Chlorination of antiviral drug ribavirin: Kinetics, nontargeted identification, and concomitant toxicity evolution

Residual antiviral drugs in wastewater may increase the risk of generating transformation products (TPs) during wastewater treatment. Therefore, chlorination behavior and toxicity evolution are essential to understand the secondary ecological risk associated with their TPs. Herein, chlorination kinetics, transformation pathways, and secondary risks of ribavirin (RBV), one of the most commonly used broad-spectrum antivirals, were investigated. The pH-dependent second-order rate constants k increased from 0.18 M-1·s-1 (pH 5.8) to 1.53 M-1·s-1 (pH 8.0) due to neutral RBV and ClO- as dominant species. 12 TPs were identified using high-resolution mass spectrometry in a nontargeted approach, of which 6 TPs were reported for the first time, and their chlorination pathways were elucidated. The luminescence inhibition rate of Vibrio fischeri exposed to chlorinated RBV solution was positively correlated with initial free active chlorine, probably due to the accumulation of toxic TPs. Quantitative structure-activity relationship prediction identified 7 TPs with elevated toxicity, concentrating on developmental toxicity and bioconcentration factors, which explained the increased toxicity of chlorinated RBV. Overall, this study highlights the urgent need to minimize the discharge of toxic chlorinated TPs into aquatic environments and contributes to environmental risk control in future pandemics and regions with high consumption of antivirals.

P21 resists ferroptosis in osteoarthritic chondrocytes by regulating GPX4 protein stability

Ferroptosis is involved in the pathogenesis of osteoarthritis (OA) while suppression of chondrocyte ferroptosis has a beneficial effect on OA. However, the molecular mechanism of ferroptosis in OA remains to be elucidated. P21, an indicator of aging, has been reported to inhibit ferroptosis, but the relationship between P21 and ferroptosis in OA remains unclear. Here, we aimed to investigate the expression and function of P21 in OA chondrocytes, and the involvement of P21 in the regulation of ferroptosis in chondrocytes. First, we demonstrated that high P21 expression was observed in the cartilage from OA patients and destabilized medial meniscus (DMM) mice, and in osteoarthritic chondrocytes induced by IL-1β, FAC and erastin. P21 knockdown exacerbated the reduction of Col2a1 and promoted the upregulation of MMP13 in osteoarthritic chondrocytes. Meanwhile, P21 knockdown exacerbated cartilage degradation in DMM-induced OA mouse models and decreased GPX4 expression in vivo. Furthermore, P21 knockdown sensitized chondrocytes to ferroptosis induced by erastin, which was closely associated with the accumulation of lipid peroxides. In mechanism, we demonstrated that P21 regulated the stability of GPX4 protein, and the regulation was independent of NRF2. Meanwhile, we found that P21 significantly affected the recruitment of GPX4 to linear ubiquitin chain assembly complex (LUBAC) and regulated the level of M1-linked ubiquitination of GPX4. Overall, our results suggest that P21 plays an essential anti-ferroptosis role in OA by regulating the stability of GPX4.

Right Ventricular Response to Cardiac Resynchronization Therapy: A Three-Dimensional and Speckle Tracking Echocardiographic Study

Cardiac resynchronization therapy (CRT) induces left ventricle reverse remodeling; however, its effects on right ventricular (RV) volumes and function were not well described. This study aimed to assess the effects of CRT on RV. Of 112 patients, 63 enrolled with a mean age of 62.77 ± 7.23 years, including 40 males (63.5%). All patients met criteria for CRT implantation and were followed at 3-month and 6-month intervals. Standard 2-dimensional/3-dimensional (3D) echocardiography and speckle-tracking analyses were conducted for assessment of LV and left atrium (LA). RV maximum diameters, tricuspid lateral annular systolic velocity, tricuspid annular plane systolic excursion, fractional area change, RV global (RV 4-chamber strain (RV4CSL), and RV free wall strain (RVFWSL), in addition to 3D echocardiographic assessment of RV, were done before CRT implantation and at follow-up visits. Mean follow-up period was 6.76 ± 1.25 months. A total of 48 patients (76.2%) were LV responders (LVR) whereas the rest were nonresponders (LVNR). Both groups had similar baseline characteristics, risk factors, device implantation, and programming values. Only LVR had significant reduction in RV basal diameter, together with significant improvement of RV systolic performance: systolic velocity, fractional area change, RV4CSL, RVFWSL, and 3D-derived RV volumes and ejection fraction, compared with baseline values. In addition, pulmonary arterial systolic pressure decreased in LVR with reduction of tricuspid regurgitation severity. LV response, percentage change of RV4CSL, LA end-systolic volume index, and LA emptying fraction at 3-month follow-up were the most independent predictors of RV response by multivariate analysis. Reduced left ventricular end-systolic volume >13.5% had 92.3% sensitivity and 81.8% specificity. In conclusion, CRT-induced RV reverse remodeling and improved RV-arterial coupling. These effects were associated with left side response to CRT.

