The preclinical toxicology of salmeterol hydroxynaphthoate

An extensive toxicology programme on salmeterol hydroxynaphthoate (SereventTM), a marketed long-acting β2-adrenoceptor agonist, has been carried out. The studies evaluated both the local (respiratory tract) and systemic tolerance to single and repeated dosing, effects on all stages of reproduction, as well as the genotoxic and oncogenic potential. High acute doses were well tolerated and caused no specific target organ toxicity. In repeat dose studies, animals tolerated salmeterol very well both locally and systemically. No significant effects on the respiratory tract of dogs were seen and only minor laryngeal changes, typical of those occurring with many inhaled medicines, were noted in rats. The high systemic concentrations achieved resulted in a number of changes that are considered to be the result of excessive and prolonged β 2-adrenoceptor stimulation. These included tachycardia, skeletal muscle hypertrophy and minor haematological and blood biochemical changes in general toxicity studies, foetal effects in rabbit organogenesis studies and increased incidences of smooth muscle tumours of the mesovarium in the rat and of the uterus in the mouse oncogenicity studies. Salmeterol showed no evidence of any genotoxic potential. Results of the extensive toxicology programme provide good assurance of the safety for the inhaled use of salmeterol in patients; this has ben confirmed by many years of clinical experience during its development and marketing.

Roles and regulation of membrane-associated serine proteases

Pericellular proteolytic activity affects many aspects of cellular behaviour, via mechanisms involving processing of the extracellular matrix, growth factors and receptors. The serine proteases have exquisitely sensitive regulatory mechanisms in this setting, involving both receptor-bound and transmembrane proteases. Receptor-bound proteases are exemplified by the uPA (urokinase plasminogen activator)/uPAR (uPAR receptor) plasminogen activation system. The mechanisms initiating the activity of this proteolytic system on the cell surface, a critical regulatory point, are poorly understood. We have found that the expression of the TTSP (type II transmembrane serine protease) matriptase is highly regulated in leucocytes, and correlates with the presence of active uPA on their surface. Using siRNA (small interfering RNA), we have demonstrated that matriptase specifically activates uPAR-associated pro-uPA. The uPA/uPAR system has been implicated in the activation of the plasminogen-related growth factor HGF (hepatocyte growth factor). However, we find no evidence for this, but instead that HGF can be activated by both matriptase and the related TTSP hepsin in purified systems. Hepsin is of particular interest, as the proteolytic cleavage sequence of HGF is an 'ideal substrate' for hepsin and membrane-associated hepsin activates HGF with high efficiency. Both of these TTSPs can be activated autocatalytically at the cell surface, an unusual mechanism among the serine proteases. Therefore these TTSPs have the capacity to be true upstream initiators of proteolytic activity with subsequent downstream effects on cell behaviour.

Comparison of lipid lowering effect of sibutramine in patients treated or not treated with statins--3 month follow-up

Older sibutramine studies showed beneficial effects on lipid profile compared to placebo. However, nowadays many obese patients are treated with lipid lowering drugs before the start of sibutramine therapy and their effects in these patients have not been investigated. Therefore we started a long-term follow up of patients on sibutramine with or without previous and continuing statins. Here we present results of the first 3 months follow up of 11 patients on sibutramine 10 mg +statin group, and that of 13 patients on sibutramine 10 mg alone. Sibutramine led to the weight loss from 101.6 to 96.9 kg and in BMI from 36.35 to 34.66 kg/m2. Lipid profile changed thus: total cholesterol 4.97...5.01mmol/l (p = 0.7), LDL cholesterol 2.83...2.82 mmol/l mmol/l (p = 0.9), HDL cholesterol 1.13...1.27 mmol/l (p = 0.003), triglycerides 1.98...1.91 mmol/l (p = 0.01). Comparison between the 2 groups did not show any significant differences in lipid levels, patients react to sibutramine in the same way regardless to the concomitant statin therapy. We can therefore preliminarily conclude that sibutramine therapy has significant positive effect on the lipid profile even in patients who were started on statins prior to initiation of sibutramine treatment.

The effects of orlistat treatment interruption on weight and associated metabolic parameters

Due to the insurance companies' restrictions, partial reimbursement of orlistat treatment in the Czech Republic is restricted to obese diabetics with BMI >35 who are concurrently treated pharmacologically for dyslipidaemia, hypertension or ischaemic heart disease, with compulsory interruption of minimum 3 months, only after which the treatment can be resumed for another year. We evaluated 32 patients with Type 2 diabetes who underwent such course of treatment, with view of establishing whether the interruption has any detrimental effect on the success of the therapy in terms of weight loss and diabetes compensation. The treatment was well tolerated, producing statistically significant decrease in BMI and triglyceride levels during the first year, which was maintained in the second year. Fasting glucose levels were improved at nearly-significant level. The interruption in treatment between the first and second year had no marked detrimental effect, although the relative failure of the second treatment year to bring further benefits to the patients can certainly be at least partially attributed to this treatment gap.

