The extrapituitary prolactin promoter polymorphism is associated with rheumatoid arthritis and anti-CCP antibodies in Mexican population

Prolactin (PRL) is a hormone–cytokine that has been involved in autoimmunity due to its immunoregulatory and lymphoproliferative effects. It is produced by various extrapituitary sites including immune cells, under control of a superdistal promoter that contains a single nucleotide polymorphism − 1149 G/T previously associated with rheumatoid arthritis (RA) susceptibility in European population. The aim of this study was to investigate the association of the extrapituitary PRL − 1149 G/T promoter polymorphism with clinical parameters, clinical activity and disability indices in RA patients from Western Mexico and to analyze the PRL mRNA expression according to the PRL − 1149 G/T promoter polymorphism in total leucocytes from RA patients and controls. We conducted a case–control study that included 258 RA patients and 333 control subjects (CS). The DNA samples were genotyped using the PCR–RFLP method and the PRL mRNA expression was determined by quantitative real time PCR. PRL serum levels and antibodies to cyclic citrullinated peptides (anti-CCP) were measured with ELISA. We found significant differences in the genotype (p = 0.022) and allelic (p = 0.046) distribution of the polymorphism between RA patients and control subjects. According to the dominant genetic model, there is an association between the T allele (GT + TT genotypes) and decreased RA susceptibility in comparison to the G allele carriers (GG genotype) (OR 0.64, 95% CI 0.45–0.92; p = 0.011). The T allele carriers (GT + TT genotypes) had lower titers of anti-CCP antibodies in comparison to the G allele carriers (GG genotype) (median, 66 U/mL vs. 125 U/mL; p = 0.03). Furthermore, the GG homozygotes had higher PRL mRNA expression in comparison to the GT heterozygotes, and this latter with respect to the TT homozygotes, in both groups (RA: 1 > 0.72 > 0.19; CS: 1 > 0.54 > 0.28). However, PRL serum levels were similar in both groups. Our results suggest that the PRL − 1149 T allele is a genetic marker for decreased RA susceptibility and is associated with lower titers of anti-CCP antibodies in Mexican population. We also suggest influence of genotype upon PRL mRNA expression.     

Diffusional interaction behavior of NSAIDs in lipid bilayer membrane using molecular dynamics (MD) simulation: Aspirin and Ibuprofen

In this research, for the first time, molecular dynamics (MD) method was used to simulate aspirin and ibuprofen at various concentrations and in neutral and charged states. Effects of the concentration (dosage), charge state, and existence of an integral protein in the membrane on the diffusion rate of drug molecules into lipid bilayer membrane were investigated on 11 systems, for which the parameters indicating diffusion rate and those affecting the rate were evaluated. Considering the diffusion rate, a suitable score was assigned to each system, based on which, analysis of variance (ANOVA) was performed. By calculating the effect size of the indicative parameters and total scores, an optimum system with the highest diffusion rate was determined. Consequently, diffusion rate controlling parameters were obtained: the drug–water hydrogen bond in protein-free systems and protein–drug hydrogen bond in the systems containing protein.     

Induced apoptosis in the prevention of colorectal cancer by non-steroidal anti-inflammatory drugs

Epidemiological, clinical and animal studies indicate non-steroidal anti-inflammatory drugs (NSAIDs) to be chemopreventive for colorectal cancer. The best established target for NSAIDs are the two isoforms of cyclooxygenase (COX), a key enzyme in the biosynthesis of prostaglandins. Recent investigations using human colorectal tumor cell lines have focused on the cellular and molecular mechanisms potentially underlying the chemopreventive effect of NSAIDs. These studies have used traditional NSAIDs and their metabolites which either do not inhibit COX, are non-selective for the COX isoforms or selectively inhibit COX-1 over COX-2, and recently developed NSAIDs that are highly selective for COX-2. In vitro, apoptosis is the dominant anti-proliferative effect of each of these classes of NSAID and sensitivity to NSAID-induced apoptosis increases with the malignant potential of the tumor cells. Limited in vivo evidence backs up these findings. Cell cycle arrest also contributes to the in vitro growth inhibitory effect of traditional NSAIDs. The induction of apoptosis by NSAIDs may result from the inhibition of the COX isoforms but other as yet undefined paths to NSAID-induced apoptosis clearly exist. A member of each class of NSAID is under trial as a chemopreventive agent for colorectal cancer.     

