16 research outputs found
Polymeric Nanocarriers of Drug Delivery Systems in Cancer Therapy
Conventional chemotherapy is the most common therapeutic method for treating cancer by the application of small toxic molecules thatinteract with DNA and causecell death. Unfortunately, these chemotherapeutic agents are non-selective and can damage both cancer and healthy tissues, producing diverse side effects, andthey can have a short circulation half-life and limited targeting. Many synthetic polymers have found application as nanocarriers of intelligent drug delivery systems (DDSs). Their unique physicochemical properties allow them to carry drugs with high efficiency, specificallytarget cancer tissue and control drug release. In recent years, considerable efforts have been made to design smart nanoplatforms, including amphiphilic block copolymers, polymer-drug conjugates and in particular pH- and redox-stimuli-responsive nanoparticles (NPs). This review is focused on a new generation of polymer-based DDSs with specific chemical functionalities that improve their hydrophilicity, drug loading and cellular interactions.Recentlydesigned multifunctional DDSs used in cancer therapy are highlighted in this review
Polimorfizm S-transferazy glutationowej (GST) może być wczesnym markerem w rozwoju zespołu policystycznych jajników (PCOS) — doświadczenia nieotyłych dorosłych pacjentów z cukrzycą insulinoniezależną
Introduction: It has been supposed that endocrine disturbances might be responsible for polycystic ovary syndrome (PCOS)-associated oxidative stress, with special emphasis on hyperandrogenism. Considering the potential relationship between hyperandrogenism and increased free radical production, parameters of oxidative stress were determined in non-obese normoinsulinemic adolescent girls newly diagnosed with PCOS.
Materials and methods: Nitrotyrosine, thiol group concentrations, glutathione peroxidase, and superoxide dismutase activities were determined under fasting conditions and during oral glucose tolerance test (OGTT) in 35 PCOS patients and 17 controls. Insulin resistance was assessed by the homeostasis model (HOMA-IR), HOMA β, insulinogenic index (IGI), Matsuda insulin sensitivity index (ISI), and AUC for glucose. Glutathione S-transferases (GSTs) polymorphisms were determined by PCR.
Results: Under fasting conditions, no significant difference of oxidative stress parameters was found between PCOS and controls. Acute hyperglycaemia during OGTT induced significant alteration in parameters of oxidative protein damage in PCOS patients. Alteration in nitrotyrosine concentrations correlated with testosterone, DHEAS, androstenediones, FAI, and LH, while changes in thiol groups correlated with DHEAS. Significant inverse association was found between LH and ISI, as well as AUC glucose and thiol groups. PCOS girls, carriers of GSTM1-null genotype, had significantly lower testosterone in comparison to ones with GSTM1-active genotype.
Conclusions: PCOS girls exhibited high free radical production together with unchanged antioxidant enzymatic capacity, independently from obesity and insulin resistance. Based on associations between oxidative stress parameters and testosterone, DHEAS, and androstenedione, it can be suggested that increased free radical production, probably as a consequence of hyperandrogenaemia, is an early event in the development of PCOS
GSTM1-null and GSTT1-active genotypes as risk determinants of primary open angle glaucoma among smokers
AIM: To evaluate glutathione transferase theta 1 and mu 1 (GSTT1 and GSTM1) polymorphisms as determinants of primary open angle glaucoma (POAG) risk, independently or in combination with cigarette smoking, hypertension and diabetes mellitus. METHODS: A case-control study with 102 POAG patients and 202 age and gender-matched controls was carried out. Multiplex-polymerase chain reaction method was used for the analysis of GSTM1 and GSTT1 polymorphisms. The differences between two groups were tested by the t-test or chi(2) test. Logistic regression analysis was used for assessing the risk for disease development. RESULTS: The presence of GSTM1-null genotype did not contribute independently towards the risk of POAG. However, individuals with GSTT1-active genotype were at almost two-fold increased risk to develop glaucoma (P=0.044) which increased up to 4.36 when combined with GSTM1-null carriers (P=0.024). When glutathione transferase (GST) genotypes were analyzed in association with cigarette smoking, hypertension and diabetes, only carriers of GSTT1-active genotype had significantly increased risk of POAG development in comparison with GSTT1-null genotype individuals with no history of smoking, hypertension and diabetes, respectively (OR=3.52, P=0.003; OR=10.02, P lt 0.001; OR=4.53, P=0.002). CONCLUSION: The results obtained indicate that both GSTM1-null and GSTT1-active genotypes are associated with increased POAG risk among smokers, suggesting potential gene-environment interaction in glaucoma development
Glutathione S-transferase A1, M1, P1 and T1 null or low-activity genotypes are associated with enhanced oxidative damage among haemodialysis patients
