RESUMO
Carbamylation is a nonenzymatic post-translational modification observed during the reaction between cyanate and amino acids and/or proteins that may occur during some pathologies such as chronic kidney disease. Evidence suggests that carbamylation may interfere with the quantification of some analytes measured using immunoturbidimetric assays. C-reactive protein (CRP) is an inflammatory response protein that is commonly quantified through immunoturbidimetry in clinical laboratories. Because the presence of modified proteins in serum can lead to impaired quantification, this study aimed to verify the impact of in vitro carbamylation on the measurement of CRP in a CRP standard solution and serum pool. The samples were incubated with 150 nM, 150 µM, or 150 mM potassium cyanate (KOCN) or 20, 100, or 500 mg/dL urea at 37 °C for 24 h. CRP concentrations were measured using an immunoturbidimetric assay. The results showed a 61%-72% decrease in the CRP detection rate after incubation with KOCN. Incubation with urea resulted in a 0.7%-8% lower CRP detection rate. The results of this study indicate that high concentrations of cyanate can lead to falsely decreased CRP levels, as measured by immunoturbidimetry.
Assuntos
Proteína C-Reativa , Carbamilação de Proteínas , Humanos , Cianatos , UreiaRESUMO
The preparation of amide-containing compounds is among the most interesting and challenging topics for the synthetic community. Such relevance is given by their reactive aspects explored in the context of organic synthesis and by the direct application of these compounds as pharmaceuticals and useful materials, and their key roles in biological structures. A simple and straightforward strategy for the amide moiety installation is the use of carbamoyl radicals - this nucleophilic one-electron intermediate is prone to undergo a series of transformations, providing a range of structurally relevant derivatives. In this review, we summarize the latest advances in the field from the perspective of photoinduced protocols. To this end, their synthetic applications are organized accordingly to the nature of the radical precursor (formamides through HAT, 4-substituted-1,4-dihydropyridines, oxamic acids, and N-hydroxyphthalimido esters), the mechanistic aspects also being highlighted. The discussion also includes a recent approach proceeding via photolytic C-S cleavage of dithiocarbamate-carbamoyl intermediates. By exploring fundamental concepts, this material aims to offer an understanding of the topic, which will encourage and facilitate the design of new synthetic strategies applying the carbamoyl radical.
Assuntos
Formamidas , Carbamilação de Proteínas , Amidas , Técnicas de Química SintéticaRESUMO
BACKGROUND AND AIMS: Abnormalities in lipid metabolism, accumulation of uremic toxins and advanced glycation end products may contribute to worsening atherosclerosis. This study characterized the glycation and carbamoylation profile of serum albumin isolated from individuals with diabetic kidney disease and its influence on cholesterol efflux. MATERIAL AND METHODS: 49 patients with type 2 diabetes (T2DM) and different eGFR evaluated glycation and carbamoylation profile by measurement of carboxymethyl lysine (CML) and carbamoylated proteins (CBL) in plasma by ELISA, homocitrulline (HCit) in plasma by colorimetry. In the isolated albumins, we quantified CBL (ELISA) and total AGE and pentosidine by fluorescence. Macrophages were treated with albumin isolated, and 14C-Cholesterol efflux mediated by HDL2 or HDL3 was measured. Kruskal-Wallis test, Jonckheere-Terpstra test and Brunner's posttest were used for comparisons among groups. RESULTS: Determination of CML, HCit, CBL in plasma, as total AGE and pentosidine in albumins, did not differ between groups; however, CBL in the isolated albumins was higher in the more advanced stages of CKD (p=0.0414). There was reduction in the 14C-cholesterol efflux after treatment for 18h with albumin isolated from patients with eGFR<60mL/min/1.73m2 compared with control group mediated by HDL2 (p=0.0288) and HDL3 (p<0.0001), as well as when compared with eGFR ≥60mL/min/1.73m2 per HDL2 (p=0.0001) and HDL3 (p<0.0001). Treatment for 48h showed that eGFR<15mL/min/1.73m2 had a lower percentage of 14C-cholesterol efflux mediated by HDL2 compared to control and other CKD groups (p=0.0274). CONCLUSIONS: Albumins isolated from individuals with T2DM and eGFR<60mL/min/1.73m2 suffer greater carbamoylation, and they impair the cholesterol efflux mediated by HDL2 and HDL3. In turn, this could promote lipids accumulation in macrophages and disorders in reverse cholesterol transport.
