Quercetin, a Flavonoid with Great Pharmacological Capacity.

Quercetin is a flavonoid with a low molecular weight that belongs to the human diet's phenolic phytochemicals and nonenergy constituents. Quercetin has a potent antioxidant capacity, being able to capture reactive oxygen species (ROS), reactive nitrogen species (RNS), and reactive chlorine species (ROC), which act as reducing agents by chelating transition-metal ions. Its structure has five functional hydroxyl groups, which work as electron donors and are responsible for capturing free radicals. In addition to its antioxidant capacity, different pharmacological properties of quercetin have been described, such as carcinostatic properties; antiviral, antihypertensive, and anti-inflammatory properties; the ability to protect low-density lipoprotein (LDL) oxidation, and the ability to inhibit angiogenesis; these are developed in this review.

mtDNA Single-Nucleotide Variants Associated with Type 2 Diabetes.

Type 2 diabetes (T2D) is a chronic systemic disease with a complex etiology, characterized by insulin resistance and mitochondrial dysfunction in various cell tissues. To explore this relationship, we conducted a secondary analysis of complete mtDNA sequences from 1261 T2D patients and 1105 control individuals. Our findings revealed significant associations between certain single-nucleotide polymorphisms (SNPs) and T2D. Notably, the variants m.1438A>G (rs2001030) (controls: 32 [27.6%], T2D: 84 [72.4%]; OR: 2.46; 95%CI: 1.64-3.78; p < 0.001), m.14766C>T (rs193302980) (controls: 498 [36.9%], T2D: 853 [63.1%]; OR: 2.57, 95%CI: 2.18-3.04, p < 0.001), and m.16519T>C (rs3937033) (controls: 363 [43.4%], T2D: 474 [56.6%]; OR: 1.24, 95%CI: 1.05-1.47, p = 0.012) were significantly associated with the likelihood of developing diabetes. The variant m.16189T>C (rs28693675), which has been previously documented in several studies across diverse populations, showed no association with T2D in our analysis (controls: 148 [13.39] T2D: 171 [13.56%]; OR: 1.03; 95%CI: 0.815-1.31; p = 0.83). These results provide evidence suggesting a link between specific mtDNA polymorphisms and T2D, possibly related to association rules, topological patterns, and three-dimensional conformations associated with regions where changes occur, rather than specific point mutations in the sequence.

Mitochondrial Control Region Variants Related to Breast Cancer.

Breast cancer has an important incidence in the worldwide female population. Although alterations in the mitochondrial genome probably play an important role in carcinogenesis, the actual evidence is ambiguous and inconclusive. Our purpose was to explore differences in mitochondrial sequences of cases with breast cancer compared with control samples from different origins. We identified 124 mtDNA sequences associated with breast cancer cases, of which 86 were complete and 38 were partial sequences. Of these 86 complete sequences, 52 belonged to patients with a confirmed diagnosis of breast cancer, and 34 sequences were obtained from healthy mammary tissue of the same patients used as controls. From the mtDNA analysis, two polymorphisms with significant statistical differences were found: m.310del (rs869289246) in 34.6% (27/78) of breast cancer cases and 61.7% (21/34) in the controls; and m.315dup (rs369786048) in 60.2% (47/78) of breast cancer cases and 38.2% (13/34) in the controls. In addition, the variant m.16519T>C (rs3937033) was found in 59% of the control sequences and 52% of the breast cancer sequences with a significant statistical difference. Polymorphic changes are evolutionarily related to the haplogroup H of Indo-European and Euro-Asiatic origins; however, they were found in all non-European breast cancers.

Automated Computer-Assisted Image Analysis for the Fast Quantification of Kidney Fibrosis.

Chronic kidney disease (CKD) is a common and worldwide health problem and one of the most important causes of morbidity and mortality. Most primary research on this disease requires evaluating the fibrosis index in animal model kidneys, specifically using Masson's trichrome stain. Different programs are used to calculate the percentage of fibrosis; however, the analysis is time-consuming since one image must be performed at a time. CellProfiler™ is a program designed to analyze data obtained from biological samples and can process multiple images through pipelines, and the results can be exported to databases. This article explains how CellProfiler™ can be used to automatically analyze kidney histology photomicrographs from samples stained with Masson's trichrome stain to assess the percentage of fibrosis in an experimental animal model of CKD. A pipeline was created to analyze Masson's trichrome-stained slides in a model of CDK induced by adenine at doses of 50 mg/kg and 100 mg/kg, in addition to samples with the vehicle (75% glycerin). The results were compared with those obtained by ImageJ, and no significant differences were found between both programs. The CellProfiler™ pipeline made here is a reliable, fast, and easy alternative for kidney fibrosis analysis and quantification in experimental animal models.

