Amino acid differences between diabetic older adults and non-diabetic older adults and their associations with cardiovascular function

BACKGROUND

Ageing and insulin resistant states such as diabetes mellitus frequently coexist and increase the risk of cardiovascular disease development among older adults. Here we investigate metabolic differences in amino acid profiles between ageing and diabetes mellitus, and their associations with cardiovascular function.

METHODS

In a group of community older adults we performed echocardiography, cardiac magnetic resonance imaging as well as cross sectional and longitudinal metabolomics profiling based on current and archived sera obtained fifteen years prior to examination.

RESULTS

We studied a total of 515 participants (women 50%, n = 255) with a mean age 73 (SD = 4.3) years. Diabetics had higher alanine (562 vs 448, p < 0.0001), higher glutamate (107 vs 95, p = 0.016), higher proline (264 vs 231, p = 0.008) and lower arginine (107 vs 117, p = 0.043), lower citrulline (30 vs 38, p = 0.006) levels (μM) compared to non-diabetics. Over time, changes in amino acid profiles differentiated diabetic older adults from non-diabetic older adults, with greater accumulation of alanine (p = 0.002), proline (p = 0.008) and (non-significant) trend towards greater accumulation of glycine (p = 0.057) among the older diabetics compared to the older non-diabetics. However, independent of diabetes status, amino acids were associated with cardiovascular functions in ageing, [archived valine (p = 0.011), leucine (p = 0.011), archived isoleucine (p = 0.0006), archived serine (p = 0.008), archived glycine (p = 0.006) methionine (p = 0.003)] which were associated with impairments in E/A ratio.

CONCLUSION

Markers of branched chain amino acids and one ‑carbon metabolism pathways were associated with changes in cardiovascular function in older adults regardless of diabetes status. However, nitrogen handling pathways were specifically altered among older adults with diabetes. These findings broaden our understanding into specific amino acid pathways that may be altered between diabetic and non-diabetic older adults, and their relevance to cardiovascular function in ageing.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02791139.

Involvement of Lipids in Alzheimer's Disease Pathology and Potential Therapies

Lipids constitute the bulk of the dry mass of the brain and have been associated with healthy function as well as the most common pathological conditions of the brain. Demographic factors, genetics, and lifestyles are the major factors that influence lipid metabolism and are also the key components of lipid disruption in Alzheimer's disease (AD). Additionally, the most common genetic risk factor of AD, APOE ϵ4 genotype, is involved in lipid transport and metabolism. We propose that lipids are at the center of Alzheimer's disease pathology based on their involvement in the blood-brain barrier function, amyloid precursor protein (APP) processing, myelination, membrane remodeling, receptor signaling, inflammation, oxidation, and energy balance. Under healthy conditions, lipid homeostasis bestows a balanced cellular environment that enables the proper functioning of brain cells. However, under pathological conditions, dyshomeostasis of brain lipid composition can result in disturbed BBB, abnormal processing of APP, dysfunction in endocytosis/exocytosis/autophagocytosis, altered myelination, disturbed signaling, unbalanced energy metabolism, and enhanced inflammation. These lipid disturbances may contribute to abnormalities in brain function that are the hallmark of AD. The wide variance of lipid disturbances associated with brain function suggest that AD pathology may present as a complex interaction between several metabolic pathways that are augmented by risk factors such as age, genetics, and lifestyles. Herewith, we examine factors that influence brain lipid composition, review the association of lipids with all known facets of AD pathology, and offer pointers for potential therapies that target lipid pathways.

Abstract OT1-03-15: The METRIC trial: A randomized international study of the antibody-drug conjugate glembatumumab vedotin (GV or CDX-011) in patients with metastatic gpNMB-overexpressing triple-negative breast cancer (TNBC)

Background

Glycoprotein NMB (gpNMB) is an internalizable transmembrane protein overexpressed in approximately 20% of breast cancer (BC), including approximately 40% of TNBC. gpNMB is a poor prognostic marker in BC (Rose CCR 2010) and preclinically has been implicated in tumor invasion, metastasis, and angiogenesis. GV is a novel antibody-drug conjugate targeting the potent cytotoxin monomethylauristatin E (MMAE) to gpNMB overexpressing cancer cells.

