Blood pressure-lowering effect of the sodium glucose co-transporter-2 inhibitor ertugliflozin, assessed via ambulatory blood pressure monitoring in patients with type 2 diabetes and hypertension

This study compared the blood pressure-lowering effect of ertugliflozin (1, 5, 25 mg), hydrochlorothiazide (HCTZ; 12.5 mg) and placebo in 194 patients with type 2 diabetes mellitus and hypertension for 4 weeks using ambulatory blood pressure monitoring. Endpoints (change from baseline to week 4) were: 24-h mean systolic blood pressure (SBP; primary); daytime, night-time, seated predose SBP, 24-h, daytime, night-time, seated predose diastolic blood pressure, 24-h urinary glucose excretion and fasting plasma glucose (FPG; secondary). Safety and tolerability were monitored. Significant decreases in placebo-corrected 24-h mean SBP (-3.0 to -4.0 mmHg) were recorded for all doses of ertugliflozin (for HCTZ, this was -3.2 mmHg). Daytime, but not night-time SBP was consistently reduced. Ertugliflozin produced dose-dependent significant decreases in FPG and increases in urinary glucose excretion. No notable changes in plasma renin activity or urinary aldosterone were seen. The most common adverse events were urinary tract infection, genital fungal infection, upper respiratory tract infection and musculoskeletal pain.

Dose-ranging efficacy and safety study of ertugliflozin, a sodium-glucose co-transporter 2 inhibitor, in patients with type 2 diabetes on a background of metformin

AIM

To investigate the efficacy and safety of ertugliflozin, in a phase II dose-ranging study, in patients with type 2 diabetes mellitus (T2DM) inadequately controlled on metformin.

METHODS

A total of 328 patients [mean T2DM duration, 6.3 years; mean glycated haemoglobin (HbA1c), 8.1%] were randomized to once-daily ertugliflozin (1, 5, 10, 25 mg), sitagliptin (100 mg) or placebo, for 12 weeks. The primary efficacy endpoint was change from baseline to week 12 in HbA1c concentration and the secondary efficacy endpoints were changes from baseline to week 12 in body weight, fasting plasma glucose (FPG) and systolic/diastolic blood pressure (SBP/DBP). Safety and tolerability were also monitored.

RESULTS

Ertugliflozin (1-25 mg/day) produced significant reductions in HbA1c concentration [placebo-corrected least-squares mean (LSM) -0.45% (1 mg) to -0.72% (25 mg); p ≤ 0.002, similar to sitagliptin (-0.76%; p = 0.0001)], FPG (LSM -1.17 to -1.90 mmol/l; p < 0.0001) and body weight (-1.15 to -2.15%; p < 0.0001). The LSM SBP decreased by -3.4 to -4.0 mmHg from baseline with ertugliflozin 5-25 mg/day. No reductions in body weight or blood pressure were observed with sitagliptin. After randomization, 2.7% of patients (9/328) withdrew because of adverse events (AEs); the frequency of AEs was evenly distributed across groups. No dose-related increase in AE frequency occurred with ertugliflozin. Hypoglycaemia was reported in 5 (1.5%) randomized participants (all in the ertugliflozin group). The frequency of urinary tract infection was 3.2% for ertugliflozin (pooled across groups), 1.8% for sitagliptin, 7.4% for placebo, and the frequency of genital fungal infections was 3.7% for ertugliflozin (pooled) versus 1.9% for placebo.

CONCLUSION

Ertugliflozin (1-25 mg/day) improved glycaemic control, body weight and blood pressure in patients with T2DM suboptimally controlled on metformin, and was well tolerated.

An anti-CD11/CD18 monoclonal antibody in patients with acute myocardial infarction having percutaneous transluminal coronary angioplasty (the FESTIVAL study)

