in 2 patients (2 %), cervical intraepithelial neoplasia grade 2 in 35 patients (34 %), and cervical intraepithelial neoplasia grade 1 in 10 patients (10 %). The agreement between histologic results of strip biopsy and loop specimen was highly significant: In all 60 strip biopsies diagnosed with high-grade squamous intraepithelial lesions this diagnosis was confirmed histologically during follow-up loop specimen excision (high-grade squamous intraepithelial lesions in 58 patients, invasive disease in 2 patients). The pain level experienced during strip biopsy was rated on average 0.25 on a scale from 0 to 10. No clinically significant bleeding was reported. Conclusion: Targeted strip biopsies with a 3 mm curette are a reliable procedure to diagnose high-grade squamous intraepithelial lesions of the uterine cervix and yield high patient satisfaction (Video 1).

Elicitation of the immune response to p-phenylenediamine in allergic patients: the role of dose and exposure time

BACKGROUND

Usage of hair dye products containing p-phenylenediamine (PPD) is a concern for PPD-allergic individuals.

OBJECTIVES

The present study investigates the role of dose and exposure time on elicitation of allergic contact dermatitis under conditions of permanent hair dyeing.

METHODS

Elicitation responses after application of a typical hair dye product containing 2% PPD for 30 min followed by rinsing were analysed in 38 PPD-allergic individuals with a documented history of hair dye-related allergy. Skin binding experiments in vitro were performed to distinguish the dose available for elicitation from the dose applied.

RESULTS

A positive reaction was elicited in 20 of 20 patients with grades ++ to +++ and 12 of 18 with grade + according to the classification of the International Contact Dermatitis Research Group. Under conditions of diagnostic patch testing (48 h exposure), the dose available for elicitation is more than 10-fold higher compared with the dose available for hair dyeing (30-min exposure, rinsing of product).

CONCLUSIONS

This investigation demonstrates that under simulated hair dye use conditions the actual exposure to PPD is more than an order of magnitude lower than under diagnostic patch testing, although sufficient to elicit a clearly noticeable reaction in 84% of PPD patch test-positive individuals.

[Individualizing treatment for locally advanced rectal cancer]

Based on results of the German Rectal Cancer Study Group CAO/ARO/AIO-94 trial, long-term chemoradiotherapy (RT/CTx) is recommended as standard treatment for locally advanced rectal cancer (UICC stages II/III) in the lower two thirds of the rectum (0-12 cm from the anocutaneous verge). Tumor response to neoadjuvant therapy is very heterogeneous, ranging from complete remission to total resistance to RT/CTx. To fulfill the clinical requirement of individual and risk-adapted multimodal treatment, distinct progress in translational research has been achieved (e.g. gene profiling). However, in clinical reality "individualization" of the therapy of rectal cancer patients has not actually been realized. This can be achieved only on the basis of successful randomized clinical trials (e.g. the CAO/ARO/AIO-04 and GAST-05 trials) translationally combined with basic scientific approaches. One simple first step toward individualizing rectal cancer therapy is being made with the ongoing GAST-05 trial. This investigator initiated phase II trial funded by the German Research Foundation (Deutsche Forschungsgemeinschaft) excludes preoperative RT/CTx for patients with rectal cancer localized in the upper third of the rectum, using only quality controlled principles of radical surgery (partial vs total mesorectal excision) followed by adjuvant chemotherapy.

Serum IFN-gamma and IL-10 levels are associated with disease progression in non-obese diabetic mice

BACKGROUND

The goal of the present study was to determine whether cytokines in the peripheral blood of naive NOD mice correlate with the disease process and thereby would provide a marker for monitoring disease activity.

METHODS

Female NOD mice (5, 10 and 14-16 weeks of age) were investigated in a cross-sectional study. In the group of 14-16-week-old mice, non-diabetic and diabetic mice were analysed as different subgroups. The Th1 cytokine (IFN-gamma) and the Th2 cytokine (IL-10) were quantified in serum by sandwich enzyme-linked immunosorbent assay (ELISA). Pancreatic mRNA for IFN-gamma and IL-10 was determined by reverse transcriptase-polymerase chain reaction (RT-PCR) from the same animals.

