Disulfiram Abrogates Morphine Tolerance—A Possible Role of µ-Opioid Receptor-Related G-Protein Activation in the Striatum

One of the key strategies for effective pain management involves delaying analgesic tolerance. Early clinical reports indicate an extraordinary effectiveness of off-label disulfiram—an agent designed for alcohol use disorder—in potentiating opioid analgesia and abrogation of tolerance. Our study aimed to determine whether sustained µ-opioid signaling upon disulfiram exposure contributes to these phenomena. Wistar rats were exposed to acute and chronic disulfiram and morphine cotreatment. Nociceptive thresholds were assessed with the mechanical Randal-Selitto and thermal tail-flick tests. µ-opioid receptor activation in brain structures important for pain processing was carried out with the [³⁵S]GTPγS assay. The results suggest that disulfiram (12.5–50 mg/kg i.g.) augmented morphine antinociception and diminished morphine (25 mg/kg, i.g.) tolerance in a supraspinal, opioid-dependent manner. Disulfiram (25 mg/kg, i.g.) induced a transient enhancement of µ-opioid receptor activation in the periaqueductal gray matter (PAG), rostral ventromedial medulla (RVM), hypothalamus, prefrontal cortex and the dorsal striatum at day 1 of morphine treatment. Disulfiram rescued µ-opioid receptor signaling in the nucleus accumbens and caudate-putamen 14 days following morphine and disulfiram cotreatment. The results of this study suggest that striatal µ-opioid receptors may contribute to the abolition of morphine tolerance following concomitant treatment with disulfiram.     

TCR Recognition of Peptide–MHC-I: Rule Makers and Breakers

T cells are a critical part of the adaptive immune system that are able to distinguish between healthy and unhealthy cells. Upon recognition of protein fragments (peptides), activated T cells will contribute to the immune response and help clear infection. The major histocompatibility complex (MHC) molecules, or human leukocyte antigens (HLA) in humans, bind these peptides to present them to T cells that recognise them with their surface T cell receptors (TCR). This recognition event is the first step that leads to T cell activation, and in turn can dictate disease outcomes. The visualisation of TCR interaction with pMHC using structural biology has been crucial in understanding this key event, unravelling the parameters that drive this interaction and their impact on the immune response. The last five years has been the most productive within the field, wherein half of current unique TCR–pMHC-I structures to date were determined within this time. Here, we review the new insights learned from these recent TCR–pMHC-I structures and their impact on T cell activation.     

Identification of Epigenetic Interactions between MicroRNA-30c-5p and DNA Methyltransferases in Neuropathic Pain

Neuropathic pain is a prevalent and severe chronic syndrome, often refractory to treatment, whose development and maintenance may involve epigenetic mechanisms. We previously demonstrated a causal relationship between miR-30c-5p upregulation in nociception-related neural structures and neuropathic pain in rats subjected to sciatic nerve injury. Furthermore, a short course of an miR-30c-5p inhibitor administered into the cisterna magna exerts long-lasting antiallodynic effects via a TGF-β1-mediated mechanism. Herein, we show that miR-30c-5p inhibition leads to global DNA hyper-methylation of neurons in the lumbar dorsal root ganglia and spinal dorsal horn in rats subjected to sciatic nerve injury. Specifically, the inhibition of miR-30-5p significantly increased the expression of the novo DNA methyltransferases DNMT3a and DNMT3b in those structures. Furthermore, we identified the mechanism and found that miR-30c-5p targets the mRNAs of DNMT3a and DNMT3b. Quantitative methylation analysis revealed that the promoter region of the antiallodynic cytokine TGF-β1 was hypomethylated in the spinal dorsal horn of nerve-injured rats treated with the miR-30c-5p inhibitor, while the promoter of Nfyc, the host gene of miR-30c-5p, was hypermethylated. These results are consistent with long-term protection against neuropathic pain development after nerve injury. Altogether, our results highlight the key role of miR-30c-5p in the epigenetic mechanisms’ underlying neuropathic pain and provide the basis for miR-30c-5p as a therapeutic target.     

