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Non-enzymatic glycation is a spontaneous and deleterious phenomenon that normally takes place inside human body and causes tissue damage. In the course of glycation reaction between glycating agents and biomolecules, several reactive perilous intermediates and finally heterogeneous group of compounds, advanced glycation end products (AGEs), are generated. Formations of AGEs are accelerated under disease conditions including diabetes and its complications. Endogenous 3-deoxyglucosone (3-DG) is a powerful glycating agent that glycates biomolecules including proteins compromising its structure and functionality. The production of 3-DG is significantly elevated during diabetes leading to vascular damage through glycation reaction. In the present study, human IgG was glycated with 3-DG to examine the AGEs production (Ne-carboxymethyllysine and pentosidine) by probing the degree of side chain modifications, formation of different intermediates and structural alterations induced by 3-DG on IgG. The results point out AGEs formation, intermediates generation (indicating oxidative stress) and structural alteration upon glycation of IgG by 3-DG, which may disturb normal functioning of IgG and compromise immune response in secondary complications of diabetes.

Introduction: SARS-CoV2, first reported in December 2019 in Wuhan as COVID-19 causing respiratory illness, rapidly evolved into a pandemic owing to its very high infectivity. There is insufficient evidence about if and how smoking affects the risk of COVID-19 infection, and the reports on whether smoking increases or reduces the risk of respiratory infections, are contradictory. Therefore, the current study was designed to determine the effects of nicotine consumption on the infectivity of COVID-19. Methods: We performed in silico computer simulation-based study. The structures of SARS-CoV2spike ectodomain, and its receptor ACE2, were obtained from PDB. The structure of nicotine and its metabolites NNK and NNAL were obtained from the PubChem chemical database. After optimization, they were interacted using AutoDock 4.2, to see the effect of nicotine, NNK, or NNAL presence on the docking of viral spike protein to its receptor ACE2. Results: ACE2 vs spike protein interaction results were used as a control (ZDOCK score 1498.484, with four hydrogen bonds). The NNK+ACE2 vs spike protein docking formed 10 hydrogen bonds with the highest ZDOCK score of 1515.564. NNAL+ ACE2 vs spike protein interaction formed eleven hydrogen bonds with the ZDOCK score of 1499.371. Nicotine+ACE2 vs spike protein docking showed the lowest ZDOCK score of 1496.302 and formed 8 hydrogen bonds. Whereas, NNK+spike vs ACE2 interaction had a ZDOCK score of 1498.490 and formed eight hydrogen bonds. NNAL+spike vs ACE2 docking formed eleven hydrogen bonds with a ZDOCK score of 1498.482. And Nicotine+spike vs ACE2 interaction showed a ZDOCK score of 1498.488 and formed 9 hydrogen bonds. Conclusions: The binding of nicotine to either spike of virus or its receptor ACE2 is not affecting the viral docking with the receptor. But binding of NNK, a metabolite of nicotine, is facilitating the viral docking with its receptor indicating that smoking may increase the risk of COVID-19 infection.

Introduction: Advanced glycation end-products (AGEs) are contributing factors to diabetes complications. The antigenic nature of AGEs established the theory of incessant accumulation of AGEs can incite an autoimmune response in a diabetic patient. Glycating agents like 3-deoxyglucosone are increased in diabetic patients, leading to the high formation of AGEs aggravating the pathophysiological conditions in diabetes. We aimed to study the immunogenicity of glycated histone H1 protein and AGEs (N-carboxymethyl-lysine and pentosidine) as well as detection of autoantibodies in the sera of type 2 diabetic subjects. Materials and Methods: Female rabbits were injected with native H1 and glycated-H1 to discern its immunogenicity. Diabetic subjects’ sera were also scanned for the detection of autoantibodies against glycated-H1 and AGEs using immunochemical assay technique. Results: Glycated-H1 was highly immunogenic, unlike the native analog. Diabetic sera showed 48% (72 of 150 samples) significantly strong binding with glycated-H1, further sera also showed 40% (60 of 150 samples), and 36% (54 of 150 samples) strong binding with CML, and pentosidine, respectively. Conclusion: The findings support modified H1 as well AGEs are highly immunogenic in nature. The presence of autoantibodies against glycated-H1 and AGEs may be utilized in the assessment of diabetes or its complications. Keywords: immunogenicity, 3-deoxyglucosone, advanced glycation end-products, diabetes