Assuntos
Colesterol/metabolismo , Nefropatias Diabéticas/metabolismo , Macrófagos , Insuficiência Renal Crônica , Albumina Sérica , Diabetes Mellitus Tipo 2/complicações , Humanos , Macrófagos/metabolismo , Carbamilação de Proteínas , Insuficiência Renal Crônica/metabolismo , Albumina Sérica/metabolismo , Toxinas UrêmicasRESUMO
Urinary albumin is one of the main markers used in clinical practice to assess kidney damage. It is usually measured in laboratories through immunological assays, but these assays may not detect molecules with conformational changes, such as carbamylated albumin/proteins. Therefore, this study aimed to investigate the impact of albumin carbamylation on the measurement of albuminuria by an immunoturbidimetric assay. The addition of the carbamylating agent to PBS buffer and urine pool promoted a lower quantification of albumin measured by the immunoturbidimetric method, indicating that this process may be responsible for an underestimation of the results in clinical practice.
Assuntos
Albuminas/metabolismo , Albuminúria/diagnóstico , Imunoturbidimetria/métodos , Carbamilação de Proteínas , Humanos , Insuficiência Renal Crônica/diagnóstico , Insuficiência Renal Crônica/urinaRESUMO
OBJECTIVE: Antibodies against carbamylated proteins/peptide (CarP) have been associated with severity in rheumatoid arthritis (RA) patients. However, their role in risk groups, specific targets and relation with periodontal disease (PD) is uncertain yet. The aim of this study was evaluated the association between the levels of anti-CarP with clinical manifestation, human leukocyte antigen (HLA) alleles, periodontal activity markers, PD diagnosis, PD severity, and presence of Porphyromonas gingivalis (P gingivalis) in relatives of patients with RA. METHODS: One hundred and twenty-four individuals with a family history of RA in first-degree relatives (FDR) and 124 healthy individuals gender- and age-matched, RA activity was assessed. Antibodies against carbamylated protein anti-FCS-Carp and 2 carbamylated peptides of fibrinogen were selected (anti-Ca-Fib2, anti-Ca-Fib3). RESULTS: Anti-FCS-Carp-positive, anti-Ca-Fib2 and anti-Ca-Fib3 were more frequent in FDR than controls (25.0% vs 14.5%, 34.7% vs 15.3% and 33.1% vs 11.3%, respectively). Anti-FCS-CarP were associated with the HLA-DRB1-SE* 1402 allele (P = .035) and highly sensitive C-reactive protein levels (P = .016), the anti-Ca-Fib2 antibodies were associated with the HLA-DRB1-SE* 1501 allele (P = .03), with non-SE* 0901 allele (P = .01), the anti-Ca-Fib3 was associated with positive rheumatoid factor (P = .0012). The FDR condition was associated with the presence of anti-Ca-Fib3 (odds ratio [OR] =4.7; 95% CI = 1.8-11.7; P = .001) and painful joints (OR = 2.2; 95% CI = 1.01-4.68; P = .045); we also detected an important trend toward the presence of P gingivalis (OR = 1.9; 95% CI = 0.9-3.7; P = .062). CONCLUSION: The presence of anti-FCS-Carp, anti-Ca-Fib3 and anti-Ca-Fib2 antibodies may have a role for these antibodies as early biomarkers in the development of RA, probably including additional mechanisms related with other non-SE alleles; the anti-peptide antibodies proposed in the present study may represent a simpler way to identify antibodies directed to a specific target.
