When tissue antigens and antibodies get along: revisiting the technical aspects of immunohistochemistry--the red, brown, and blue technique

Sildenafil abrogates radiation-induced hepatotoxicity in animal model: The impact of NF-κB-p65, P53, Nrf2, and SIRT 1 pathway

Ionizing radiation has both beneficial and harmful effects on human health, prompting researchers to find ways to protect organs from its adverse impacts. Sildenafil (SIL) has gained attention in protective medicine due to its antioxidant, anti-inflammatory, and anti-apoptotic properties.

AIM

This study aimed to investigate SIL's protective mechanisms against radiation-induced liver damage.

METHOD

Forty adult male Wistar rats were divided into: control group, SIL group (2.5 mg/kg,p.o), irradiation group (rats were exposed to single shot at a dose of 10 Gy to induce liver damage), and SIL + irradiation group. Serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) were evaluated. Liver samples were used to evaluate oxidative stress indicators, reduced glutathione (GSH), malondialdehyde (MDA), nitric oxide(NO), Hepatic antioxidant nuclear factor erythroid 2-related factor 2(Nrf2), and apoptoticp53 upregulated modulator of apoptosis(P53) gene expression were determined by Western blot analysis. Immunohistochemical analysis for hepatic nuclear factor-kappa B (NF-κB) and silent information regulator-1(SIRT1) were performed along with histopathological examination.

RESULTS

SIL effectively diminished inflammation by reducing p-NF-κB-p65 and increasing Nrf2 and SIRT 1 expression. Additionally, SIL restrained apoptosis by reducing P53 protein expressions. Moreover, SIL significantly improved radiation-induced histopathological changes.

SIGNIFICANCE

SIL preventing hepatotoxicity associated with radiation exposure.

Oxyresveratrol and/or Dapagliflozin Attenuate Doxorubicin-Induced Nephrotoxicity via Modulation of PPAR-γ/Nrf-2/HO-1, NF-κB/TNF-α/Keap-1, and Bcl-2/Caspase-3/ATG-5 signaling pathways in rats

PURPOSE

Among the most undesirable effects that lead to the restriction of doxorubicin (DOX) use in chemotherapy is kidney damage. This research aimed to assess the possible defenses against DOX-induced nephrotoxicity offered by oxyresveratrol (ORES) and/or dapagliflozin (DAPA).

METHODS

Five groups of eight male Swiss albino rats each were created from a total of sixty-four. One intravenous injection of DOX (10 mg/kg) was given into the tail vein on the fourteenth day of the experiment; in the meantime, ORES (80 mg/kg) and DAPA (10 mg/kg) were given orally 14 days prior to the DOX injection and 2 days following the DOX injection.

RESULTS

In rats given DOX, ORES and/or DAPA both successfully reduced the kidney weight, kidney/bodyweight ratio, and blood levels of creatinine, uric acid, and urea. They also increased final body weight and albumin serum levels. Additionally, lower serum concentrations of TNF-α and IL-6 were noted, along with a lower kidney content of caspase-3. Furthermore, the expression of the Bcl-2 gene was upregulated, as were the Nrf-2, PPAR-γ, and HO-1 proteins, and there was a downregulation of the ATG-5, Keap-1, and NF-κB renal gene expression. These findings support a decrease in oxidative stress and relief of histopathological alterations.

CONCLUSION

The current study's findings suggest that ORES and/or DAPA pretreatment could be a viable therapeutic approach to ameliorate DOX-induced nephrotoxicity.

Involvement of GSK-3β, NF-κB, PPARγ, and apoptosis in amlodipine's anticancer effect in BALB/c mice

Lung cancer is the primary cause of death due to cancer all over the world despite the decrease in the mortality rates from cancer in general. While chemotherapy is a commonly employed treatment for lung cancer, its efficacy is limited due to poor tissue selectivity, inadequate delivery to tumor sites, and associated side effects. The present work aims to assess the potential anti-cancer effectiveness of amlodipine, a calcium channel blocker, on murine lung cancer via modulating GSK-3β, NF-κB, PPARγ, and apoptosis. Lung cancer was induced in BALB/c mice by intraperitoneal injection of 1.5 g/kg in two doses of urethane: once on the 1st and the second on the 60th day of the experiment. Amlodipine was administered orally at a dose of 10 mg/kg/day for the last 28 days of experiment. Relative to urethane group, amlodipine mitigated urethane-induced histopathological abnormalities. It restored oxidant/antioxidant balance by normalizing MDA, GSH, and SOD. Furthermore, it exerted a marked anti-inflammatory effect through downregulating lung MPO, ICAM-1, IL-6, TNF-α, and NF-қB expressions. Amlodipine enhanced apoptosis of cancer cells as evidenced by increasing Bax and decreasing Bcl-2 expression. The anticancer effect of amlodipine was suggested to be mediated through increasing PPARγ and reducing GSK3β and p-GSK3β signaling. Collectively, these results suggest that amlodipine could exert a promising anticancer effect against lung cancer through modulating GSK-3β, NF-κB, PPARγ, and apoptosis. Our findings could be highly significant in clinical settings, offering a valuable adjuvant option for managing lung carcinoma, particularly in patients with cardiovascular disorders.

A novel rotation and scale-invariant deep learning framework leveraging conical transformers for precise differentiation between meningioma and solitary fibrous tumor

Meningiomas, the most prevalent tumors of the central nervous system, can have overlapping histopathological features with solitary fibrous tumors (SFT), presenting a significant diagnostic challenge. Accurate differentiation between these two diagnoses is crucial for optimal medical management. Currently, immunohistochemistry and molecular techniques are the methods of choice for distinguishing between them; however, these techniques are expensive and not universally available. In this article, we propose a rotational and scale-invariant deep learning framework to enable accurate discrimination between these two tumor types. The proposed framework employs a novel architecture of conical transformers to capture both global and local imaging markers from whole-slide images, accommodating variations across different magnification scales. A weighted majority voting schema is utilized to combine individual scale decisions, ultimately producing a complementary and more accurate diagnostic outcome. A dataset comprising 92 patients (46 with meningioma and 46 with SFT) was used for evaluation. The experimental results demonstrate robust performance across different validation methods. In train-test evaluation, the model achieved 92.27% accuracy, 87.77% sensitivity, 97.55% specificity, and 92.46% F1-score. Performance further improved in 4-fold cross-validation, achieving 94.68% accuracy, 96.05% sensitivity, 93.11% specificity, and 95.07% F1-score. These findings highlight the potential of AI-based diagnostic approaches for precise differentiation between meningioma and SFT, paving the way for innovative diagnostic tools in pathology.

Piribedil and thymol mitigate vancomycin-evoked nephrotoxicity in rats through modulation of Keap-1/Nrf2/HO-1 and NF-κB/Bax/caspase 3 signalings

Nephrotoxicity is a sign in which endogenous or exogenous toxicants have damaged the kidney-specific detoxification and excretion processes. Vancomycin (VAN) exposure mostly causes kidney damage and a loss of body homeostasis regulation. This study aimed to investigate the protective effects of piribedil and thymol and its basic mechanisms against nephrotoxicity caused by VAN. Randomly, the animals were categorized into six groups (n = 8). For 7 d, Group I only received vehicles, Group II received piribedil (5 mg/kg/once daily, i.p.), Group III received thymol (25 mg/kg/once daily, i.p), Group IV was administered a single daily dose of VAN (200 mg/kg, i.p.), VAN+ piribedil was administered to Group V, and VAN + thymol was administered to Group VI. The findings showed that piribedil or thymol improved renal function parameters by an increase in serum albumin level in parallel to a decrease in serum creatinine and blood urea nitrogen (BUN) levels in addition to decreased levels of KIM-1 and serum cystatin C. Furthermore, enhanced oxidative stress biomarkers as GSH, myeloperoxidase (MPO), and malondialdehyde (MDA) as well as tumor necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1β), indicators of inflammatory mediators, were markedly reduced compared to VAN group. Moreover, piribedil or thymol markedly improved the histopathological aberrations provoked by VAN, increased the Nrf-2 and HO-1 renal protein expressions and reduced VAN-induced elevation of Keap-1 protein expression. In addition, NF-kB, Bax, and caspase 3 expression levels were considerably declined after piribedil or thymol co-treatment. These findings revealed that co-administration of piribedil or thymol with VAN may be a sensible therapeutic approach for reducing renal intoxication caused by VAN.

Optic Nerve Crush Does Not Induce Retinal Ganglion Cell Loss in the Contralateral Eye

Purpose

Optic nerve crush (ONC) is a model for studying optic nerve trauma. Unilateral ONC induces massive retinal ganglion cell (RGC) degeneration in the affected eye, leading to vision loss within a month. A common assumption has been that the non-injured contralateral eye is unaffected due to the minimal retino-retinal projections of the RGCs at the chiasm. Yet, recently, microglia, the brain-resident macrophages, have shown a responsive phenotype in the contralateral eye after ONC. Whether RGC loss accompanies this phenotype is still controversial.

Methods

Using the available RGCode algorithm and developing our own RGC-Quant deep-learning-based tool, we quantify RGC's total number and density across the entire retina after ONC.