Taxane for Operable Breast Cancer Patients in Indonesia

BACKGROUND

Breast cancer is the deadliest cancer among women worldwide including Indonesia. Both FAC and Taxane-based chemotherapies are often used for patients with early node-positive breast cancer. However, the study regarding the cost-effectiveness of those regiments is still rare. This study aims to analyze the cost-effectiveness of Taxane versus FAC in the Indonesia setting.

METHODS

Twenty-four patients with stage I-IIIA breast cancer who had received surgery, FAC or Taxane-based adjuvant chemotherapy, and radiation were included in this study. Health-related quality of life was assessed using INA-BCHRQoL. INA-BCHRQoL was mapped to the EuroQoL 5D (EQ-5D) index calculator to get the utility score. All direct cost was retrieved from electronic medical records and hospital information system. Whereas, a questionnaire was designed to collect information about society cost from patients. ICER was counted to summarize the cost-effectiveness of two chemotherapy regiments (Taxane versus FAC). A sensitivity analysis was done to assess the uncertainty result.

RESULTS

The results showed there was no significant difference between the score of quality of life and utility in respondents who received FAC chemotherapy and Taxane-based chemotherapy. However, in terms of cost, Taxane was 6.5 times higher than the FAC group per patient for chemotherapy drugs only. Moreover, the total cost of treatments in Taxane-based chemotherapy was approximately 3.7 times more costly than the counterpart in the FAC arm (p=0.000). Taxane-based chemotherapy dominated with ICER IDR 765.213.092 per QALY gained. Overall, FAC was found more cost-effective compared to the Taxane regiment.

CONCLUSION

FAC represents the value of money compared to Taxane-based for breast cancer patients with stage I-IIIA in Indonesia.

Characterization of cells expressing MRI reporters for the analysis of epigenetics

Epigenetics is thought to be involved in highly advanced life phenomena, and its regulation has created new opportunities in regenerative medicine. Mintbody (modification-specific intracellular antibody) can track a posttranslational protein modification in epigenetics using a genetic system encoded within a single chain of variable fragments tagged with a fluorescent protein. Magnetic resonance imaging (MRI) is a technique that allows observation of specific molecules in living organisms. The ferritin heavy chain (FTH1) is one of the MRI reporters used in mammals. The combination of FTH1 with mintbody may show remarkable ability as a reporter for MRI to investigate epigenetics in the deep part of a living organism. This article discusses the suitability and safety of FTH1 for use in the analysis of epigenetics by MRI. Cells expressing the FTH1 hybrid of mintbody showed insufficiently increased sensitivity by MRI even in the presence of excess iron. After incubation with ferric ammonium citrate, DNA damage was found in cells expressing the FTH1 hybrid of mintbody. The use of FTH1 as a genetically encoded reporter for MRI appears to be limited by the requirement of metal and its relatively low sensitivity. These results suggest future directionality and the possibility of studying epigenetics in vivo.

Prognostic Value of Echocardiographic Right Ventricular Function Parameters in the Presence of Severe Tricuspid Regurgitation

Background: Presence of severe tricuspid regurgitation (TR) has a significant impact on assessment of right ventricular function (RVF) in transthoracic echocardiography (TTE). High trans-valvular pendulous volume leads to backward-unloading of the right ventricle. Consequently, established cut-offs for normal systolic performance may overestimate true systolic RVF. Methods: A retrospective analysis was performed entailing all patients who underwent TTE at our institution between 1 January 2013 and 31 December 2016. Only patients with normal left ventricular systolic function and with no other valvular lesion were included. All recorded loops were re-read by one experienced examiner. Patients without severe TR (defined as vena contracta width ≥7 mm) were excluded. All-cause 2-year mortality was chosen as the end-point. The prognostic value of several RVF parameters was tested. Results: The final cohort consisted of 220 patients, 88/220 (40%) were male. Median age was 69 years (IQR 52–79), all-cause two-year mortality was 29%, median TAPSE was 19 mm (15–22) and median FAC was 42% (30–52). In multivariate analysis, TAPSE with the cutoff 17 mm and FAC with the cutoff 35% revealed non-significant hazard ratios (HR) of 0.75 (95%CI 0.396–1.421, p = 0.38) and 0.845 (95%CI 0.383–1.867, p = 0.68), respectively. TAPSE with the cutoff 19 mm and visual eyeballing significantly predicted survival with HRs of 0.512 (95%CI 0.296–0.886, p = 0.017) and 1.631 (95%CI 1.101–2.416, p = 0.015), respectively. Conclusions: This large-scale all-comer study confirms that RVF is one of the main drivers of mortality in patients with severe isolated TR. However, the current cut-offs for established echocardiographic parameters did not predict survival. Further studies should investigate the prognostic value of higher thresholds for RVF parameters in these patients.