L-Carnitine Supplementation does not Promote Weight Loss in Ovariectomized Rats Despite Endurance Exercise

In this five-week study, we tested the hypotheses that free access to a maintenance diet supplemented with L-carnitine (L-C) would reduce body fat in adult, sedentary, ovariectomized (OVX) rats, and that there would be an additive effect of L-C on weight reduction in swim-trained animals. As expected, serum carnitine was higher in rats fed the L-C diet, and the OVX-induced weight gain and abdominal fat were counteracted by swimming. L-C supplementation did not reduce the weight gain or abdominal fat in these adult female rats. Moreover, though not reaching statistical significance, rats that were fed L-C demonstrated a tendency for greater weight gain than their basal-fed counterparts despite no difference in energy intake. If the results of this study on ovariectomized rats can be translated to postmenopausal women, moderate intensity exercise may be recommended, but L-C supplementation, with no energy restriction, may be contraindicated as a weight loss method in this cohort.

Phytoestrogens are potent inhibitors of estrogen sulfation: implications for breast cancer risk and treatment

We investigated the ability of 37 flavonoids and flavonoid sulfoconjugates, including some abundant dietary constituents, to act as substrates and/or inhibitors of the sulfotransferase and sulfatase enzymes that interconvert active estrogens and inactive estrogen sulfates in human tissues. The enzymes studied include estrogen sulfotransferase, the thermostable phenolsulfotransferase that acts on a range of substrates including estrogens; steroid sulfatase; and two related enzymes, monoamine phenolsulfotransferase and arylsulfatase A. Several dietary flavonoids, including the soy isoflavones genistein and daidzein, were sulfated by these human sulfotransferases. Many flavonoids were potent inhibitors of thermostable phenolsulfotransferase. Genistein and equol were potent mixed inhibitors of hepatic estrogen sulfotransferase, with inhibitory constant values of 500 nM and 400 nM, respectively. Monoamine phenolsulfotransferase activity was relatively unaffected by flavonoids, but this enzyme was mainly responsible for the sulfation of flavonoids at concentrations greater than 1 micro M. Of the compounds tested, only daidzein 4,7-bisulfate, a trace metabolite in humans, significantly inhibited steroid sulfatase in the micromolar concentration range. Hence, dietary flavonoids may be able to influence the bioavailability of endogenous estrogens, and disrupt endocrine balance, by increasing the ratio of active estrogens to inactive estrogen sulfates in human tissues.

[Cytokines and soluble cytokine receptors in the perioperative period]

The common basis of systemic inflammatory response to surgical trauma is the activation of cytokine cascade, accompanied by the release of soluble cytokine receptors. The main cytokine axis stimulates the release of acute phase proteins (APP) form liver, modulates metabolic pathways and hormonal responses. The aim of this study was to assess characteristic changes in levels of pro- and anti-inflammatory cytokines in early post-op stages after a major intraabdominal surgery and to compare the results with dynamic changes in APP levels. The results will form a basis of evaluation of diagnostic value of certain cytokines and APP in post-operative complications.

SUBJECTS AND METHODS

Subjects fell into three categories: 1--patients after colonic resection for colorectal carcinoma I. and II. grade (N = 20), 2--patients after hemipancreatoduodenectomia (N = 17) and 3--control group of 18 healthy subjects. The levels of following parameters were measured between from one day before to three days after surgery: tumour necrosis factor-alpha, interleukin (IL)-1 beta, IL-1ra, IL-2, IL-6, IL-8, IL-10, soluble IL-2 receptors, C reactive protein (CRP) and alpha1-antitrypsin (AAT).

RESULTS

Measured parameters exhibited different dynamic changes in reaction to surgical trauma, according to their roles in immune reaction. Main pro-inflammatory cytokines culminated within 24 hours from the onset of surgery, marked elevations were noted in IL-1ra and the soluble IL-2 receptor. Both measured APP were rising until he 72nd hour post surgery, and their rise was markedly delayed compared to cytokines. The extent of immune reaction as measured by the amplitude of changes in both types of surgery was similar in most measured parameters, apart from marked difference in IL-2R. We also noted significant correlation of plasma levels of IL-6 and IL-1ra.