Methylglyoxal (MG) is a reactive dicarbonyl intermediate and a precursor of advanced glycation end products (AGEs). The authors investigated the role played by AGEs in muscle myopathy and the amelioration of its effects by curcumin and gingerol. In addition to producing phenotypical changes, MG increased oxidative stress and reduced myotube formation in C2C12 cells. RAGE (receptor for AGEs) expression was up-regulated and MYOD and myogenin (MYOG) expressions were concomitantly down-regulated in MG-treated cells. Interestingly, AGE levels were higher in plasma (~32 fold) and muscle (~26 fold) of diabetic mice than in control mice. RAGE knock-down (RAGEkd) reduced the expressions of MYOD and MYOG and myotube formation in C2C12 cells. In silico studies of interactions between curcumin or gingerol and myostatin (MSTN; an inhibitor of myogenesis) and their observed affinities for activin receptor type IIB (ACVRIIB) suggested curcumin and gingerol reduce the interaction between MSTN and ACVRIIB. The findings of this study suggest enhanced AGE production and subsequent RAGE-AGE interaction obstruct the muscle development program, and that curcumin and gingerol attenuate the effect of AGEs on myoblasts.

Advanced glycation end-products (AGEs) have been found to be critically involved in initiation or progression of diabetes secondary complications (nephropathy, retinopathy, neuropathy, and angiopathy). Various hyper-glycating carbonyl compounds such as 3-deoxyglucosone (3-DG) are produced in pathophysiological conditions that form AGEs in high quantity both in vivo and in vitro. In the first stage of this study, we glycated histone H2A protein by 3-DG, and the results showed the formation of various intermediates and AGEs as well as structural changes in the protein. In the second stage, we studied the immunogenicity of native and 3-DG-glycated H2A protein in female rabbits. The modified H2A was highly immunogenic, eliciting high titer immunogen-specific antibodies, while the unmodified form was almost nonimmunogenic. Antibodies against standard carboxymethyllysine (CML) and pentosidine were detected in the immunized female rabbits, which demonstrates the immunogenic nature of AGEs (CML and pentosidine) as well. The results show both structural perturbation and AGEs have the capacity of triggering the immune system due to the generation of neoepitopes that render the molecule immunogenic. This study shows the presence of autoantibodies against 3-DG-modified H2A, CML, and pentosidine in the sera of type 2 diabetes patients having secondary complications. Autoantibodies against damaged H2A and AGEs may be significant in the assessment of initiation/progression of secondary complications in type 2 diabetes mellitus patients or may be used as a marker for early detection of secondary complications in diabetes.

Protein bound toxins are poorly removed by conventional extracorporeal therapies. Venous thromboembolism (VTE) is a major cause of morbidity and mortality in patients with cancer. The interaction between tinzaparin, an inhibitor of angiotensin converting enzyme and human serum albumin, a principal plasma protein in the liver has been investigated in vitro under a simulated physiological condition by UV–vis spectrophotometry and fluorescence spectrometry. The intrinsic fluorescence intensity of human serum albumin was strongly quenched by tinzaparin (TP). The binding constants and binding stoichiometry can be calculated from the data obtained from fluorescence quenching experiments. The negative value of ΔG° reveals that the binding process is a spontaneous process. Thermodynamic analysis shows that the HSA-TP complex formation occurs via hydrogen bonds, hydrophobic interactions and undergoes slight structural changes as evident by far-UV CD. It indicated that the hydrophobic interactions play a main role in the binding of TP to human serum albumin. In addition, the distance between TP (acceptor) and tryptophan residues of human serum albumin (donor) was estimated to be 2.21 nm according to the Forster's resonance energy transfer theory. For the deeper understanding of the interaction, thermodynamic, and molecular docking studies were performed as well. Our docking results suggest that TP forms stable complex with HSA (Kb ∼ 104) and its primary binding site is located in subdomain IIA (Sudlow Site I). The results obtained herein will be of biological significance in pharmacology and clinical medicine.

Non-enzymatic glycation is the addition of a free carbonyl group of a reducing sugar to the free amino groups of proteins, which results in the formation of early and advanced glycation end-products (AGEs). Glycation reaction is profoundly associated with diabetes and its secondary complications, such as nephropathy and neuropathy. Glyoxal is a carbonyl species that reacts rapidly with the free amino groups of proteins to form AGEs. While the formation of AGEs with various glycating agents has previously been demonstrated, no extensive studies have been conducted to assess the role of quercetin in all three stages of glycation (early, intermediate and late). In this study, we report the glycation of HSA (human serum albumin) and its characterization by several spectroscopic techniques. Furthermore, inhibition of products at all stages of glycation was studied by various assays. Spectroscopic analysis suggests structural perturbations in the HSA macromolecule as a result of modification, which might be due to the generation of free radicals and the formation of AGEs. Inhibition in the formation of glycation has established that quercetin is a better and a more potent antiglycating agent than aminoguanidine at all stages of glycation.