RESULTS

Serum levels of IFN-gamma were initially low but increased with age in NOD mice, reaching the highest levels at diabetes onset (p<0.002 compared to 10 weeks). A similar rise was noted in IFN-gamma gene expression in pancreatic lesions. In contrast, an early peak of serum IL-10 levels was observed in non-diabetic NOD mice (10 weeks) at a stage where non-destructive insulitis occurs. With increasing age a continuous loss of IL-10 until progression towards diabetes was observed. The pancreatic IL-10 mRNA expression correlated with serum IL-10 changes. As a consequence, the ratio of IFN-gamma/IL-10, reflecting the Th1/Th2 balance in the serum, was significantly increased in diabetic compared to non-diabetic NOD mice (p<0.005).

CONCLUSION

These results demonstrate, for the first time, that an increased Th2 pattern in the non-diabetic stage preceding a Th1 shift is associated with the development of diabetes in naive NOD mice. Serum cytokines correlate with disease progression and pancreatic cytokine expression during prediabetes. Soluble cytokines measured in the periphery are therefore promising surrogate markers of diabetes development.

Immunoregulation during disease progression in prediabetic NOD mice: inverse expression of arginase and prostaglandin H synthase 2 vs. interleukin-15

Non-obese diabetic (NOD) mice spontaneously develop insulin dependent diabetes due to autoimmune destruction of beta-cells. The progression of insulitis can be accelerated and synchronized in the pancreas by a single injection of 250 mg/kg cyclophosphamide. In this study, we will report on three immune mediators that were not known to be expressed during insulitis until now. Early insulitis in ten-week-old female NOD mice was associated with strong expression of prostaglandin H synthase 2 in the pancreas and of arginase, an antagonist enzyme of the inducible NO synthase. After acceleration of insulitis progression by cyclophosphamide, expression of the two enzymes was downregulated within 24 h. There was strong concomitant upregulation of IL-15 gene expression that preceded lymphocyte invasion of islets and a rise of IFN-gamma mRNA levels by several days. The comparison of individual pancreata showed that the expression of IL-12 and IL-18 mRNA closely correlated with levels of IL-15 gene expression. We conclude that arginase and prostaglandin H synthase 2 expression is associated with peri-insulitis, while IL-15 is a candidate cytokine in driving destructive insulitis, as it elicits Th1-cytotoxic responses in lymphoid as well as in non-lymphoid immune cells and is unusually resistant to downregulation by antagonistic cytokines. This is the first report on arginase, prostaglandin H synthase 2 and IL-15 expression in pancreatic lesions of prediabetic NOD mice.

Disease resistant, NOD-related strains reveal checkpoints of immunoregulation in the pancreas

The autoimmune diabetic NOD mouse serves as a model for human type 1 diabetes. Disease development is due to islet beta cell destruction in the context of immune cell infiltration of islets and inflammatory changes throughout the pancreas. In the present study we tried to identify immune reactivity patterns in the pancreas associated with diabetes resistance in NOD-related mouse strains. The pancreata of diabetes-prone female NOD/LtJ, NOD/Bom and of genetically related but diabetes-resistant strains; NOR, NON, NON.NOD-H2g7, NOD.NON-H-2nbl were obtained at the age of 70 days for semiquantitative analysis of insulitis and of mRNA expression by reverse transcriptase PCR. In addition, the response to a single dose of cyclophosphamide for synchronizing and accelerating the progression of insulitis was determined. The progression of insulitis and immune gene expression in response to cyclophosphamide revealed characteristic differences between the six strains. NOD/LtJ and NOD/Bom mice were found significantly to upregulate pancreatic IL-12p40 and IL-18 expression after cyclophosphamide treatment, followed by an increase in IFN-gamma mRNA levels. In contrast, the two MHC-haplotype H-2nbl expressing strains either up-regulated neither IL-12/IL-18 nor IFN-gamma gene expression. The two strains sharing MHC haplotype H-2g7 expression with NOD did respond to cyclophosphamide with IL-12p40/IL-18 gene expression. However, NON.NOD-H-2g7 mice failed to progress to IFN-gamma gene expression. NOR mice progressed to IFN-gamma expression but exhibited sustained IL-4 gene expression. Only severe intra-insulitis was associated with the expression of inducible NO synthase. The comparison of diabetes-prone and diabetes-resistant strains revealed three checkpoints of immune regulation in the pancreas. The earliest checkpoint is the induction of an IL-12p40/IL-18 response in innate immune or antigen-presenting cells. The next level of control is at the induction of IFN-gamma gene expression, and a third checkpoint is the maintenance or loss of antagonistic Th2 type reactions.