Nanoparticles Formulation Improves the Antifibrogenic Effect of Quercetin on an Adenine-Induced Model of Chronic Kidney Disease.

Renal fibrosis is the final stage of chronic kidney injury characterized by glomerulosclerosis and tubulointerstitial fibrosis with parenchymal destruction. Quercetin belongs to the most studied flavonoids with antioxidant, anti-inflammatory, antifibrogenic, and antitumor activity. It modifies the TGF-ß/Smad signaling pathway, decreasing profibrogenic expression molecules and inducing the expression of antioxidant, anti-inflammatory, and antifibrogenic molecules. However, quercetin exhibits poor water solubility and low absorption and bioavailability. This limitation was solved by developing a nanoparticles formulation that improves the solubility and bioavailability of several bioactive compounds. Therefore, we aimed to investigate the in vivo antifibrogenic effect of a quercetin nanoparticles formulation. Male C57BL/6 mice were induced into chronic renal failure with 50 mg/kg of adenine for four weeks. The animals were randomly grouped and treated with 25, 50, or 100 mg/kg of quercetin, either macroparticles or nanoparticles formulation. We performed biochemical, histological, and molecular analyses to evaluate and compare the effect of macroparticles versus nanoparticles formulation on kidney damage. Here, we demonstrated that smaller doses of nanoparticles exhibited the same beneficial effect as larger doses of macroparticles on preventing kidney damage. This finding translates into less quercetin consumption reaching the desired therapeutic effect.

Class I MHC Polymorphisms Associated with Type 2 Diabetes in the Mexican Population.

Type 2 diabetes (T2D) has been linked to the expression of Human Leukocyte Antigens, principally to the Major Histocompatibility Complex Class II, with only scarce reports of Major Histocompatibility Complex Class I in specific populations. The objective of the present work was to explore the presence of polymorphisms in the MHC Class I related to T2D in the Mexican population using the Genome-Wide Association Studies Slim Initiative in Genomic Medicine of the Americas (GWAS SIGMA) database. This database contains information on 3848 Mexican individuals with T2D and 4366 control individuals from the same population without a clinical or hereditary history of the disease. The searching criteria considered a p-value of <0.005 and an odds ratio (OR) of >1.0. Ten novel, statistically significant nucleotide variants were identified: four polymorphisms associated with HLA-A (A*03:01:01:01) and six with HLA-C (C*01:02:01:01). These alleles have a high prevalence in Latin American populations and could potentially be associated with autoimmunity mechanisms related to the development of T2D complications.

The utility of genomic public databases to mitochondrial haplotyping in contemporary Mestizo population of Mexican origin.

There are different public databases and open access information that can be exploited to be reused in different research projects. With this concept in mind, we carried out a study to answer the question about the prevalence of haplogroups in human populations of modern Mexico. Since the publication of genomic and mitochondrial data in Latin American populations are very scarce and with very small samples, our work proposes to consider the availability of genomic and genetic data collections that can be reused for other purposes, different from those initially proposed in the investigations where the sequences were obtained. The objective of the present study was to explore the population structure of Mexico using available information in the public database. Through the search of information in the nucleotide database of National Center of Biotechnology Information (NCBI) of complete sequences of mitochondrial genome (16 Kb) of indigenous people, Mexican Mestizo population and Mexican-Americans living in the United States, they were classified according to the polymorphisms associated with haplogroups A, B, C and D reported in the literature as the most frequent. We obtained 283 sequences, of which 255 were selected with the criteria mentioned. The haplotyping results showed 113 different clades and subclades distributed in a general way in eight haplogroups. The most frequent groups that dominate the population were the haplogroup A with 90 individuals representing 36%, followed by haplogroup B in 65 individuals representing 26% of the sample.

New gene therapy strategies for hepatic fibrosis.