Results

We confirm a short-term microglia response in the contralateral eye after ONC, but this did not affect the microglia number. Furthermore, we cannot confirm the previously reported RGC loss between naïve and contralateral retinas 5 weeks after ONC induction across the commonly used Cx3cr1creERT2 and C57BL6/J mouse models. Neither sex nor the direct comparison of the RGC markers Brn3a and RBPMS, with Brn3a co-labeling, on average, 89% of the RBPMS+-cells, explained this discrepancy, suggesting that the early microglia-responsive phenotype does not have immediate consequences on the RGC number.

Conclusions

Our results corroborate that unilateral optic nerve injury elicits a microglial response in the uninjured contralateral eye but without RGC loss. Therefore, the contralateral eye should be treated separately and not as an ONC control.

Immunohistochemical identification of immune cell subsets in formalin- and zinc-fixed, paraffin-embedded tissues from chicken and duck using commercial antibodies

Immunohistochemical identification of immune cells in poultry has primarily been performed using frozen tissues, with limited identification in paraffin-embedded tissues. In this study, the following 18 commercially available primary antibodies associated with immune cell phenotypes were tested: anti-CD3, CD4 (clone CT-4 and 2-35), TCRγδ, TCRαVβ1, TCRαVβ2, CD8, BAFF-R, PAX5, Bu-1a/b, Iba-1, MRC1L-B, CSF-1R, TIM4, MHC class II (clone 2D5 and 21-1A6), MUM1, and CD45 antibodies in formalin-fixed, paraffin-embedded (FFPE) and zinc-fixed, paraffin-embedded (ZFPE) chicken and duck lymphoid tissues. In chickens, 11 antibodies in FFPE tissue and 16 in ZFPE tissue reacted with the expected antigens under some of the antigen retrieval conditions tested. Antibodies against CD4 (clone CT-4), TCRγδ, TCRαVβ1, CSF-1R, and MHC class II (clone 21-1A6) were effective only in ZFPE tissue. In ducks, cells in both FFPE and ZFPE tissues were immunolabeled by five antibodies under some of the conditions tested. Antigen retrieval suitable for cellular membrane antigen tended to be heat for FFPE tissues and no treatment for ZFPE tissues. Heat-induced antigen retrieval allowed for better detection of nuclear antigens in both FFPE and ZFPE sections. Our results indicate that commercially available antibodies can immunohistochemically detect some of chicken and duck immune cell subsets in paraffin-embedded sections.

CD163, a novel receptor for TNF, was revealed in situ by proximity ligation assay

Cytokine therapy utilizes cytokines to enhance the immune system to fight diseases. These strategies rely on advanced knowledge, including the communication between cytokines and their receptors. In situ, cytokine-receptor interactions are typically analyzed by co-localization using immunolabeling. Our study compared co-localization using the Proximity Ligation Assay (PLA), a recently developed in situ protein-protein interaction technique. In an inflamed porcine lung model, we demonstrated the efficacy of PLA in detecting interactions between tumor necrosis factor (TNF) and its receptors TNFR1 and TNFR2. Additionally, the CD163 receptor was identified as a novel partner of TNF. Furthermore, the combination of immunolabeling and PLA offered additional insights, particularly, the internalization of TNF following its binding with CD163 in macrophages. Our work focused on in situ interactions of TNF with macrophages TNF receptors and suggested exciting perspectives for further understanding and application of cytokine-based therapies.

Broad-spectrum detection of benzimidazoles with lateral flow immunoassay: A computational chemistry-assisted hapten design strategy and explore of molecular recognition mechanism

Benzimidazoles (BMZs) are a class of veterinary drugs with a benzimidazole ring, the abuse of which poses a serious threat to ecological balance and human health. Consequently, the development of broad-spectrum antibodies and rapid assays are crucial for detecting BMZs in food samples. Herein, we scientifically designed three hapten structures, predicted the availability of the hapten with computational chemistry, and subsequently verified the broad-spectrum with immunological experiments. A broad-spectrum monoclonal antibody (6F10) was prepared based on the predicted hapten-2. Molecular recognition studies illustrated intricate interactions between mAb 6F10 binding to BMZs attributed to halogen bonds and π-π/π-alkyl interactions, revealing key amino acid sites and demonstrating the reliability of the hapten prediction strategies. Finally, a broad-spectrum, rapid, and sensitive lateral flow immunoassay based on aggregation-induced emission microspheres with high fluorescence intensity was established. The LOD values of the proposed method for eight kinds of BMZs were 0.027, 0.032, 0.058, 0.091, 0.087, 0.246, 0.369, and 0.311 ng mL-1, respectively. In this work, a hapten prediction strategy based on a computational chemistry method effectively guided the preparation of antibodies for broad-spectrum recognition of BMZs, and the molecular recognition studies verified the interaction of mAb 6F10 with BMZs, enabling broad-spectrum and sensitive detection of BMZs in milk.

Impact of immunohistochemistry staining conditions on the incidence of human epidermal growth factor receptor 2 (HER2)-low breast cancer

We investigated frequencies of HER2-low breast cancer (BC) (immunohistochemistry [IHC] 1+ or 2+ without gene amplification) before and after IHC conditions were modified in order to understand the impact of IHC staining conditions on frequencies of HER2-low BC. Primary BC cases diagnosed at the Yeungnam University Hospital (YUH, n = 728) or Keimyung University Dongsan Hospital (KUDH, n = 290) in 2022 were reviewed, and data on HER2 status and IHC conditions were collected (cohort 1). Both institutions used the 4B5 antibody for HER2 IHC but had different staining protocols. After modifications of the IHC conditions at both institutions, primary BC cases (YUH, n = 324 and KUDH, n = 135) diagnosed from April to July 2023 (cohort 2) were reviewed to assess any changes in the frequency of HER2 status. In cohort 1, of the 728 cases diagnosed at YUH, 556 (76.4%) were HER2-zero, 76 (10.4%) were HER2-low, and 96 (13.2%) were HER2-positive, and of the 290 cases diagnosed at KUDH, 135 (46.6%) were HER2-zero, 82 (28.3%) were HER2-low, and 73 (25.2%) were HER2-positive. Modifications in HER2 IHC staining conditions dramatically increased the frequencies of HER2-low BC in cohort 2 (YUH 38.9% and KUDH 49.6%), but they did not result in significant changes in the HER2-positive rates (YUH 15.4% and KUDH 25.2%) compared to cohort 1. In conclusion, minor modifications in HER2 IHC staining conditions significantly affected the frequency of HER2-low BC but had little impact on the HER2-positivity rate. Each pathology laboratory should verify IHC conditions using control slides (including 1+) to enable the accurate identification of HER2-low BC.

Sorafenib and edaravone protect against renal fibrosis induced by unilateral ureteral obstruction via inhibition of oxidative stress, inflammation, and RIPK-3/MLKL pathway

Renal fibrosis is the common endpoint of nearly all chronic and progressive nephropathies. Cell death and sterile inflammation are the main characteristics of renal fibrosis, which can lead to end-stage renal failure. The inflammatory reaction triggered by tissue damage is strongly related to necroptosis, a type of caspase-independent, regulated cell death. Using an animal model of unilateral ureteral obstruction (UUO), the anti-fibrotic effects of sorafenib (SOF), a multi-kinase inhibitor, and edaravone (EDV), a potent antioxidant and free radical scavenger, were examined in rats with obstructive nephropathy. Experimentally, animals were divided randomly into five groups: sham; UUO; UUO + SOF (5 mg/kg/day, P.O.); UUO + EDV (20 mg/kg/day, P.O.); and UUO + SOF + EDV groups. The kidney function biomarkers, oxidant/antioxidant status, renal mRNA expressions of TNF-α, collagen-1α, protein expressions of RIPK-1, RIPK-3, MLKL, caspase-8, HYP, MPO, and TNF-α were all significantly modulated by UUO. Administration of either SOF or EDV significantly attenuated cellular and molecular changes induced by UUO. Also, histopathological changes were improved. Moreover, SOF in combination with EDV, significantly improved UUO-induced renal fibrosis compared with each drug alone. Collectively, administration of either SOF or EDV or both of them significantly attenuated the rats with obstructive nephropathy, possibly by blocking the RIPK-3/MLKL necroptotic pathway and suppressing renal oxidative stress and inflammation.

A Nationwide Study on HER2-Low Breast Cancer in South Korea: Its Incidence of 2022 Real World Data and the Importance of Immunohistochemical Staining Protocols

PURPOSE

Notable effectiveness of trastuzumab deruxtecan in patients with human epidermal growth factor receptor 2 (HER2)-low advanced breast cancer (BC) has focused pathologists' attention. We studied the incidence and clinicopathologic characteristics of HER2-low BC, and the effects of immunohistochemistry (IHC) associated factors on HER2 IHC results.

MATERIALS AND METHODS

The Breast Pathology Study Group of the Korean Society of Pathologists conducted a nationwide study using real-world data on HER2 status generated between January 2022 and December 2022. Information on HER2 IHC protocols at each participating institution was also collected.