Maximal benefits of coronary reperfusion after acute myocardial infarction (AMI) with ST-segment elevation may be attenuated by neutrophil-mediated reperfusion injury. Inflammatory mediators released from potentially viable myocytes cause activation of neutrophils, which traverse the endothelium and enter the myocardium. This process involves interaction between the neutrophil-expressed CD11/CD18 and endothelial-expressed intercellular adhesion molecule-1 (ICAM-1). Preclinical studies have shown that monoclonal antibodies (MAb) to CD18 can limit infarct size and preserve left ventricular function. We sought to determine the initial clinical safety and tolerability of Hu23F2G (LeukArrest), a humanized MAb to CD11/CD18, in patients with AMI who underwent percutaneous transluminal coronary angioplasty (PTCA). Sixty patients with AMI were randomized to low- (0.3 mg/kg) or high-dose (1.0 mg/kg) Hu23F2G or to placebo immediately before PTCA. We found no clinically significant differences in vital signs, physical examination, laboratory evaluation, or need for subsequent cardiac interventions. In Hu23F2G treatment groups, serum concentration of Hu23F2G increased rapidly to 3,234 +/- 1,298 microg/L (low-dose group) and 15,558 +/- 4409 microg/L (high-dose group) between 5 and 60 minutes, then declined over 72 hours to near-baseline values. Myocardial single-photon emission computed tomographic imaging 120 to 260 hours after PTCA showed no statistically significant differences in final left ventricular defect size. Hu23F2G was well tolerated, with no increase in adverse events, including infections. Thus, Hu23F2G appears safe and well tolerated in patients undergoing PTCA for AMI.

Pharmacogenomics: a clinician's primer on emerging technologies for improved patient care

Pharmacogenomics is a term recently coined to embody the concept of individualized and rational drug selection based on the genotype of a particular patient. Customization of drug therapy offers the potential for optimal safety and efficacy in an individual patient. Such a process contrasts current prescribing practices, which use medications shown to be safe and effective in patient populations or based on anecdotal experiences. Within patient populations, medications vary in their efficacy among individual patients. More importantly, a medication that is safe and effective in one patient may be ineffective or even harmful in another. Underlying many of these phenotypic differences are genotypic variants (polymorphisms) of key enzymes and proteins that affect the safety and efficacy of a drug in an individual patient. An understanding of these polymorphisms has the potential to enhance patient care by allowing physicians to customize the selection of medication to meet individual patient needs. Pharmacogenomics may also lead to improved compliance and shorter time to optimal disease management, thereby reducing morbidity and mortality. Significant cost savings could result from reductions in polypharmacy as well as from fewer physician encounters and hospitalizations for exacerbations of underlying illness and because of adverse drug reactions.

A targeted library of small-molecule, tyrosine, and dual-specificity phosphatase inhibitors derived from a rational core design and random side chain variation

Tyrosine phosphatases (PTPases) dephosphorylate phosphotyrosines while dual-specificity phosphatases (DSPases) dephosphorylate contiguous and semicontiguous phosphothreonine and phosphotyrosine on cyclin dependent kinases and mitogen-activated protein kinases. Consequently, PTPases and DSPases have a central role controlling signal transduction and cell cycle progression. Currently, there are few readily available potent inhibitors of PTPases or DSPases other than vanadate. Using a pharmacophore modeled on natural product inhibitors of phosphothreonine phosphatases, we generated a refined library of novel, phosphate-free, small-molecule compounds synthesized by a parallel, solid-phase combinatorial-based approach. Among the initial 18 members of this targeted diversity library, we identified several inhibitors of DSPases: Cdc25A, -B, and -C and the PTPase PTP1B. These compounds at 100 microM did not significantly inhibit the protein serine/threonine phosphatases PP1 and PP2A. Kinetic studies with two members of this library indicated competitive inhibition for Cdc25 DSPases and noncompetitive inhibition for PTP1B. Compound AC-alphaalpha69 had a Ki of approximately 10 microM for recombinant human Cdc25A, -B, and -C, and a Ki of 0.85 microM for the PTP1B. The marked differences in Cdc25 inhibition as compared to PTP1B inhibition seen with relatively modest chemical modifications in the modular side chains demonstrate the structurally demanding nature of the DSPase catalytic site distinct from the PTPase catalytic site. These results represent the first fundamental advance toward a readily modifiable pharmacophore for synthetic PTPase and DSPase inhibitors and illustrate the significant potential of a combinatorial-based strategy that supplements the rational design of a core structure by a randomized variation of peripheral substituents.

Enhanced apoptosis in metallothionein null cells

Metallothioneins (MTs) are major intracellular, zinc-binding proteins with antioxidant properties. Mouse embryonic cells null for MT due to loss of functional MT I and II genes (MT-/-) were more susceptible to apoptotic death after exposure to tert-butyl hydroperoxide or the anti-cancer agents cytosine arabinoside, bleomycin, melphalan, and cis-dichlorodiammineplatinum(II) compared with wild-type mouse embryonic cells (MT+/+). We measured basal levels of the tumor suppressor protein p53 and the death effector protein Bax and found the basal levels of both proteins were higher in MT null cells compared with MT+/+ cells. After treatment with the DNA-damaging agent cis-dichlorodiammineplatinum(II), p53 protein levels were induced in both MT+/+ and MT-/- cells with MT null cells always maintaining the highest p53 levels. The elevated sensitivity to apoptosis was not restricted to embryonic cells. Primary pulmonary fibroblasts were isolated from distinct litters of MT null, heterozygous, and wild-type mice, and all had undetectable basal MT levels. Zinc exposure increased MT levels in the wild-type and heterozygous fibroblasts but not in the MT null fibroblasts. Consistent with the induced MT levels, we found MT+/+ and MT+/- embryonic cells were less sensitive to cis-dichlorodiammineplatinum(II)-induced apoptosis compared with MT-/- cells. Our results implicate MT as a stress-responsive factor that can regulate apoptotic engagement.