Combination of Simvastatin and FAC Improves Response to Neoadjuvant Chemotherapy in Advanced Local Breast Cancer

Purpose

The efficacy of neoadjuvant chemotherapy for locally advanced breast cancer (LABC) is limited due to drug resistance and cardiotoxic effects. Preclinical studies have shown that statin induces apoptosis and decreases breast cancer cell growth. This study aims to evaluate the role of statin in combination with fluorouracil, adriamycin, and cyclophosphamide (FAC) therapy in LABC patients.

Materials and Methods

We undertook a randomized, double-blinded, placebo-controlled trial in two centers of Indonesia. Patients were randomly assigned to FAC plus simvastatin (40 mg/day orally) or FAC plus placebo (40 mg/day) for 21 days. The FAC regimen was repeated every 3 weeks. We evaluated the clinical response, pathological response, and toxicities.

Results

The objective response rate (ORR) for FAC plus simvastatin was 90% (95% confidence interval [CI], 0.99 to 1.67) by per-protocol analysis. No complete responses (CR) were recorded, but there were 48 partial responses. No significant difference was observed between the two groups with the ORR (p=0.103). The pathological CR rate was 6.25% (2 in simvastatin group and 1 in placebo group). Adverse events in both arms were generally mild, mainly consisted of myotoxicity. Human epidermal growth factor receptor 2 (HER2) expression was a factor related to the success of therapeutic response (odds ratio, 4.2; 95% CI, 1.121 to 15.731; p=0.033).

Conclusion

This study suggests that simvastatin combined with FAC shows improvements in ORR and pathological response in patients with LABC. Although no statistically significant difference was documented, there was a trend for better activity and tolerability. The addition of 40 mg simvastatin may improve the efficacy of FAC in LABC patients with HER2 overexpression.

Responsiveness and Minimal Clinically Important Difference of the Five Times Sit-to-Stand Test in Patients with Stroke

This study aimed to analyze the responsiveness of the 5STS test among stroke patients and to estimate the MCIDs (minimal clinically important differences) for different severity levels of community ambulation and stages of recovery. The 5STS and comparator instruments (gait speed and Functional Ambulatory Category (FAC)) were evaluated at baseline. These measures were repeated at 4 (Stage 1) and 8 weeks (Stage 2), together with the Global Rating of Change (GROC). The MCIDs were calculated with two anchor-based methods using the GROC as the external criterion. Responsiveness to change for the 5STS was estimated analyzing the correlation with changes in the two comparator instruments and their capacity to discriminate improvement. For the 5STS test, while the MCIDs of the limited community ambulators were similar in the two stages (around 3 s), those of the household ambulators decreased from 1.9 s to 0.72 s. Spearman’s rho coefficients showed an acceptable correlation between changes in 5STS and changes for both the FAC and gait speed changes in both stages of recovery. Our study revealed that the 5STS is responsive to functional changes in patients with stroke and that their degree of severity and stage of recovery influence the MCID values of the 5STS.

Changes in Right Ventricular Function After Off-Pump Coronary Artery Bypass Grafting

OBJECTIVE

Right ventricular (RV) dysfunction is associated with poor outcomes after cardiac surgery. The aim of this study was to assess RV systolic and diastolic function in the perioperative period after off-pump coronary artery bypass grafting (OPCAB).

DESIGN

Prospective observational study.

SETTINGS

Tertiary care hospital.

PARTICIPANTS

Thirty adult patients undergoing OPCAB.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Transthoracic echocardiography was performed twice: first preoperatively and second postoperatively, when patients were moved to wards. The following five parameters of RV systolic function were used: tricuspid annular plane systolic excursion (TAPSE), systolic tissue Doppler imaging of lateral tricuspid annulus (S'), fractional area change (FAC), RV myocardial performance index (RIMP), and isovolumic acceleration (IVA). Grading of RV diastolic function (RVDD) was done as per guidelines. Paired t test was used for comparing means and χ² test was used for categorical and ordinal data. The parameters of RV longitudinal function (TAPSE and S') reduced significantly (preoperative 21.93 ± 2.80 mm and 13.24 ± 2.24 cm/s to postoperative 11.67 ± 1.91 mm and 10.31 ± 1.56 cm/s, respectively, p < 0.001), whereas parameters of RV global function (FAC, RIMP, and IVA) remained preserved (preoperative 46.75 ± 6.80%, 0.34 ± 0.06, and 4.66 ± 0.87 m/s² to postoperative 46.21 ± 6.44%, 0.36 ± 0.06, and 4.37 ± 0.83 m/s²; p values of 0.76, 0.13, and 0.11, respectively). The median grade of RVDD worsened from normal in the preoperative period to pseudo-normal in the postoperative period (p < 0.001). The changes in both RV systolic and diastolic function were similar in patients with normal and reduced left ventricular systolic function.