Nonenzymatic glycation of amino groups of DNA bases by reducing sugars can generate advanced glycation end products (AGEs). Cellular formation of AGEs under normal physiology is continuously scanned and removed by efficient system in the cells. However, excess formation and accumulation of AGEs may be cause or consequence of some human diseases. Mammalian DNA incubated with d-glucose for 28 days at 37°C showed structural changes in DNA as confirmed by UV, fluorescence, CD, melting temperature, S1 nuclease sensitivity and gel electrophoresis. Formation of DNA-AGE was confirmed by HPLC and LC-MS. Enzyme immunoassay and electrophoretic mobility shift assay of autoantibodies in type 2 diabetes patients' sera with disease duration of 5-15 years exhibited significantly high binding with DNA-AGE as compared to patients with 1-5 years of disease duration. Autoantibodies against aberrant DNA-AGE may be important in the assessment of initiation/progression of secondary complications in type 2 diabetes mellitus patients.

Advanced glycation end products (AGEs) are implicated in several central nervous system (CNS) pathologies including Alzheimer and Parkinson’s diseases. In the face-off of AGE menace, we have attempted to investigate the zinc oxide nanoparticle (ZnONP) role in inhibition of AGE formation. Synthesized ZnONPs were used to investigate the inhibitory effects on AGE formation. The inhibitory effects of ZnONPs on AGE formation were determined by biophysical immunological and biochemical techniques. The results showed that ZnONP is a potential anti-glycating agent inhibiting AGE formation as well as protecting the protein structure from change. Therefore, our findings suggest ZnONPs may be used as a therapeutic in resolving the AGE role in CNS-related complications.

Oxidative, carbonyl, and glycative stress have gained substantial attention recently for their alleged influence on cancer progression. Oxidative stress can trigger variable transcription factors, such as nuclear factor erythroid-2-related factor (Nrf2), nuclear factor kappa B (NF-κB), protein-53 (p-53), activating protein-1 (AP-1), hypoxia-inducible factor-1α (HIF-1α), β-catenin/Wnt and peroxisome proliferator-activated receptor-γ (PPAR-γ). Activated transcription factors can lead to approximately 500 different alterations in gene expression, and can alter expression patterns of inflammatory cytokines, growth factors, regulatory cell cycle molecules, and anti-inflammatory molecules. These alterations of gene expression can induce a normal cell to become a tumor cell. Glycative stress resulting from advanced glycation end products (AGEs) and reactive dicarbonyls can significantly affect cancer progression. AGEs are fashioned from the multifaceted chemical reaction of reducing sugars with a compound containing an amino group. AGEs bind to and trigger the receptor for AGEs (RAGE) through AGE-RAGE interaction, which is a major modulator of inflammation allied tumors. Dicarbonyls like, GO (glyoxal), MG (methylglyoxal) and 3-DG (3-deoxyglucosone) fashioned throughout lipid peroxidation, glycolysis, and protein degradation are viewed as key precursors of AGEs. These dicarbonyls lead to the carbonyl stress in living organisms, possibly resulting in carbonyl impairment of proteins, carbohydrates, DNA, and lipoproteins. The damage caused by carbonyls results in numerous lesions, some of which are involved in cancer pathogenesis. In this review, the effects of oxidative, carbonyl and glycative stress on cancer initiation and progression are thoroughly discussed, including probable signaling pathways and the effects on tumorigenesis.

Objective: PTEN, a tumor-suppressor gene, located on chromosome 10q23.3, is implicated in various types of cancer including breast cancer. The aim of this study is to investigate the promoter methylation, loss of expression and significance of PTEN gene in breast cancer and to determine the correlation between promoter methylation and gene expression. Methods: Promoter methylation and loss of expression of PTEN gene were analyzed using methylation-specific PCR and immunohistochemical methods respectively. The chi square test is used to correlate the promoter methylation and gene expression with their clincopathologic parameters. Results: We examined 53 breast cancer specimens and 10 normal tissues adjacent to tumor. The results showed a 58.5% promoter methylation in PTEN gene and none in normal tissue. PTEN methylation was observed in advanced stages III-IV (81.8%, 18 of 22, P=0.015) and higher grades G2-G3 (71.4%, 20 of 28, P=0.043) of disease. The correlation of PTEN methylation with clinical stage and tumor grade was found to be statistically significant. Nuclear PTEN expression was detected in 73.6% (39 of 53) cases of breast cancer and in the remaining 26.4% (14 of 53) cases expressional loss was observed. The loss of PTEN expression was observed in all normal tissues (10 of 10). The loss of PTEN expression was significantly correlated with patient’s age (P=0.028) and clinical stage (P = 0.029). The expressional loss was observed in 12 (38.7%) cases among 31 methylation positive cases, whereas among 22 methylation- negative cases, only 2 (9.1%) cases were seen as immunostaining negative with the statistically significant value (P=0.016). Conclusion: Promoter methylation and loss of expression of PTEN gene occur frequently in breast cancer. Our results suggest that PTEN plays an important role in breast carcinogenesis.