In a Phase I/II study and the Phase II "EMERGE" study, GV demonstrated promising activity with TNBC patients (pts) deriving the greatest benefit and exhibiting the highest degree of gpNMB overexpression. GV was well-tolerated with the most frequent treatment-related toxicities consisting of rash, neutropenia, and neuropathy. In subset analyses of the EMERGE trial, objective response rate (ORR) was 30% (7/23) for GV vs. 9% (1/11) for investigator's choice in tumors with gpNMB overexpression (&gt;25% of tumor epithelium); 18% (5/28) vs. 0% (0/11) in TNBC; and 40% (4/10) vs. 0% (0/6) in gpNMB-overexpressing TNBC for GV and IC respectively, with apparent improvements in progression-free survival (PFS; hazard ratio (HR) = 0.11) and overall survival (OS; HR = 0.14).

Trial design

The METRIC Trial (NCT#01997333) is an international (USA, CA, Aus), two-arm phase II study. Pts are randomized 2:1 to GV (1.88 mg/kg IV q 21 days) or capecitabine, a current standard of care for this population (2,500 mg/m2 daily for d1-14, q21 days) until progression or intolerance. Crossover is not permitted.

Eligibility criteria

Key eligibility criteria include: &gt;25% of tumor epithelium gpNMB+ by central immunohistochemistry (IHC) screening of archival tissue; estrogen receptor and progesterone receptor &lt;10% and HER2 negative [0-1+ IHC, or ISH copy number &lt;4.0/ratio &lt;2.0] by local assessment; ECOG 0-1; taxane resistance; anthracycline exposure (if indicated); &lt;2 chemotherapy regimens for advanced BC; measurable disease; no persistent Grade &gt;2 toxicity.

Specific aims

The primary endpoint is PFS per independent, blinded central review committee according to RECIST 1.1. Secondary endpoints are ORR, duration of response, OS, safety, pharmacokinetics and pharmacodynamics. Exploratory endpoints are quality of life and/or cancer-related pain.

Statistical methods and target accrual

The trial has 85% power to detect a PFS HR of 0.64 with two sided α = 0.05. The hypothesized median PFS is 4.0 months for capecitabine and 6.25 months for GV. Target accrual is open for 300 pts.

Citation Format: Melisko M, Yardley DA, Blackwell K, Forero A, Ma C, Montero A, Daniel BR, Wright G, Fehrenbacher L, Chew H, Ferrario C, Nanda R, Seiler Jr M, Guthrie T, Vance K, Ouellette G, He Y, Bagley RG, Zhang J, Vahdat LT. The METRIC trial: A randomized international study of the antibody-drug conjugate glembatumumab vedotin (GV or CDX-011) in patients with metastatic gpNMB-overexpressing triple-negative breast cancer (TNBC). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr OT1-03-15.

Abstract P2-16-05: Efficacy of ABT-888 (veliparib) in patients with BRCA-associated breast cancer