Modulation of NSAID-induced antinociceptive and anti-inflammatory effects by alpha2-adrenoceptor agonists with gastroprotective effects

Tizanidine, an alpha2-adrenergic receptor agonist with myospasmolytic action, is indicated for the treatment of back pain either as monotherapy or in combination with nonsteridal anti-inflammatory drugs (NSAIDs). Tizanidine (0.25-1.0 mg/kg) significantly produced analgesic and anti-inflammatory effect in acetic acid induced writhing in mice and carrageenan-induced paw edema in rats, respectively. The effects were comparable with clonidine (0.25 and 0.50 mg/kg), another alpha2-agonist. Yohimbine (1 mg/kg), alpha2-adrenergic antagonist reversed the effect of tizanidine. Tizanidine (0.25 mg/kg) and clonidine (0.25 mg/kg) significantly potentiated the antinociceptive and anti-inflammatory effect of NSAIDs (nimesulide, meloxicam and naproxen). Tizanidine (1 mg/kg) did not alter basal pH, acidity (free and total) of gastric content and did not produce any mucosal injury in fasted rats. Tizanidine (1 mg/kg) significantly reduced meloxicam (UD50 3.21 mg/kg), nimesulide (UD50 24.52 mg/kg) and naproxen (UD50 14.10 mg/kg)-induced ulcerogenic effect (ulcer index, pH and free/total acidity). It is expected that tizanidine exerted gastrotprotection through stimulation of gastric and central alpha2-adrenergic receptors. Present investigation suggested that tizanidine not only enhance the analgesic and anti-inflammatory effect of NSAIDs but also improved gatstrointestinal tolerability of NSAIDs through modulation of central alpha-2-receptors. From this study, it can be speculated that tizanidine and NSAID combination therapy would prove to be a novel approach to treat nociceptive/inflammatory conditions with improved gastric tolerability of NSAIDs.     

Effects of inflammation and antiinflammatory treatment on serum trace elements concentrations

We investigated the serum concentrations of zinc and copper during the inflammatory process together with the effect of treatment with a nonsteroid anti-inflammatory agent on these trace elements concentrations. In the present study, we used 92 guinea pigs, 12 of which constituted the control group; the remaining 80 were the experimental group. To start with, proquazone (as anti-inflammatory agent) was administered orally to 40 guinea pigs of the experimental group at 20-mg/kg doses 2 h before the surgery. Throughout the experimental period, the above dose was administered to the animals twice a day. We produced inflammation in all animals of the experimental group by using carrageenan (inflammatory agent) dropped into mandibular surgical defects. Serum concentrations of zinc and copper were determined by atomic absorption spectrophotometry in both groups at the 6th, 48th, 120th, 168th, and 240th h. The serum zinc concentrations of the carrageenan-administered group decreased significantly (p<0.01). When comparing the serum zinc concentrations of the carrageenan plus proquazone-administered group with those of control group, the decrease (p<0.05) at the 6th, 48th, and 120th h were statistically significant. When the copper serum concentrations of the carrageenan-administered group were compared with those of the control group, at the 48th, 120th, and 168th h, a statistically significant increase (p<0.01) was observed. However, there was no significant change in the carrageenan plus proquazone-administered group at the 168th and 240th h. As a result during the acute phase of inflammation, serum zinc concentrations decreased, whereas serum copper concentrations increased. The alterations in zinc concentrations were more rapid than those in copper concentrations, but the administration of proquazone slowed the rate of decrease in serum zinc concentrations. This work was presented at the Fourth International Congress of Pathophysiology, June 29–July 5, 2002, Budapest, Hungary.     

Liquid nitrogen for the treatment of actinic keratosis: A longitudinal assessment

Cryosurgery with liquid nitrogen is one of the most used treatments for actinic keratosis. We aimed to study the effectiveness of two consecutive sessions of cryosurgery for actinic keratosis and investigate factors associated with its therapeutic success. Hence, we conducted a longitudinal study including 92 patients of both sexes, aged 50–75 years with 5–50 actinic keratosis on the face and forearms, who underwent cryosurgery and treatment with sunscreen SPF 30, at baseline and after 120 days. The lesions were counted in duplicate by the same examiner before the start of treatment and after 120 (N = 92) and 300 days (N = 33), represented by their medians and quartiles and compared using the generalized linear mixed effects model (negative binomial). Treatment behavior was investigated in relation to sex, age, education, skin type, smoking, sun exposure at work and the use of aspirin, anti-inflammatory and angiotensin-converting enzyme inhibitors. There was a significant reduction in the actinic keratosis count on the face and forearms (p < 0.05). Our results confirmed the effectiveness of cryosurgery for actinic keratosis, with a 57% reduction in the number, and size of the lesions. Higher education levels (p = 0.02) and less sun exposure at work (p = 0.02) independently promoted a significant reduction in the actinic keratosis count. Different population groups showed characteristic responses to the treatment, which may be explained by the degree of adherence to the use of photoprotection. In two sessions, cryosurgery with liquid nitrogen reduced the actinic keratosis count.     

