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Background: Emerging evidence suggests that treatment of NSCLC brain metastases with immune checkpoint inhibitors (ICIs) is associated with response rates similar to those of extracranial disease. Programmed death-ligand 1 (PD-L1) tumor proportion score (TPS) serves as a predictive biomarker for ICI response. However, the predictive value of brain metastasis-specific (intracranial) PD-L1 TPS is not established. We investigated the role of intra- and extracranial PD-L1 TPS in NSCLC patients treated with ICI following brain metastasis resection. Methods: Clinical data from NSCLC patients treated with ICI following brain metastasis resection (n = 64) were analyzed. PD-L1 TPS of brain metastases (n = 64) and available matched extracranial tumor tissue (n = 44) were assessed via immunohistochemistry. Statistical analyses included cut point estimation via maximally selected rank statistics, Kaplan–Meier estimates, and multivariable Cox regression analysis for intracranial progression-free survival (icPFS), extracranial progression-free survival (ecPFS), and overall survival (OS). Results: PD-L1 expression was found in 54.7% of brain metastases and 68.2% of extracranial tumor tissues, with a median intra- and extracranial PD-L1 TPS of 7.5% (0 – 50%, IQR) and 15.0% (0 – 80%, IQR), respectively. In matched tissue samples, extracranial PD-L1 TPS was significantly higher than intracranial PD-L1 TPS (p = 0.013). Optimal cut points for intracranial and extracranial PD-L1 TPS varied according to outcome parameter assessed. Notably, patients with a high intracranial PD-L1 TPS (> 40%) exhibited significantly longer icPFS as compared to patients with a low intracranial PD-L1 TPS (≤ 40%). The cut point of 40% for intracranial PD-L1 TPS was independently associated with OS, icPFS and ecPFS in multivariable analyses. Conclusion: Our study highlights the potential role of intracranial PD-L1 TPS in NSCLC, which could be used to predict ICI response in cases where extracranial tissue is not available for PD-L1 assessment as well as to specifically predict intracranial response. [ABSTRACT FROM AUTHOR]

Multiple sclerosis (MS) is a chronic neuroinflammatory disease that involves both white and gray matter. Although gray matter damage is a major contributor to disability in MS patients, conventional clinical magnetic resonance imaging (MRI) fails to accurately detect gray matter pathology and establish a clear correlation with clinical symptoms. Using magnetic resonance elastography (MRE), we previously reported global brain softening in MS and experimental autoimmune encephalomyelitis (EAE). However, it needs to be established if changes of the spatiotemporal patterns of brain tissue mechanics constitute a marker of neuroinflammation. Here, we use advanced multifrequency MRE with tomoelastography postprocessing to investigate longitudinal and regional inflammation-induced tissue changes in EAE and in a small group of MS patients. Surprisingly, we found reversible softening in synchrony with the EAE disease course predominantly in the cortex of the mouse brain. This cortical softening was associated neither with a shift of tissue water compartments as quantified by T2-mapping and diffusion-weighted MRI, nor with leukocyte infiltration as seen by histopathology. Instead, cortical softening correlated with transient structural remodeling of perineuronal nets (PNNs), which involved abnormal chondroitin sulfate expression and microgliosis. These mechanisms also appear to be critical in humans with MS, where tomoelastography for the first time demonstrated marked cortical softening. Taken together, our study shows that neuroinflammation (i) critically affects the integrity of PNNs in cortical brain tissue, in a reversible process that correlates with disease disability in EAE, (ii) reduces the mechanical integrity of brain tissue rather than leading to water accumulation, and (iii) shows similar spatial patterns in humans and mice. These results raise the prospect of leveraging MRE and quantitative MRI for MS staging and monitoring treatment in affected patients. [ABSTRACT FROM AUTHOR]

A newly developed UVC LED source with an emission wavelength of 233 nm was proved on bactericidal efficacy and skin tolerability. The bactericidal efficacy was qualitatively analysed using blood agar test. Subsequently, quantitative analyses were performed on germ carrier tests using the MRSA strain DSM11822, the MSSA strain DSM799, S. epidermidis DSM1798 with various soil loads. Additionally, the compatibility of the germicidal radiation doses on excised human skin and reconstructed human epidermis was proved. Cell viability, DNA damage and production of radicals were assessed in comparison to typical UVC radiation from discharge lamps (222 nm, 254 nm) and UVB (280–380 nm) radiation for clinical assessment. At a dose of 40 mJ/cm2, the 233 nm light source reduced the viable microorganisms by a log10 reduction (LR) of 5 log10 levels if no soil load was present. Mucin and protein containing soil loads diminished the effect to an LR of 1.5–3.3. A salt solution representing artificial sweat (pH 8.4) had only minor effects on the reduction. The viability of the skin models was not reduced and the DNA damage was far below the damage evoked by 0.1 UVB minimal erythema dose, which can be regarded as safe. Furthermore, the induced damage vanished after 24 h. Irradiation on four consecutive days also did not evoke DNA damage. The radical formation was far lower than 20 min outdoor visible light would cause, which is classified as low radical load and can be compensated by the antioxidant defence system. [ABSTRACT FROM AUTHOR]