The non-enzymatic glycation reaction results in the generation of free radicals which play an important role in the pathophysiology of aging, diabetes, and cancer. 3-Deoxyglucosone (3-DG) is a dicarbonyl species which may lead to the formation of advanced glycation end products (AGEs). 3-DG also reacts with free amino group of nucleic acids resulting in the formation of DNA-AGEs. While the establishment of nucleoside AGEs has been revealed before, no extensive studies have been done to probe the role of 3-DG in the generation of immunogenicity and induction of cancer auto-antibodies. In this study, we report the immunogenicity of AGEs formed by 3-DG-Arg-Fe(3+) system. Spectroscopic analysis and melting temperature studies suggest structural perturbations in the DNA as a result of modification. Immunogenicity of native and 3-DG-Arg-Fe(3+) DNA was probed in female rabbits. The modified DNA was highly immunogenic eliciting high-titer immunogen-specific antibodies, while the unmodified form was almost non-immunogenic. We also report the presence of auto-antibodies against 3-DG-Arg-Fe(3+)-modified DNA in the sera of patients with different types of cancers. The glycoxidative lesions were also detected in the lymphocyte DNA isolated from selected cancer patients. The results show structural perturbations in 3-DG-Arg-Fe(3+)-DNA generating new epitopes that render the molecule immunogenic.

Advanced glycation end-products (AGEs) resulting from non-enzymatic glycation are one of the major factors implicated in secondary complications of diabetes. Scientists are focusing on discovering new compounds that may be used as potential AGEs inhibitors without affecting the normal structure and function of biomolecules. A number of natural and synthetic compounds have been proposed as AGE inhibitors. In this study, we investigated the inhibitory effects of AgNPs (silver nanoparticles) in AGEs formation. AgNPs (~30.5 nm) synthesized from Aloe Vera leaf extract were characterized using UV-Vis spectroscopy, energy-dispersive X-ray spectroscopy (EDX), high resolution-transmission electron microscopy, X-ray diffraction and dynamic light scattering (DLS) techniques. The inhibitory effects of AgNPs on AGEs formation were evaluated by investigating the degree of reactivity of free amino groups (lysine and arginine residues), protein-bound carbonyl and carboxymethyl lysine (CML) content and the effects on protein structure using various physicochemical techniques. The results showed that AgNPs significantly inhibit AGEs formation in a concentration dependent manner and that AgNPs have a positive effect on protein structure. These findings strongly suggest that AgNPs may play a therapeutic role in diabetes-related complications.

Glycation is the result of covalent bonding of a free amino group of biological macromolecules with a reducing sugar, which results in the formation of a Schiff base that undergoes rearrangement, dehydration and cyclization to form a more stable Amadori product. The final products of nonenzymatic glycation of biomacromolecules like DNA, proteins and lipids are known as advanced glycation end products (AGEs). AGEs may be generated rapidly or over long times stimulated by distinct triggering mechanisms, thereby accounting for their roles in multiple settings and disease states. Both Schiff base and Amadori glycation products generate free radicals resulting in decline of antioxidant defense mechanisms and can damage cellular organelles and enzymes. This critical review primarily focuses on the mechanistic insight of glycation and the most probable route for the formation of glycation products and their therapeutic interventions. Furthermore, the prevention of glycation reaction using therapeutic drugs such as metformin, pyridoxamine and aminoguanidine (AG) are discussed with special emphasis on the novel concept of the bioconjugation of these drugs like, AG with gold nanoparticles (GNPs). At or above 10 mM concentration, AG is found to be toxic and therefore has serious health concerns, and the study warrants doing this novel bioconjugation of AG with GNPs. This approach might increase the efficacy of the AG at a reduced concentration with low or no toxicity. Using the concept of synthesis of GNPs with abovementioned drugs, it is assumed that toxicity of various drugs which are used at high doses can be minimized more effectively.