Diclofenac-induced stimulation of SMCT1 (SLC5A8) in a heterologous expression system: A RPE specific phenomenon

SMCT1 is a Na⁺-coupled monocarboxylate transporter expressed in a variety of tissues including kidney, thyroid, small intestine, colon, brain, and retina. We found recently that several non-steroidal anti-inflammatory drugs (NSAIDs) inhibit the activity of SMCT1. Here we evaluated the effect of diclofenac, also a NSAID, on SMCT1. SMCT1 cDNA was expressed heterologously in the human retinal pigment epithelial cell lines HRPE and ARPE-19, the human mammary epithelial cell line MCF7, and in Xenopus laevis oocytes. Transport was monitored by substrate uptake and substrate-induced currents. Na⁺-dependent uptake/current was considered as SMCT1 activity. The effect of diclofenac was evaluated for specificity, dose-response, and influence on transport kinetics. To study the specificity of the diclofenac effect, we evaluated the influence of this NSAID on the activity of several other cloned transporters in mammalian cells under identical conditions. In contrast to several NSAIDs that inhibited SMCT1, diclofenac stimulated SMCT1 when expressed in HRPE and ARPE-19 cells. The stimulation was marked, ranging from 2- to 5-fold depending on the concentration of diclofenac. The stimulation was associated with an increase in the maximal velocity of the transport system as well as with an increase in substrate affinity. The observed effect on SMCT1 was selective because the activity of several other cloned transporters, when expressed in HRPE cells and studied under identical conditions, was not affected by diclofenac. Interestingly, the stimulatory effect on SMCT1 observed in HRPE and ARPE-19 cells was not evident in MCF7 cells nor in the X. laevis expression system, indicating that SMCT1 was not the direct target for diclofenac. The RPE-specific effect suggests that the target of diclofenac that mediates the stimulatory effect is expressed in RPE cells but not in MCF7 cells or in X. laevis oocytes. Since SMCT1 is a concentrative transporter for metabolically important compounds such as pyruvate, lactate, β-hydroxybutyrate, and nicotinate, the stimulation of its activity by diclofenac in RPE cells has biological and clinical significance.     

Novel pathways that contribute to the anti-proliferative and chemopreventive activities of calcitriol in prostate cancer

Calcitriol, the hormonally active form of Vitamin D, inhibits the growth and development of many cancers through multiple mechanisms. Our recent research supports the contributory role of several new and diverse pathways that add to the mechanisms already established as playing a role in the actions of calcitriol to inhibit the development and progression of prostate cancer (PCa). Calcitriol increases the expression of insulin-like growth factor binding protein-3 (IGFBP-3), which plays a critical role in the inhibition of PCa cell growth by increasing the expression of the cell cycle inhibitor p21. Calcitriol inhibits the prostaglandin (PG) pathway by three actions: (i) the inhibition of the expression of cyclooxygenase-2 (COX-2), the enzyme that synthesizes PGs, (ii) the induction of the expression of 15-prostaglandin dehydrogenase (15-PGDH), the enzyme that inactivates PGs and (iii) decreasing the expression of EP and FP PG receptors that are essential for PG signaling. Since PGs have been shown to promote carcinogenesis and progression of multiple cancers, the inhibition of the PG pathway may add to the ability of calcitriol to prevent and inhibit PCa development and growth. The combination of calcitriol and non-steroidal anti-inflammatory drugs (NSAIDs) result in a synergistic inhibition of PCa cell growth and offers a potential therapeutic strategy. Mitogen activated protein kinase phosphatase 5 (MKP5) is a member of a family of phosphatases that are negative regulators of MAP kinases. Calcitriol induces MKP5 expression in prostate cells leading to the selective dephosphorylation and inactivation of the stress-activated kinase p38. Since p38 activation is pro-carcinogenic and is a mediator of inflammation, this calcitriol action, especially coupled with the inhibition of the PG pathway, contributes to the chemopreventive activity of calcitriol in PCa. Mullerian Inhibiting Substance (MIS) has been evaluated for its inhibitory effects in cancers of the reproductive tissues and is in development as an anti-cancer drug. Calcitriol induces MIS expression in prostate cells revealing yet another mechanism contributing to the anti-cancer activity of calcitriol in PCa. Thus, we conclude that calcitriol regulates myriad pathways that contribute to the potential chemopreventive and therapeutic utility of calcitriol in PCa.