CONCLUSIONS

RV function can be assessed in perioperative settings with two-dimensional and tissue Doppler imaging. For systolic function assessment, exclusive measurement of longitudinal parameters might be inadequate; use of complementary global parameters like FAC, RIMP, and IVA is essential to complete the RV assessment after OPCAB. RVDD worsened significantly after OPCABG.

Frontal Affinity Chromatography: A Highly Suitable Retardation Phenomenon-Based Research Tool for Analyzing Weak Interactions Between Biomolecules

The greatest advantage of frontal affinity chromatography (FAC) is that the analyte concentration does not need to be taken into consideration, and this renders FAC an extremely favorable analytical tool for weak interactions. In this short review, we propose a straightforward explanation of the underlying mechanism. When FAC is performed using analyte solutions at relatively high concentrations, concentration-dependent retardation is observed due to competition among analyte molecules, and the elution volume changes depending on the degree of saturation of the immobilized ligand.However, when the analyte concentration is very low, no competition occurs among the analytes, and the elution volume reaches a constant value, which reflects the proportion of bound state to free state of a single analyte molecule. Therefore, the binding strength can be determined using a minimum analyte concentration.

Direct measurements of ferric reductase activity of human 101F6 and its enhancement upon reconstitution into phospholipid bilayer nanodisc

We studied human 101F6 protein to clarify its physiological function as a ferric reductase and its relationship to tumor suppression activity. We found for the first time that purified 101F6 both in detergent micelle state and in phospholipid bilayer nanodisc state has an authentic ferric reductase activity by single turnover kinetic analyses. The kinetic analysis on the ferrous heme oxidation of reduced 101F6 upon the addition of a ferric substrate, ferric ammonium citrate (FAC), showed concentration-dependent accelerations of its reaction with reasonable values of K_M and V_max. We further verified the authenticity of the ferric reductase activity of 101F6 using nitroso-PSAP as a Fe²⁺-specific colorimetric chelator. 101F6 in nanodisc state showed higher efficiency for FAC than in detergent micelle state.

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Human tumor suppressor 101F6 protein was reconstituted into nanodisc.

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101F6 functions as a ferric reductase both in detergent micelle and in nanodisc.

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101F6 in nanodisc showed higher efficiency in the reductase activity.

Doxorubicin Is Key for the Cardiotoxicity of FAC (5-Fluorouracil + Adriamycin + Cyclophosphamide) Combination in Differentiated H9c2 Cells

Currently, a common therapeutic approach in cancer treatment encompasses a drug combination to attain an overall better efficacy. Unfortunately, it leads to a higher incidence of severe side effects, namely cardiotoxicity. This work aimed to assess the cytotoxicity of doxorubicin (DOX, also known as Adriamycin), 5-fluorouracil (5-FU), cyclophosphamide (CYA), and their combination (5-Fluorouracil + Adriamycin + Cyclophosphamide, FAC) in H9c2 cardiac cells, for a better understanding of the contribution of each drug to FAC-induced cardiotoxicity. Differentiated H9c2 cells were exposed to pharmacological relevant concentrations of DOX (0.13–5 μM), 5-FU (0.13–5 μM), CYA (0.13–5 μM) for 24 or 48 h. Cells were also exposed to FAC mixtures (0.2, 1 or 5 μM of each drug and 50 μM 5-FU + 1 μM DOX + 50 μM CYA). DOX was the most cytotoxic drug, followed by 5-FU and lastly CYA in both cytotoxicity assays (reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and neutral red (NR) uptake). Concerning the equimolar combination with 1 or 5 μM, FAC caused similar cytotoxicity to DOX alone. Even in the presence of higher concentrations of 5-FU and CYA (50 μM 5-FU + 1 μM DOX + 50 μM CYA), 1 μM DOX was still a determinant for the cardiotoxicity observed in the cytotoxicity assays, phase contrast morphological evaluation, and mitochondrial potential depolarization evaluation. To the best of our knowledge, this was the first in vitro work with this combination regimen, DOX being the most toxic drug and key to the toxicity of FAC.