Background: The potential for exploiting BRCA deficiencies with DNA repair inhibitors has both pre-clinical and clinical support. ABT-888 (veliparib), a DNA repair inhibitor initially thought to target Poly(ADP-Ribose) Polymerases (PARP), has demonstrated in vitro inhibition of BRCA1 and BRCA2 deficient mouse embryonic stell cells, with a larger effect on BRCA1 cells. We report on the pre-planned interim analysis of the efficacy of single agent veliparib in patients with either BRCA1 or BRCA2-associated stage IV breast cancer. Methods: BRCA 1 or 2 carrier patients with stage IV breast cancer, with measurable disease, without prior exposure to a PARP inhibitor or a platinum compound in the metastatic setting, were eligible. Velapirib was administered orally, at doses of 400 mg twice daily. Dose adjustments based on toxicity were permitted. Patients progressing on velapirib alone received carboplatin at an AUC of 5, IV, given Q 21 days, and velapirib 150 mg twice daily (the maximum tolerated dose [MTD] of the combination from our completed Phase I study: J Clin Oncol 30, 2012 [suppl; abstr 1024]). Patients were to be accrued from 7 NCI NO1- supported consortia. Initially 10 patients were to be accrued to each stratum (BRCA1 and BRCA2) to provide evidence of single agent activity. If there was sufficient activity to warrant consideration of velapirib as single agent therapy (defined as 2 or more confirmed partial [PR] or better responses out of 10 per stratum), an additional 12 patients would be accrued per stratum. Results: 20 evaluable patients (11 BRCA1 and 9 BRCA2 [1 in screening]) have been accrued, the majority with lung or liver as visceral metastatic sites of disease. Median age (range) is 46 (29-68) years. Tumors from 9 patients were hormone receptor positive. BRCA1 cohort: 4 of 11 patients are off treatment at a median of 2 months (1-4); 1 patient stopped velapirib due to toxicity (grade 2 rash/pruritus, grade 2 vomiting), 3 stopped for progressive disease (one with an unconfirmed PR). Seven patients are still on single agent veliparib with 1 unconfirmed PR, and 1 patient with two evaluations showing stable disease. BRCA2 cohort: 2 patients are off treatment at 2 months for progressive disease, 7 are still on treatment with 1 confirmed PR, and 3 unconfirmed PRs. Data on patients receiving combination of velapirib and carboplatin after progression is too early. Treatment-related toxicity is being updated and has so far been reported from 14 patients: 1 patient had grade 3 fatigue, 1 patient with liver metastasis had both grade 3 alanine aminotransferase elevation and grade 3 abdominal pain. Grade 2 toxicities occurring in more than 1 patient included nausea/vomiting (6 patients), chills (2 patients), and fatigue (2 patients). Conclusion: Velapirib has single agent activity in both BRCA1 and BRCA2-associated stage IV breast cancer patients, and is well-tolerated. Mature response, treatment, and toxicity data will be presented.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-16-05.

Clinical herbal interactions with conventional drugs: from molecules to maladies

Clinical studies and case reports have identified a number of herb-drug interactions potentiated by the concurrent use of herbal medicines with prescription drugs. The purpose of this paper is to discuss the mechanisms and clinical implications of such herb-drug interactions by reviewing published human studies. Both pharmacokinetic and pharmacodynamic components may be involved in herbdrug interactions, although metabolic induction or inhibition is a common underlying mechanism for many herb-drug interactions. Drugs that have a high potential to interact with herbal medicines usually have a narrow therapeutic index, including warfarin, digoxin, cyclosporine, tacrolimus, amitriptyline, midazolam, indinavir, and irinotecan. Many of them are substrates of cytochrome P450s (CYPs) and/or P-glycoprotein (P-gp). Herbal medicines that are reported to interact with drugs include garlic (Allium sativum), ginger (Zingiber officinale), ginkgo (Ginkgo biloba), ginseng (Panax ginseng), and St. John's wort (Hypericum perforatum). For example, garlic has been shown to increase the clotting time and international normalized ratio (INR) of warfarin, cause hypoglycaemia when taken with chlorpropamide, and reduce the area under the plasma concentration-time curve (AUC) and maximum concentration of saquinavir in humans. Similarly, case reports have demonstrated that ginkgo may potentiate bleeding when combined with warfarin or aspirin, increases blood pressure when combined with thiazide diuretics, and has even led to a coma when combined with trazodone, a serotonin antagonist and reuptake inhibitor used to treat depression. Furthermore, ginseng reduced the blood levels of warfarin and alcohol as well as induced mania if taken concomitantly with phenelzine, a non-selective and irreversible monoamine oxidase inhibitor used as an antidepressant and anxiolytic agent. Lastly, multiple herb-drug interactions have been identified with St. John's wort that involve significantly reduced AUC and blood concentrations of warfarin, digoxin, indinavir, theophylline, cyclosporine, tacrolimus, amitriptyline, midazolam, and phenprocoumon. The clinical consequence of herb-drug interactions varies, from being well-tolerated to moderate or serious adverse reactions, or possibly life-threatening events. Undoubtedly, the early and timely identification of herb-drug interactions is imperative to prevent potentially dangerous clinical outcomes. Further well-designed studies are warranted to address the mechanisms and clinical significance of important herb-drug interactions.