New index for histologic activity assessment in ulcerative colitis and Crohn's disease For these reasons, the objectives of the 2020 International Consensus Conference on IBD Activity Scoring were (i) to review existing recommendations and to agree upon ten recommendations with the highest impact to maximize diagnostic information from biopsies for UC and CD and (ii) to agree on a simple, histologic scoring system for both types of IBD that is able to distinguish between quiescent disease and mucosal healing and has potential for use in daily routine practice as well as for clinical trials. Diagnosing the two main forms of IBD, ulcerative colitis (UC) and Crohn's disease (CD), involves a combination of clinical history, laboratory findings, imaging, endoscopy and histology [[2]]. Recommendation 5 I The information between pathologist and clinician should include core features that are relevant for the IBD diagnosis as well as for IBD activity scoring (vote: strong consensus (98%), level of evidence: 1a-3b, recommendation grade: C). i The following core features (or key elements) refer to details that are essential for the pathologist to be able to establish a diagnosis of IBD. This article is part of the Topical Collection on Quality in Pathology Introduction Chronic idiopathic inflammatory bowel disease (IBD) cases are on the rise, with approximately 6.8 million people diagnosed in 2017 [[1]]. [Extracted from the article]

NKp46+ innate lymphoid cells (ILC) modulate tissue homeostasis and anti-microbial immune responses. ILC development and function are regulated by cytokines such as Interleukin (IL)−7 and IL-15. However, the ILC-intrinsic pathways translating cytokine signals into developmental programs are largely unknown. Here we show that the anti-apoptotic molecule cellular FLICE-like inhibitory protein (c-FLIP) is crucial for the generation of IL-7/IL-15-dependent NKp46+ ILC1, including conventional natural killer (cNK) cells, and ILC3. Cytokine-induced phosphorylation of signal transducer and activator of transcription 5 (STAT5) precedes up-regulation of c-FLIP, which protects developing NKp46+ ILC from TNF-induced apoptosis. NKp46+ ILC-specific inactivation of c-FLIP leads to the loss of all IL-7/IL-15-dependent NKp46+ ILC, thereby inducing early-onset chronic colitis and subsequently microbial dysbiosis; meanwhile, the depletion of cNK, but not NKp46+ ILC1/3, aggravates experimental colitis. In summary, our data demonstrate a non-redundant function of c-FLIP for the generation of NKp46+ ILC, which protect T/B lymphocyte-sufficient mice from intestinal inflammation. Innate lymphoid cells (ILC) are important immune cells for maintaining the gut homeostasis. Here the authors show that c-FLIP, an anti-apoptotic molecule, is important for the development of NKP46+ ILC1, including conventional natural killer (cNK) cells, and ILC3, with cNK being more critical for ameliorating intestinal inflammation. [ABSTRACT FROM AUTHOR]

Leptin has been shown to modulate intestinal inflammation in mice. However, clinical evidence regarding its immune-stimulatory potential in human Crohn's disease remains sparse. We here describe a patient with the unique combination of acquired generalized lipodystrophy and Crohn's disease (AGLCD) featuring a lack of adipose tissue, leptin deficiency and intestinal inflammation. Using mass and flow cytometry, immunohistochemistry and functional metabolic analyses, the AGLCD patient was compared to healthy individuals and Crohn's disease patients regarding immune cell composition, function and metabolism and the effects of recombinant N-methionylleptin (rLeptin) were evaluated. We provide evidence that rLeptin exerts diverse pro-inflammatory effects on immune cell differentiation and function, including the metabolic reprogramming of immune cells and the induction of TNFα, ultimately aggravating Crohn's disease in the AGLCD patient, which can be reversed by anti-TNFα therapy. Our results indicate that leptin is required for human immune homeostasis and contributes to autoimmunity in a TNFα-dependent manner. The adipokine leptin modulates intestinal inflammation in mice. Here the authors describe a patient with inflammatory bowel disease and lipodystrophy, providing evidence that leptin aggravates intestinal inflammation with proinflammatory effects on leukocytes that are reversible by TNFα blockade. [ABSTRACT FROM AUTHOR]