The size of differences as a quality criterion for characters in phylogenetics

One important aspect regarding the suitability of a character for phylogenetic reconstruction is the separability of compared groups with regard to different character states. Therefore, it is recommendable to standardize mean differences with respect to the dispersion of individual data.

The influence of abiotic factors on the onset and cessation of activity of semi-free Callithrix jacchus

The influence of abiotic environmental factors on the period of activity of a single group of South American common marmosets (Callithrix jacchus, Callitrichidae, Primates) was investigated under semi-free conditions. A group of eight members had a territory consisting of a heated wooden hut with a veranda, surrounded by an open area with a few trees (ca. 3.5 m high) and three runways made out of roofing slats, on which feeding places and sleeping boxes were fixed. The food supply was held constant throughout the observation period with respect to amount, composition and spatial distribution. From July to November 1995, the times of the onset and cessation of activity were determined using a video camera. An electronic weather station recorded the temperature, humidity, air pressure, wind speed, wind direction, precipitation, and light intensity at intervals of 5 min. There was a linear correlation between day light length and the length of the period of activity over a day length of 10 to 14 hr. With shorter day lengths, the marmosets were also active during the twilight, whereas with longer day lengths a sleep phase during the late morning was introduced. Ambient temperature and humidity had also an effect on the time when activity began or ceased. Callithrix jacchus has one of the longest activity periods within the Callitrichidae. The time of sunrise or sunset, temperature, and humidity accounted for 66.2% of the variation in the time when activity began and 75.5% of the variance in the cessation of activity of the study group within the multivariate model. The results from the present study add to the indications that in the Callitrichidae there is a strong selection pressure for the highest possible energy saving during the comparatively long phase of inactivity.

IL-18 inhibits diabetes development in nonobese diabetic mice by counterregulation of Th1-dependent destructive insulitis

The development of type 1 diabetes in animal models is T cell and macrophage dependent. Islet inflammation begins as peripheral benign Th2 type insulitis and progresses to destructive Th1 type insulitis, which is driven by the innate immune system via secretion of IL-12 and IL-18. We now report that daily application of IL-18 to diabetes-prone female nonobese diabetic mice, starting at 10 wk of age, suppresses diabetes development (p < 0.001, 65% in sham-treated animals vs 33% in IL-18-treated animals by 140 days of age). In IL-18-treated animals, we detected significantly lower intraislet infiltration (p < 0.05) and concomitantly an impaired progression from Th2 insulitis to Th1-dependent insulitis, as evidenced from IFN-gamma and IL-10 mRNA levels in tissue. The deficient progression was probably due to lesser mRNA expression of the Th1 driving cytokines IL-12 and IL-18 by the innate immune system (p < 0.05). Furthermore, the mRNA expression of inducible NO synthase, a marker of destructive insulitis, was also not up-regulated in the IL-18-treated group. IL-18 did not exert its effect at the levels of islet cells. Cultivation of islets with IL-18 affected NO production or mitochondrial activity and did not protect from the toxicity mediated by IL-1beta, TNF-alpha, and IFN-gamma. In conclusion, we show for the first time that administration of IL-18, a mediator of the innate immune system, suppresses autoimmune diabetes in nonobese diabetic mice by targeting the Th1/Th2 balance of inflammatory immune reactivity in the pancreas.

"You know that our old institute was entirely destroyed": on the history of the Frankfurt Psychoanalytical Institute (FPI), 1929-1933

Psychoanalytical Institutes had been founded in Berlin in 1920, in Vienna in 1922 and in London in 1925; the Frankfurt Psychoanalytical Institute (1929-1933) was thus among the first European Institutes. The closure in 1933 at the hands of the National Socialists obliterated virtually all memory, for decades, of psychoanalysis. It was not until the 1980s that a general interest in the history of the movement was revived and the Frankfurt Institute was rescued from oblivion. An interdisciplinary group, in which the authors participated, commenced with the documentation of interviews with survivors and the reconstruction from records and archives. The results were published in a remarkable volume to present the history of psychoanalysis in one city. The article illustrates the opening phase of the history from an institutional viewpoint.