Vorinostat (suberoylanilide hydroxamic acid) as salvage therapy in metastatic breast cancer (MBC): A California Cancer Consortium phase II study

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Background: MBC patients (pts) have a median survival of 27 mo. Vorinostat is a small molecule inhibitor of histone deacetylase that exerts its targeted action during post-translational acetylation of core nucleosomal histones, affecting chromatin structure, thereby regulating genes implicated in cell survival, proliferation, differentiation, and apoptosis. The primary end point was to evaluate the response rate. Secondary endpoints included: time to progression, overall survival, toxicity, and assessment of biologic correlates. Method: From 6/05 to 3/06, we enrolled 14 pts with measurable MBC. Response and progression were evaluated using RECIST criteria. Two pts had no, 5 pts had one, and 7 pts had two prior regimens. Median age was 60.5 years (37- 89). Six were ER/PR positive, four were Her2neu overexpressers. Sites of metastatic disease included brain (1), liver, lungs, and bone (5), pelvic and chest wall (1), liver and bone (2), distant lymph nodes (3), pleura and bone (1). Pts received Vorinostat 200mg oral twice daily for 14 of 21 days per cycle. Tumor measurements were performed after every 2 cycles. Biopsies (pre and on-treatment) were collected from 6 of 14 pts. Results: The mean cycles delivered was 5 (range: 1–18). Four pts had SD for a median of >8.7 mo (4–13 mo); 1 pt with ER/PR/Her2neu negative tumor who received no prior treatment for MBC to mediastinal nodes and chest wall continues to receive treatment having completed cycle 18 with stable disease for >11.4 mo. The median duration on treatment for all pts is 3.2 mo (1–12 mo). Toxicities included gr 3 fatigue (1), gr 2–3 diarrhea (3), gr 2–3 nausea (2), gr 2 mucositis(1), gr 4 lymphopenia (1), gr 2–3 lymphopenia (6). Correlative studies of pre- and on-treatment tumor samples will be presented describing gene expression profiling using custom Agilent oligonucleotide microarrays optimized for analysis of RNA isolated from formalin fixed paraffin embedded tissues (FFPET). Conclusion: In this trial Vorinostat demonstrated disease stabilization rate in 4/14 (29%) pts by intention to treat analysis. With ease of administration, further investigation in combination with other agents is warranted. (NCI-NO1-CM- 62209)

No significant financial relationships to disclose.

Brca1 heterozygous mice have shortened life span and are prone to ovarian tumorigenesis with haploinsufficiency upon ionizing irradiation

BRCA1 mutation carriers have an 85% lifetime risk of breast cancer and 60% for ovarian cancer. BRCA1 facilitates DNA double-strand break repair, and dysfunction of BRCA1 leads to hypersensitivity to DNA damaging agents and consequently genomic instability of cells. In this communication, we have examined the tumor incidence and survival of Brca1 heterozygous female mice. Brca1 heterozygotes appear to have a shortened life span with 70% tumor incidence. Lymphoma, but not ovarian and mammary gland tumors, occurs commonly in these mice. After a whole-body exposure to ionizing radiation, Brca1 heterozygous mice have a 3-5-fold higher incidence specific to ovarian tumors, but not lymphoma, when compared with the Brca1+/+ mice. All the tumors from heterozygous mice examined retain the wild-type allele and the cancer cells express Brca1 protein, precluding the chromosomal mechanism for loss of heterozygosity of Brca1 locus. Although the manifestation of BRCA1 haploinsufficiency may be different between human and mouse, this study suggests that women carrying Brca1 mutations may be more prone to ovarian tumor formation after IR exposure than nonmutation carriers.