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Chronic exposure to inorganic arsenic (As) [As(III) + As(V)], which affects millions of people, increases the incidence of some kinds of cancer and other non-carcinogenic pathologies. Although the oral pathway is the main form of exposure, in vivo studies have not been conducted to verify the intestinal toxicity of this metalloid. The aim of this study is to perform an in vivo evaluation of the intestinal toxicity of inorganic As, using female BALB/c mice exposed through drinking water to various concentrations of As(III) (20, 50, and 80 mg/L) for 2 months. An increase was observed in oxygen and/or nitrogen reactive species, and in gene and protein expression of pro-inflammatory cytokines (IL-1β, IL-2, IL-6) at concentrations equal to or greater than 50 mg/L. These changes were accompanied by a profound remodeling of the intestinal microbial profile in terms of diversity and global composition, which could be at the basis or exacerbate As(III) toxic effects. The histological study showed that there was moderate inflammation of the mucosa and submucosa, accompanied by hyperplasia of crypts at the highest administered dose. In addition, all the treatments with As(III) resulted in a decreased expression of Muc2, which encodes one of the main components of the intestinal layer of mucus. The effects described are compatible with the increased intestinal permeability observed at concentrations equal to or greater than 50 mg/L, indicative of loss of barrier function. Highlights: In vivo intestinal toxicity of As(III) was evaluated using female BALB/c mice. As(III) increases oxidative stress and the pro-inflammatory response in large intestine. As(III) produces down-regulation of Muc2, the main mucin of the intestinal mucus. As(III) alters the barrier function and produces changes in the intestinal microbiota. This is the first study that shows the intestinal toxicity of As(III) in subchronic exposure. [ABSTRACT FROM AUTHOR]

Graft versus host disease (GvHD) is a clinically important complication after allogeneic hematopoietic stem cell transplantation (HSCT). Its diagnosis relies on clinical and histopathological findings. In order to evaluate and improve inter-institutional diagnostic agreement on histological diagnosis and grading of acute gastrointestinal GvHD, we conducted a round robin test, which included 33 biopsies from 23 patients after HSCT. Five pathologists from different institutions independently evaluated the original sections from the biopsies submitted for diagnosis. Based on their results, consensus qualitative criteria for the assessment of typical histological features of GvHD (e.g., apoptosis, crypt destruction, mucosa denudation) were proposed, including detailed descriptions as well as histological images. In a second round robin test with involvement of the same pathologists, the reproducibility of both diagnosis and grading had improved. Remaining differences were mostly related to differential diagnostic considerations, including viral infection or toxic side effects of medication, which should be resolved by integrating histopathological findings with proper clinical information. [ABSTRACT FROM AUTHOR]

After being activated by antigen, helper T lymphocytes switch from a resting state to clonal expansion. This switch requires inactivation of the transcription factor Foxo1, a suppressor of proliferation expressed in resting helper T lymphocytes. In the early antigen-dependent phase of expansion, Foxo1 is inactivated by antigen receptor-mediated post-translational modifications. Here we show that in the late phase of expansion, Foxo1 was no longer post-translationally regulated but was inhibited post-transcriptionally by the interleukin 2 (IL-2)-induced microRNA miR-182. Specific inhibition of miR-182 in helper T lymphocytes limited their population expansion in vitro and in vivo. Our results demonstrate a central role for miR-182 in the physiological regulation of IL-2-driven helper T cell-mediated immune responses and open new therapeutic possibilities. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is a hypervascularized tumor entity with association of arterial vessel density with poor prognosis. The hypoxia-inducible transcription factor HIF-1α represents a pivotal regulator of angiogenesis and is thought to determine the angiogenic nature of HCC. However, the precise role of HIF-1α during the pathogenesis of HCC remains elusive. We established a functional inactivation of HIF-1α in vitro and in vivo via RNAi and Cre/loxP-mediated recombination, respectively, to determine HIF-1α’s role for tumor growth and chemosensitivity in transgenic and orthotopic murine HCC models. HIF-1α-deficient HCC cells displayed significantly reduced anchorage-independent growth and enhanced sensitivity toward etoposide, while basic cellular proliferation was unaffected. Analysis of gross tumor growth failed to detect reduced growth of HIF-1α-deficient tumors in the orthotopic and the transgenic HCC model, respectively. In line with the in vitro data, treatment of HIF-1α-deficient tumors with etoposide resulted in greater antiproliferative efficacy when compared to wild-type mice. Taken together, our study does not support a pivotal role of HIF-1α for tumor growth and angiogenesis in two murine HCC models. However, our data point toward a significant function of HIF-1α in determining chemosensitivity of HCC and therefore warrant validation of HIF-1α-inhibitors as adjuvant therapeutic agents in clinical studies of human HCC. [ABSTRACT FROM AUTHOR]