The Frankfurt Psychoanalytical Institute was established with guest status within the Institute for Social Research and under the auspices of Max Horkheimer, one of the founders of ‘Critical Theory’. Horkheimer's subsequent analysis of the relationship of ‘History and Psychology’ was based on the outcome of psychoanalytical work with Karl Landauer, the Director of the FPI in collaboration with Heinrich Meng. Other psychoanalysts from the FPI, Frieda Fromm-Reichmann, Erich Fromm and S.H. Foulkes, were to reach international acclaim for their pioneering work after their emigration. The intention is to show the inauguration of the FPI in 1929, its concept, members and results and the circumstances of its closure in 1933.

Strategies of protection from nitric oxide toxicity in islet inflammation

Nitric oxide is thought to contribute to beta cell destruction during islet inflammation in animal models of type I diabetes. In vitro, inhibition of inducible nitric oxide synthase protects islet cells from the damaging effects of inflammatory cells or cytokines. However, the administration of several inducible nitric oxide synthase inhibitors to prediabetic animals had variable effects on disease progression. An alternative approach is to prevent the lethal consequences of nitric oxide action at the level of islet cells. We observed that the suppression of poly-(ADP-ribose)-polymerase ensures survival of islet cells exposed to nitric oxide. Cells could also be rendered resistant by the induction of endogenous stress proteins in particular of heat shock protein 70. Nitric oxide is not only a strong cytotoxic agent, but is also able to modulate immune reactions by interfering with Th1/Th2 reactivities. This may occur via induction of the interleukin-12 antagonist IL-12(p40)2. Development of type 1 diabetes is known to be correlated with a shift from a Th2 status during benign insulitis to a Th1 status during destructive insulitis. This shift was found dependent on local interleukin-12 gene expression. Indeed, administration of a natural interleukin-12 antagonist suppressed the progression of islet inflammation and concomitant upregulation of the inducible nitric oxide synthase.

Soluble forms of intercellular adhesion molecule-1 inhibit insulitis and onset of autoimmune diabetes

Increased concentration of circulating adhesion molecules in human serum have been described in different immune-mediated diseases. Recently, we proposed an immunomodulatory function of soluble forms of the intercellular adhesion molecule-1 (ICAM-1) during the pathogenesis of human Type I (insulin-dependent) diabetes mellitus. To test this hypothesis in nonobese diabetic (NOD) mice, a spontaneous animal model for human Type I diabetes, two recombinant forms of soluble murine ICAM-1 were generated, one monomeric soluble ICAM-1 containing all five extracellular Ig-like domains of ICAM-1 (rICAM-1) and one dimeric protein with the N-terminal extracellular domains fused to the constant regions of murine IgG2a (rICAM-1-Ig). Beginning at age 35 days prediabetic NOD mice received i. p. injections of 5 microg recombinant ICAM-1-proteins three times a week for 4.5 months. At day 170 diabetes development was reduced (p < 0.001) in NOD mice receiving rICAM-1 (8%) or rICAM-1-Ig (8%) treatment in comparison with sham treated animals (45%). After termination of therapy animals treated with multimeric rICAM-1-Ig were protected longer than animals treated with rICAM-1. Prevention of diabetes was associated with decreased infiltration of pancreatic islets by mononuclear cells. A selective downregulation of Th1-type cytokine expression was observed in a second set of experiments in which diabetes development was synchronised by cyclophosphamide. These data support the hypothesis that circulating forms of adhesion molecules have an immunomodulatory function and can intervene in islet inflammation.

The APC1 concept of type I diabetes

Type I diabetes appears to be a T cell dependent disease. T cell reactivity is regulated by antigen presenting cells (APCs). In animal models of type I diabetes, abnormal reactivity of APCs, in particular of macrophages, probably is responsible for the progression of islet inflammation from T helper type 2 dependent benign periinsulitis to T helper type I dependent destructive intrainsulitis. The functional state of APCs during preferential stimulation of Th1 reactivities (APC1 state) is characterized by the release of TNFalpha, IL-12 and/or IL-18. The bias towards APC1 reactivity has been found due to defective inhibition via IL-10 and PGE2.