Assuntos
Artrite Reumatoide/imunologia , Autoanticorpos/imunologia , Carbamatos/imunologia , Adulto , Artrite Reumatoide/diagnóstico , Artrite Reumatoide/metabolismo , Biomarcadores/metabolismo , Carbamatos/metabolismo , Estudos Transversais , Feminino , Humanos , Inflamação/imunologia , Inflamação/metabolismo , Masculino , Carbamilação de ProteínasRESUMO
BACKGROUND AND AIMS: Diabetic kidney disease (DKD) is associated with lipid derangements that worsen kidney function and enhance cardiovascular (CVD) risk. The management of dyslipidemia, hypertension and other traditional risk factors does not completely prevent CVD complications, bringing up the participation of nontraditional risk factors such as advanced glycation end products (AGEs), carbamoylation and changes in the HDL proteome and functionality. The HDL composition, proteome, chemical modification and functionality were analyzed in nondialysis subjects with DKD categorized according to the estimated glomerular filtration rate (eGFR) and urinary albumin excretion rate (AER). METHODS: Individuals with DKD were divided into eGFR> 60 mL/min/1.73 m2 plus AER stages A1 and A2 (n = 10) and eGFR< 60 plus A3 (n = 25) and matched by age with control subjects (eGFR> 60; n = 8). RESULTS: Targeted proteomic analyses quantified 28 proteins associated with HDL in all groups, although only 2 were more highly expressed in the eGFR< 60 + A3 group than in the controls: apolipoprotein D (apoD) and apoA-IV. HDL from the eGFR< 60 + A3 group presented higher levels of total AGEs (20%), pentosidine (6.3%) and carbamoylation (4.2 x) and a reduced ability to remove 14C-cholesterol from macrophages (33%) in comparison to HDL from controls. The antioxidant role of HDL (lag time for LDL oxidation) was similar among groups, but HDL from the eGFR< 60 + A3 group presented a greater ability to inhibit the secretion of IL-6 and TNF-alpha (95%) in LPS-elicited macrophages in comparison to the control group. CONCLUSION: The increase in apoD and apoA-IV could contribute to counteracting the HDL chemical modification by AGEs and carbamoylation, which contributes to HDL loss of function in well-established DKD.
Assuntos
Apolipoproteínas A/sangue , Apolipoproteínas D/sangue , Nefropatias Diabéticas/sangue , Lipoproteínas HDL/sangue , Proteoma/metabolismo , Idoso , Idoso de 80 Anos ou mais , Albuminúria/sangue , Albuminúria/genética , Albuminúria/patologia , Apolipoproteínas A/genética , Apolipoproteínas D/genética , Arginina/análogos & derivados , Arginina/sangue , Arginina/genética , Estudos de Casos e Controles , Nefropatias Diabéticas/genética , Nefropatias Diabéticas/patologia , Feminino , Expressão Gênica , Taxa de Filtração Glomerular , Produtos Finais de Glicação Avançada/sangue , Produtos Finais de Glicação Avançada/genética , Humanos , Interleucina-6/genética , Interleucina-6/metabolismo , Rim/metabolismo , Rim/patologia , Lipopolissacarídeos/farmacologia , Lipoproteínas HDL/genética , Lisina/análogos & derivados , Lisina/sangue , Lisina/genética , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Macrófagos/patologia , Masculino , Pessoa de Meia-Idade , Cultura Primária de Células , Carbamilação de Proteínas , Proteoma/classificação , Proteoma/genética , Diálise Renal , Fatores de Risco , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Rheumatoid arthritis (RA) is an autoimmune/inflammatory disease affecting 0.5 to 1% of adults worldwide and frequently leads to joint destruction and disability. Early diagnosis and early and effective therapy may prevent joint damage and lead to better long-term results. Therefore, reliable biomarkers and outcome measures are needed. Refinement of the understanding of molecular pathways involved in disease pathogenesis have been achieved by combining knowledge on RA-associated genes, environmental factors and the presence of serological elements. The presence of autoantibodies is a distinctive feature of RA. Rheumatoid Factor and Anti-Citrullinated Protein Antibodies are the two most remarkable autoantibodies in RA and provide different clinical and pathophysiological information. They precede the onset of disease symptoms and predict a more severe disease course, indicating a pathogenetic role in RA. Therefore, they promote a more accurate prognosis and contribute for a better disease management. Several RA-associated autoantibody systems have been identified: Anti-Carbamylated Antibodies, Anti-BRAF, Anti-Acetylated, Anti-PAD4 antibodies and others. Hopefully, the characterization of a comprehensive array of novel autoantibody systems in RA will provide unique pathogenic insights of relevance for the development of diagnostic and prognostic approaches compatible with an effective personalized medicine.