The intestinal immune system is continuously challenged by antigen without becoming dysregulated. However, injury of the mucosa by, i.e. dextran sulphate sodium causes severe inflammation in γδ T-cell-deficient mice. We therefore asked whether γδ T cells have regulatory functions. γδ T cells were isolated from spleens and mesenteric lymph nodes of C57BL/6 wild-type (wt) mice. Proliferation and cytokine secretion of γδ T cells were quantified by [3H] thymidine incorporation and ELISA. Additionally, proliferation of carboxyfluorescein diacetate succinimidylester-labelled CD4+ T cells cocultured with γδ T cells was analysed by flow cytometry. Finally, γδ T cells from wt or interleukin-10 transgenic (IL-10tg) mice were transferred into congenic mice with 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced colitis. γδ T cells were hyporesponsive to CD3/CD28 stimulation and suppressed CD4+ T-cell proliferation (up to 66 ± 7% suppression) in vitro. Further, the preventive transfer of wt or IL-10tg γδ T cells ameliorated TNBS-induced colitis resulting in prolonged survival and reduced histological damage (1.5 ± 0.4 and 1.3 ± 0.2, respectively vs. 3.8 ± 0.3 in untransferred mice, p < 0.05). This was accompanied by reduced TNF-α and increased IL-10 and TGF-β secretion from intestinal and splenic lymphocytes. Murine γδ T cells are a new type of regulatory T cells in vitro and act protective on mouse TNBS-induced colitis in vivo. Future studies have to define the underlying mechanism and to investigate whether γδ T cells can be used for immunotherapy of human inflammatory bowel disease. [ABSTRACT FROM AUTHOR]

Background: Hybrid positron emission tomography and magnetic resonance imaging (PET/MRI) scanners are increasingly used for both clinical and preclinical imaging. Especially functional MRI sequences such as diffusion-weighted imaging (DWI) are of great interest as they provide information on a molecular level, thus, can be used as surrogate biomarkers. Due to technical restrictions, MR sequences need to be adapted for each system to perform reliable imaging. There is, to our knowledge, no suitable DWI protocol for 1 Tesla PET/MRI scanners. We aimed to establish such DWI protocol with focus on the choice of b values, suitable for longitudinal monitoring of tumor characteristics in a rat liver tumor model.Material and methods: DWI was first performed in 18 healthy rat livers using the scanner-dependent maximum of 4 b values (0, 100, 200, 300 s/mm2). Apparent diffusion coefficients (ADC) were calculated from different b value combinations and compared to the reference measurement with four b values. T2-weighted MRI and optimized DWI with best agreement between accuracy, scanning time, and system performance stability were used to monitor orthotopic hepatocellular carcinomas (HCC) in five rats of which three underwent additional 2-deoxy-2-(18F)fluoro-D-glucose(FDG)-PET imaging. ADCs were calculated for the tumor and the surrounding liver parenchyma and verified by histopathological analysis.Results: Compared to the reference measurements, the combination b = 0, 200, 300 s/mm2 showed the highest correlation coefficient (rs = 0.92) and agreement while reducing the acquisition time. However, measurements with less than four b values yielded significantly higher ADCs (p < 0.001). When monitoring the HCC, an expected drop of the ADC was observed over time. These findings were paralleled by FDG-PET showing both an increase in tumor size and uptake heterogeneity. Interestingly, surrounding liver parenchyma also showed a change in ADC values revealing varying levels of inflammation by immunohistochemistry.Conclusion: We established a respiratory-gated DWI protocol for a preclinical 1 T PET/MRI scanner allowing to monitor growth-related changes in ADC values of orthotopic HCC liver tumors. By monitoring the changes in tumor ADCs over time, different cellular stages were described. However, each study needs to adapt the protocol further according to their question to generate best possible results. [ABSTRACT FROM AUTHOR]