CONCLUSIONS

Surgical trauma as any other significant painful stimulus activates the pro-inflammatory cytokine axis with secondary response of APP. The release or pro-inflammatory cytokines, i.e. TNF-alpha, IL-1, IL-6 and IL-8 is synchronized with the release of antagonistic mediators (i.e. IL-1ra, IL-10, IL-2 and IL-6 soluble receptors), who precede the acceleration of APP production and thus modulate its extent. The evaluation of relationships between pro- and anti-inflammatory factors with regard to prognosis is confounded by unclear interpretation of their changes. The maximum effect of cytokines takes place at local autocrine and paracrine level and systemic levels do not reflect this. This is how we explain minimal changes in plasma levels of IL-1 beta and IL-2, despite their key role as initiators of cytokine cascade. In order to increase their diagnostic value the use a series of measurements is advocated in combination with other clinical and laboratory parameters of inflammation, such as the levels of acute phase proteins.

[Procalcitonin in the diagnosis of postoperative complications]

The dynamic changes in levels of procalcitonin (PCT), as well as other cytokines and acute phase proteins (APP) in post-operative stages reflect the systemic immune response, integrating perioperative infectious and non-infectious stimuli. This study evaluates PCT in context of 16 other inflammatory parameters in patients with different types of infectious post-operative complications. It analyses the specificity and sensitivity of PCT, cytokines and APP and their relationships during systemic inflammatory response.

SUBJECTS AND METHODS

The study involved the following groups of patients: those with confirmed bacterial sepsis, fulfilling the SIRS criteria (N = 28), those with limited infectious site at the wound (N = 16), those with post-operative pneumonia (N = 15) and a control group of N = 25. In 24-hour interval we assessed plasma levels of: PCT, TNF-alpha, IL-1 beta, IL-1ra, IL-6, IL-8, sIL-2R and a spectrum of APP.

RESULTS

PCT in patients with wound infection (1.4 +/- 0.31 ng/ml) and in those with pneumonia (0.7 +/- 0.30 ng/ml) does not rise above levels expected in uncomplicated post-op course (1.7 +/- 0.04 ng/ml), but it differs significantly in comparison to healthy controls (0.2 +/- 0.07 ng/ml). Initial levels of PCT as well as their maximum levels were significantly different in septic patients compared to other groups (p < 0.001). According to specificity and sensitivity tests PCT is the most significant marker for diagnosis of sepsis as opposed to uncomplicated post-operative course (AUC 0.91, CI 0.82-1.0).

CONCLUSION

Individual inflammatory parameters vary in sensitivity and specificity to causative stimulus. PCT when compared to major cytokines and APP reacts sensitively mainly to systemic stimuli accompanying bacterial infection, notably endotoxin. It is characterized by markedly lower sensitivity to non-bacterial stimuli (trauma of surgery) or localized bacterial inflammations. It is this behaviour that makes it a useful diagnostic tool in post-op courses. Unlike other parameters, PCT allows with sufficient sensitivity and specificity single-test diagnosis of initial sepsis.

[Weight reduction and aspects of the metabolic syndrome]

We carried out analysis of the influence of long-term weight reduction on individual parameters of metabolic syndrome X. We enrolled the total of 30 obese patients (22 with, 8 without syndrome X). During weight reduction, the mean BMI decreased by 4.08 +/- 3.00 kg/m2 leading to significant (p < 0.001) decrease in insulinaemia from 33.4 +/- 25.9 to 21.2 +/- 19.625 mu j/ml. In patients with syndrome X, the decrease in BMI of 3.50 +/- 2.76 kg/m2 was coupled with significant (p < 0.001) decrease in insulinaemia from 39.7 +/- 27.7 to 24.0 +/- 21.725 mu j/ml. Using cluster analysis of cases syndrome X patients formed two distinctive groups with different behaviour. It seems, that diagnosis of metabolic syndrome, based on arbitrary criteria, encompasses stable patients, in our study characterized by higher age and presence of hypertension, and volatile patients, who form somewhat transition stage between simple obesity and fully developed syndrome X. Moreover, relationships between individual parameters at the beginning of the study can elucidate the environmental influences (relationship between insulinaemia and hypertension), whereas those at the end of the study represent true pathogenetic relationships (insulinaemia and glycaemia) and relationships between syndrome X constituents (hypertension, hypertriglyceridaemia and decrease in HDL cholesterol).

A putative functional polymorphism in the IGF-I gene: association studies with type 2 diabetes, adult height, glucose tolerance, and fetal growth in U.K. populations

IGF-I has a critical role in growth and metabolism. A microsatellite polymorphism 1 kb upstream to the IGF-I gene has recently been associated with several adult phenotypes. In a large Dutch cohort, the absence of the commonest allele (Z) was associated with reduced serum IGF-I levels, reduced height, and an increased risk of type 2 diabetes and myocardial infarction. This result has not been replicated, and the role of this polymorphism in these traits in U.K. subjects is not known. We sought further evidence for the involvement of this variant in type 2 diabetes using a case-control study and IGF-I and diabetes-related traits in a population cohort of 640 U.K. individuals aged 25 years. Absence of the common allele was not associated with type 2 diabetes (odds ratio 0.70, 95% CI 0.47-1.04 for X/X versus Z/Z genotype, chi(2) test for trend across genotypes, P = 0.018). In the population cohort, the common allele (Z) was associated with decreased IGF-I levels (P = 0.01), contrary to the Dutch study, but not with adult height (P = 0.23), glucose tolerance (P = 0.84), oral glucose tolerance test-derived values of beta-cell function (P = 0.90), or insulin resistance (P = 0.66). There was no association with measures of fetal growth, including birth weight (P = 0.17). Our results do not support the previous associations and suggest that the promoter microsatellite is unlikely to be functionally important.

