Non-enzymatic Glycation Of Proteins Research Articles

Diabetes and SGLT2-iss inhibitors in patients with heart failure with preserved or mid-range left ventricular ejection fractions.

Diabetic patients frequently develop heart failure with preserved (HFpEF) or mid-range (HFmEF) cardiac ejection fractions. This condition may be secondary to diabetic cardiomyopathy or one of several relevant comorbidities, mainly hypertension. Several mechanisms link diabetes to HFpEF or HFmEF. Among these, non-enzymatic glycation of interstitial proteins, lipotoxicity, and endothelial dysfunction may promote structural damage and ultimate lead to heart failure. Findings from several large-scale trials indicated that treatment with sodium/glucose cotransporter 2 inhibitors (SGLT2-iss) resulted in significant improvements in cardiovascular outcomes in diabetic patients with high cardiovascular risk. However, there is currently some evidence that suggests a clinical advantage of using SGLT2-iss specifically in cases of HFpEF or HFmEF. Preclinical and clinical studies revealed that SGLT2-iss treatment results in a reduction in left ventricular mass and improved diastolic function. While some of the beneficial effects of SGLT2-iss have already been characterized (e.g., increased natriuresis and diuresis as well as reduced blood pressure, plasma volume, and arterial stiffness, and nephron-protective activities), there is increasing evidence suggesting that SGLT2-iss may have direct actions on the heart. These findings include SGLT2-iss-mediated reductions in the expression of hypertrophic foetal genes and diastolic myofilaments stiffness, increases in global phosphorylation of myofilament regulatory proteins (in HFpEF), inhibition of cardiac late sodium channel current and Na+/H+ exchanger activity, metabolic shifts, and effects on calcium cycling. Preliminary data from previously published studies suggest that SGLT2-iss could be useful for the treatment of HFpEF and HFmEF. Several large ongoing trials, including DELIVER AND EMPEROR -preserved have been designed to evalute the efficacy of SGLT2-iss in improving clinical outcomes in patients diagnosed with HFpEF. The goal of this manuscript is to review the use of SGLT2-iss inhibitors for HFpEF or HFmEF associated with diabetes.

Potential of Vasoprotectives to Inhibit Non-Enzymatic Protein Glycation, and Reactive Carbonyl and Oxygen Species Uptake.

Reactive carbonyl species (RCS) such as methylglyoxal (MGO) or glyoxal (GO) are the main precursors of the formation of advanced glycation end products (AGEs). AGEs are a major factor in the development of vascular complications in diabetes. Vasoprotectives (VPs) exhibit a wide range of activities beneficial to cardiovascular health. The present study aimed to investigate selected VPs and their structural analogs for their ability to trap MGO/GO, inhibit AGE formation, and evaluate their antioxidant potential. Ultra-high-performance liquid chromatography coupled with an electrospray ionization mass spectrometer (UHPLC-ESI-MS) and diode-array detector (UHPLC-DAD) was used to investigate direct trapping capacity and kinetics of quenching MGO/GO, respectively. Fluorimetric and colorimetric measurements were used to evaluate antiglycation and antioxidant action. All tested substances showed antiglycative effects, but hesperetin was the most effective in RCS scavenging. We demonstrated that rutin, diosmetin, hesperidin, and hesperetin could trap both MGO and GO by forming adducts, whose structures we proposed. MGO-derived AGE formation was inhibited the most by hesperetin, and GO-derived AGEs by diosmetin. High reducing and antiradical activity was confirmed for quercetin, rutin, hesperetin, and calcium dobesilate. Therefore, in addition to other therapeutic applications, some VPs could be potential candidates as antiglycative agents to prevent AGE-related complications of diabetes.

Патогенез діабетичної ретинопатії: огляд літератури

В огляді подані дані про патогенез діабетичної ретинопатії (ДР). Вказано на значущість підвищення активності поліолового шляху обміну глюкози, неферментативного глікування білків, активації протеїнкінази С, карбоангідрази, гемодинамічних змін і активності ренін-ангіотензинової системи в розвитку цукрового діабету та його мікросудинних ускладнень. Особлива увага приділяється ролі оксидативного стресу, факторів росту, а також метаболічного синдрому й ожиріння в розвитку і прогресуванні ДР.

The cross-talk between RAGE and DIAPH1 in neurological complications of diabetes: A review.