The heat-shock response attenuates lipopolysaccharide-mediated apoptosis in cultured sheep pulmonary artery endothelial cells

We recently reported that lipopolysaccharide (LPS) induces apoptosis in cultured sheep pulmonary artery endothelial cells (SPAEC). Information about survival signals against this and other stimuli for endothelial cell apoptosis is limited to factors in the extracellular space. In other cell types, apoptosis is also affected by intracellular gene products. The heat-shock response is a highly conserved cellular stress response affording cytoprotection against a variety of cytotoxic conditions. Accordingly, we tested the hypothesis that prior induction of the heat-shock response would affect apoptosis in cultured SPAEC. Exposure of SPAEC to either heat (43 degrees C, 90 min) or sodium arsenite (100 microM, 90 min) induced expression of heat-shock protein-70 (HSP-70). LPS (0.1 microg/ml) treatment of SPAEC induced apoptotic morphology, cell detachment, high molecular weight (> 30 kb) DNA fragmentation, and internucleosomal DNA fragmentation. Prior induction of the heat-shock response attenuated LPS-mediated apoptosis, a protective event associated with a concomitant attenuation of rapid (within minutes) LPS-stimulated superoxide anion (O2.-) generation. Subsequent experiments involving transient overexpression of HSP-70, by direct gene transfer, suggest a direct role for HSP-70 in the attenuation of LPS-mediated apoptosis. We conclude that the heat-shock response is an intracellular survival signal against LPS-mediated apoptosis, and that the protective mechanism may involve HSP-70 directly, as well as inhibition of LPS-mediated O2.- generation.

Synthesis of chemoreversible prodrugs of ara-C with variable time-release profiles. Biological evaluation of their apoptotic activity

N4-Dipeptidyl slow-release forms of the anticancer drug ara-C were prepared by acylation of the lithiated nucleotide with 4,4-dialkyloxazolinones. An azapeptide prodrug of ara-C was obtained by condensation of an amino acid hydrazide with an activated nucleotide urea. The use of unnatural amino acid residues at N4 prevented nonspecific proteolytic cleavage in biological medium. Ara-C prodrugs 10, 15, 17, and 19 released active drug with half-lives from a few minutes to several days, respectively. Activation via intramolecular N4-deacylation did not require enzymatic intervention but was strictly dependent on the structure of the peptide chain. The prodrugs 10, 15, and 17 produced similar growth inhibition as ara-C in cultured murine leukemia cells while the azapeptide prodrug 19 was less potent reflecting the slow release of active drug with this compound. All four prodrugs retained the ability to induce apoptosis in human HL-60 leukemia cells with kinetics dictated by the rate of intramolecular N4-deacylation. This the first demonstration for the control of apoptotic cell death by the modulation of drug release from prodrugs.

Integrin activation suppresses etoposide-induced DNA strand breakage in cultured murine tumor-derived endothelial cells

Tumor endothelium is critical for solid tumor growth and is a potential site for anticancer drug action. Within 2 h, etoposide caused marked DNA strand breakage in xenograft tumor-derived endothelial cells (TDECs). Etoposide-induced DNA breakage was inhibited by culturing TDECs on gelatin, type IV collagen, laminin, fibronectin, and the integrin ligand hexapeptide, GRGDSP, but not the inactive peptide, GRADSP. It was also inhibited when TDECs were on surfaces coated with antibodies to alpha 5, beta 1, or beta 3 integrin subunits and by clustering integrins with soluble antibodies. After 8 h with etoposide, TDECs detached from the monolayer, and 50-kb DNA fragments were seen. Fibronectin inhibited both processes. Thus, integrins are survival factors for TDEC that inhibit the genotoxicity of etoposide and may influence the sensitivity of tumors to drugs.