The liver is the largest internal organ of the body, which may suffer acute or chronic injury induced by many factors, leading to cirrhosis and hepatocarcinoma. Cirrhosis is the irreversible end result of fibrous scarring and hepatocellular regeneration, characterized by diffuse disorganization of the normal hepatic structure, regenerative nodules and fibrotic tissue. Cirrhosis is associated with a high co-morbidity and mortality without effective treatment, and much research has been aimed at developing new therapeutic strategies to guarantee recovery. Liver-based gene therapy has been used to downregulate specific genes, to block the expression of deleterious genes, to delivery therapeutic genes, to prevent allograft rejection and to augment liver regeneration. Viral and non-viral vectors have been used, with viral vectors proving to be more efficient. This review provides an overview of the main strategies used in liver-gene therapy represented by non-viral vectors, viral vectors, novel administration methods like hydrodynamic injection, hybrids of two viral vectors and blocking molecules, with the hope of translating findings from the laboratory to the patient's bed-side.

Nrf2 and Snail-1 in the prevention of experimental liver fibrosis by caffeine.

AIM: To determine the molecular mechanisms involved in experimental hepatic fibrosis prevention by caffeine (CFA). METHODS: Liver fibrosis was induced in Wistar rats by intraperitoneal thioacetamide or bile duct ligation and they were concomitantly treated with CFA (15 mg/kg per day). Fibrosis and inflammatory cell infiltrate were evaluated and classified by Knodell index. Inflammatory infiltrate was quantified by immunohistochemistry (anti-CD11b). Gene expression was analyzed by quantitative reverse transcription-polymerase chain reaction for collagen I (Col-1), connective tissue growth factor (CTGF), transforming growth factor ß1 (TGF-ß1), tumor necrosis factor alpha (TNF-α), interleukin-1 (IL-1), IL-6, superoxide dismutase (SOD) and catalase (CAT). Activation of Nrf2 and Snail-1 was analyzed by Western-blot. TNF-α expression was proved by enzyme-linked immunosorbant assay, CAT activity was performed by zymography. RESULTS: CFA treatment diminished fibrosis index in treated animals. The Knodell index showed both lower fibrosis and necroinflammation. Expression of profibrogenic genes CTGF, Col-1 and TGF-ß1 and proinflammatory genes TNF-α, IL-6 and IL-1 was substantially diminished with CFA treatment with less CD11b positive areas. Significantly lower values of transcriptional factor Snail-1 were detected in CFA treated rats compared with cirrhotic rats without treatment; in contrast Nrf2 was increased in the presence of CFA. Expression of SOD and CAT was greater in animals treated with CFA showing a strong correlation between mRNA expression and enzyme activity. CONCLUSION: Our results suggest that CFA inhibits the transcriptional factor Snail-1, down-regulating profibrogenic genes, and activates Nrf2 inducing antioxidant enzymes system, preventing inflammation and fibrosis.

Quercetin improves hepatic fibrosis reducing hepatic stellate cells and regulating pro-fibrogenic/anti-fibrogenic molecules balance.

BACKGROUND AND AIM: Development of hepatic cirrhosis involves oxidative stress, inflammation, hepatic stellate cells (HSC)s activation and fibrosis. On the other hand, quercetin, a natural flavonoid is a potent antioxidant and activator of superoxide dismutase and catalase. The aim was to determinate the effect of quercetin on HSCs and development of hepatic fibrosis. METHODS: Wistar male rats were chronically intoxicated with CCl(4) for 8 weeks and concomitantly treated with 100 mg/kg per day of quercetin. Oxidative state, inflammation and fibrosis were evaluated. Effect of quercetin on apoptosis of HSC was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling reaction. RESULTS: Sixty percent of reduction in fibrosis index was observed with quercetin treatment compared with control animals. Considerable reduction on hepatic enzymes was detected in the quercetin group. Expression of pro-fibrotic genes (transforming growth factor-ß [TGF-ß], Collagen 1α [Col-1α] and connective tissue growth factor [CTGF]) were decreased by quercetin. Quercetin increased gene expression and functional activity of antioxidant enzymes superoxide dismutase and catalase. Inflammatory index was highly reduced as determined by H-E staining and pro-inflammatory cytokines expression and nuclear factor-κB activation were also inhibited. A significant reduction of 65% on activated HSC number was detected when rats were treated with quercetin. Quercetin also induced activation of matrix metalloproteinases MMP2 and MMP9 contributing to decreased index of fibrosis. CONCLUSIONS: Treatment with quercetin reduces oxidation and inflammation and also prevents liver fibrosis, through induction of HSC apoptosis and activation of MMPs.