β–Lactam TRPM8 Antagonist RGM8-51 Displays Antinociceptive Activity in Different Animal Models

Transient receptor potential melastatin subtype 8 (TRPM8) is a cation channel extensively expressed in sensory neurons and implicated in different painful states. However, the effectiveness of TRPM8 modulators for pain relief is still a matter of discussion, since structurally diverse modulators lead to different results, depending on the animal pain model. In this work, we described the antinociceptive activity of a β–lactam derivative, RGM8-51, showing good TRPM8 antagonist activity, and selectivity against related thermoTRP channels and other pain-mediating receptors. In primary cultures of rat dorsal root ganglion (DRG) neurons, RGM8-51 potently reduced menthol-evoked neuronal firing without affecting the major ion conductances responsible for action potential generation. This compound has in vivo antinociceptive activity in response to cold, in a mouse model of oxaliplatin-induced peripheral neuropathy. In addition, it reduces cold, mechanical and heat hypersensitivity in a rat model of neuropathic pain arising after chronic constriction of the sciatic nerve. Furthermore, RGM8-51 exhibits mechanical hypersensitivity-relieving activity, in a mouse model of NTG-induced hyperesthesia. Taken together, these preclinical results substantiate that this TRPM8 antagonist is a promising pharmacological tool to study TRPM8-related diseases.     

TNF-α-Mediated RIPK1 Pathway Participates in the Development of Trigeminal Neuropathic Pain in Rats

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) participates in the regulation of cellular stress and inflammatory responses, but its function in neuropathic pain remains poorly understood. This study evaluated the role of RIPK1 in neuropathic pain following inferior alveolar nerve injury. We developed a model using malpositioned dental implants in male Sprague Dawley rats. This model resulted in significant mechanical allodynia and upregulated RIPK1 expression in the trigeminal subnucleus caudalis (TSC). The intracisternal administration of Necrosatin-1 (Nec-1), an RIPK1 inhibitor, blocked the mechanical allodynia produced by inferior alveolar nerve injury The intracisternal administration of recombinant rat tumor necrosis factor-α (rrTNF-α) protein in naive rats produced mechanical allodynia and upregulated RIPK1 expression in the TSC. Moreover, an intracisternal pretreatment with Nec-1 inhibited the mechanical allodynia produced by rrTNF-α protein. Nerve injury caused elevated TNF-α concentration in the TSC and a TNF-α block had anti-allodynic effects, thereby attenuating RIPK1 expression in the TSC. Finally, double immunofluorescence analyses revealed the colocalization of TNF receptor and RIPK1 with astrocytes. Hence, we have identified that astroglial RIPK1, activated by the TNF-α pathway, is a central driver of neuropathic pain and that the TNF-α-mediated RIPK1 pathway is a potential therapeutic target for reducing neuropathic pain following nerve injury.     

Differences between Human and Mouse IgM Fc Receptor (FcµR)

Both non-immune “natural” and antigen-induced “immune” IgM are important for protection against pathogens and for regulation of immune responses to self-antigens. Since the bona fide IgM Fc receptor (FcµR) was identified in humans by a functional cloning strategy in 2009, the roles of FcµR in these IgM effector functions have begun to be explored. In this short essay, we describe the differences between human and mouse FcµRs in terms of their identification processes, cellular distributions and ligand binding activities with emphasis on our recent findings from the mutational analysis of human FcµR. We have identified at least three sites of human FcµR, i.e., Asn66 in the CDR2, Lys79 to Arg83 in the DE loop and Asn109 in the CDR3, responsible for its constitutive IgM-ligand binding. Results of computational structural modeling analysis are consistent with these mutational data and a model of the ligand binding, Ig-like domain of human FcµR is proposed. Serendipitously, substitution of Glu41 and Met42 in the CDR1 of human FcµR with mouse equivalents Gln and Leu, either single or more prominently in combination, enhances both the receptor expression and IgM binding. These findings would help in the future development of preventive and therapeutic interventions targeting FcµR.     