Insulin therapy of prediabetes suppresses TH1 associated gene expression in BB rat pancreas

Subcutaneous insulin treatment of young diabetes prone BB rats has been shown previously to suppress the development of autoimmune diabetes. In this study the hypothesis was tested that exogenous insulin may deviate the autoimmune process by acting on the Th1/Th2 cytokine balance in the pancreas. BB rats were implanted with pellets which continuously released insulin, at 50 d of age. Three weeks later cytokine mRNA expression in the pancreas and insulitis score were determined. While in control BB rats high levels of IFNgamma mRNA were detectable by RT-PCR, insulin treatment almost completely suppressed IFNgamma mRNA levels without concomitant upregulation of counterregulatory IL-10 and TGFbeta gene expression. Insulin also suppressed gene expression of inducible nitric oxide synthase. Mean insulitis scores were decreased after insulin treatment. We conclude that the protective effects of insulin treatment may not be due to the induction of protective Th2 immune reactivity but to general downregulation of immune activation in the pancreas, and hence also of Th1 autoimmunity.

Intervention in autoimmune diabetes by targeting the gut immune system

BB rats and nonobese diabetic (NOD) mice spontaneously develop autoimmune insulin dependent diabetes and serve as models for human type I diabetes. During progression of the disease the cytokine pattern elaborated by islet infiltrating immune cells shifts from a Th2 or Th0 toward Th1 type. Only the latter is associated with "destructive" insulitis. We discuss here attempts to modulate disease progression by targeting the gut immune system with bacterial immunostimulants. Oral dosing of diabetes prone BB rats with lipopolysaccharide (LPS) or the Escherichia coli extract OM-89 lead to a Th2-shift of pancreatic mRNA expression. In vitro studies showed that repeated exposure toward LPS or OM-89 lead to downregulation of proinflammatory macrophage responses. In the NOD mouse, repeated oral dosing of OM-89 caused a Th2 shift in the gut cytokine gene expression, probably because of desensitization of macrophages and other antigen presenting cells. Concomitantly, diabetes prevention by oral insulin was improved. In conclusion, oral dosing with bacterial immunostimulants dampens Th1 type immune reactivities of the gut immune system and thereby promotes oral tolerance mechanisms. Downregulation of proinflammatory immune reactivities by repeated exposure to bacterial stimulants requires intact desensitization mechanisms in macrophages or other antigen presenting cells.

Suppression of cyclophosphamide induced diabetes development and pancreatic Th1 reactivity in NOD mice treated with the interleukin (IL)-12 antagonist IL-12(p40)2

The macrophage product interleukin (IL)-12 is known to drive Th1 reactions in physiological and pathological immune responses. Here we report that treatment with the homodimeric IL-12p40 subunit, an antagonist of the bioactive IL-12p35/p40 heterodimer, suppresses diabetes development in cyclophosphamide-injected NOD mice. Female mice of 70 days old received cyclophosphamide (250 mg/kg) to accelerate and synchronize diabetes development, and daily injections of 1 microgram IL-12(p40)2. While there was no delay of the first diabetes cases, the incidence of overt diabetes was significantly decreased in treated mice (46 vs 23%, p < 0.05). Analysis of mRNA expression in the pancreas showed that administration of the IL-12 antagonist had dampened interferon-gamma gene expression, decreased the ratio of interferon-gamma/IL-10 mRNA levels and in parallel suppressed the expression of the inducible nitric oxide synthase. At the same time intra-islet infiltration was significantly decreased (p < 0.001). Interestingly, the administration of IL-12(p40)2 also affected IL-12 gene expression, by downregulation of p35 mRNA. We conclude that IL-12 p40 homodimer suppresses diabetes development in the NOD mouse by dampening islet inflammation via selective down-regulation of Th1 type responses. The naturally occurring IL-12 antagonist IL-12(p40)2 represents a new and specific Th1 directed approach to prevent autoimmune diabetes.

