Sandra Mendoza

The possible role of the kynurenine pathway in adolescent depression with melancholic features

BACKGROUND Although adolescent major depressive disorder (MDD) is acknowledged to be a heterogeneous disorder, no studies have reported on biological correlates of its clinical subgroups. This study addresses this issue by examining whether adolescent MDD with and without melancholic features (M-MDD and NonM-MDD) have distinct biological features in the kynurenine pathway (KP). The KP is initiated by pro-inflammatory cytokines via induction of the enzyme indoleamine 2,3-dioxygenase (IDO), which degrades tryptophan (TRP) into kynurenine (KYN). KYN is further metabolized into neurotoxins linked to neuronal dysfunction in MDD. Hypotheses were that, compared to healthy controls and to NonM-MDD adolescents, adolescents with M-MDD would exhibit: (i) increased activation of the KP [i.e., increased KYN and KYN/TRP (reflecting IDO activity)]; (ii) greater neurotoxic loads [i.e., increased 3-hydroxyanthranilic acid (3-HAA, neurotoxin) and 3-HAA/KYN (reflecting production of neurotoxins)]; and (iii) decreased TRP. We also examined relationships between severity of MDD and KP metabolites. METHODS Subjects were 20 adolescents with M-MDD, 30 adolescents with NonM-MDD, and 22 healthy adolescents. MDD episode duration had to be >or= 6 weeks and Childrens Depression Rating Scale-Revised (CDRS-R) scores were >or= 36. Blood samples were collected at AM after an overnight fast and analyzed using high-performance liquid chromatography. Group contrasts relied on analysis of covariance based on ranks, adjusted for age, gender, and CDRS-R scores. Analyses were repeated excluding medicated patients. Fishers protected least significant difference was used for multiple comparisons. RESULTS As hypothesized, KYN/TRP ratios were elevated and TRP concentrations were reduced in adolescents with M-MDD compared to NonM-MDD adolescents (p = .001 and .006, respectively) and to healthy controls (p = .008 and .022, respectively). These findings remained significant when medicated patients were excluded from the analyses. Significant correlations were obtained exclusively in the M-MDD group between KYN and 3-HAA/KYN and CDRS-R. CONCLUSIONS Findings support the notion that adolescent M-MDD may represent a biologically distinct clinical syndrome.

A method for the quantitation of hypericin, an antiviral agent, in biological fluids by high-performance liquid chromatography

Hypericin, a polycyclic aromatic dianthroquinone, is a natural plant product with antiviral properties. We report here the development of a methodology for the extraction and quantitation of hypericin from plasma and biological fluids and the adaptation of a sensitive and selective method for detection of the compound by high-performance liquid chromatography. The methodology offers a rapid and specific means of monitoring drug blood levels in clinical and pharmacokinetic studies. The chromatographic procedure utilizes the substantial retentive properties of hypericin on reverse-phase media and detection by the strong visible absorbance maximum at 590 nm. Verification by the fluorescence spectral properties of hypericin in organic media can also be utilized. The assay is linear over a 3 log concentration range and hypericin is consistently recovered from murine, simian, and human plasma. The methodology was applied to assess the pharmacokinetic properties of hypericin in mice receiving a single bolus injection of 350 micrograms. A distribution half-life of 2.0 h and an elimination half-life of 38.5 h were calculated. We also discuss the limitations of direct analysis of hypericin by absorbance or fluorescence measurements.

Kinetin improves IKBKAP mRNA splicing in patients with familial dysautonomia.

Familial dysautonomia (FD) is caused by an intronic splice mutation in the IKBKAP gene that leads to partial skipping of exon 20 and tissue-specific reduction in I-κ-B kinase complex-associated protein/elongation protein 1 (IKAP/ELP-1) expression. Kinetin (6-furfurylaminopurine) has been shown to improve splicing and increase WT IKBKAP mRNA and IKAP protein expression in FD cell lines and carriers. To determine whether oral kinetin treatment could alter mRNA splicing in FD subjects and was tolerable, we administered kinetin to eight FD individuals homozygous for the splice mutation. Subjects received 23.5 mg/Kg/d for 28 d. An increase in WT IKBKAP mRNA expression in leukocytes was noted after 8 d in six of eight individuals; after 28 d, the mean increase compared with baseline was significant (p = 0.002). We have demonstrated that kinetin is tolerable in this medically fragile population. Not only did kinetin produce the desired effect on splicing in FD patients but also that effect seems to improve with time despite lack of dose change. This is the first report of a drug that produces in vivo mRNA splicing changes in individuals with FD and supports future long-term trials to determine whether kinetin will prove therapeutic in FD patients.

Phase I Trial of Escalating Doses of Paclitaxel Plus Doxorubicin and Dexrazoxane in Patients With Advanced Breast Cancer