RESULTS

Total 11,416 patients from 25 institutions included in this study. Of these patients, 40.7% (range, 6.0% to 76.3%) were classified as HER2-zero, 41.7% (range, 10.5% to 69.1%) as HER2-low, and 17.5% (range, 6.7% to 34.0%) as HER2-positive. HER2-low tumors were associated with positive estrogen receptor and progesterone receptor statuses (p < 0.001 and p < 0.001, respectively). Antigen retrieval times (≥ 36 minutes vs. < 36 minutes) and antibody incubation times (≥ 12 minutes vs. < 12 minutes) affected on the frequency of HER2 IHC 1+ BC at institutions using the PATHWAY HER2 (4B5) IHC assay and BenchMark XT or Ultra staining instruments. Furthermore, discordant results between core needle biopsy and subsequent resection specimen HER2 statuses were observed in 24.1% (787/3,259) of the patients.

CONCLUSION

The overall incidence of HER2-low BC in South Korea concurs with those reported in previously published studies. Significant inter-institutional differences in HER2 IHC protocols were observed, and it may have impact on HER2-low status. Thus, we recommend standardizing HER2 IHC conditions to ensure precise patient selection for targeted therapy.

Distinguishing of Histopathological Staging Features of H-E Stained Human cSCC by Microscopical Multispectral Imaging

Cutaneous squamous cell carcinoma (cSCC) is the second most common malignant skin tumor. Early and precise diagnosis of tumor staging is crucial for long-term outcomes. While pathological diagnosis has traditionally served as the gold standard, the assessment of differentiation levels heavily depends on subjective judgments. Therefore, how to improve the diagnosis accuracy and objectivity of pathologists has become an urgent problem to be solved. We used multispectral imaging (MSI) to enhance tumor classification. The hematoxylin and eosin (H&E) stained cSCC slides were from Shanghai Ruijin Hospital. Scale-invariant feature transform was applied to multispectral images for image stitching, while the adaptive threshold segmentation method and random forest segmentation method were used for image segmentation, respectively. Synthetic pseudo-color images effectively highlight tissue differences. Quantitative analysis confirms significant variation in the nuclear area between normal and cSCC tissues (p < 0.001), supported by an AUC of 1 in ROC analysis. The AUC within cSCC tissues is 0.57. Further study shows higher nuclear atypia in poorly differentiated cSCC tissues compared to well-differentiated cSCC (p < 0.001), also with an AUC of 1. Lastly, well differentiated cSCC tissues show more and larger keratin pearls. These results have shown that combined MSI with imaging processing techniques will improve H&E stained human cSCC diagnosis accuracy, and it will be well utilized to distinguish histopathological staging features.

Identification of monoclonal antibodies from naive antibody phage-display libraries for protein detection in formalin-fixed paraffin-embedded tissues

Most antibodies used in immunohistochemistry (IHC) have been developed by animal immunization. We wanted to explore naive antibody repertoires displayed on filamentous phages as a source of full-length antibodies for IHC on Formalin-Fixed and Paraffin-Embedded (FFPE) tissues. We used two isogenic mouse fibroblast cell lines that express or not human HER2 to generate positive and negative FFPE pseudo-tissue respectively. Using these pseudo-tissues and previously described approaches based on differential panning, we isolated very efficient antibody clones, but not against HER2. To optimize HER2 targeting and tissue specificity, we first performed 3-4 rounds of in vitro panning using recombinant HER2 extracellular domain (ECD) to enrich the phage library in HER2 binders, followed by one panning round using the two FFPE pseudo-tissues to retain binders for IHC conditions. We then analyzed the bound phages using next-generation sequencing to identify antibody sequences specifically associated with the HER2-positive pseudo-tissue. Using this approach, the top-ranked clone identified by sequencing was specific to the HER2-positive pseudo-tissue and showed a staining pattern similar to that of the antibody used for the clinical diagnosis of HER2-positive breast cancer. However, we could not optimize staining on other tissues, showing that specificity was restricted to the tissue used for selection and screening. Therefore, future optimized protocols must consider tissue diversity early during the selection by panning using a wide collection of tissue types.

The impact of PPAR-γ/Nrf-2/HO-1, NF-κB/IL-6/ Keap-1, and Bcl-2/caspase-3/ATG-5 pathways in mitigation of DOX-induced cardiotoxicity in an animal model: The potential cardioprotective role of oxyresveratrol and/or dapagliflozin

Antioxidants given concurrently with chemotherapy offer an effective strategy for reducing the negative effects of the drug. One remaining obstacle to the use of doxorubicin (DOX) in chemotherapy is cardiotoxicity. Using vitamin E (Vit. E) as a reference standard, our study focuses on the potential preventive benefits of oxyresveratrol (ORES) and/or dapagliflozin (DAPA) against DOX-induced cardiac injury. Acute cardiotoxicity was noticed after a single intravenous injection of a male rat's tail vein with 10 mg/kg of DOX. Oral doses of ORES (80 mg/kg), DAPA (10 mg/kg), and Vit. E (1 g/kg) were given, respectively. Pretreatment of animals with Vit. E, ORES and/or DAPA revealed a considerable alleviation of heart damage, as evidenced by histopathological change mitigation and a notable drop in serum AST, LDH, CK, CK-MB, and cardiac contents of MDA and NO2-. Also, serum TAC, tissue GSH, and SOD showed substantial increases. Additionally, tissue caspase-3, serum IL-6, and TNF-α were considerably reduced. Moreover, a downregulation in cardiac gene expression of ATG-5, Keap-1, and NF-κB in addition to an upregulation of Bcl-2 gene expression and HO-1, Nrf-2, and PPAR-γ protein expression clearly appeared. Ultimately, ORES and/or DAPA have an optimistic preventive action against severe heart deterioration caused by DOX.

Comparison of Antigen Retrieval Methods for Immunohistochemical Analysis of Cartilage Matrix Glycoproteins Using Cartilage Intermediate Layer Protein 2 (CILP-2) as an Example

The aim of this study was to compare different antigen retrieval methods to improve the outcome of immunohistochemistry (IHC) performed on osteoarthritic (OA) cartilage obtained from total knee replacement operation. A voluminous and dense extracellular matrix of articular cartilage inhibits antibody penetration, and therefore, proteins present at low concentrations and masked during fixation may need antigen retrieval to enhance an IHC outcome. We focused on the IHC detection of a minor but diagnostically promising cartilage glycoprotein, CILP-2 (cartilage intermediate layer protein 2), to demonstrate the effect of four different protocols: (1) heat-induced epitope retrieval (HIER), (2) proteolytic-induced epitope retrieval applying proteinase K and hyaluronidase (PIER), (3) HIER combined with PIER, and (4) no antigen retrieval (control). A semi-quantitative staining assessment based on the CILP-2 staining extent was applied. Out of the tested antigen retrieval protocols, the best CILP-2 IHC staining results were achieved by PIER. Combining PIER with HIER did not improve CILP-2 staining in the given experimental setting. Rather the opposite, the application of heat reduced the positive effect of PIER on CILP-2 staining and resulted in the frequent detachment of sections from the slides. Our findings emphasize the need for proper adaptation of antigen retrieval protocols for IHC to maximize the quantitative evaluation of minor matrix proteins in OA articular cartilage samples.

Multi-Tissue Controls and Multiplex Immunocytochemistry in Pulmonary Cytology

INTRODUCTION

The World Health Organization 2021 lung cancer classification highlights the central role of immunohistochemistry (IHC) in diagnostic pathology. Despite traditional IHC being essential, its limitation to one marker per tissue section brings challenges, particularly when facing cytological limitedly sized samples. To overcome these challenges, multiplex immunocytochemistry (mICC) techniques offer the simultaneous detection of multiple markers from a single section. These advances complement the highly complex imaging techniques that enable additional analyses of cellular interactions.

METHODS

The present study outlines a comprehensive mICC methodology of an automated multiplex immunoperoxidase staining method and multiple tissue hybrid controls for ICC/mICC. Protocols are presented in detail and demonstrate a careful approach to optimizing various markers for diagnostic workup including immunotherapy.

CONCLUSION

Multiplex IHC/ICC emerges as a transformative force in biomedical diagnostics and research. Beyond simultaneous marker detection, it unravels complexities within tissues - unveiling co-localization nuances, deciphering expression patterns, and enhancing understanding of cellular populations. As personalized treatments gain prominence, the study emphasizes the heightened importance of diagnostic tools and sample adequacy. The present methodological study, encapsulating an automated multiplex immunoperoxidase staining method, symbolizes a stride towards precision in pulmonary carcinoma diagnosis. Multi-tissue controls represent a key element in quality assurance in pathology laboratories.