Systemic production of interferon-gamma inducing factor (IGIF) versus local IFN-gamma expression involved in the development of Th1 insulitis in NOD mice

We report that the onset of Th1 insulitis is preceded by a rise of interferon-gamma inducing factor (IGIF) mRNA expression in the spleen. This systemic shift towards Th1 reactivities was underlined by a close correlation of IGIF and IL-12p40 mRNA levels in the spleen, as determined by semi-quantitative RT-PCR. Cyclophosphamide-induced IGIF expression was also observed in MHC congenic NOR mice, but not in MHC class II-incompatible NON mice. The systemic rise of IGIF was followed by the development of destructive Th1-associated intra-insulitis. Interestingly, immunohistochemistry showed IL-4-positive cells evenly dispersed throughout the infiltrate, while IFN-gamma-positive cells were restricted to the vicinity of beta-cells. We conclude that cyclophosphamide induces a systemic shift in antigen presenting cells towards favouring Th1 responses, in an MHC dependent manner. Despite this general bias in immune reactivity, activation of Th1 cells in insulitis occurs only close to beta-cells, indicating a crucial role of antigen presentation by beta-cells or in their immediate vicinity.

Active stage of autoimmune diabetes is associated with the expression of a novel cytokine, IGIF, which is located near Idd2

Recently, interferon-gamma-inducing-factor (IGIF) has been described as a novel monokine that is a more potent interferon-gamma (IFN-gamma) inducer than IL-12. By cloning IGIF from affected tissue and studying IGIF gene expression, we describe for the first time a close association of this cytokine with an autoimmune disease. The non-obese diabetic (NOD) mouse spontaneously develops autoimmune insulitis and diabetes which can be accelerated and synchronized by a single injection of cyclophosphamide. IGIF mRNA was demonstrated by reverse transcriptase PCR in NOD mouse pancreas during early stages of insulitis. Levels of IGIF mRNA increased rapidly after cyclophosphamide treatment and preceded a rise in IFN-gamma mRNA, and subsequently diabetes. Interestingly, these kinetics mimick that of IL-12p40 mRNA, resulting in a close correlation of individual mRNA levels. Cloning of the IGIF cDNA from pancreas RNA followed by sequencing revealed identity with the IGIF sequence cloned from Kupffer cells and in vivo preactivated macrophages. When extending our study to macrophages of the spleen we observed that NOD mouse macrophages responded to cyclophosphamide with IGIF gene expression while macrophages from Balb/c mice treated in parallel did not. The IGIF gene position is located within the Idd2 interval on mouse chromosome 9 and therefore it is a candidate for the Idd2 susceptible gene. We conclude that IGIF expression is abnormally regulated in autoimmune NOD mice and closely associated with diabetes development.

Cytokine gene expression in the BB rat pancreas: natural course and impact of bacterial vaccines

In diabetes prone BB rat pancreas the Th1/ Th2 cytokine balance and the expression of inducible nitric oxide synthase (iNOS) was determined by mRNA analysis before and after the onset of insulitis. Specific mRNA was amplified by reverse transcriptase polymerase chain reaction, quantitated with radiolabelled probes by phosphoimaging and calibrated with the amount of co-amplified beta-actin mRNA. At 50 days of age, prior to recognizable insulitis, there was already significantly enhanced expression of both, Th1 and Th2 cytokines, and of iNOS mRNA, when compared to Wistar rat pancreas (p < 0.001). This supports the concept of an inconspicuous early phase of islet infiltration by single immunocytes, called single cell insulitis. At 70 days of age mononuclear infiltration of islets had begun and was associated with upregulation of interferon gamma (IFN gamma) and iNOS, but downregulation of interleukin-10 and transforming growth factor beta mRNA (p < 0.001). These findings correlate the onset of insulitis with a shift of the Th1/Th2 cytokine balance towards Th1 cell reactivity. Indeed there was a close correlation of the Th1/Th2 cytokine ratio but not of absolute IFN gamma mRNA levels with the insulitis score. Vaccination at day 50 with tetanus toxoid did not affect cytokine gene expression while diphtheria toxoid and even more strongly BCG administration induced a shift towards Th2 reactivity (p < 0.001) while iNOS mRNA was decreased (p < 0.01). Oral dosing with immunostimulatory components of Escherichia coli also changed the quality of inflammation. Oral lipopolysaccharide (LPS) from E. coli and OM-89, an endotoxin free extract containing immunostimulatory glycolipopeptides and heat shock protein (hsp) 65, both downregulated IFN gamma mRNA while only OM-89 in addition suppressed iNOS mRNA and enhanced Th2 cytokine gene expression (p < 0.001). We conclude that the onset of insulitis is associated with a shift towards Th1 cytokine and iNOS gene expression. Diphtheria toxoid and BCG vaccination stimulates Th2 reactivity but does not downregulate Th1. The latter can be achieved through oral administration of LPS or a glycopeptide fraction (OM-89) from E. coli.