In Vitro and In Vivo Comparison of Gemcitabine and the Gemcitabine Analog 1-(2'-deoxy-2'-fluoroarabinofuranosyl) Cytosine (FAC) in Human Orthotopic and Genetically Modified Mouse Pancreatic Cancer Models

PURPOSE

Although gemcitabine is a mainstay of pancreatic cancer therapy, it is only moderately effective, and it would be desirable to measure drug uptake in patients. 1-(2'-deoxy-2'-fluoroarabinofuranosyl) cytosine (FAC), is an analog of gemcitabine, and when labeled with F-18, it may be a potential surrogate PET tracer for the drug.

PROCEDURES

[¹⁸F]FAC was synthesized to a radiochemical purity of >96 %. The human tumor lines AsPC1, BxPC3, Capan-1, Panc1, and MiaPaca2 were grown orthotopically in nude mice. KPC mice that conditionally express oncogenic K-ras and p53 mutations in pancreatic tissue were also used. The intra-tumoral distributions of [¹⁴C]gemcitabine and [¹⁸F]FAC were mapped with autoradiography. The inter-tumor correlation between [¹⁴C]gemcitabine and [¹⁸F]FAC was established in the orthotopic tumors. Expression of the equilibrative and concentrative nucleoside transporters (ENT, CNT) in vitro was detected by western blotting. Drug uptake was characterized in vitro using [³H]gemcitabine and the effect of transporter inhibition on gemcitabine and FAC uptake was investigated. The relative affinity of cells for gemcitabine and FAC was tested in competition assays. The cell lines differed in sensitivity to transport inhibitors and in competition studies. There was a good in vivo correlation between the total uptake of [¹⁸F]FAC and [¹⁴C]gemcitabine, measured across all orthotopic tumors. Using the KPC and BxPC3 models, we found that [¹⁴C]gemcitabine and [¹⁸F]FAC were largely co-localized.

CONCLUSIONS

In the lines examined here, [¹⁸F]FAC uptake correlates well with gemcitabine in vivo, supporting the notion that [¹⁸F]FAC can serve as a PET radiotracer surrogate to determine the uptake and distribution of gemcitabine within pancreatic tumors.

An insight into metastasis: Random or evolving paradigms?

Mechanical or fostered molecular events define metastatic cascade. Three distinct sets of molecular events characterize metastasis, viz invasion of extracellular matrix; angiogenesis, vascular dissemination and anoikis resistance; tumor homing and relocation of tumor cells to selective organ. Invasion of extracellular matrix requires epithelial to mesenchymal transition through disrupted lamellopodia formation and contraction of actin cytoskeleton; aberration of Focal adhesion complex formation involving integrins and the extracellular matrix; degradation of extracellular matrix by matrix metalloproteases; faulty immune surveillance in tumor microenvironment and an upregulated proton efflux pump NHE1 in tumors. Vascular dissemination and anoikis resistance depend upon upregulation of integrins, phosphorylation of CDCP1, attenuated apoptotic pathways and upregulation of angiogenesis. Tumor homing depends on recruitment of mesenchymal stem cells, expression on chemokines and growth factors, upregulated stem cell renewal pathways. Despite of many potential challenges in curbing metastasis, future targeted therapies involving immunotherapy, stem cell engineered and oncolytic virus based therapy, pharmacological activation of circadian clock are held promising. To sum up, metastasis is a complex cascade of events and warrants detailed molecular understanding for development of therapeutic strategies.

Genetic polymorphisms and response to 5-fluorouracil, doxorubicin and cyclophosphamide chemotherapy in breast cancer patients

Clinical resistance to chemotherapy is one of the major problems in breast cancer treatment. In this study we analyzed possible impact of 22 polymorphic variants on the treatment response in 324 breast cancer patients. Selected genes were involved in FAC chemotherapy drugs transport (ABCB1, ABCC2, ABCG2, SLC22A16), metabolism (CYP1B1, CYP2C19, GSTT1, GSTM1, GSTP1, TYMS, MTHFR, DPYD), drug-induced damage repair (ERCC1, ERCC2, XRCC1) and involved in regulation of DNA damage response and cell cycle control (ATM, TP53).