SGLT2 inhibitor as a potential therapeutic approach in hyperthyroidism-induced cardiopulmonary injury in rats

Hyperthyroidism-induced cardiac disease is an evolving health, economic, and social problem affecting well-being. Sodium-glucose cotransporter protein 2 inhibitors (SGLT2-I) have been proven to be cardio-protective when administered in cases of heart failure. This study intended to investigate the potential therapeutic effect of SGLT2-I on hyperthyroidism-related cardiopulmonary injury, targeting the possible underlying mechanisms. The impact of the SGLT2-I, dapagliflozin (DAPA), (1 mg/kg/day, p.o) on LT4 (0.3 mg/kg/day, i.p)-induced cardiopulmonary injury was investigated in rats. The body weight, ECG, and serum hormones were evaluated. Also, redox balance, DNA fragmentation, inflammatory cytokines, and PCR quantification in heart and lung tissues were employed to investigate the effect of DAPA in experimentally induced hyperthyroid rats along with histological and immunohistochemical examination. Coadministration of DAPA with LT4 effectively restored all serum biomarkers to nearly average levels, improved ECG findings, and reinstated the redox balance. Also, DAPA could improve DNA fragmentation, elevate mtTFA, and lessen TNF-α and IGF-1 gene expression in both organs of treated animals. Furthermore, DAPA markedly improved the necro-inflammatory and fibrotic cardiopulmonary histological alterations and reduced the tissue immunohistochemical expression of TNF-α and caspase-3. Although further clinical and deep molecular studies are required before transposing to humans, our study emphasized DAPA's potential to relieve hyperthyroidism-induced cardiopulmonary injury in rats through its antioxidant, anti-inflammatory, and anti-apoptotic effects, as well as via antagonizing the sympathetic over activity.

Low Detection of High-risk Human Papilloma Virus in Individuals with Ameloblastoma in a Tertiary Hospital in Lagos, Nigeria

BACKGROUND

Ameloblastoma is a benign but aggressive epithelial odontogenic neoplasm of unknown etiology. The role of human papilloma virus (HPV) in the etiology of oral squamous cell carcinoma has prompted the investigation of HPV as an etiologic factor in ameloblastoma. This study aimed to determine the frequency of high-risk (HR) HPV in conventional ameloblastoma and the clinical parameters associated with infection.

MATERIALS AND METHODS

The study was approved by the ethical review boards of the institution. DNA was extracted from fresh tissue collected 750 μL of DNA/RNA Shield (Zymo Research, United States) using Invitrogen PureLink Viral RNA/DNA Mini Kit (Invitrogen, USA). The extracted DNA was assayed for the detection of 14 HR HPV types (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, and 68) using Anyplex™ II HPV HR Detection kit (Cat. No. HP7E00X) (Seegene Inc., Republic of Korea) on CFX-96TM Real-Time Polymerase Chain Reaction (PCR) System (Bio-Rad). Data on gender, age of patient, site of lesion, clinicohistological types of ameloblastoma and history of smoking, alcohol consumption, and practice of oral sex were collected. Data analysis was performed using analysis program SPSS version 25 and statistical significance was set at P < 0.05.

RESULTS

Two cases of conventional ameloblastoma were positive with HPV and none of the ameloblastic carcinoma cases were positive. The HPV 16 serotype was observed in both cases. While 5 of the cases had a history of alcohol consumption, none of these cases were positive for HPV serotype.

CONCLUSIONS

HPV 16 positivity was detected in two cases of conventional ameloblastomas and none in ameloblastic carcinoma using real-time PCR. There was no effect of exposure to smoking, alcohol consumption, and practice of oral sex and HPV in the etiology of ameloblastoma. Data available are suggestive of a limited role of HPV in the etiology of ameloblastoma.

Celastrol Mitigates Acetaminophen-Induced Nephrotoxicity in Rats via Targeting Renal Oxidative Stress, Inflammation, Apoptosis with Enhancement in Aquaporin 1 Level

Background

Acetaminophen also name paracetamol is apopular antipyretic and analgesic drug, in alarge doses produces a cute kidney injury either in human and animals. The aim of this study to assess the effect of celastrol in reducing acetaminophen-induced nephrotoxicity and to elucidate its underlying mechanisms.

Methods

Rats were divided into four groups: control, celastrol-treated, acetaminophen-exposed, and a group receiving both acetaminophen and celastrol. After 24 hours, blood samples were taken and kidney tissues were harvested for histological and molecular analyses. The findings shed light on the protective effects of celastrol against acetaminophen-induced nephrotoxicity, offering insights into its therapeutic potential.

Results

paracetamol oral intake altered renal histology with significantly P< 0.05 increased serum creatinine, blood urea nitrogen (BUN), and homogenate malonaldhyde (MDA), and immunoexpression of tumor necrosis- alpha (TNF-α), interleukin-6 (IL-6), caspase-3, Bcl-2-associated X- protein (Bax). Furthermore, it decreases homogenate level of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and gene expression of nuclear factor erythroid 2-related factor 2 (Nrf2), and haem oxygenase-1 (HO-1). Meanwhile, intraperitoneal injection of celastrol with acetaminophen reaffirms the previous results.

Conclusions

We provided a novel treatment against acetaminophen induced-nephrotoxicity with targeting renal oxidative stress, inflammation, apoptosis with elevation of Aquaporin 1 (AQP1) level.

State of the Art and Science of Immunocytochemistry

BACKGROUND

Immunocytochemistry (ICC) is a widely available and extensively used ancillary method in diagnostic cytopathology with great variability in all test phases and a low level of adequate quality management. The non-standardized ICC landscape is now challenged with the introduction of the new European (EU) In Vitro Diagnostic Medical Devices Regulation (IVDR). According to this regulation, ICC on cytological slides falls under the category of Laboratory-Developed Tests (LDT), which requires rigorous standardization, validation, and thorough quality management.

SUMMARY

Complete standardization of pre-analytical and analytical steps in ICC is impossible due to the complexity of the method and the constantly evolving antibodies, detection systems, and platforms. However, similar to the approach in immunohistochemistry, improving and standardizing "best practices" in quality management will result in high-quality, correct, accurate, and reliable ICC results. In this review, the current challenges of ICC in diagnostic cytopathology will be discussed, along with practical insights into ICC standardization and validation.

KEY MESSAGES

Control slides prepared in the same manner as the patient samples, optimized ICC protocols, and participation in external quality control for ICC are the pillars of good quality management and essential to ensure safe and reliable patient diagnostics.

Angiotensin II Type 1 receptor blockade attenuates the neuropathological changes in the spinal cords of diabetic rats with modulation of nuclear factor erythroid 2-related factor 2/ heme oxygenase 1 system

Peripheral and central neuropathies frequently complicate worldwide diabetes. Compared to peripheral neuropathy, central neuropathy didn`t gain a major research interest. Angiotensin II is reported to be involved in diabetic neuropathic pain but its role in the central pathological changes in the spinal cord is not clear. Here, we study the role of Losartan; an Angiotensin II receptor 1 (AT1) antagonist in suppression of the diabetes-induced changes in the spinal cord. Three groups of rats were applied; a negative control group, a streptozotocin (STZ) diabetic group, and a group receiving STZ and Losartan. After two months, the pathological alteration in the spinal cord was investigated, and an immunohistochemical study was performed for neuronal, astrocytic, and microglial markers; nuclear protein (NeuN), Glial fibrillary acidic protein (GFAP), and Ionized calcium-binding adaptor molecule 1 (Iba1), respectively, and for an apoptosis marker; caspase-3, and the inflammatory marker; nuclear factor kappa B (NF-kB) signaling, heme oxygenase-1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf2); physiological antioxidant system. The results showed that Losartan caused recovery of spinal cord changes, by inhibiting the microglial and astrocytic activation, suppressing neuronal apoptosis and NF-kB expression with activation of Nrf2/HO-1 (P<0.0005). It is suggested, herein, that Losartan can suppress diabetes-induced glial activation, inflammation, neuronal apoptosis, and oxidative stress in the spinal cord; the mechanisms that may underlie the role of AT1 antagonism in suppressing diabetic neuropathic pain.

Involvement of Nrf2-PPAR-γ signaling in Coenzyme Q10 protecting effect against methotrexate-induced testicular oxidative damage

Studies have identified Coenzyme Q10 (CoQ10) as a promising agent in improving idiopathic male infertility; however, its role in chemically or environmentally induced testicular dysfunction is not well-established. We investigated the potential of CoQ10 to attenuate methotrexate (MTX)-induced testicular damage and to identify molecular targets of CoQ10 effects. Wistar rats received a single intraperitoneal dose of 20 mg/kg MTX on the fifth day of the 10-day experimental protocol. 100 mg/kg CoQ10 was given orally daily for ten days, alone or combined with MTX. The testes of MTX-treated animals showed thickened tunica albuginea, distortion of seminiferous tubules with a marked reduction of germinal lining, a few primary spermatocytes with no spermatozoa, apoptotic cells, congested sub-capsular and interstitial blood vessels, and interstitial edema. Reduction of reproductive hormones and increased oxidative, inflammatory, and apoptotic biomarkers levels were also seen in the MTX-treated rats. CoQ10 + MTX-treated rats were protected against MTX-induced testicular histological changes and showed improvement in testosterone, luteinizing-, and follicle-stimulating hormone serum levels compared to the MTX group. The testes of the CoQ10 + MTX-treated rats showed reduced malondialdehyde, myloperoxidase, tumor necrosis factor -α, interleukin-6 and -1β and Bax: Bcl2 ratio and enhanced glutathione, and catalase compared to MTX alone. CoQ10 enhanced MTX-induced downregulation of Nrf2 and PPAR-γ signaling and modulated its downstream targets, the inducible nitric oxide synthase, NF-κB, Bax, and Bcl2. In conclusion, CoQ10 targeted the Nrf2-PPAR-γ signaling loop and its downstream pathways, mitigating MTX-induced oxidative stress-related damages and alleviating the testicular dysfunction MTX caused. Our data suggest Nrf2-PPAR-γ signaling as a potential therapeutic target in testicular toxicity, where oxidative stress, inflammation, and apoptosis trigger damage.