Hydrazine Radiolysis by Gamma-Ray in the N2H4–Cu+–HNO3 System

Radiolysis of chemical agents occurs during the decontamination of nuclear power plants. The γ-ray irradiation tests of the N₂H₄–Cu⁺–HNO₃ solution, a decontamination agent, were performed to investigate the effect of Cu⁺ ion and HNO₃ on N₂H₄ decomposition using a Co-60 high-dose irradiator. After the irradiation, the residues of N₂H₄ decomposition were analyzed by Ultraviolet-visible (UV) spectroscopy. NH₄⁺ ions generated from N₂H₄ radiolysis were analyzed by ion chromatography. Based on the results, the decomposition mechanism of N₂H₄ in the N₂H₄–Cu⁺–HNO₃ solution under γ-ray irradiation condition was derived. Cu⁺ ions form Cu⁺N₂H₄ complexes with N₂H₄, and then N₂H₄ is decomposed into intermediates. H⁺ ions and H^● radicals generated from the reaction between H⁺ ion and e_aq⁻ increased the N₂H₄ decomposition reaction. NO₃⁻ ions promoted the N₂H₄ decomposition by providing additional reaction paths: (1) the reaction between NO₃⁻ ions and N₂H₄^●+, and (2) the reaction between NO^● radical, which is the radiolysis product of NO₃⁻ ion, and N₂H₅⁺. Finally, the radiolytic decomposition mechanism of N₂H₄ obtained in the N₂H₄–Cu⁺–HNO₃ was schematically suggested.     

Improvements,Variations and Biomedical Applications of the Michaelis–Arbuzov Reaction

Compounds bearing the phosphorus–carbon (P–C) bond have important pharmacological, biochemical, and toxicological properties. Historically, the most notable reaction for the formation of the P–C bond is the Michaelis–Arbuzov reaction, first described in 1898. The classical Michaelis–Arbuzov reaction entails a reaction between an alkyl halide and a trialkyl phosphite to yield a dialkylalkylphosphonate. Nonetheless, deviations from the classical mechanisms and new modifications have appeared that allowed the expansion of the library of reactants and consequently the chemical space of the yielded products. These involve the use of Lewis acid catalysts, green methods, ultrasound, microwave, photochemically-assisted reactions, aryne-based reactions, etc. Here, a detailed presentation of the Michaelis–Arbuzov reaction and its developments and applications in the synthesis of biomedically important agents is provided. Certain examples of such applications include the development of alkylphosphonofluoridates as serine hydrolase inhibitors and activity-based probes, and the P–C containing antiviral and anticancer agents.     

Characterization of Mitochondrial Alterations in Aicardi–Goutières Patients Mutated in RNASEH2A and RNASEH2B Genes

Aicardi–Goutières syndrome (AGS) is a rare encephalopathy characterized by neurological and immunological features. Mitochondrial dysfunctions may lead to mitochondrial DNA (mtDNA) release and consequent immune system activation. We investigated the role of mitochondria and mtDNA in AGS pathogenesis by studying patients mutated in RNASEH2B and RNASEH2A genes. Lymphoblastoid cell lines (LCLs) from RNASEH2A- and RNASEH2B-mutated patients and healthy control were used. Transmission Electron Microscopy (TEM) and flow cytometry were used to assess morphological alterations, reactive oxygen species (ROS) production and mitochondrial membrane potential variations. Seahorse Analyzer was used to investigate metabolic alterations, and mtDNA oxidation and VDAC1 oligomerization were assessed by immunofluorescence. Western blot and RT-qPCR were used to quantify mtTFA protein and mtDNA release. Morphological alterations of mitochondria were observed in both mutated LCLs, and loss of physiological membrane potential was mainly identified in RNASEH2A LCLs. ROS production and 8-oxoGuanine levels were increased in RNASEH2B LCLs. Additionally, the VDAC1 signal was increased, suggesting a mitochondrial pore formation possibly determining mtDNA release. Indeed, higher cytoplasmic mtDNA levels were found in RNASEH2B LCLs. Metabolic alterations confirmed mitochondrial damage in both LCLs. Data highlighted mitochondrial alterations in AGS patients’ LCLs suggesting a pivotal role in AGS pathogenesis.     

Study of Novel Furocoumarin Derivatives on Anti-Vitiligo Activity,Molecular Docking and Mechanism of Action