PURPOSE To determine the maximum-tolerable dose (MTD) of paclitaxel given as a 3-hour intravenous (IV) infusion that could be used in conjunction with doxorubicin and dexrazoxane, and to determine the effect of dexrazoxane on the pharmacokinetics of paclitaxel and doxorubicin. PATIENTS AND METHODS Twenty-five patients with advanced breast cancer received dexrazoxane (600 mg/m2 by IV infusion over 15 minutes), followed 15 minutes later by doxorubicin (60 mg/m2 IV), followed 15 minutes later by paclitaxel (150 or 175 mg/m2 by IV infusion over 3 hours) in cohorts of three to six patients using a standard phase I design without (group A) and with (group B) granulocyte colony-stimulating factor (G-CSF). Treatment continued until there was a substantial decrease in the left ventricular ejection fraction (LVEF), congestive heart failure, progressive disease, or physician discretion to discontinue. RESULTS The MTD of paclitaxel was 150 mg/m2, and adjunctive therapy with G-CSF was required to prevent febrile neutropenia. Dexrazoxane had no significant effect on the pharmacokinetics of paclitaxel or doxorubicin. After a median cumulative doxorubicin dose of 360 mg/m2 (range, 60 to 870 mg/m2), no patient developed congestive heart failure or had a decrease in LVEF below normal. An objective response occurred in all five patients with locally advanced breast cancer and in eight of 20 patients (40%; 95% confidence interval, 19% to 61%) with metastatic breast cancer. CONCLUSION When combined with doxorubicin (60 mg/m2) and dexrazoxane (600 mg/m2), paclitaxel given as a 3-hour infusion had an MTD of 150 mg/m2, and G-CSF was required to prevent febrile neutropenia. Dexrazoxane had no effect on the pharmacokinetics of paclitaxel or doxorubicin. No patient in this trial had a decrease in the LVEF below normal, compared with about 20% to 50% of patients treated with doxorubicin and paclitaxel without dexrazoxane in other trials.

The kynurenine pathway in adolescent depression: Preliminary findings from a proton MR spectroscopy study

BACKGROUND Cytokine induction of the enzyme indoleamine 2,3-dioxygenase (IDO) has been implicated in the development of major depressive disorder (MDD). IDO metabolizes tryptophan (TRP) into kynurenine (KYN), thereby decreasing TRP availability to the brain. KYN is further metabolized into several neurotoxins. The aims of this pilot were to examine possible relationships between plasma TRP, KYN, and 3-hydroxyanthranilic acid (3-HAA, neurotoxic metabolite) and striatal total choline (tCho, cell membrane turnover biomarker) in adolescents with MDD. We hypothesized that MDD adolescents would exhibit: i) positive correlations between KYN and 3-HAA and striatal tCho and a negative correlation between TRP and striatal tCho; and, ii) the anticipated correlations would be more pronounced in the melancholic subtype group. METHODS Fourteen adolescents with MDD (seven with melancholic features) and six healthy controls were enrolled. Minimums of 6 weeks MDD duration and a severity score of 40 on the Childrens Depression Rating Scale-Revised were required. All were scanned at 3T with MRI, multi-voxel 3-dimensional, high, 0.75 cm(3), spatial resolution proton magnetic resonance spectroscopic imaging. Striatal tCho concentrations were assessed using phantom replacement. Spearman correlation coefficients were Bonferroni-corrected. RESULTS Positive correlations were found only in the melancholic group, between KYN and 3-HAA and tCho in the right caudate (r=0.93, p=0.03) and the left putamen (r=0.96, p=.006), respectively. CONCLUSIONS These preliminary findings suggest a possible role of the KYN pathway in adolescent melancholic MDD. Larger studies should follow.

Abstract 4617: Hu177 cryptic epitope: A novel biomarker for the monitoring of treatment of ovarian cancer

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL Background: Distinct cryptic collagen epitopes are among the protein fragments exposed by collagen type IV remodeling, and recent data indicate that these cryptic epitopes may facilitate tumor migration and angiogenesis. In studies with melanoma patients we tested the hypothesis that melanoma can induce detectable changes in systemic levels of cryptic epitope shedding, specifically the HU177 epitope and were able correlate the levels of HU177 shedding with clinical and pathologic parameters (Ng et al Clin Can Res, 14:6253,2008). In addition in a follow-up study the increased shedding of the Hu177 epitope was shown to correlate with a worse prognosis in primary melanoma (Hamilton et al, J Trans Med8:19,2010). In this study we examined wether the serum levels of these unique cryptic epitopes may be useful to monitor, in a phase II study with ovarian patients, the course of the combination treatment of continuous infusion topotecan with erlotinib over multiple cycles of therapeutic intervention. Methods: We made use of our previously published ELISA serum assay (Ng et al) of which the key components involve the anchoring of the primary Hu177 directed antibody followed by blocking with albumin and then incubation with patient serum. The assay is further developed with a sandwich ELISA consisting of biotinylated anti-collagen IV and an anti-biotin antibody conjugated to horseradish peroxidase, followed by chromagenic color development. A parallel examination of the Hu177 epitope was also conducted with a humanized version of the Hu177 antibody (D93). Serial blood samples were monitored for weekly time periods ranging from 6-20 weeks from 5 patients enrolled in this study. Serum were collected and stored in multiple aliquots at –20oC. Results: All 5 patients demonstrated an eventual lowering of shed epitopes, with the time course for a sustained reduction varying with each patient. Once a nadir in the Hu177 epitope occurred it would last from 4-6 weeks. In one patient (KL) the nadir levels were the most sustained and developed late in the course of treatment who had remarkable decreased changes in CA125 that was previously rapidly increasing. This patient had platinum resistant peritoneal carcinomatosis without any dominant masses. Upon failure of topotecan erlotinib as demonstrated by rising markers and development of ascites and a pleural effusion, the shed epitopes rapidly recurred starting at week 18 of the treatment. Comparable serial data were found with the humanized D93 antibody although the sensitivity was more pronounced with the Hu177 antibody. Conclusions: Our interpretation is that this Hu177 determination may provide an indication of active invasion of extracellular matrix (such as in the peritoneum) and may be a useful indicator of a biological effect. We cannot exclude at this point that erlotinib may be contributing to such effects by changes in the matrix. Supported by a grant from the Chemotherapy Foundation Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4617. doi:1538-7445.AM2012-4617