Guidelines on antibody use in physiology research

Antibodies are one of the most used reagents in scientific laboratories and are critical components for a multitude of experiments in physiology research. Over the past decade, concerns about many biological methods, including those that use antibodies, have arisen as several laboratories were unable to reproduce the scientific data obtained in other laboratories. The lack of reproducibility could be largely attributed to inadequate reporting of detailed methods, no or limited verification by authors, and the production and use of unvalidated antibodies. The goal of this guideline article is to review best practices concerning commonly used techniques involving antibodies, including immunoblotting, immunohistochemistry, and flow cytometry. Awareness and integration of best practices will increase the rigor and reproducibility of these techniques and elevate the quality of physiology research.

Modulation of CXCL10 activity as a therapeutic target of ocular toxoplasmosis in diabetic mice

Ocular toxoplasmosis is likely the most common cause of infectious posterior uveitis worldwide. CXCL10 chemokine has an important role in the maintenance of the T-cell response and the control of Toxoplasma gondii in the eye during chronic infection. Drugs that can modulate the chemokine activity could be effective against the parasite. In this work, CXCL10 local retinal expression was investigated in a diabetic mouse model with ocular toxoplasmosis for the first time. In addition, the efficacy of naphthoquinones and quinolones was compared to spiramycin (SP) in treating the infection and modulating the chemokine expression. Our results revealed that chloroquine (CQ) achieved the best results regarding the reduction of cerebral cyst burden (84.36%), improving the retinal histopathological changes, cellular infiltrates, and vasculitis significantly (P < 0.005), and balancing the strong CXCL10 expression caused by the infection. Buparvaquone-treated mice showed a significant percentage of reduction of brain cysts (76.25%), moderate improvement of histopathology, and mild to moderate CXCL10 expression. While SP showed the least efficacy against the parasite in the eye in the form of mild improvement of histopathological changes and downregulation of retinal chemokine expression with the least reduction rate of cerebral parasitic burden (57%). In conclusion, Optimal control of pathogens probably needs a balanced immune response with an optimum expression of chemokines. So, targeting the modulation of retinal CXCL10 may eventually be beneficial in the management of ocular toxoplasmosis plus its potential to act as a marker for predictive local immunological response during the infection.

HCR spectral imaging: 10-plex, quantitative, high-resolution RNA and protein imaging in highly autofluorescent samples

Signal amplification based on the mechanism of hybridization chain reaction (HCR) provides a unified framework for multiplex, quantitative, high-resolution imaging of RNA and protein targets in highly autofluorescent samples. With conventional bandpass imaging, multiplexing is typically limited to four or five targets owing to the difficulty in separating signals generated by fluorophores with overlapping spectra. Spectral imaging has offered the conceptual promise of higher levels of multiplexing, but it has been challenging to realize this potential in highly autofluorescent samples, including whole-mount vertebrate embryos. Here, we demonstrate robust HCR spectral imaging with linear unmixing, enabling simultaneous imaging of ten RNA and/or protein targets in whole-mount zebrafish embryos and mouse brain sections. Further, we demonstrate that the amplified and unmixed signal in each of the ten channels is quantitative, enabling accurate and precise relative quantitation of RNA and/or protein targets with subcellular resolution, and RNA absolute quantitation with single-molecule resolution, in the anatomical context of highly autofluorescent samples.

Intersectional strategy to study cortical inhibitory parvalbumin-expressing interneurons

Parvalbumin-expressing (PV) interneurons are key neuronal elements to a global excitatory-inhibitory balance in normal cortical functioning. To better understand the circuit functions of PV interneurons, reliable animal models are needed. This study investigated the sensitivity and specificity of the most frequently used PV-Cre/tdTomato mouse line in this regard. The colocalization of the transgene (tdTomato) with the parvalbumin protein, with GAD1 (a conclusive inhibitory cell marker) and Vglut1 (a conclusive excitatory cell marker) as well as with a marker for perineuronal nets (WFA) was assessed and a substantial proportion of layer 5 PV neurons was found to be excitatory and not inhibitory in the PV-Cre/tdTomato mouse. The intersectional transgenic mouse line Vgat-Cre/PV-Flp/tdTomato provided a solution, since no colocalization of tdTomato with the Vglut1 probe was found there. In conclusion, the Vgat-Cre/PV-Flp/tdTomato mouse line seems to be a more reliable animal model for functional studies of GABAergic PV interneurons.

Deep Learning-Based H-Score Quantification of Immunohistochemistry-Stained Images

Immunohistochemistry (IHC) is a well-established and commonly used staining method for clinical diagnosis and biomedical research. In most IHC images, the target protein is conjugated with a specific antibody and stained using diaminobenzidine (DAB), resulting in a brown coloration, whereas hematoxylin serves as a blue counterstain for cell nuclei. The protein expression level is quantified through the H-score, calculated from DAB staining intensity within the target cell region. Traditionally, this process requires evaluation by 2 expert pathologists, which is both time consuming and subjective. To enhance the efficiency and accuracy of this process, we have developed an automatic algorithm for quantifying the H-score of IHC images. To characterize protein expression in specific cell regions, a deep learning model for region recognition was trained based on hematoxylin staining only, achieving pixel accuracy for each class ranging from 0.92 to 0.99. Within the desired area, the algorithm categorizes DAB intensity of each pixel as negative, weak, moderate, or strong staining and calculates the final H-score based on the percentage of each intensity category. Overall, this algorithm takes an IHC image as input and directly outputs the H-score within a few seconds, significantly enhancing the speed of IHC image analysis. This automated tool provides H-score quantification with precision and consistency comparable to experienced pathologists but at a significantly reduced cost during IHC diagnostic workups. It holds significant potential to advance biomedical research reliant on IHC staining for protein expression quantification.

Neuroprotective effect of ranolazine improves behavioral discrepancies in a rat model of scopolamine-induced dementia

Background

Ranolazine (Rn), an antianginal agent, acts in the central nervous system and has been used as a potential treatment agent for pain and epileptic disorders. Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases and the leading factor in dementia in the elderly.

Aim

We examined the impact of Rn on scopolamine (Sco)-induced dementia in rats.

Methods

Thirty-two albino male rats were divided into four groups: control, Rn, Sco, and Rn + Sco.

Results

A significant decrease in the escape latency in the Morris water maze test after pre-treatment with Rn explained better learning and memory in rats. Additionally, Rn significantly upregulated the activities of the antioxidant enzymes in the treated group compared to the Sco group but substantially reduced acetylcholinesterase activity levels in the hippocampus. Moreover, Rn dramatically reduced interleukin-1 β (IL-1β) and IL-6 and upregulated the gene expression of brain-derived neurotrophic factor (BDNF). Furthermore, in the Sco group, the hippocampal tissue's immunohistochemical reaction of Tau and glial factor activating protein (GFAP) was significantly increased in addition to the upregulation of the Caspase-3 gene expression, which was markedly improved by pre-treatment with Rn. The majority of pyramidal neurons had large vesicular nuclei with prominent nucleoli and appeared to be more or less normal, reflecting the all-beneficial effects of Rn when the hippocampal tissue was examined under a microscope.

Conclusion

Our findings indicated that Rn, through its antioxidative, anti-inflammatory, and anti-apoptotic effects, as well as the control of the expression of GFAP, BDNF, and Tau proteins, has a novel neuroprotective impact against scopolamine-induced dementia in rats.

A comprehensive review on anticancer evaluation techniques

The development of effective anticancer strategies and the improvement of our understanding of cancer need analytical tools. Utilizing a variety of analytical approaches while investigating anti-cancer medicines gives us a thorough understanding of the traits and mechanisms concerned to cancer cells, which enables us to develop potent treatments to combat them. The importance of anticancer research may be attributed to various analytical techniques that contributes to the identification of therapeutic targets and the assessment of medication efficacy, which are crucial things in expanding our understanding of cancer biology. The study looks at methods that are often used in cancer research, including cell viability assays, clonogenic assay, flow cytometry, 2D electrophoresis, microarray, immunofluorescence, western blot caspase activation assay, bioinformatics, etc. The fundamentals, applications, and how each technique analytical advances our understanding of cancer are briefly reviewed.

The Compartmentalization of Amyloid-β in Idiopathic Normal Pressure Hydrocephalus Brain Biopsies

Background

Amyloid-β (Aβ) is one of the hallmark lesions of Alzheimer's disease (AD). During the disease process, Aβ undergoes biochemical changes, producing toxic Aβ variants, proposed to be detected within the neurons. Idiopathic normal pressure hydrocephalus (iNPH) causes cognitive impairment, gait, and urinary symptoms in elderly, that can be reversed by a ventriculo-peritoneal shunt. Majority of iNPH subjects display different Aβ variants in their brain biopsies, obtained during shunting.

Objective

To study the cellular compartmentalization of different Aβ variants in brain biopsies from iNPH subjects.