Vitiligo is a common chronic dermatological abnormality that afflicts tens of millions of people. Furocoumarins isolated from Uygur traditional medicinal material Psoralen corylifolia L. have been proven to be highly effective for the treatment of vitiligo. Although many furocoumarin derivatives with anti-vitiligo activity have been synthesized, their targets with respect to the disease are still ambiguous. Fortunately, the JAKs were identified as potential targets for the disease and its inhibitors have been proved to be effective in the treatment of vitiligo in many clinical trials. Thus, sixty-five benzene sulfonate and benzoate derivatives of furocoumarins (7a–7ad, 8a–8ag) with superior anti-vitiligo activity targeting JAKs were designed and synthesized based on preliminary research. The SAR was characterized after the anti-vitiligo-activity evaluation in B16 cells. Twenty-two derivatives showed more potent effects on melanin synthesis in B16 cells than the positive control (8-MOP). Among them, compounds 7y and 8 not only could increase melanin content, but they also improved the catecholase activity of tyrosinase in a concentration-dependent manner. The docking studies indicated that they were able to interact with amino acid residues in JAK1 and JAK2 via hydrogen bonds. Furthermore, candidate 8 showed a moderate inhibition of CXCL−10, which plays an important role in JAK–STAT signaling. The RT-PCR and Western blotting analyses illustrated that compounds 7y and 8 promoted melanogenesis by activating the p38 MAPK and Akt/GSK-3β/β-catenin pathways, as well as increasing the expressions of the MITF and tyrosinase-family genes. Finally, furocoumarin derivative 8 was recognized as a promising candidate for the fight against the disease and worthy of further research in vivo.     

The One‐Pot Wittig Reaction: A Facile Synthesis of α,β‐Unsaturated Esters and Nitriles by Using Nanocrystalline Magnesium Oxide

Nanocrystalline magnesium oxide was found to be an effective heterogeneous, solid base catalyst for the one‐pot Wittig reaction to afford α,β‐unsaturated esters and nitriles in excellent yields with high E‐stereoselectivity in the presence of triphenylphosphine under mild conditions.     

Role of Receptor Protein Tyrosine Phosphatase β/ζ in Neuron–Microglia Communication in a Cellular Model of Parkinson’s Disease

Pleiotrophin (PTN) is a neurotrophic factor that regulates glial responses in animal models of different types of central nervous system (CNS) injuries. PTN is upregulated in the brain in different pathologies characterized by exacerbated neuroinflammation, including Parkinson’s disease. PTN is an endogenous inhibitor of Receptor Protein Tyrosine Phosphatase (RPTP) β/ζ, which is abundantly expressed in the CNS. Using a specific inhibitor of RPTPβ/ζ (MY10), we aimed to assess whether the PTN/RPTPβ/ζ axis is involved in neuronal and glial injury induced by the toxin MPP+. Treatment with the RPTPβ/ζ inhibitor MY10 alone decreased the viability of both SH-SY5Y neuroblastoma cells and BV2 microglial cultures, suggesting that normal RPTPβ/ζ function is involved in neuronal and microglial viability. We observed that PTN partially decreased the cytotoxicity induced by MPP+ in SH-SY5Y cells underpinning the neuroprotective function of PTN. However, MY10 did not seem to modulate the SH-SY5Y cell loss induced by MPP+. Interestingly, we observed that media from SH-SY5Y cells treated with MPP+ and MY10 decreases microglial viability but may elicit a neuroprotective response of microglia by upregulating Ptn expression. The data suggest a neurotrophic role of microglia in response to neuronal injury through upregulation of Ptn levels.     

Chronic Rhinosinusitis and Alzheimer’s Disease—A Possible Role for the Nasal Microbiome in Causing Neurodegeneration in the Elderly

Among millions of sufferers of chronic rhinosinusitis (CRS), the challenge is not only constantly coping with CRS-related symptoms, such as congested nose, sinus pain, and headaches, but also various complications, such as attention difficulties and possible depression. These complications suggest that neural activity in the central nervous system may be altered in those patients, leading to unexpected conditions, such as neurodegeneration in elderly patients. Recently, some studies linked the presence of CRS and cognitive impairments that could further develop into Alzheimer’s disease (AD). AD is the leading cause of dementia in the elderly and is characterised by progressive memory loss, cognitive behavioural deficits, and significant personality changes. The microbiome, especially those in the gut, has been recognised as a human organ and plays an important role in the development of various conditions, including AD. However, less attention has been paid to the microbiome in the nasal cavity. Increased nasal inflammatory responses due to CRS may be an initial event that changes local microbiome homeostasis, which may further affect neuronal integrity in the central nervous system resulting in AD. Evidence suggests a potential of β-amyloid deposition starting in olfactory neurons, which is then expanded from the nasal cavity to the central nervous system. In this paper, we reviewed currently available evidence that suggests this potential mechanism to advise the need to investigate the link between these two conditions.     