Apart from preexisting metastases three polymorphic variants were independent prognostic high risk factors of lack of response to FAC chemotherapy. Our results showed that the response to treatment depended of the variability in genes engaged in drugs’ transport (ABCC2 c.-24C>T, ABCB1 p.Ser893Ala/Thr) and in DNA repair machinery (ERCC2 p.Lys751Gln). Furthermore, the growing number of high-risk genotypes was reflected in gradual increase in risk of the non-responsiveness to treatment- from OR 2.68 for presence of two genotypes to OR 9.93 for carriers of all three negative genotypes in the group of all patients. Similar gene-dosage effect was observed in the subgroup of TNBCs. Also, TFFS significantly shortened with the increasing number of high-risk genotypes, with median of 54.4 months for carriers of one variant, to 51.5 and 34.9 months for the carriers of two and three genotypes, respectively.

Our results demonstrate that results of cancer treatment are the effect of many clinical and genetic factors. It seems that multifactorial polymorphic models could be a potentially useful tool in personalization of cancer therapies. The novelty in our model is the over representation of triple negative breast cancer (TNBC) patients among the carriers of all unfavorable polymorphic variants. This finding contributes to the elucidation of the mechanisms of drug resistance in this subgroup of breast cancer patients.

Pharmacogenetics of toxicity of 5-fluorouracil, doxorubicin and cyclophosphamide chemotherapy in breast cancer patients

The differences in patients' response to the same medication, toxicity included, are one of the major problems in breast cancer treatment. Chemotherapy toxicity makes a significant clinical problem due to decreased quality of life, prolongation of treatment and reinforcement of negative emotions associated with therapy. In this study we evaluated the genetic and clinical risk factors of FAC chemotherapy-related toxicities in the group of 324 breast cancer patients. Selected genes and their polymorphisms were involved in FAC drugs transport (ABCB1, ABCC2, ABCG2,SLC22A16), metabolism (ALDH3A1, CBR1, CYP1B1, CYP2C19, DPYD, GSTM1, GSTP1, GSTT1, MTHFR,TYMS), DNA damage recognition, repair and cell cycle control (ATM, ERCC1, ERCC2, TP53, XRCC1). The multifactorial risk models that combine genetic risk modifiers and clinical characteristics were constructed for 12 toxic symptoms. The majority of toxicities was dependent on the modifications in components of more than one pathway of FAC drugs, while the impact level of clinical factors was comparable to the genetic ones. For the carriers of multiple high risk factors the chance of developing given symptom was significantly elevated which proved the factor-dosage effect. We found the strongest associations between concurrent presence of clinical factors - overall and recurrent anemia, nephrotoxicity and early nausea and genetic polymorphisms in genes responsible for DNA repair, drugs metabolism and transport pathways. These results indicate the possibility of selection of the patients with expected high tolerance to FAC treatment and consequently with high chance of chemotherapy completion without the dose reduction, treatment delays and decline in the quality of life.

Iron Homeostasis Controls Myeloid Blood Cell Differentiation in Drosophila

Iron is an essential divalent ion for aerobic life. Life has evolved to maintain iron homeostasis for normal cellular and physiological functions and therefore imbalances in iron levels exert a wide range of consequences. Responses to iron dysregulation in blood development, however, remain elusive. Here, we found that iron homeostasis is critical for differentiation of Drosophila blood cells in the larval hematopoietic organ, called the lymph gland. Supplementation of an iron chelator, bathophenanthroline disulfate (BPS) results in an excessive differentiation of the crystal cell in the lymph gland. This phenotype is recapitulated by loss of Fer1HCH in the intestine, indicating that reduced levels of systemic iron enhances crystal cell differentiation. Detailed analysis of Fer1HCH-tagged-GFP revealed that Fer1HCH is also expressed in the hematopoietic systems. Lastly, blocking Fer1HCH expression in the mature blood cells showed marked increase in the blood differentiation of both crystal cells and plasmatocytes. Thus, our work suggests a relevance of systemic and local iron homeostasis in blood differentiation, prompting further investigation of molecular mechanisms underlying iron regulation and cell fate determination in the hematopoietic system.

Nasal delivery of nanoliposome-encapsulated ferric ammonium citrate can increase the iron content of rat brain

BACKGROUND

Iron deficiency in children can have significant neurological consequences, and iron supplementation is an effective treatment of choice. However, traditional routes of iron supplementation do not allow efficient iron delivery to the brain due to the presence of the blood-brain barrier. So an easily delivered iron formulation with high absorption efficiency potentially could find widespread application in iron deficient infants.

RESULTS

In this study, we have developed and characterized a nanovesicular formulation of ferric ammonium citrate (ferric ammonium citrate nanoliposomes, FAC-LIP) and have shown that it can increase brain iron levels in rats following nasal administration. FAC was incorporated into liposomes with high efficiency (97%) and the liposomes were small (40 nm) and stable. Following intranasal delivery in rats, FAC-LIP significantly increased the iron content in the olfactory bulb, cerebral cortex, striatum, cerebellum and hippocampus, and was more efficient at doing so than FAC alone. No signs of apoptosis or abnormal cell morphology were observed in the brain following FAC-LIP administration, and there were no significant changes in the levels of SOD and MDA, except in the cerebellum and hippocampus. No obvious morphological changes were observed in lung epithelial cells or tracheal mucosa after nasal delivery, suggesting that the formulation was not overtly toxic.