Polymorphisms of DNA-repair genes associated with clinical outcome in metastatic breast cancer (MBC) patients treated with gemcitabine/cisplatin (GC) (California Cancer Consortium)

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Background: DNA repair enzymes may play an important role in determining efficacy of chemotherapy in MBC. In particular, GC combination therapy may be dependent on activity of DNA repair enzymes in host cells, since cisplatin acts by inducing DNA damage. Cancer cells with increased DNA repair capacity may be resistant to GC, and specific genes may be responsible for this increased repair capacity. We examined whether polymorphisms in genes related to DNA repair were associated with clinical outcome in MBC patients treated with GC, enrolled in a parent phase II clinical trial (Ph II-14 A & B). Methods: Fifty-five patients with MBC were evaluated. Patients received the following regimen: 25 mg/m2 cisplatin on days 1–4; 1000 mg/m2 gemcitabine on days 2 and 8 of 21-day cycle. Thirteen polymorphisms in 10 cancer-related genes were tested for association with overall survival, time to tumor progression, and tumor response using a PCR RFLP based assay. Results: Of 55 patients evaluated, there were 17 responders (31%) and 33 non-responders (60%). Five patients (9%) inevaluable for response. Of 33 non-responders, 15 had stable disease, 18 had progressive disease. Median survival: 11.7 months with median follow-up 32.4 months for 4 patients alive at time of analysis. Median progression-free survival: 4.2 months. XPD Lys751Gln polymorphism was associated with overall survival and time to tumor progression (p=0.0003, p=0.006, respectively, log-rank test). Thirty-five patients carried Lys/Lys genotype, of which 29% resopnded. Fourteen patients carried Lys/Gln genotype, of which 54% resopnded. Five patients carried Gln/Gln genotype, with no responders. XRCC3 Thr241Met polymorphism was associated with time to tumor progression and tumor response (p=0.03, p=0.002, respectively). Eighteen patients had Met/Met genotype, of which 47% responded. Twenty-six patients had heterozygous genotype, of which 17% responded. Five patients had homozygous Thr/Thr, of which 100% responded. Conclusions: Our results suggest that polymorphisms in DNA repair genes XPD and XRCC3 may be important markers in predicting clinical outcome in MBC patients treated with GC. Supported by the following NCI grant: N01 CM1701.

[Table: see text]

Surface enhanced Raman scattering (SERS) by molecules adsorbed at spherical particles: errata

A model for Raman scattering by a molecule adsorbed at the surface of a spherical particle is articulated by treating the molecule as a classical electric dipole. This follows Moskovits's suggestion [J. Chem. Phys. 69, 4159 (1978)] and the experiments by Creighton et al. [J. Chem. Soc. Faraday Trans. II, 75, 790 (1979)] that such a system may exhibit SERS similar to that at roughened electrode surfaces. The molecule is stimulated by a primary field comprised of the incident and near-scattered fields. Emission consists of the dipole field plus a scattered field, each at the shifted frequency. Addition of feedback terms between the dipole and the particle makes only a negligible contribution to the fields. For pyridine adsorbed at the surface of a silver sphere, the 1010-cm(-1) band is enhanced by ~10(6) if the radius is much less than the wavelengths and the excitation wavelength is ~382 nm, a wavelength for which the relative refractive index of silver is close to m = radical2i. Detailed results are given for the effect upon the angular distribution and the polarization of the Raman emission of particle size, distance from the surface, excitation wavelength, and location of the molecule upon the surface. These results simulate those observed at roughened silver electrodes and suggest that the mechanism of SERS at those electrodes may resemble the electromagnetic mechanism elucidated here. We predict that comparable effects should be observed for fluorescent scattering.