Neuropathy, or dysfunction of peripheral nerve, is one of the most common neurological manifestation in patients with diabetes mellitus (DM). DM is typically associated with a hyperglycaemic milieu, which promotes non-enzymatic glycation of proteins. Proteins with advanced glycation are known to engage a cell-surface receptor called the receptor for advanced glycation end products (RAGE). Thus, it is reasonable to assume that RAGE and its associated molecule-mediated cellular signalling may contribute to DM-induced symmetrical axonal (length-dependent) neuropathy. Of particular interest is diaphanous related formin 1 (DIAPH1), a cytoskeletal organizing molecule, which interacts with the cytosolic domain of RAGE and whose dysfunction may precipitate axonopathy/neuropathy. Indeed, it has been demonstrated that both RAGE and DIAPH1 are expressed in the motor and sensory fibres of nerve harvested from DM animal models. Although the detailed molecular role of RAGE and DIAPH1 in diabetic neurological complications remains unclear, here we will discuss available evidence of their involvement in peripheral diabetic neuropathy. Specifically, we will discuss how a hyperglycaemic environment is not only likely to elevate advanced glycation end products (ligands of RAGE) and induce a pro-inflammatory environment but also alter signalling via RAGE and DIAPH1. Further, hyperglycaemia may regulate epigenetic mechanisms that interacts with RAGE signalling. We suggest the cumulative effect of hyperglycaemia on RAGE-DIAPH1-mediated signalling may be disruptive to axonal cytoskeletal organization and transport and is therefore likely to play a key role in pathogenesis of diabetic symmetrical axonal neuropathy.

Skin advanced glycation end products as a diagnostic and monitoring tool among psoriatic patients: how the therapy helps reduce cardiovascular disease risk.

Psoriasis is a disturbing and burdensome inflammatory skin disorder, with a global prevalence of 2-3%. An increased risk of cardiometabolic disease between psoriatic patients has been recently demonstrated. This is probably due to the psoriasis systemic inflammation and the increased levels of inflammatory cytokines, such as IL-17, IL-23, and TNF-α. Advanced glycation end products (AGEs) are the products of nonenzymatic glycation and oxidation of proteins and lipids which modify their structure and function. They have a significant role in the pathogenesis of diabetic nephropathy, atherosclerosis, and cardiovascular diseases of diabetic adults and children. The accumulation of AGEs can be measured by skin autofluorescence (SAF). Adalimumab (Humira ®) is a fully human monoclonal antibody, administered via subcutaneous injection, which binds the tumor necrosis factor (TNF) and is used to treat moderate-to-severe chronic plaque psoriasis. We performed an observational prospective study of 24 weeks to assess the reduction of AGEs through SAF measurement during treatment with adalimumab. SAF measurements in patients were performed at T0 and after 24 weeks of therapy. Adalimumab efficacy was assessed using Psoriasis Area and Severity Index (PASI), Visual Analogue Scale (VAS) for pain, and erythrocyte sedimentation rate (ESR). ESR, AGEs, PASI, and VAS for pain decreased throughout the study period. Adalimumab reduced AGEs in psoriatic patients. Biologic therapies may also prevent cardiovascular disease, suggesting a new approach of combined therapy for psoriasis and cardiovascular diseases.

Fundamentals of Diabetic Cataractogenesis and Promising Ways of its Pharmacological Correction

Cataracts in diabetes mellitus lead to decreased visual function and blindness. Cataract surgery for diabetes mellitus has limitations and complications. The search for effective means of conservative cataract therapy continues. The review presents the analysis of data from scientific sources, mainly for 2015–2020 using Internet resources (PubMed, Web of Science, Medline, eLibrary.Ru, Cyberleninka). In the work, diabetic cataractogenesis is presented as a sum of interrelated pathobiochemical processes. The main ones are the polyol pathway of glucose conversion, non-enzymatic glycation and oxidative modification of lens proteins, which are enhanced in diabetes mellitus. The lens has a high protein content. The formation of high molecular weight protein aggregates is of particular importance for the appearance of light scattering zones and a decrease in lens transparency. This review presents data on anti-cataract compounds that affect post-translational crystallin modification, prevent osmotic and oxidative stress in the lens, and exhibit antiglycation properties. This information shows that the search for means of pharmacological correction of cataractogenesis should be carried out among compounds with antioxidant and antiglycation activity.