Downregulation of protein kinase C suppresses induction of apoptosis in human prostatic carcinoma cells

Protein kinase C (PKC) has been implicated in propagating signals for apoptosis. We have investigated the effect of pharmacological modulation of PKC activity in DU-145 human androgen-independent prostatic carcinoma cells. The apoptotic death of these cells is characterized by the acquisition of classical apoptotic morphology and generation of > or = 1-mbp and 450- to 600-kbp DNA fragments in attached preapoptotic cell populations prior to cellular detachment and accrual of 30- to 50-kbp DNA fragments. We found that induction of apoptosis was arrested by downregulation of PKC activity and not by transient activation or inhibition of the enzyme. Concentrations and durations of exposure to phorbol esters that downregulated PKC activity correlated with inhibition of VP-16 or melphalan-induced morphological apoptosis and generation of the 30-to-50-kbp DNA fragments. Chronic exposure to phorbol-12,13-dibutyrate (PDBu) did not, however, suppress production of the > or = 1-mbp and 450- to 600-kbp DNA fragments found in preapoptotic cell populations, suggesting that PKC downregulation may interfere with the transition between a preapoptotic cell and an apoptotic cell. PKC isozyme analysis revealed that chronic PDBu treatment caused downregulation of PKC-alpha and -epsilon in DU-145 cells. Using concentrations of the PKC inhibitor UCN-01 that were consistent with PKC-alpha inhibition (but not PKC-epsilon inhibition), however, did not mimic the effects of chronic PDBu treatment, implying that downregulation of PKC-epsilon may be of particular importance. Together, these findings suggest that phorbol esters may act as tumor promoters by suppressing apoptosis.

Genesis of discrete higher order DNA fragments in apoptotic human prostatic carcinoma cells

Higher order DNA fragmentation may be an essential signal in apoptosis. We found that etoposide (VP-16) induced apoptosis in human DU-145 prostatic carcinoma cells in a time- and concentration-dependent manner. Chromatin condensation was morphologically evident only when cells detached from the monolayer; untreated or VP-16-treated attached cells retained a normal morphology. We describe a radiolabeled alu-I sequence-based quantitative field inversion gel electrophoresis (QFIGE) method that permitted observation and quantification of discrete high molecular weight DNA fragments in detached (apoptotic) and attached (preapoptotic) DU-145 cells. The DNA fragments generated during the apoptotic death of these cells were > or = 1 (mega-base pairs) mbp, 450-600 (kilo-base pairs) kbp, and 30-50 kbp; we observed that these DNA fragments increased 9 +/- 2-, 8 +/- 2-, and 25 +/- 11-fold versus control, respectively, with a 24-hr exposure to 30 microM VP-16 in attached cell populations. In detached VP-16-treated cells, there was accrual of 30-50-kbp DNA fragments with a concomitant loss of the > or = 1-mbp and 450-600-kbp fragments; internucleosomal DNA cleavage was never observed. This pattern of high molecular weight DNA fragmentation was inhibited by cycloheximide treatment and was common to other apoptotic agents, including melphalan and bleomycin. These findings suggest that the > or = 1-mbp and 450-600-kbp DNA fragments are products of endonuclease activation and are not topoisomerase II/DNA interactions. Finally, the generation of the 30-50-kbp DNA fragments may mediate chromatin condensation, which characterizes apoptosis.

Collagen is a survival factor against LPS-induced apoptosis in cultured sheep pulmonary artery endothelial cells

Lipopolysaccharide (LPS) causes direct pulmonary endothelial injury that can precipitate cell death. We investigated the ability of LPS to produce apoptosis in sheep pulmonary artery endothelial cells (SPAEC) grown in monolayer on plastic or collagen. When SPAEC were grown on plastic, LPS (100 ng/ml) caused internucleosomal DNA fragmentation (IDF) to 180- to 200-base pair ladders after 4 h. Higher-order chromatin damage, producing 50-kilobase DNA fragments, occurred within 2 h. Significant DNA strand breaks were seen in attached cells within 1 h incubation with > or = 1 ng LPS/ml, using in situ labeling by break extension (ISBE). DNA strand breakage in attached cells peaked after 2 h and remained elevated after 4 h. Detachment of SPAEC from the monolayer did not begin until 4 h. SPAEC cultured on collagen were protected from LPS-induced apoptosis; DNA damage measured by IDF, high-molecular-weight DNA fragmentation, and ISBE were suppressed. The protective effect of collagen was not due to inactivation of LPS. Thus LPS-induced apoptosis occurs in SPAEC after genotoxic damage and this process is suppressed by the extracellular matrix.