Therapeutic Effect of Calcimimetics on Osteoclast–Osteoblast Crosslink in Chronic Kidney Disease and Mineral Bone Disease

We have previously demonstrated calcimimetics optimize the balance between osteoclastic bone resorption and osteoblastic mineralization through upregulating Wingless and int-1 (Wnt) signaling pathways in the mouse and cell model. Nonetheless, definitive human data are unavailable concerning therapeutic effects of Cinacalcet on chronic kidney disease and mineral bone disease (CKD-MBD) and osteoclast–osteoblast interaction. We aim to investigate whether Cinacalcet therapy improves bone mineral density (BMD) through optimizing osteocytic homeostasis in a human model. Hemodialysis patients with persistently high intact parathyroid hormone (iPTH) levels > 300 pg/mL for more than 3 months were included and received fixed dose Cinacalcet (25 mg/day, orally) for 6 months. Bone markers presenting osteoclast–osteoblast communication were evaluated at baseline, the 3rd and the 6th month. Eighty percent of study patients were responding to Cinacalcet treatment, capable of improving BMD, T score and Z score (16.4%, 20.7% and 11.1%, respectively). A significant correlation between BMD improvement and iPTH changes was noted (r = −0.26, p < 0.01). Nonetheless, baseline lower iPTH level was associated with better responsiveness to Cinacalcet therapy. Sclerostin, an inhibitor of canonical Wnt/β-catenin signaling, was decreased from 127.3 ± 102.3 pg/mL to 57.9 ± 33.6 pg/mL. Furthermore, Wnt-10b/Wnt 16 expressions were increased from 12.4 ± 24.2/166.6 ± 73.3 pg/mL to 33.8 ± 2.1/217.3 ± 62.6 pg/mL. Notably, procollagen type I amino-terminal propeptide (PINP), a marker of bone formation and osteoblastic activity, was increased from baseline 0.9 ± 0.4 pg/mL to 91.4 ± 42.3 pg/mL. In contrast, tartrate-resistant acid phosphatase isoform 5b (TRACP-5b), a marker of osteoclast activity, was decreased from baseline 16.5 ± 0.4 mIU/mL to 7.7 ± 2.2 mIU/mL. Moreover, C-reactive protein levels were suppressed from 2.5 ± 0.6 to 0.8 ± 0.5 mg/L, suggesting the systemic inflammatory burden may be benefited after optimizing the parathyroid–bone axis. In conclusion, beyond iPTH suppression, our human model suggests Cinacalcet intensifies BMD through inhibiting sclerostin expression and upregulating Wnt-10b/Wnt 16 signaling that activates osteoblastic bone formation and inhibits osteoclastic bone resorption and inflammation. From the perspective of translation to humans, this research trial brings a meaningful insight into the osteoblast–osteoclast homeostasis in Cinacalcet therapy for CKD-MBD.     

Entrectinib Induces Apoptosis and Inhibits the Epithelial–Mesenchymal Transition in Gastric Cancer with NTRK Overexpression

Tropomyosin receptor kinase (TRK) and receptor tyrosine kinase (RTK class VII) expression are important in many human diseases, especially cancers, including colorectal, lung, and gastric cancer. Using RNA sequencing analysis, we evaluated the mRNA expression and mutation profiles of gastric cancer patients with neurotropic tropomyosin receptor kinase (NTRK) 1-3 overexpression (defined as a ≥2.0-fold change). Furthermore, we screened eight TRK inhibitors in NCI-N87, SNU16, MKN28, MKN7, and AGS cells. Among these inhibitors, entrectinib showed the highest inhibitory activity; therefore, this drug was selected for analysis of its therapeutic mechanisms in gastric cancer. Entrectinib treatment induced apoptosis in NTRK1-3-expressing and VEGFR2-expressing NCI-N87 and AGS cells, but it had no effect on NTRK1-3-, VEGFR2-, TGFBR1-, and CD274-expressing MKN7 cells. SNU16 and MKN28 cells with low NTRK1-3 expression were not affected by entrectinib. Therefore, a mechanistic study was conducted in NCI-N87 (high expression of NTRK1-3 but mutation of NTRK3), AGS (high expression of NTRK1-3) and MKN28 (low expression of NTRK1-3) gastric cancer cell lines. Entrectinib treatment significantly reduced expression levels of phosphorylated NFκB, AKT, ERK, and β-catenin in NCI-N87 and AGS cells, whereas it upregulated the expression levels of ECAD in NCI-N87 cells. Together, these results suggest that entrectinib has anti-cancer activity not only in GC cells overexpressing pan NTRK but also in VEGFR2 GC cells via the inhibition of the pan NTRK and VEGFR signaling pathways.     