In vitro Antidiabetic, Antioxidant and Antiglycation Activity of Ethanolic Leaf Extract of Gomphrena globosa (Linn.)

G. globosa L. is an everlasting tropical annual plant reported to possess several biological activities for curing ailments such as arthritis, diabetes, asthma, bronchitis and also known to possess anti tussive, anti-oxidant, anti-asthmatic and anti-cancer activities. The amino group of protein and carbonyl group of reducing sugar undergoes a non-enzymatic protein glycation reaction that leads to major complications in Diabetic patients. Several antiglycation agents of natural or synthetic origin are there to inhibit protein glycation reaction. But due to its toxicity, antiglycation agents of plant origin are gaining importance as an effective strategy to minimize diabetic complications. The aim of this study was to evaluate the antidiabetic, antioxidant and antiglycation activity of ethanolic leaf extract of G. globosa. The ethanolic leaf extract exerted its antidiabetic effect by inhibiting the activity of α-amylase (p<0.05) resulting in the delayed digestion of the dietary carbohydrates and lowering the amount of glucose liberated. The highest scavenging was observed at 500 μg concentrations and the percent inhibition was found to be 50.80% for DPPH assay and 57.24% (p<0.05) for hydroxyl free radical scavenging assay. 25mM of glucose concentration showed the highest uptake of glucose. The glucose adsorption capacities of G. globosa ethanolic leaf extract was directly proportional to the glucose concentration in the medium resulting in significantly higher glucose adsorption. The effect of antiglycation activity of G. globosa ethanolic leaf extract was found to be increasing with increase in time. The inhibition of ethanolic leaf extract was found to be maximum (27.66%) at 72 hr, followed by 23.7% at 48 hr and 13.7% at 24 hr for fructation with ROS modification/UV/guanosine. This result indicates that ethanolic leaf extract of G. globosa possess significant activity at desirable concentration.

Self-assembled elastin-like polypeptide fusion protein coacervates as competitive inhibitors of advanced glycation end-products enhance diabetic wound healing

Chronic and non-healing skin wounds are some of the most significant complications in patients with advanced diabetes. A contributing mechanism to this pathology is the non-enzymatic glycation of proteins due to hyperglycemia, leading to the formation of advanced glycation end products (AGEs). AGEs bind to the receptor for AGEs (RAGE), which triggers pro-inflammatory signals that may inhibit the proliferative phase of wound healing. Soluble forms of RAGE (sRAGE) may be used as a competitive inhibitor of AGE-mediated signaling; however, sRAGE is short-lived in the highly proteolytic wound environment. We developed a recombinant fusion protein containing the binding domain of RAGE (vRAGE) linked to elastin-like polypeptides (ELPs) that self-assembles into coacervates at around 30–31 °C. The coacervate size was concentration and temperature-dependent, ranging between 500 and 1600 nm. vRAGE-ELP reversed several AGE-mediated changes in cultured human umbilical vein endothelial cells, including a decrease in viable cell number, an increase in levels of reactive oxygen species (ROS), and an increased expression of the pro-inflammatory marker, intercellular adhesion molecule-1 (ICAM-1). vRAGE-ELP was stable in elastase in vitro for 7 days. When used in a single topical application on full-thickness excisional skin wounds in diabetic mice, wound closure was accelerated, with 90% and 100% wound closure on post-wounding days 28 and 35, respectively, compared to 62% and 85% on the same days in animals treated with vehicle control, consisting of ELP alone. This coacervate system topically delivering a competitive inhibitor of AGEs has potential for the treatment of diabetic wounds.

Discovery of Flazin, an Alkaloid Isolated from Cherry Tomato Juice, As a Novel Non-Enzymatic Protein Glycation Inhibitor via in Vitro and in Silico Studies.

Both overproduced reactive oxygen species/reactive nitrogen species and hyperglycemic conditions accompany a significant increase in protein glycation and nitration that contribute to the initiation and progression of diabetic complications and neuronal disorders. In this study, 19 compounds, including steroidal saponins, alkaloids, cerebroside, phenolic compounds, sterols, and nucleosides, were isolated from cherry tomato (Solanum lycopersicum var. cerasiforme) juice, of which flazin showed good inhibition on monosaccharide-induced non-enzymatic bovine pancreas insulin and bovine serum albumin (BSA) glycation. Molecular dynamics simulations revealed that flazin continuously interacts with Phe1, Val2, Tyr26, and Lys29 insulin residues, which play a key role in insulin glycation/dimerization. In addition, depending upon the flazin dose, this blocked the tyrosine nitration of BSA via scavenging peroxynitrite anions. Taken together, our novel findings suggest that flazin could be a lead compound for the treatment of diabetes and neuronal disorders via the inhibition of non-enzymatic protein glycation and the elimination of peroxynitrite.