[Obesity, type 2 diabetes and their quantitative relation]

Diabetes type 2 and obesity are diseases which have marked mutual relations. The pathogenesis of these relations is in many respects obscure. Also the molecular biological knowledge of the two diseases is inadequate so far. In the submitted brief paper the authors present only a review of some quantitative aspects of the relationship of obesity and diabetes supplemented by some of their own results. The authors summarize the epidemiological relations of diabetes and obesity, possible prediction of the development of diabetes in obese subjects, possible prevention of diabetes in obese subjects and possible treatment of obese diabetics. Slight weight reduction, e.g. by using modern anti-obesity drugs is of fundamental importance for reducing the incidence of diabetes and for its treatment. Based on their own experience the authors present their own results of cluster and factor analysis for evaluating the links between diabetes and obesity with the metabolic syndrome. The authors' work similarly as work quoted in the discussion indicate that diabetes as well as obesity are beyond the so-called nucleus of the metabolic syndrome. Even slight body weight reduction by 5-10%, within the reach of everybody, influences in a fundamental way the incidence and compensation of diabetes as well as other components of the metabolic syndrome.

[Changes in levels of acute phase proteins in patients with central hypercortisolism]

BACKGROUND

Acute phase protein reaction depends on complex interaction of proinflammatory cytokines and hormones, especially glucocorticoids. Glucocorticoids are essential factors for hepatocellular microenvironment and proteosynthesis during both rest and inflammatory period. Cushing's disease represents a model of glucocorticoid hyperstimulation of acute phase protein synthesis without interleukin-6 and other cytokine influence.

METHODS AND RESULTS

20 patients (age of 38 +/- 11, 11 males, 9 females) with a diagnosis of central hypercorticolism were examined. Plasma levels of 11 acute phase proteins were estimated. These results were compared with plasma ACTH, interleukin-6, and U-cortisol concentrations and correlated to the control group (healthy volunteers, age 30 +/- 5, 13 males, 7 females). Plasma levels of albumin and prealbumin in patients with Cusing's disease were significantly lower. We proved significant elevation of alpha 1-acid glycoprotein, haemopexin, and fibrinogen compared with healthy subjects. The positive correlation of alpha 1-acid glycoprotein and U-cortisol (r = 0.51, p < 0.01), haemopexin and U-cortisol (r = 0.47, p < 0.05) respectively was found.

CONCLUSIONS

The interaction between glucocorticoids and proinflammatory cytokines in acute phase protein synthesis depends on permissive effects of corticoids on cytokine signal transduction in hepatocytes. However, our results document that corticoida themselves significantly stimulate acute phase protein synthesis, and this stimulation differs from inflammatory pattern of hepatic proteosynthesis.

Association studies of genetic variation in the WFS1 gene and type 2 diabetes in U.K. populations

Mutations in the WFS1 gene cause beta-cell death, resulting in a monogenic form of diabetes known as Wolfram syndrome. The role of variation in WFS1 in type 2 diabetes susceptibility is not known. We sequenced the WFS1 gene in 29 type 2 diabetic probands and identified 12 coding variants. We used 152 parent-offspring trios to look for familial association; the R allele at residue 456 (P = 0.04) and the H allele at residue 611 (P = 0.05) as well as the R456-H611 haplotype (P = 0.032) were overtransmitted to affected offspring from heterozygous parents. In a further cohort of 327 type 2 diabetic subjects and 357 normoglycemic control subjects, the H611 allele and the R456-H611 haplotype were present in more type 2 diabetic subjects than control subjects (one-tailed P = 0.06 and P = 0.023, respectively). In a combined analysis, the H611 allele was present in 60% of all diabetes chromosomes and 55% of all control chromosomes (odds ratio [OR] 1.24 [95% CI 1.03-1.48], P = 0.02), and the R456-H611 haplotype was significantly more frequent in type 2 diabetic subjects than in control subjects (60 vs. 54%, OR 1.29 [95% CI 1.08-1.54], P = 0.0053). Our results provide the first evidence that variation in the WFS1 gene may influence susceptibility to type 2 diabetes.