Genotoxicological Characterization of (±)cis-4,4′-DMAR and (±)trans-4,4′-DMAR and Their Association

The novel psychoactive substance (NPS) 4-Methyl-5-(4-methylphenyl)-4,5-dihydroxazol-2-amine (4,4′-DMAR) shows psychostimulant activity. Data on the acute toxicity of 4,4′-DMAR are becoming increasingly available, yet the long-term effects are still almost unknown. In particular, no data on genotoxicity are available. Therefore, the aim of the present study was to evaluate its genotoxic potential using the “In Vitro Mammalian Cell Micronucleus Test” (MNvit) on (±)cis-4,4′-DMAR and (±)trans-4,4′-DMAR and their associations. The analyses were conducted in vitro on human TK6 cells. To select suitable concentrations for MNvit, we preliminarily evaluated cytotoxicity and apoptosis. All endpoints were analysed by flow cytometry. The results reveal the two racemates’ opposite behaviours: (±)cis-4,4′-DMAR shows a statistically significant increase in micronuclei (MNi) frequency that (±)trans-4,4′-DMAR is completely incapable of. This contrast confirms the well-known possibility of observing opposite biological effects of the cis- and trans- isomers of a compound, and it highlights the importance of testing single NPSs that show even small differences in structure or conformation. The genotoxic capacity demonstrated stresses an additional alarming toxicological concern related to this NPS. Moreover, the co-treatments indicate that consuming both racemates will magnify the genotoxic effect, an aspect to consider given the unpredictability of illicit drug composition.     

Effects of Itxasol© Components on Gene Expression in Bacteria Related to Infections of the Urinary Tract and to the Inflammation Process

Urinary tract infections (UTIs) represent a health problem of the first magnitude since they affect large segments of the population, cause increased mortality and comorbidity, and have a high incidence of relapse. Therefore, UTIs cause a major socioeconomic concern. Current antibiotic treatments have various limitations such as the appearance of resistance to antibiotics, nephrotoxicity, and side effects such as gastrointestinal problems including microbiota alterations that contribute to increasing antibiotic resistance. In this context, Itxasol© has emerged, approved as an adjuvant for the treatment of UTIs. Designed with biomimetic principles, it is composed of arbutin, umbelliferon, and N-acetyl cysteine. In this work, we review the activities of these three compounds concerning the changes they produce in the expression of bacterial genes and those related to inflammation as well as assess how they are capable of affecting the DNA of bacteria and fungi.     

Extracellular Prion Protein Aggregates in Nine Gerstmann–Sträussler–Scheinker Syndrome Subjects with Mutation P102L: A Micromorphological Study and Comparison with Literature Data

Gerstmann–Sträussler–Scheinker syndrome (GSS) is a hereditary neurodegenerative disease characterized by extracellular aggregations of pathological prion protein (PrP) forming characteristic plaques. Our study aimed to evaluate the micromorphology and protein composition of these plaques in relation to age, disease duration, and co-expression of other pathogenic proteins related to other neurodegenerations. Hippocampal regions of nine clinically, neuropathologically, and genetically confirmed GSS subjects were investigated using immunohistochemistry and multichannel confocal fluorescent microscopy. Most pathognomic prion protein plaques were small (2–10 µm), condensed, globous, and did not contain any of the other investigated proteinaceous components, particularly dystrophic neurites. Equally rare (in two cases out of nine) were plaques over 50 µm having predominantly fibrillar structure and exhibit the presence of dystrophic neuritic structures; in one case, the plaques also included bulbous dystrophic neurites. Co-expression with hyperphosphorylated protein tau protein or amyloid beta-peptide (Aβ) in GSS PrP plaques is generally a rare observation, even in cases with comorbid neuropathology. The dominant picture of the GSS brain is small, condensed plaques, often multicentric, while presence of dystrophic neuritic changes accumulating hyperphosphorylated protein tau or Aβ in the PrP plaques are rare and, thus, their presence probably constitutes a trivial observation without any relationship to GSS development and progression.