Methods

We studied the cellular localization of different proteoforms of Aβ using antibodies towards different amino acid sequences or post-translational modifications of Aβ, including clones 4G8, 6F/3D, unmodified- (7H3D6), pyroglutamylated- (N3pE), phosphorylated-(1E4E11) Aβ and Aβ protein precursor (AβPP), in brain biopsies from 3 iNPH subjects, using immunohistochemistry and light microscopy (LM), light microscopy on semi-thin sections (LMst), and electron microscopy (EM).

Results

In LM all Aβ variants were detected. In LMst and EM, the Aβ 4G8, 6F/3D, and the pyroglutamylated Aβ were detected. The AβPP was visualized by all methods. The Aβ labelling was located extracellularly with no specific signal within the intracellular compartment, whereas the AβPP was seen both intra- and extracellularly.

Conclusions

The Aβ markers displayed extracellular localization when visualized by three assessment techniques, reflecting the pathological extracellular accumulation of Aβ in the human brain. No intracellular Aβ pathology was seen. AβPP was visualized in intra- and extracellularly, which corresponds to the localization of the protein in the membranes of cells and organelles.

Correlation Between ImageJ and Conventional Manual Scoring Methods for Programmed Death-Ligand 1 Immuno-Histochemically Stained Sections

Background: One of the most frequently used methods for quantifying PD-L1 (programmed cell death-ligand 1) expression in tumor tissue is IHC (immunohistochemistry). This may predict the patient's response to anti-PD1/PD-L1 therapy in cancer. Methods: ImageJ software was used to score IHC-stained sections for PD-L1 and compare the results with the conventional manual method. Results: In diffuse large B cell lymphoma, no significant difference between the scores obtained by the conventional method and ImageJ scores obtained using the option "RGB" or "Brightness/Contrast." On the other hand, a significant difference was found between the conventional and HSB scoring methods. ImageJ faced some challenges in analyzing head and neck squamous cell carcinoma tissues because of tissue heterogenicity. A significant difference was found between the conventional and ImageJ scores using HSB or RGB but not with the "Brightness/Contrast" option. Scores obtained by ImageJ analysis after taking images using 20 × objective lens gave significantly higher readings compared to 40 × magnification. A significant difference between camera-captured images' scores and scanner whole slide images' scores was observed. Conclusion: ImageJ can be used to score homogeneous tissues. In the case of highly heterogeneous tissues, it is advised to use the conventional method rather than ImageJ scoring.

Increase in the specificity of immunoassay methods by direct targeting different epitopes; sequential chain reactions

BACKGROUND

Immunoassay methods typically involve the use of antibodies, which are either labeled with an enzyme to generate a detectable product or directly tagged with a radioactive or fluorescent substrate.

METHODS

One approach to enhance the specificity of immuno-detection methods is by employing a combination of different antibodies, such as primary and secondary.

RESULTS

However, relying solely on one antibody targeting another may not offer the highest level of precision for improving immunoassay specificity; A novel strategy for enhancing the specificity of immunoassay techniques involves directly targeting different epitopes of an antigen.

CONCLUSIONS

This approach entails utilizing sequential chain reactions facilitated by distinct enzymes bound to various antibodies, each directed at specific epitopes on the antigen. Such an innovative method holds promise for advancing the specificity of immunoassay methods.

Cytochemical and Histochemical Staining with Peptide Antibodies

Peptide antibodies are particularly useful for immunocytochemistry (ICC) and immunohistochemistry (IHC), where antigens may denature due to fixation of tissues and cells. Peptide antibodies can be made to any defined sequence, including unknown putative proteins and posttranslationally modified sequences. Moreover, the availability of large amounts of the antigen (peptide) allows inhibition/absorption controls, which are important in ICC/IHC, due to the many possibilities for false-positive reactions caused by immunoglobulin Fc receptors, nonspecific reactions and cross-reactivity of primary and secondary antibodies with other antigens and endogenous immunoglobulins, respectively. Here, simple protocols for ICC and IHC are described together with recommendations for appropriate controls.

Genetic and Immunohistochemistry Tools to Visualize Rat Macrophages In Situ

Macrophages contribute to many aspects of development and homeostasis, innate and acquired immunity, immunopathology, and tissue repair. Every tissue contains an abundant resident macrophage population. Inflammatory stimuli promote the recruitment of monocytes from the blood and their adaptation promotes the removal of the stimulus and subsequent restoration of normal tissue architecture. Dysregulation of this response leads to chronic inflammation and tissue injury. In many tissues, their differentiation and survival are dependent on the colony stimulating factor 1 receptor (CSF1R) signalling axis, which is highly conserved across all vertebrates. Complete loss of either CSF1R or its cognate ligands, colony stimulating factor 1 (CSF1), and interleukin 34 (IL-34), results in the loss of many tissue-resident macrophage populations. This provides a useful paradigm to study macrophages.There are many tools used to visualize tissue-resident macrophages and their precursors, monocytes, in mice and humans. Particularly in mice there are genetic tools available to delete, enhance and manipulate monocytes and macrophages and their gene products to gain insight into phenotype and function. The laboratory rat has many advantages as an experimental model for the understanding of human disease, but the analytical resources are currently more limited than in mice. Here, we describe available genetic models, antibodies, and immunohistochemistry (IHC) methods that may be used to visualize tissue-resident macrophages in rats.

Canagliflozin ameliorates ulcerative colitis via regulation of TLR4/MAPK/NF-κB and Nrf2/PPAR-γ/SIRT1 signaling pathways

Ulcerative colitis (UC) is one of the most common subtypes of inflammatory bowel disease (IBD) that affects the colon and is characterized by severe intestinal inflammation. Canagliflozin is a widely used antihyperglycemic agent, a sodium-glucose cotransporter-2 (SGLT2) inhibitor that enhances urinary glucose excretion. This study aims to provide insights into the potential benefits of canagliflozin as a treatment for UC by addressing possible cellular signals. Acetic acid (AA; 4% v/v) was administered intrarectally to induce colitis. Canagliflozin is given orally at a dose of 10 mg/kg/day. Canagliflozin attenuates inflammation in AA-induced colitis, evidenced by significant and dose-dependently downregulation of p38 MAPK, NF-κB-p65, IKK, IRF3, and NADPH-oxidase as well as colonic levels of IL-6 and IL-1β and MPO enzymatic activity. Canagliflozin mitigates colonic oxidative stress by decreasing MDA content and restoring SOD enzymatic activities and GSH levels mediated by co-activating of Nrf2, PPARγ, and SIRT1 pathways. Moreover, an in-silico study confirmed that canagliflozin was specific to all target proteins in this study. Canagliflozin's binding affinity with its target proteins indicates and confirms its effectiveness in regulating these pathways. Also, network pharmacology analysis supported that canagliflozin potently attenuates UC via a multi-target and multi-pathway approach.

Effect of SGLT2 Inhibitor on Cardiomyopathy in a Rat Model of T2DM: Possible involvement of Cardiac Aquaporins

Diabetic cardiomyopathy (DCM) causes arrhythmia, heart failure, and sudden death. Empagliflozin, an SGLT-2 (Sodium glucose co-transporter) inhibitor, is an anti-diabetic medication that decreases blood glucose levels by stimulating urinary glucose excretion. Several aquaporins (AQPs) including AQP-1-3 and - 4 and their involvement in the pathogenesis in different cardiac diseases were detected. In the current study the effect of Empagliflozin on diabetic cardiomyopathy and the possible involvement of cardiac AQPs were investigated.

METHODS

56 adult male Sprague-Dawley rats were divided into 4 groups: Control, DCM: type 2 diabetic rats, low EMPA+DCM received empagliflozin (10 mg/kg/day) and high EMPA+DCM received empagliflozin (30 mg/kg/day) for 6 weeks.

RESULTS

Administration of both EMPA doses, especially in high dose group, led to significant improvement in ECG parameters. Also, a significant improvement in biochemical and cardiac oxidative stress markers (significant decrease in serum CK-MB, and malondialdehyde while increasing catalase) with decreased fibrosis and edema in histopathological examination and a significant attenuation in apoptosis (caspase-3) and edema (AQP-1& -4).

CONCLUSION

Both doses of Empagliflozin have a cardioprotective effect and reduced myocardial tissue edema with high dose having a greater effect. This might be due to attenuation of oxidative stress, fibrosis and edema mediated through AQP-1, - 3& - 4 expression.

Diagnostic Role and Prognostic Impact of PSAP Immunohistochemistry: A Tissue Microarray Study on 31,358 Cancer Tissues

Prostate-specific acid phosphatase (PSAP) is a marker for prostate cancer. To assess the specificity and prognostic impact of PSAP, 14,137 samples from 127 different tumor (sub)types, 17,747 prostate cancers, and 76 different normal tissue types were analyzed via immunohistochemistry in a tissue microarray format. In normal tissues, PSAP staining was limited to the prostate epithelial cells. In prostate cancers, PSAP was seen in 100% of Gleason 3 + 3, 95.5% of Gleason 4 + 4, 93.8% of recurrent cancer under androgen deprivation therapy, 91.0% of Gleason 5 + 5, and 31.2% of small cell neuroendocrine cancer. In non-prostatic tumors, PSAP immunostaining was only found in 3.2% of pancreatic neuroendocrine tumors and in 0.8% of diffuse-type gastric adenocarcinomas. In prostate cancer, reduced PSAP staining was strongly linked to an advanced pT stage, a high classical and quantitative Gleason score, lymph node metastasis, high pre-operative PSA levels, early PSA recurrence (p < 0.0001 each), high androgen receptor expression, and TMPRSS2:ERG fusions. A low level of PSAP expression was linked to PSA recurrence independent of pre- and postoperative prognostic markers in ERG-negative cancers. Positive PSAP immunostaining is highly specific for prostate cancer. Reduced PSAP expression is associated with aggressive prostate cancers. These findings make PSAP a candidate marker for prognostic multiparameter panels in ERG-negative prostate cancers.