Photodynamic therapy (PDT) is used in curative and palliative treatment of head and neck squamous cell carcinoma (HNSCC) and other oral lesions. Oral infections (such as mucosal and endodontic infections, periodontal diseases, caries, and peri-implantitis) are among the specific targets where PDT can be applied Photodynamic therapy (PDT) efficacy depends on the local dose deposited in the lesion as well as oxygen availability in the lesion. Further long-term clinical studies are necessary in establishing a more specific place of the technique in the field of dentistry.

Proteins modifications in diabetes may lead to early glycation products (EGPs) as well as advanced glycation end products (AGEs). Whereas no extensive studies have been carried out to assess the role of EGPs in secondary complications of diabetes, numerous investigators have demonstrated the role of AGEs. Early glycation involves attachment of glucose on e-NH2 of lysine residues of proteins leading to generation of the Amadori product (an early glycation species). This study reports the structural and immunological characterization of EGPs of HSA because we believe that during persistent hyperglycemia the HSA, one of the major blood proteins, can undergo fast glycation. Glucose mediated generation of EGPs of HSA was quantitated as Amadori products by NBT assay and authenticated by boronate affinity chromatography and LC/MS. Compared to native HSA changes in glycated-HSA were characterized by hyperchromicity, loss in fluorescence intensity and a new peak in the FTIR profile. Immunogenicity of native- and glycated-HSA was evaluated by inducing antibodies in rabbits. Results suggest generation of neo-epitopes on glycated-HSA rendering it highly immunogenic compared to native HSA. Quantization of EGPs of HSA by authentic antibodies against HSA-EGPs can be used as marker for early detection of the initiation/progression of secondary complications of diabetes.

Background Venetoclax is a highly selective, potent, oral BCL-2 inhibitor, which induces apoptosis in multiple myeloma cells. Venetoclax plus bortezomib and dexamethasone has shown encouraging clinical efficacy with acceptable safety and tolerability in a phase 1 trial. The aim of this study was to evaluate venetoclax plus bortezomib and dexamethasone in patients with relapsed or refractory multiple myeloma. Methods In this randomised, double-blind, multicentre, phase 3 trial, patients aged 18 years or older with relapsed or refractory multiple myeloma, an Eastern Cooperative Oncology Group performance status of 2 or less, who had received one to three previous therapies were enrolled from 90 hospitals in 16 countries. Eligible patients were randomly assigned (2:1) centrally using an interactive response technology system and a block size of three to receive venetoclax (800 mg per day orally) or placebo with bortezomib (1.3 mg/m(2) subcutaneously or intravenously and dexamethasone (20 mg orally). Treatment was given in 21-day cycles for the first eight cycles and 35-day cycles from the ninth cycle until disease progression, unacceptable toxicity, or patient withdrawal. Randomisation was stratified by previous exposure to a proteasome inhibitor and the number of previous therapies. Sponsors, investigators, study site personnel, and patients were masked to the treatment allocation throughout the study. The primary endpoint was independent review committee-assessed progression-free survival in the intention-to-treat population. Safety analyses were done in patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, NCT02755597. Findings Between July 19, 2016, and Oct 31, 2017, 291 patients were randomly assigned to receive venetoclax (n=194) or placebo (n=97). With a median follow-up of 18.7 months (IQR 16.6-21.0), median progression-free survival according to independent review committee was 22.4 months (95% CI 15.3-not estimable) with venetoclax versus 11.5 months (9.6-15.0) with placebo (hazard ratio [HR] 0.63 [95% CI 0.44-0.90]; p=0.010). The most common grade 3 or worse treatment-emergent adverse events were neutropenia (35 [18%] of 193 patients in the venetoclax group vs seven [7%] of 96 patients in the placebo group), pneumonia (30 [16%] vs nine [9%]), thrombocytopenia (28 [15%] vs 29 [30%]), anaemia (28 [15%] vs 14 [15%]), and diarrhoea (28 [15%] vs 11 [11%]). Serious treatment-emergent adverse events occurred in 93 (48%) patients in the venetoclax group and 48 (50%) patients in the placebo group, with eight (4%) treatment-emergent fatal infections reported in the venetoclax group and none reported in the placebo group. Three deaths in the venetoclax group (two from pneumonia and one from septic shock) were considered treatment-related; no deaths in the placebo group were treatment-related. Interpretation The primary endpoint was met with a significant improvement in independent review committee-assessed progression-free survival with venetoclax versus placebo plus bortezomib and dexamethasone. However, increased mortality was seen in the venetoclax group, mostly because of an increased rate of infections, highlighting the importance of appropriate selection of patients for this treatment option. Copyright (C) 2020 Elsevier Ltd. All rights reserved.