Multivariate models for predicting progression to AIDS and survival in human immunodeficiency virus-infected persons

Nine hundred thirty persons enrolled in the US Air Force Human Immunodeficiency Virus (HIV) Natural History Study were evaluated with a standard battery of 30 potential surrogate markers of disease progression. A risk score for predicting progression to AIDS was then calculated for each patient in the cohort by using the four highest-ranking variables from multivariate analysis: percentage of CD4 CD29 cells, anergy status, age, and hemoglobin. For predicting survival, beta 2-microglobulin replaced age in the Cox model. Stratification according to the risk score demonstrated that rates of progression to AIDS and survival were significantly different between risk groups (P < .0001). The novel combination of these markers results in extremely accurate risk scores, which may serve as the basis for the development of true surrogate markers of disease progression.

Differential induction of etoposide-mediated apoptosis in human leukemia HL-60 and K562 cells

Etoposide (VP-16) is one of several DNA-damaging agents that induce subcellular structural changes associated with apoptosis. VP-16 exerts its DNA-damaging and cytotoxic effects subsequent to interference with DNA topoisomerase II activity. VP-16 also stimulates c-jun and c-fos mRNA expression in some cell lines, including human leukemia K562 and HL-60 cells. To compare the temporal relationship between drug-induced c-jun expression and apoptosis, we examined cell morphology, cell viability, DNA integrity, and c-jun induction during VP-16 treatment of K562 and HL-60 cells. VP-16 (10 microM)-induced internucleosomal DNA damage and nuclear fragmentation were readily apparent within 6 hr in HL-60 cells but were absent in K562 cells treated for up to 24 hr. Some internucleosomal DNA damage was observed in K562 cells but only after treatment with 100 microM VP-16 for 24 hr. In contrast, VP-16-induced DNA single-strand breaks, VP-16-induced topoisomerase II/DNA covalent complex formation, and VP-16-mediated growth inhibition were similar in K562 and HL-60 cells. Also, the time course of VP-16-induced c-jun mRNA expression was comparable for both K562 and HL-60 cell lines. Western blot analysis of whole-cell lysates showed that Bcl-2 protein levels were 13-fold greater in HL-60 cells than in K562 cells. Thus, the resistance of VP-16-treated K562 cells to apoptosis was not attributable to protection by Bcl-2. Furthermore, the relatively high levels of Bcl-2 in HL-60 cells were not sufficient to protect these cells against apoptosis. Together, our results indicate that the temporal coupling of VP-16-induced DNA damage, c-jun expression, and apoptosis is cell type specific and suggest that different signaling pathways for apoptosis are operating in these two human leukemia cell lines.

False-positive rapid plasma reagin tests in human immunodeficiency virus infection and relationship to anti-cardiolipin antibody and serum immunoglobulin levels

The incidence of biologic false-positive rapid plasma reagin (RPR) tests may be increased in human immunodeficiency virus (HIV) infection; however, injecting drug use has not been excluded as the cause. Review of 3371 periodic syphilis serology results from 1077 HIV-seropositive patients in the United States Air Force HIV Natural History Study between January 1986 and June 1992 revealed a cumulative biologic false-positive RPR rate of 1%. Most (6/9) were transient low-titer results associated with a recent acute infectious process. False-positive RPR tests did not appear to correlate with anticardiolipin antibody levels or serum IgG or IgA levels, which are increased in HIV infection. Although not statistically significant, there was a trend toward higher IgM levels in patients with biologic false-positive tests. Thus, the incidence of false-positive RPR in an HIV-infected population with a low risk of injecting drug use is similar to that in the general population, and the mechanism may correlate with elevated serum IgM levels.

Clinical gnathostomiasis: case report and review of the English-language literature

Human gnathostomiasis is most frequently caused by the nematode Gnathostoma spinigerum. This disease is endemic to Southeast Asia, particularly Thailand and Japan. The clinical presentation is most commonly characterized by localized, intermittent, migratory swellings of the skin and subcutaneous tissues, often in association with localized pain, pruritus, and erythema. Since this worm can migrate to deeper tissues, any organ system may become involved. Characteristically, patients with gnathostomiasis have a moderate to severe elevation of the peripheral eosinophil count, with values not uncommonly exceeding 50% of the total white blood cell count. With modern-day travel and immigration, cases of gnathostomiasis are being diagnosed with increased frequency in the United States. Because of its rarity in this country, however, gnathostomiasis often is not included in an initial differential diagnosis despite the characteristic triad of intermittent migratory swelling, a history of travel to Southeast Asia, and eosinophilia. We report a case of cutaneous gnathostomiasis diagnosed in the United States, and we present a clinical review of the English-language literature on human gnathostomiasis.