Influence of Dopamine on Fluorescent Advanced Glycation End Products Formation Using Drosophila melanogaster.

Non-enzymatic glycation and covalent modification of proteins leads to Advanced Glycation End products (AGEs). AGEs are biomarkers of aging and neurodegenerative disease, and can be induced by impaired neuronal signaling. The objective of this study was to investigate if manipulation of dopamine (DA) in vitro using the model protein, bovine serum albumin (BSA), and in vivo using the model organism Drosophila melanogaster, influences fluorescent AGEs (fAGEs) formation as an indicator of dopamine-induced oxidation events. DA inhibited fAGEs-BSA synthesis in vitro, suggesting an anti-oxidative effect, which was not observed when flies were fed DA. Feeding flies cocaine and methamphetamine led to increased fAGEs formation. Mutants lacking the dopaminergic transporter or the D1-type showed further elevation of fAGEs accumulation, indicating that the long-term perturbation in DA function leads to higher production of fAGEs. To confirm that DA has oxidative properties in vivo, we fed flies antioxidant quercetin (QUE) together with methamphetamine. QUE significantly decreased methamphetamine-induced fAGEs formation suggesting that the perturbation of DA function in vivo leads to increased oxidation. These findings present arguments for the use of fAGEs as a biomarker of DA-associated neurodegenerative changes and for assessment of antioxidant interventions such as QUE treatment.

Inhibition of Protein Glycation and OH &lt;sup&gt;•&lt;/sup&gt;-Induced Protein Fragmentation by Fenugreek Phytochemicals

Glycation of proteins and generation of advanced glycation end products (AGEs) are the fundamental causes in the development of oxidative stress-induced protein modification and diabetes complications. The hyperglycemic condition causes non-enzymatic protein glycation, initiated by the reaction between the carbonyl groups of sugars with the amino groups of proteins forming the amadori products. Amadori products induce further oxidation, generating dicarbonyl compounds to form cross-linking fluorescent and non-fluorescent adduct called AGEs. In this study, the protective effect of fenugreek phytochemicals on protein glycation and oxidation-induced protein fragmentation was evaluated. Fenugreek phytochemicals (phenolics and alkaloids) protected oxidation-induced protein fragmentation and inhibited protein glycation. They also prevented the formation of fluorescent and non-fluorescent AGEs, and glycation-mediated protein conformational changes. Fenugreek phytochemicals effectively scavenged reactive carbonyl intermediates and decreased protein thiol modification. Collectively, these results suggest the potential utility of fenugreek phytochemicals as functional food ingredients for the control of diabetes and its complications. Funding Information: This work is financially supported by the planning commission and Council of Scientific and Industrial Research, Govt. India, as part of 12th- five-year plan project (BSC-0404). Declaration of Interests: The authors declare that they have no competing interests.

An Evolutionary Remedy for an Abominable Physiological Mystery: Benign Hyperglycemia in Birds.

Relative to other vertebrates, birds have unusually high blood glucose levels. In humans, the hyperglycemia observed in birds would be associated with diabetes mellitus and the non-enzymatic glycation of proteins, which leads to the accumulation of advanced glycation products and to a plethora of microvascular pathologies. How do birds avoid the negative effects of hyperglycemia? Anthony-Regnitz et al. (J Mol Evol 88: 653-661, 2020) discovered that birds might have evolved glycation-resistant proteins. Serum albumin is an important multifunctional protein susceptible to glycation. Anthony-Regnitz et al. (J Mol Evol 88: 653-661, 2020) found that chicken albumin is resistant to glycation relative to bovine serum albumin. Protein glycation takes place primarily in lysine residues, which are less abundant in chicken than in bovine serum albumin. A multispecies comparison of serum albumin sequences revealed lower numbers of lysine residues in birds than in mammals. Benign hyperglycemia is a shared derived trait of birds and glycation resistance mechanisms appear to have accompanied its evolution. The evolution of benign hyperglycemia in birds coincided with a genomic upheaval that included the loss of important genes, including the one that codes for GLUT4, the transporter responsible for insulin-dependent glucose transport in other vertebrates' insulin-sensitive cells. This loss seems to have resulted in the remodeling of the insulin-signaling pathway in bird tissues. Avian hyperglycemia has been considered a mystery for a long time. Although we remain ignorant of its origins and its repercussions for the physiology of birds, the discovery of resistance to glycation in bird serum albumin offers a path forward to solve this mystery.