Background. Increased oxidative stress is a hallmark of end-stage renal disease (ESRD). Glutathione S-transferases (GST) are involved in the detoxification of xenobiotics and protection of oxidative damage. We hypothesized that genetic polymorphism in antioxidant enzymes GSTA1, GSTM1, GSTP1 and GSTT1 is more frequent in ESRD and modulates the degree of oxidative stress in these patients. Methods. GSTA1, GSTM1, GSTP1 and GSTT1 genotypes were determined in 199 ESRD patients and 199 age- and gender-matched controls. Markers of protein and lipid oxidative damage [thiol groups, carbonyl groups, advanced oxidative protein products, nitrotyrosine, malondialdehyde (MDA) and MDA adducts], together with total oxidant status and pro-oxidant antioxidant balance were determined. Results. Individual GST polymorphisms influence vulnerability to both protein and lipid oxidation, with GSTM1-null gene variant having the most pronounced effect. Furthermore, a strong combined effect of null/low-activity GSTM1, GSM, GSTA1 and GSTP1 genotypes in terms of susceptibility towards oxidative and carbonyl stress was found in ESRD patients. When patients were stratified according to GSTM1 and GSTT1, the highest oxidant damage was noted in those with the GSTM1-null/GSTT1-null genotype. The observed effect was even stronger in patients with the third low-activity GSTP1 or GSTA1 genotype. Finally, the level of oxidative and carbonyl stress was most pronounced in the subgroup of patients with all four null or low-activity GSTM1, GSTT1, GSTP1 and GSTA1 genotypes. Conclusions. According to the GST genotype, ESRD patients may be stratified in terms of the level of oxidative and carbonyl stress that might influence cardiovascular prognosis, but could also improve efforts towards individualization of antioxidant treatment
Oxidative stress and other risk factors associated with diabetic nephropathy in type 2 diabetes mellitus
Introduction. The aim of the study was to examine whether biomarkers
of oxidative stress and antioxidant enzyme activities are among other risk
factors for diabetic nephropathy (DN).
Methods. The study involved 70 patients with type 2 diabetes (37 males,
aged 41 to 81 years) allocated to two groups: one of 32 patients with DN
and the other of 38 patients without DN. In the study of oxidative stress 15
healthy persons were included. All examined patients were interviewed and
underwent objective examination. Their serum and urine samples were analyzed
in order to estimate the quality of glycoregulation and kidney function.
Protein thiol groups (P-SH), antioxidant enzyme activities [superoxide
dismutase (SOD) and glutathione peroxidase (GPX)] were determined in
plasma spectrophotometrically and malondialdehyde-adducts (MDA) by
enzyme immunoassay.
Results. No significant differences were found between the two groups
for demographic characteristics, duration and treatment of diabetes, blood
pressure, fasting glucose level and HbA1c. Patients with DN had a higher
body mass index, lower estimated glomerular filtration rate (eGFR) and
higher albuminuria and proteinuria. Plasma activity of GPX and SOD as well
as levels of MDA adducts and P-SH groups were similar in patients with and
without DN, but GPX and SOD plasma activities were significantly lower and
plasma level of MDA significantly higher in all patients than in healthy controls.
Patient gender, age, BMI, HbA1c and plasma level of P-SH and MDA
were selected as significant predictors of DN. Patient age, duration of diabetes,
serum phosphorus, uric acid levels and plasma SOD activity were negatively
associated with eGFR. Patient age, serum levels of protein and albumin
and plasma GPX activity were negatively, while systolic BP, serum levels
of uric acid and cholesterol were positively associated with proteinuria.
Conclusion. Biomarkers of oxidative protein and lipid damage were selected
as risk factors for DN, besides several other well known risk factors
The Double-Faced Role of Nitric Oxide and Reactive Oxygen Species in Solid Tumors
Disturbed redox homeostasis represents a hallmark of cancer phenotypes, affecting cellular metabolism and redox signaling. Since reactive oxygen and nitrogen species (ROS/RNS) are involved in regulation of proliferation and apoptosis, they may play a double-faced role in cancer, entailing protumorigenic and tumor-suppressing effects in early and later stages, respectively. In addition, ROS and RNS impact the activity and communication of all tumor constituents, mediating their reprogramming from anti- to protumorigenic phenotypes, and vice versa. An important role in this dichotomic action is played by the variable amounts of O2 in the tumor microenvironment, which dictates the ultimate outcome of the influence of ROS/RNS on carcinogenesis. Moreover, ROS/RNS levels remarkably influence the cancer response to therapy. The relevance of ROS/RNS signaling in solid tumors is witnessed by the emergence of novel targeted treatments of solid tumors with compounds that target ROS/RNS action and production, such as tyrosine kinase inhibitors and monoclonal antibodies, which might contribute to the complexity of redox regulation in cancer. Prospectively, the dual role of ROS/RNS in the different stages of tumorigenesis through different impact on oxidation and nitrosylation may also allow development of tailored diagnostic and therapeutic approaches