Immunohistochemical identification of a malignant catarrhal fever virus in cattle with renal diseases from Paraná state, Southern Brazil: a retrospective epidemiological study

Malignant catarrhal fever (MCF) is a viral infectious disease caused by specific members of the Macavirus genus that are referred to as the MCF virus (MCFV) complex group. This study determined the prevalence of MCFV-associated infections in cattle within the mesoregions of the state of Paraná, Southern Brazil, by analyzing the histopathologic patterns of renal lesions in association with positive immunoreactivity to intralesional antigens of MCFV. Intracytoplasmic MCFV antigens were identified in 41.7% (48/115) of the kidneys of cattle evaluated. Lymphocytic interstitial nephritis, vascular degeneration, and ballooning degeneration of the renal tubules were the principal histopathological findings associated with positive immunoreactivity to MCFV. The results indicate that MCFV infections are endemic within the state of Paraná and suggest that the kidney can be of diagnostic value in suspected cases of MCF-associated infections in cattle. Furthermore, the utilization of an in situ diagnostic technique resulted in the detection of a greater number of cases of infections by MCFV than previously identified using other diagnostic methods. Additionally, degenerative vascular lesions of the kidney should be considered during the establishment of a histological diagnosis of MCFV-induced infections in cattle in the absence of fibrinoid change or necrotizing vasculitis.

Generation of Antibodies Selectively Recognizing Epitopes in a Formaldehyde-Fixed Cell-Surface Antigen Using Virus-like Particle Display and Hybridoma Technology

Efficient induction of target-specific antibodies can be elicited upon immunization with highly immunogenic virus-like particles (VLPs) decorated with desired membrane-anchored target antigens (Ags). However, for example, for diagnostic purposes, monoclonal antibodies (mAbs) are required to enable the histological examination of formaldehyde-fixed paraffin-embedded (FFPE) biopsy tissue samples. Aiming at the generation of FFPE-antigen-specific mAbs and as a proof of concept (POC), we first established a simplified protocol using only formaldehyde and 90 °C heat fixation (FF90) of cells expressing the target Ag nerve growth factor receptor (NGFR). The FF90 procedure was validated using flow cytometric analysis and two mAbs recognizing either the native and FFPE-Ag or exclusively the native Ag. C-terminally truncated NGFR (trNGFR)-displaying native and FF90-treated VLPs derived from HIV-1 did not reveal distinctive changes in particle morphology using transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis. Mice were subsequently repetitively immunized with trNGFR-decorated FF90-VLPs and hybridoma technology was used to establish mAb-producing cell clones. In multiple screening rounds, nine cell clones were identified producing mAbs distinctively recognizing epitopes in FF90- and FFPE-NGFR. This POC of a new methodology should foster the future generation of mAbs selectively targeting FFPE-fixed cell-surface Ags.

Impact of Decalcification, Cold Ischemia, and Deglycosylation on Performance of Programmed Cell Death Ligand-1 Antibodies With Different Binding Epitopes: Comparison of 7 Clones

Programmed cell death ligand-1 (PD-L1) expression levels in patients' tumors have demonstrated clinical utility across many cancer types and are used to determine treatment eligibility. Several independently developed PD-L1 immunohistochemical (IHC) predictive assays are commercially available and have demonstrated different levels of staining between assays, generating interest in understanding the similarities and differences between assays. Previously, we identified epitopes in the internal and external domains of PD-L1, bound by antibodies in routine clinical use (SP263, SP142, 22C3, and 28-8). Variance in performance of assays utilizing these antibodies, observed following exposure to preanalytical factors such as decalcification, cold ischemia, and duration of fixation, encouraged additional investigation of antibody-binding sites, to understand whether binding site structures/conformations contribute to differential PD-L1 IHC assay staining. We proceeded to further investigate the epitopes on PD-L1 bound by these antibodies, alongside the major clones utilized in laboratory-developed tests (E1L3N, QR1, and 73-10). Characterization of QR1 and 73-10 clones demonstrated that both bind the PD-L1 C-terminal internal domain, similar to SP263/SP142. Our results also demonstrate that under suboptimal decalcification or fixation conditions, the performance of internal domain antibodies is less detrimentally affected than that of external domain antibodies 22C3/28-8. Furthermore, we show that the binding sites of external domain antibodies are susceptible to deglycosylation and conformational structural changes, which directly result in IHC staining reduction or loss. The binding sites of internal domain antibodies were unaffected by deglycosylation or conformational structural change. This study demonstrates that the location and conformation of binding sites, recognized by antibodies employed in PD-L1 diagnostic assays, differ significantly and exhibit differing degrees of robustness. These findings should reinforce the need for vigilance when performing clinical testing with different PD-L1 IHC assays, particularly in the control of cold ischemia and the selection of fixation and decalcification conditions.

Development of a LAG-3 immunohistochemistry assay for melanoma

AIMS

A robust immunohistochemistry (IHC) assay was developed to detect lymphocyte-activation gene 3 (LAG-3) expression by immune cells (ICs) in tumour tissues. LAG-3 is an immuno-oncology target with demonstrable clinical benefit, and there is a need for a standardised, well-characterised assay to measure its expression. This study aims to describe LAG-3 scoring criteria and present the specificity, sensitivity, analytical precision and reproducibility of this assay.

METHODS

The specificity of the assay was investigated by antigen competition and with LAG3 knockout cell lines. A melanin pigment removal procedure was implemented to prevent melanin interference in IHC interpretation. Formalin-fixed paraffin-embedded (FFPE) human melanoma samples with a range of LAG-3 expression levels were used to assess the sensitivity and analytical precision of the assay with a ≥1% cut-off to determine LAG-3 positivity. Interobserver and intraobserver reproducibility were evaluated with 60 samples in intralaboratory studies and 70 samples in interlaboratory studies.

RESULTS

The LAG-3 IHC method demonstrated performance suitable for analysis of LAG-3 IC expression in clinical melanoma samples. The pretreatment step effectively removed melanin pigment that could interfere with interpretation. LAG-3 antigen competition and analysis of LAG3 knockout cell lines indicated that the 17B4 antibody clone binds specifically to LAG-3. The intrarun repeatability, interday, interinstrument, interoperator and inter-reagent lot reproducibility demonstrated a high scoring concordance (>95%). The interobserver and intraobserver reproducibility and overall interlaboratory and intralaboratory reproducibility also showed high scoring concordance (>90%).

CONCLUSIONS

We have demonstrated that the assay reliably assesses LAG-3 expression in FFPE human melanoma samples by IHC.

Ivermectin modulated cerebral γ-aminobutyric acid (GABA) and reduced the number of chronic Toxoplasma gondii cysts significantly in the brains of immunocompromised mice

Disruption of GABAergic signaling could exaggerate the inflammatory reaction associated with Toxoplasma gondii infection, as well as produce neurophysiological consequences including seizures that occur within the brain tissues. The current study aimed to evaluate the efficacy of ivermectin (IVM) in treating latent cerebral toxoplasmosis and define its role in the neuromodulation of cerebral tissue GABA expression, conducted in an immunocompromised dexamethasone-treated mouse model infected with the ME49 Toxoplasma strain. The control (non-infected non-treated) group showed a mean of 22.1 ± 0.71 for local expression of GABA. Significantly lower expression (3.78 ± 1.38) was recorded in the infected non-treated group (p ≤ 0.05). On the contrary, a significantly higher expression was reported in the group infected and treated with IVM than in the infected non-treated group (19.8 ± 0.8). While the infected spiramycin (SP)-treated group reported a significantly lower level than the control. Non-infected groups that received only IVM or SP recorded 22.3 ± 0.45 and 22 ± 0.89 respectively with no significant difference. IVM is shown in this work, not only to reduce the size and the number of Toxoplasma cystic lesions within the brain significantly with a reduction rate of 68.85% but to also increase the level of GABA local expression significantly in addition to improving cerebral histopathology. Thus, IVM by its ability to modulate GABA expression may improve such clinical situations, if used as a treatment either exclusively or in combination with other medications.