Effect of Glyoxal Modification on a Critical Arginine Residue (Arg-31α) of Hemoglobin: Physiological Implications of Advanced Glycated end Product an in vitro Study.

Non-enzymatic protein glycation is involved in structure and stability changes that impair protein functionality, resulting in several human diseases, such as diabetes and amyloidotic neuropathies (Alzheimer's disease, Parkinson's disease and Andrade's syndrome). Glyoxal, an endogenous reactive oxoaldehyde, increases in diabetes and reacts with several proteins to form advanced glycation end products through Maillard-like reaction. Human hemoglobin, the most abundant protein in blood cells is subjected to nonenzymatic modification by reactive oxoaldehydes in diabetic condition. In the present study, the effect of a low concentration of glyoxal (5 μM) on hemoglobin (10 μM) has been investigated following a period of 30 days incubation in vitro. Different techniques, mostly biophysical and spectroscopic (e.g. circular dichroism, differential scanning calorimetric study, dynamic light scattering, mass spectrometry, etc.) were used to study glyoxal-induced changes of hemoglobin. Glyoxal-treated hemoglobin exhibits decreased absorbance around 280 nm, decreased fluorescence and reduced surface hydrophobicity compared to normal hemoglobin. Glyoxal treatment enhances the stability of hemoglobin and lowers its susceptibility to thermal aggregation compared to control hemoglobin as seen by different studies. Finally, peptide mass fingerprinting study showed glyoxal to modify an arginine residue of α-chain of hemoglobin (Arg-31α) to hydroimidazolone. Increased level of glyoxal in diabetes mellitus as well as its high reactivity may cause modifications of the heme protein. Thus, considering the significance of glyoxal-induced protein modification under physiological conditions, the observation appears clinically relevant in terms of understanding hydroimidazolone-mediated protein modification under in vivo conditions.

Ribosylation induced structural changes in Bovine Serum Albumin: understanding high dietary sugar induced protein aggregation and amyloid formation

Non-enzymatic glycation of proteins is believed to be the root cause of high dietary sugar associated pathophysiological maladies. We investigated the structural changes in protein during progression of glycation using ribosylated Bovine Serum Albumin (BSA). Non enzymatic attachment of about 45 ribose molecules to BSA resulted in gradual reduction of hydrophobicity and aggregation as indicated by red-shifted tryptophan fluorescence, reduced ANS binding and lower anisotropy of FITC-conjugated protein. Parallely, there was a significant decrease of alpha helicity as revealed by Circular Dichroism (CD) and Fourier transformed-Infra Red (FT-IR) spectra. The glycated proteins assumed compact globular structures with enhanced Thioflavin-T binding resembling amyloids. The gross structural transition affected by ribosylation led to enhanced thermostability as indicated by melting temperature and Transmission Electron Microscopy. At a later stage of glycation, the glycated proteins developed non-specific aggregates with increase in size and loss of amyloidogenic behaviour. A parallel non-glycated control incubated under similar conditions indicated that amyloid formation and associated changes were specific for ribosylation and not driven by thermal denaturation due to incubation at 37 °C. Functionality of the glycated protein was significantly altered as probed by Isothermal Titration Calorimetry using polyphenols as substrates. The studies demonstrated that glycation driven globular amyloids form and persist as transient intermediates during formation of misfolded glycated adducts. To the best of our knowledge, the present study is the first systematic attempt to understand glycation associated changes in a protein and provides important insights towards designing therapeutics for arresting dietary sugar induced amyloid formation.