Surface enhanced Raman scattering (SERS) by molecules adsorbed at spherical particles

A model for Raman scattering by a molecule adsorbed at the surface of a spherical particle is articulated by treating the molecule as a classical electric dipole. This follows Moskovits's suggestion [J. Chem. Phys. 69, 4159 (1978)] and the experiments by Creighton et al. [J. Chem. Soc. Faraday Trans. II, 75, 790 (1979)] that such a system may exhibit SERS similar to that at roughened electrode surfaces. The molecule is stimulated by a primary field comprised of the incident and near-scattered fields. Emission consists of the dipole field plus a scattered field, each at the shifted frequency. Addition of feedback terms between the dipole and the particle makes only a negligible contribution to the fields. For pyridine adsorbed at the surface of a silver sphere, the 1010-cm(-1) band is enhanced by ~10(6) if the radius is much less than the wavelengths and the excitation wavelength is ~382 nm, a wavelength for which the relative refractive index of silver is close to m = radical2i. Detailed results are given for the effect, upon the angular distribution and the polarization of the Raman emission, of particle size, distance from the surface, excitation wavelength, and location of the molecule upon the surface. These results simulate those observed at roughened silver electrodes and suggest that the mechanism of SERS at those electrodes may resemble the electromagnetic mechanism elucidated here. We predict that comparable effects should be observed for fluorescent scattering.

Raman and fluorescent scattering by molecules embedded in dielectric cylinders

Fluorescent and Raman scattering by molecules embedded in dielectric particles is strongly dependent on the morphology and optical properties of the particle and the distribution of active molecules within the particle. In this paper, the formalism is derived for the case where the scattering molecules are embedded in an infinite dielectric cylinder. Analytical results for the scattered fields are given for arbitrary angles of incidence. The general results, which involve an integral and a sum, are rather lengthy. Accordingly, the saddle-point method has been used to carry out the integration approximately. Numerical results are given for perpendicular incidence and for observation in the plane perpendicular to the cylinder axis, for single dipoles variously located within the cylinder, and for a uniform distribution of isotropic incoherent dipoles. The angular distribution and polarization of the scattered irradiance depends sensitively upon cylinder radius and refractive index, so that this effect must be considered if inelastic scattering signals are to be used as a diagnostic tool.

Elastic scattering of evanescent electromagnetic waves

Analytic and numerical results are given for the elastic scattering of evanescent electromagnetic waves by dielectric spheres. Some polarization and symmetry effects not found in Lorenz-Mie scattering are noted. The possibility of experimental studies is also discussed.

Light scattering and fluorescence by small particles having internal structure

We consider two related, yet distinct queries: 1. How does the internal morphology of a small particle affect the elastic light scattering signals? We have devised an algorithm, presently accurate for particles comparable only to small biological spheres (diameter less than 1 micron), which suggests that light scattering is sensitive to internal morphology only in the backward directions. Accordingly, observations should be obtained in these directions when probing for internal morphology. 2. How are fluorescent signals affected when the active molecules are variously distributed within small particles? One cannot assume that the fluorescent signals are simply proportional to the number of active molecules contained in the particle because there may also be a dependence upon the geometrical and optical properties of the particle and upon the particular spatial distribution of these molecules within the particle. Indeed, even the measured emission spectrum may be affected by such morphological features. Here, too, these calculations are mainly restricted to small particles (diameter less than 1 micron) in which the fluorescent molecules are isotropic and immobile. Under these conditions the effects are quite dramatic. These effects should be considered in quantitative procedures which utilize fluorescence for determining the concentration of specific molecules in small particles such as biological cells. They may provide a clue for discriminating among cells which differ morphologically or in which the spatial distribution of the fluorescent moiety differs. These effects may be minimized by utilizing a light source which is polarized perpendicularly to the scattering plane.

Light scattering in converging beams

Light scattering by spherical particles in a converging beam is obtained from the earlier solution for a particle in the beam of a dipole light source by reversing the direction of energy flow so that the dipole source becomes a sink. The results are not drastically different from Lorenz-Mie scattering as long as the sink is located at a distance greater than several particle radii from the focus.