A Primer for Research Scientists on Assessing Mouse Gross and Histopathology Images in the Biomedical Literature

Advances in genomic technologies have enabled the development of abundant mouse models of human disease, requiring accurate phenotyping to elucidate the consequences of genetic manipulation. Anatomic pathology, an important component of the mouse phenotyping pipeline, is ideally performed by human or veterinary pathologists; however, due to insufficient numbers of pathologists qualified to assess these mouse models morphologically, research scientists may perform "do-it-yourself" pathology, resulting in diagnostic error. In the biomedical literature, pathology data is commonly presented as images of tissue sections, stained with either hematoxylin and eosin or antibodies via immunohistochemistry, accompanied by a figure legend. Data presented in such images and figure legends may contain inaccuracies. Furthermore, there is limited guidance for non-pathologist research scientists concerning the elements required in an ideal pathology image and figure legend in a research publication. In this overview, the components of an ideal pathology image and figure legend are outlined and comprise image quality, image composition, and image interpretation. Background knowledge is important for producing accurate pathology images and critically assessing these images in the literature. This foundational knowledge includes understanding relevant human and mouse anatomy and histology and, for cancer researchers, an understanding of human and mouse tumor classification and morphology, mouse stain background lesions, and tissue processing artifacts. Accurate interpretation of immunohistochemistry is also vitally important and is detailed with emphasis on the requirement for tissue controls and the distribution, intensity, and intracellular location of staining. Common pitfalls in immunohistochemistry interpretation are outlined, and a checklist of questions is provided by which any pathology image may be critically examined. Collaboration with pathologist colleagues is encouraged. This overview aims to equip researchers to critically assess the quality and accuracy of pathology images in the literature to improve the reliability and reproducibility of published pathology data. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC.

HCR spectral imaging: 10-plex, quantitative, high-resolution RNA and protein imaging in highly autofluorescent samples

Signal amplification based on the mechanism of hybridization chain reaction (HCR) provides a unified framework for multiplex, quantitative, high-resolution imaging of RNA and protein targets in highly autofluorescent samples. With conventional bandpass imaging, multiplexing is typically limited to four or five targets due to the difficulty in separating signals generated by fluorophores with overlapping spectra. Spectral imaging has offered the conceptual promise of higher levels of multiplexing, but it has been challenging to realize this potential in highly autofluorescent samples including whole-mount vertebrate embryos. Here, we demonstrate robust HCR spectral imaging with linear unmixing, enabling simultaneous imaging of 10 RNA and/or protein targets in whole-mount zebrafish embryos and mouse brain sections. Further, we demonstrate that the amplified and unmixed signal in each of 10 channels is quantitative, enabling accurate and precise relative quantitation of RNA and/or protein targets with subcellular resolution, and RNA absolute quantitation with single-molecule resolution, in the anatomical context of highly autofluorescent samples.

SUMMARY

Spectral imaging with signal amplification based on the mechanism of hybridization chain reaction enables robust 10-plex, quantitative, high-resolution imaging of RNA and protein targets in whole-mount vertebrate embryos and brain sections.

Is islet amyloid polypeptide indeed expressed in the human brain?

AIMS

This study aims to study the association between pancreatic islet amyloid polypeptide (IAPP) and Alzheimer's disease neuropathological change (ADNC) in brain biopsies obtained from subjects with idiopathic normal pressure hydrocephalus (iNPH) and in post-mortem (PM) brain samples obtained from aged individuals.

METHODS

For the immunohistochemical (IHC) analyses, two IAPP antibodies (Abs), monoclonal and polyclonal, and Abs directed towards ADNC were applied.

RESULTS

The iNPH cohort included 113 subjects. Amyloid-β (Aβ) was detected in 50% and hyperphosphorylated τ (HPτ) in 47% of the cases. Concomitant pathology was seen in 32%. The PM cohort included 77 subjects. Aβ was detected in 69% and HPτ in 91% of the cases. Combined Aβ/HPτ pathology was seen in 62%. Reactivity for the monoclonal IAPP was not detected in the brain tissue in either of the cohorts. Reactivity for the polyclonal IAPP was observed in all 77 PM brain samples.

CONCLUSIONS

There was no specific expression of IAPP in human brain tissue; hence, an association between IAPP and ADNC is not assessable. Of note, the observed reactivity of the polyclonal IAPP Ab was not reproduced with a specific monoclonal Ab; thus, we considered the observed staining with the polyclonal Ab to be unreliable. When using IHC, several pitfalls, especially the choice of an Ab, always need to be considered. Polyclonal Abs cross-react with other epitopes and proteins, thus leading to false-positive results. This seems to be the case for the polyclonal IAPP Abs in the human brain.

Back to the Basics: Usefulness of Naturally Aged Mouse Models and Immunohistochemical and Quantitative Morphologic Methods in Studying Mechanisms of Lung Aging and Associated Diseases

Aging-related molecular and cellular alterations in the lung contribute to an increased susceptibility of the elderly to devastating diseases. Although the study of the aging process in the lung may benefit from the use of genetically modified mouse models and omics techniques, these approaches are still not available to most researchers and produce complex results. In this article, we review works that used naturally aged mouse models, together with immunohistochemistry (IHC) and quantitative morphologic (QM) methods in the study of the mechanisms of the aging process in the lung and its most commonly associated disorders: cancer, chronic obstructive pulmonary disease (COPD), and infectious diseases. The advantage of using naturally aged mice is that they present characteristics similar to those observed in human aging. The advantage of using IHC and QM methods lies in their simplicity, economic accessibility, and easy interpretation, in addition to the fact that they provide extremely important information. The study of the aging process in the lung and its associated diseases could allow the design of appropriate therapeutic strategies, which is extremely important considering that life expectancy and the number of elderly people continue to increase considerably worldwide.

Versatile and Accessible Magnetic Diagnosis Platform with Different Types of Magnetic Particles for Liquid and Solid Biopsies

The diagnosis of liquid and solid biopsies by different instruments makes the clinic loading difficult in many aspects. Given the compositions of magnetic particles (MPs) with diverse characterizations and the innovative acoustic type of vibration sample magnetometer (VSM), the versatile, accessible magnetic diagnosis platform was proposed to meet clinical demands, such as low loading for multiple biopsies. In liquid biopsies of alpha-fetoprotein (AFP) standard solutions and subject serums, molecular concentration was analyzed from saturation magnetization by the soft type of Fe3O4 MPs with AFP bioprobe coating. In the phantom mixture simulated as bounded MPs in tissue, the bounded MPs was evaluated from the area of the hysteresis loop by hard type of cobalt MPs without bio-probes coating. Not only a calibration curve was founded for many hepatic cell carcinoma stages, but also microscale images verified the Ms increase due to magnetic protein clusters, etc. Hence, its wide populations in clinics could be expected.

Type-1 diabetes mellitus down-regulated local cerebral glial fibrillary acidic protein expression in experimental toxoplasmosis

Cerebral toxoplasmosis is an opportunistic infection, occurring mostly in immunosuppressed patients due to the reactivation of latent Toxoplasma cysts. The cerebral comorbidity in diabetic patients tends to intensify the burden of pathogenic infection within the brain. The aim of this work was to study the effect of cerebral toxoplasmosis in experimentally infected hyperglycemic mice, on histopathology and glial fibrillary acidic protein (GFAP) expression, compared to normoglycemic mice at different time intervals. Vasculopathy was exclusively observed in diabetic groups, with features of increased severity during Toxoplasma infection. Gliosis was observed in diabetic groups, while hyperactive astroglial activity was detected in normoglycemic groups, especially at 6 weeks of infection. GFAP expression showed significant up-regulation in normoglycemic mice at 6 weeks of infection (40.03 ± 1.41) afterwards, it decreased to 22.22 ± 3.14 at 12 weeks which was statistically insignificant to the normal level, possibly indicating the successful Toxoplasma stage transformation (to bradyzoite), thereby limiting the infection within the brain. In hyperglycemic infected groups, GFAP was significantly down-regulated, in both acute and chronic phases of infection, most likely indicating failure of stage transformation and infection limitation. This may expose those vulnerable groups to the risk of dissemination, resulting in life-threatening diffuse encephalitis. The current study emphasized the importance of rapid diagnosis of Toxoplasma infection in diabetic subjects, and highlighted the value of using GFAP as a neurological indicator of disease progression in those comorbid cases.

Umbelliferone potentiates intestinal protective effect of Lactobacillus Acidophilus against methotrexate-induced intestinal injury: Biochemical and histological study

Intestinal injury is a common adverse effect of methotrexate (MTX) therapy, limiting its clinical use. Despite oxidative stress and inflammation being the most embedded mechanism of injury, pharmacological agents that exhibit antioxidant and anti-inflammatory impacts could prevent such toxicities. This study aimed to assess the enteroprotective effect of lactobacillus acidophilus (LB) and/or umbelliferone (UMB) against MTX-induced intestinal injury. Histologically, pretreatment with LB, UMB, or their combinations preserve the intestinal histological structure and mucin content with superior effect in combination therapy. In addition, oral pretreatment with UMB, LB, or their combinations significantly restored oxidant/antioxidant status, as evidenced by the upregulation of Nrf2, SOD3, HO-1, GSH, and GST levels concurrent with a decline in MDA contents. Besides, they suppressed the inflammatory burden by inhibiting STAT3, MPO, TLR4, NF-κB, TNF-α, and IL-6 levels. Moreover, LB, UMB, or their combinations significantly upregulated Wnt and β-catenin expression. Notably, pretreatment with the combination therapy is superior to monotherapy in protecting rats' small intestines from MTX-induced enteritis. In conclusion, combined pretreatment with LB and UMB could be a novel therapeutic regimen for conditions of intestinal injury induced by MTX via restoring oxidant/antioxidant balance and suppressing inflammatory burden.