Dysregulation of miRNA and its reversal with l-ascorbic acid during AGE-BSA induced ER stress in Mus musculus neuronal cells

Loss of function and progressive death of neurons, the pathological mechanism of neurodegenerative diseases (NDDs) can occur as a result of apoptotic unfolded protein response (UPR) signaling induced by endoplasmic reticulum (ER) stress resulting from misfolded protein accumulation in ER lumen. Non-enzymatic glycation of proteins have been implicated in the pathophysiology of NDDs and are known to cause cellular oxidative stress leading to ER stress mediated neuronal apoptosis. MicroRNAs (miRNAs), post transcriptional regulators of gene expression are identified as regulators of UPR and the altered brain miRNA profiles in NDDs suggest the involvement of miRNA dysregulation in neuronal death. l-ascorbic acid, a micro nutrient and an important neuroprotectant has been suggested to be a modulator of gene expression. However there are few reports on miRNAs targeting the genes involved in neuronal apoptotic UPR signaling as well as l-ascorbic acid mediated regulation of neuronal UPR pathway and miRNA expression. Here, we identified a statistically significant downregulation of 7 miRNAs such as mmu-miR-24, 27b, 124, 224, 290, 351 and 488 and inverse expression relationship with their UPR related targets such as Perk, Ire1α, Chop and Puma during advanced glycated BSA (AGE-BSA) induced ER stress in Mus musculus cortical and hippocampal neurons. We also observed that a pretreatment with l-ascorbic acid alleviated AGE-BSA induced neuronal ER stress as well as the downregulation of the 7 potential miRNAs.

Polyphenols Attenuate Highly-Glycosylated Haemoglobin-Induced Damage in Human Peritoneal Mesothelial Cells.

We investigated the cytoprotective role of the dietary polyphenols on putative damage induced by Amadori adducts in Human Peritoneal Mesothelial Cells (HPMCs). Increased accumulation of early products of non-enzymatic protein glycation—Amadori adducts—in the peritoneal dialysis fluid due to their high glucose, induces severe damage in mesothelial cells during peritoneal dialysis. Dietary polyphenols reportedly have numerous health benefits in various diseases and have been used as an efficient antioxidant in the context of several oxidative stress-related pathologies. HPMCs isolated from different patients were exposed to Amadori adducts (highly glycated haemoglobin, at physiological concentrations), and subsequently treated with several polyphenols, mostly presented in our Mediterranean diet. We studied several Amadori-induced effects in pro-apoptotic and oxidative stress markers, as well as the expression of several pro-inflammatory genes (nuclear factor-kappaB, NF-kB; inducible Nitric Oxide synthetase, iNOS), different caspase-activities, level of P53 protein or production of different reactive oxygen species in the presence of different polyphenols. In fact, cytoprotective agents such as dietary polyphenols may represent an alternate approach to protect mesothelial cells from the cytotoxicity of Amadori adducts. The interference with the Amadori adducts-triggered mechanisms could represent a therapeutic tool to reduce complications associated with peritoneal dialysis in the peritoneum, helping to maintain peritoneal membrane function longer in patients undergoing peritoneal dialysis.

SUN-668 Elevated Osmolal Gap in Long-Term Complication of Type 2 Diabetes

Osmolal gap (OG) is the difference between the measured osmolality and calculated osmolality estimated by using the mathematical equation. Elevated OG indicates the presence of osmotically active particles undetected in the plasma of healthy individuals. Elevated OG has been observed in multiorgan trauma as a useful prognostic factor of patient survival [1, 2]. We hypothesized that elevated OG may occur in patients with type 2 diabetes (T2D) and may become a useful indicator of unmeasured endotoxins. One of the major mechanisms of this phenomenon may be non-enzymatic glycation of proteins in hyperglycemia, in which the osmotic active carbonyl compounds such as glyoxal, methylglyoxal, and 3-deoxyglucosone, are formed. Testing was performed for participants with T2D, aged 18 to 85. The osmolality measurement was performed with venous blood using the osmometer. The concentration of individual osmols (sodium, potassium, glucose, urea) was determined and on this basis, osmolality was calculated using the Dorwart-Chalmers formula: osmolality (mOsm/kg H2O) = 1.86 x [Na+] + glucose + urea + 9 (Dorwart, 1975). The clinical profile of patients was established based on history and physical examination (age, sex, age, duration of T2D, complications of T2D, HbA1c, LDL-cholesterol, triglyceride, BMI, coexisting diseases, medication). Data were analyzed using descriptive statistics. This study is currently ongoing, but preliminary data from the pilot study suggest an increased mean measured osmolality as well as elevated OG in patients with T2D compared to the reference values for healthy adults. These values differed depending on the type of long-term complications and the duration of the disease. In the pilot study, the highest OG was reported in diabetic retinopathy. A follow-up study with a larger sample may have a better ability to detect the statistical significance of the association of OG and complications of T2D. The association of the osmolal gap and complication of type 2 diabetes is poorly understood, and further investigation is warranted.