CONCLUSIONS

In this study, nanoscale FAC-LIP proved an effective system delivering iron to the brain, with high encapsulation efficiency and low toxicity in rats. Our studies provide the foundation for more detailed investigations into the applications of niosomal nasal delivery of liposomal formulations of iron as a simple and safe therapy for iron deficiency anemia. Graphical abstract The diagrammatic sketch of "Nasal delivery of nanoliposome-encapsulated ferric ammonium citrate can increase the iron content of rat brain". Nanoliposome-encapsulated ferric ammonium citrate (FAC-LIP) was successfully prepared and intranasal administration of FAC-LIP increased both the total iron contents and iron storage protein (FTL) expression in rat olfactory bulb, cerebral cortex, striatum and hippocampus, compared with those of FAC groups. Moreover, there was not overtly toxic affects to brain, lung epithelial cells and tracheal mucosa.

FRET studies of various conformational states adopted by transthyretin

Transthyretin (TTR) is an extracellular protein able to deposit into well-defined protein aggregates called amyloid, in pathological conditions known as senile systemic amyloidosis, familial amyloid polyneuropathy, familial amyloid cardiomyopathy and leptomeningeal amyloidosis. At least three distinct partially folded states have been described for TTR, including the widely studied amyloidogenic state at mildly acidic pH. Here, we have used fluorescence resonance energy transfer (FRET) experiments in a monomeric variant of TTR (M-TTR) and in its W41F and W79F mutants, taking advantage of the presence of a unique, solvent-exposed, cysteine residue at position 10, that we have labelled with a coumarin derivative (DACM, acceptor), and of the two natural tryptophan residues at positions 41 and 79 (donors). Trp41 is located in an ideal position as it is one of the residues of β-strand C, whose degree of unfolding is debated. We found that the amyloidogenic state at low pH has the same FRET efficiency as the folded state at neutral pH in both M-TTR and W79F-M-TTR, indicating an unmodified Cys10-Trp41 distance. The partially folded state populated at low denaturant concentrations also has a similar FRET efficiency, but other spectroscopic probes indicate that it is distinct from the amyloidogenic state at acidic pH. By contrast, the off-pathway state accumulating transiently during refolding has a higher FRET efficiency, indicating non-native interactions that reduce the Cys10-Trp41 spatial distance, revealing a third distinct conformational state. Overall, our results clarify a negligible degree of unfolding of β-strand C in the formation of the amyloidogenic state and establish the concept that TTR is a highly plastic protein able to populate at least three distinct conformational states.

Suppressing transthyretin production in mice, monkeys and humans using 2nd-Generation antisense oligonucleotides

Transthyretin amyloidosis (ATTR amyloidosis) is a rare disease that results from the deposition of misfolded transthyretin (TTR) protein from the plasma into tissues as amyloid fibrils, leading to polyneuropathy and cardiomyopathy. IONIS-TTR_Rx (ISIS 420915) is a 2nd-Generation 2'-O-(2-methoxyethyl) modified "2'-MOE" antisense oligonucleotide (ASO) that targets the TTR RNA transcript and reduces the levels of the TTR transcript through an RNaseH1 mechanism of action, leading to reductions in both mutant and wild-type TTR protein. The activity of IONIS-TTR_Rx to decrease TTR protein levels was studied in transgenic mice bearing the Ile84Ser human TTR mutant, in cynomolgus monkeys and in healthy human volunteers. Robust (>80%) reductions of plasma TTR protein were obtained in all three species treated with IONIS-TTR_Rx, which in mice and monkeys was associated with substantial reductions in hepatic TTR RNA levels. These effects were dose-dependent and lasted for weeks post-dosing. In a Phase 1 healthy volunteer study, treatment with IONIS-TTR_Rx for four weeks was well tolerated without any remarkable safety issues. TTR protein reductions up to 96% in plasma were observed. These nonclinical and clinical results support the ongoing Phase 3 development of IONIS-TTR_Rx in patients with ATTR amyloidosis.