Primary nonfunction of islet grafts in autoimmune diabetic nonobese diabetic mice is prevented by treatment with interleukin-4 and interleukin-10

In isologous islet transplantation in spontaneously diabetic nonobese (NOD) mice, destruction of the islet graft is caused by recurrence of T helper (Th)1-driven insulitis[fnc,1. We established a model of transplantation in which female NOD recipients were rendered diabetic by a single injection of cyclophosphamide (250 mg/kg). Under these conditions, 500 freshly isolated islets from young NOD mice transplanted under the kidney capsule did not lead to normoglycemia within 3 day after transplantation, but underwent immediate impairment of function. This primary nonfunction was seen in > 80% of the recipients. Treatment of the recipients with the Th2-associated cytokine interleukin (IL)-4 alone did not prevent primary nonfunction, whereas treatment of the recipients with a combination of IL-4 and IL-10 restored immediate function of the grafts. Cytokine treatment did not prevent later rejection of grafts. Histological analysis of the grafts revealed less severely infiltrated islets, with well preserved islet architecture, in only normoglycemic animals treated with IL-4 or with IL-4 and IL-10. Staining for lymphocytes, macrophages, and tumor necrosis factor (TNF)-alpha did not show differences between the groups, but IFN-gamma was markedly less expressed in IL-4- and IL-10-treated grafts. Concomitantly, analysis of animals treated for 8 days after injection of cyclophosphamide, with IL-4 and IL-10, revealed a reduction of IL-12 mRNA in the pancreas. We conclude from these data that primary nonfunction of islet grafts is prevented by treatment of the recipients with a combination of IL-4 and IL-10, via downregulation of Th1 cytokines.

Interleukin-12 gene-expression of macrophages is regulated by nitric oxide

Interleukin-12 is a heterodimeric cytokine, mainly produced by macrophages. In our present study we demonstrate that interleukin-12 expression is regulated by nitric oxide. Incubation of the macrophage cell line IC 21 with interferon-gamma gave rise to both interleukin-12 p40 mRNA and nitric oxide production. The concurrent addition of the nitric oxide synthase inhibitor N(G)-monomethyl-L-arginine inhibited nitrite production and in parallel completely suppressed interleukin-12 p40 mRNA formation. This indicated that endogenous nitric oxide synthase activity was required for IL-12 p40 gene expression. Exposure of the cells towards the nitric oxide generating compounds nitroprusside or S-nitroso-N-acetyl-penicillamine induced interleukin-12 p40 mRNA. Maximal mRNA levels were induced with nitric oxide donors at 1 microM concentration. We conclude that nitric oxide may exert an autoregulatory and paracrine control of interleukin-12 gene expression.

Generation and characterization of inducible nitric oxide synthase deficient macrophage cell lines

Stable inducible nitric oxide synthase deficient mouse macrophage cell lines were generated by the antisense technology. A 666 bp fragment of a mouse inducible nitric oxide synthase cDNA was cloned in antisense orientation into a mammalian expression vector behind the CMV promoter. This construct was transfected into J774.1A cells, a mouse macrophage cell line. The inducible nitric oxide synthase antisense lines showed up to 84% reduction of nitric oxide production in response to lipopolysaccharide stimulation and 66% reduction of nitric oxide production in response to interferon-gamma and a combination of interferon-gamma and lipopolysaccharide stimulation. The deficiency in inducible nitric oxide synthase expression had no impact on lipopolysaccharide induced tumor necrosis factor alpha and interleukin-1 secretion. The stable and specific inhibition of inducible nitric oxide synthase expression by antisense DNA vectors allows a direct analysis of contribution of inducible nitric oxide synthase activity to macrophage regulatory and immune defence functions.