Structural stability and solubility of glycated camel lens ζ-crystallin

The camel has several biochemical, physiological, and anatomical features to withstand the harsh desert climate. Camel eye lens contains a novel protein (ζ-crystallin) in bulk quantity. Previous reports suggest that non-enzymatic glycation of eye lens proteins plays an important role in the etiology of cataract. In this study, we have characterized the role of glucose, fructose, and methylglyoxal (MGO) in the glycation of camel lens ζ-crystallin. From the results obtained, it was found that MGO reacted rapidly, fructose reacted moderately, and glucose was the least reactive even after prolonged incubation (>100 days). Glycation with MGO and fructose led to changes in the structure of ζ-crystallin, while glucose had no remarkable effect. The surface hydrophobicity did not change and no aggregates or amyloid fibrils were observed in the glycated ζ-crystallin. Moreover, the secondary structure of glycated ζ-crystallin remained similar after glycation. Our results suggested that due to natural adaptation, the camel lens protein ζ-crystallin retained its structure and solubility even after glycation to perform the single known function of the lens proteins: to focus unscattered light on the retina.

A biochemical & biophysical study on in-vitro anti-glycating potential of iridin against d-Ribose modified BSA

Non-enzymatic protein glycation results in the formation of advanced glycation end products (AGEs) leads to the pathogenesis of long-term diabetic complications. Iridin (ID), an antioxidant, plays an important role in protecting against oxidative stress and could therefore be an efficacious anti-glycating regimen. Herein, we assessed the anti-glycating potential of ID against d-ribose induced glycation of bovine serum albumin (BSA) by various biophysical and biochemical techniques. Our results from several physicochemical assays advocated that ID was able to evidently prevent the AGEs generation via reducing hyperchromicity, early glycation products (EGPs), carbonyl content (CC), hydroxymethyl furfural (HMF) content, production of fluorescent AGEs, protection against loss of secondary structure (i.e. α-helix and β-sheets) of proteins, increasing the free lysine and free arginine content, reduced binding of congo red (CR), and reduced thioflavin T (ThT) and 8-aninilo-1-napthalene sulphonate (ANS)-specific fuorescence in glycated-BSA (Gly-BSA). On the basis of these findings, we concluded that ID possesses the significant anti-glycation potential and may be established as a remarkable anti-AGEs therapeutic agent. Further in-vivo and clinical studies are still warranted to uncover the therapeutic effects of ID against age-related as well as metabolic diseases.

First-Days Reduction of Plasma and Skin Advanced Glycation End Products is Related to Outcome in Septic Patients.

Advanced glycation end products (AGEs) are a result of nonenzymatic glycation of proteins and lipids, which can attach to either their cell surface receptor (RAGE) or its soluble form (sRAGE). Evidence exists for the implication of AGE-RAGE axis in sepsis, but data are still insufficient and conflicting. We aimed to analyze the kinetics of plasma and skin AGEs and sRAGE during sepsis, and their association with outcome in septic patients. We performed a prospective observational study. We enrolled 90 consecutive patients with severe sepsis or septic shock, within the first 24 h of Intensive Care Unit admission. During the first 5 days of sepsis, we measured plasma autofluorescence (PAF) and skin autofluorescence (SAF) as surrogates of circulating and skin AGEs, respectively. sRAGE was measured on days 1, 3, and 5. Delta values were defined as the difference between the PAF, SAF, or sRAGE on a specific day and the value on day 1. 28-day mortality was 18%. Bivariate analysis found that ΔPAF3-1, ΔPAF4-1, ΔPAF5-1, and ΔSAF5-1 were significantly associated with 28-day mortality. Additionally, sRAGE1 was inversely correlated to ΔPAF4-1 (r = -0.250, P = 0.019) and ΔPAF5-1 (r = -0.246, P = 0.024), and significantly associated with 28-day mortality. In an adjusted multivariate logistic regression analysis, ΔPAF2-1, ΔPAF3-1, ΔPAF4-1, ΔPAF5-1, and ΔSAF5-1 were associated with 28-day mortality. Kinetics of plasma and skin AGEs during the first days of sepsis are independently associated with mortality, where a decrease of plasma and skin AGEs are related to higher mortality.