Interleukin-12 gene expression is associated with rapid development of diabetes mellitus in non-obese diabetic mice

A single dose of cyclophosphamide (250 mg/kg) is known to synchronize and accelerate development of diabetes in non-obese diabetic mice. We have reported previously that cyclophosphamide treatment of 10-week-old female non-obese diabetic mice induces a shift from T-helper type 2 to T-helper type 1 activity in islet lesions. We now show that this shift in regulatory T-cell function is preceded by the expression of interleukin-12 in the islets as well as in the spleen. In the spleen macrophages were identified as the interleukin-12 expressing cell type. At the same time there was little induction of tumour necrosis factor alpha gene expression by macrophages. Since interleukin-12 is well known to drive T-helper cell type 1 responses we assume that interleukin-12 released by macrophages mediates the accelerating effect of cyclophosphamide on islet inflammation in non-obese diabetic mice. mRNA expression of the p40 chain of interleukin-12 in response to cyclophosphamide was not seen in macrophages of Balb/c mice and thus represents an immune abnormality of non-obese diabetic mice favouring T-helper type 1 reactions.

Cyclophosphamide treatment of female non-obese diabetic mice causes enhanced expression of inducible nitric oxide synthase and interferon-gamma, but not of interleukin-4

In pancreatic lesions of non-obese diabetic (NOD) mice the expression of inducible nitric oxide synthase (iNOS) and of the cytokines interferon-gamma and interleukin-4 were studied. Strong iNOS expression as determined at the level of transcription, translation and of enzyme activity was associated with destructive insulitis as seen 8-10 days after cyclophosphamide treatment of 70- to 80-day-old female NOD mice. Immunohistochemistry showed iNOS associated with infiltrating macrophages but not in endocrine cells. The enhancement of iNOS after cyclophosphamide correlated with an increase of T-helper type 1 (Th1) associated interferon-gamma expression while T-helper type 2 (Th2) associated interleukin-4 was the dominant cytokine prior to cyclophosphamide and after diabetes onset. We conclude that insulitis in young NOD mice is carried by Th2 cells while cyclophosphamide enhanced insulitis is determined by Th1 cells. Macrophages show two different functional states in insulitis; strong iNOS expression in macrophages is associated with destructive insulitis.

[Incidence of lichens in the area of the Hamburg airport]

It was examined whether the co-additional effect of kerosene and benzine influences the air quality and the population of lichens. These plants were chosen since lichens serve as important indicators of air pollution. It was found that exhaust gases from a much frequented highway influence the number and the variation of species of lichens, whereas near the runway some less common species were found. These results show that air traffic exercises less influence on the lichen population than the road traffic emissions.

Abnormal TNF-alpha production in diabetes-prone BB rats: enhanced TNF-alpha expression and defective PGE2 feedback inhibition

Upon stimulation with lipopolysaccharide (LPS), peritoneal macrophages from diabetes-prone Bio-Breeding (BB) rats secrete more tumour necrosis factor-alpha (TNF-alpha) than macrophages from diabetes-resistant BB or normal Wistar rats. Enhanced transcription was demonstrated by Northern blot analysis and at the single cell level by mRNA: RNA hybridization. Cytofluorometry analysis showed 2-4 times more plasma membrane and total cell-associated TNF-alpha in macrophages of diabetes-prone BB rats. The analysis of fluorescence intensity showed a single peak, and TNF-alpha mRNA was found in > 90% of macrophages. These findings exclude TNF hypersecretion as being due to an abnormal subfraction of cells. TNF-alpha gene hyperexpression in diabetes-prone BB rats was not due to mutations in the regulatory regions of the promoter, which could be shown by cloning and sequencing of the TNF-alpha promoter in the three rat strains. When searching for other regulatory defects we found the production of prostaglandin E2 (PGE2) in response to LPS to be up to 10 times lower in macrophages from diabetes-prone BB rats than from Wistar rats. Furthermore, BB rats macrophages required significantly higher concentrations of PGE2 for suppression of TNF-alpha secretion. We conclude that abnormal TNF-alpha production in macrophages from diabetes-prone BB rats is due to enhanced gene transcription and translation and that this is associated with defective PGE2 feedback inhibition.