The polyphenol Oleuropein aglycone hinders the growth of toxic transthyretin amyloid assemblies

Transthyretin (TTR) is involved in a subset of familial or sporadic amyloid diseases including senile systemic amyloidosis (SSA), familial amyloid polyneuropathy and cardiomyopathy (FAP/FAC) for which no effective therapy has been found yet. These conditions are characterized by extracellular deposits primarily found in the heart parenchyma and in peripheral nerves whose main component are amyloid fibrils, presently considered the main culprits of cell sufferance. The latter are polymeric assemblies grown from misfolded TTR, either wt or carrying one out of many identified mutations. The recent introduction in the clinical practice of synthetic TTR-stabilizing molecules that reduce protein aggregation provides the rationale to search natural effective molecules able to interfere with TTR amyloid aggregation by hindering the appearance of toxic species or by favoring the growth of harmless aggregates. Here we carried out an in depth biophysical and morphological study on the molecular features of the aggregation of wt- and L55P-TTR involved in SSA or FAP/FAC, respectively, and on the interference with fibril aggregation, stability and toxicity to cardiac HL-1 cells to demonstrate the ability of Oleuropein aglycone (OleA), the main phenolic component of the extra virgin olive oil. We describe the molecular basis of such interference and the resulting reduction of TTR amyloid aggregate cytotoxicity. Our data offer the possibility to validate and optimize the use of OleA or its molecular scaffold to rationally design promising drugs against TTR-related pathologies that could enter a clinical experimental phase.

MAPK signaling: a key element in plant defense response to insects

Insects have long been the most abundant herbivores, and plants have evolved sophisticated mechanisms to defend against their attack. In particular, plants can perceive specific patterns of tissue damage associated with insect herbivory. Some plant species can perceive certain elicitors in insect oral secretions (OS) that enter wounds during feeding, and rapidly activate a series of intertwined signaling pathways to orchestrate the biosynthesis of various defensive metabolites. Mitogen-activated protein kinases (MAPKs), common to all eukaryotes, are involved in the orchestration of many cellular processes, including development and stress responses. In plants, at least two MAPKs, salicylic acid-induced protein kinase (SIPK) and wound-induced protein kinase (WIPK), are rapidly activated by wounding or insect OS; importantly, genetic studies using transgenic or mutant plants impaired in MAPK signaling indicated that MAPKs play critical roles in regulating the herbivory-induced dynamics of phytohormones, such as jasmonic acid, ethylene and salicylic acid, and MAPKs are also required for transcriptional activation of herbivore defense-related genes and accumulation of defensive metabolites. In this review, we summarize recent developments in understanding the functions of MAPKs in plant resistance to insect herbivores.

Assessment of myocardial performance in preterm infants less than 29 weeks gestation during the transitional period

BACKGROUND

The transitional circulation and its effect on myocardial performance are poorly understood in preterm infants.

AIMS

We assessed myocardial performance in infants less than 29 weeks gestation in the first 48 h of life using a comprehensive echocardiographic assessment.

DESIGN

Infants <29 weeks gestation were prospectively enrolled. Small for gestation, infants on inotropes and/or inhaled nitric oxide and septic infants were excluded. Conventional echocardiography, left ventricular (LV), septal and right ventricular (RV) tissue Doppler imaging (TDI) and tissue Doppler-derived strain and strain rate (SR), tricuspid annular plane systolic excursion (TAPSE) and global RV fractional area change (FAC) were assessed at a median of 10 and 45 h post-delivery.

RESULTS

Fifty-four infants with a median [IQR] gestation and birth weight of 26.5 weeks [25.8-28.0 weeks] and 915 g [758-1142 g] were included. There was no change in shortening or ejection fraction across the two time points. Systolic and diastolic TDI of the LV, septum and RV increased across the two time points (all p values ≤ 0.01). There was an increase in septal peak systolic and early diastolic SR (p=0.002). Septal systolic strain and late diastolic SR did not change. With the exception of RV strain and early diastolic SR, all RV functional parameters including SR, late diastolic SR, TAPSE, and FAC increased across the two time points (all p values<0.01).

CONCLUSION

Describing the normal hemodynamic adaptations in stable preterm infants during the transitional period provides the necessary information for the assessment of those parameters in various disease states.

Transcription factor NRF2 protects mice against dietary iron-induced liver injury by preventing hepatocytic cell death

BACKGROUND & AIMS

The liver, being the major site of iron storage, is particularly exposed to the toxic effects of iron. Transcription factor NRF2 is critical for protecting the liver against disease by activating the transcription of genes encoding detoxification/antioxidant enzymes. We aimed to determine if the NRF2 pathway plays a significant role in the protection against hepatic iron overload.

METHODS

Wild-type and Nrf2(-/-) mouse primary hepatocytes were incubated with ferric ammonium citrate. Wild-type and Nrf2(-/-) mice were fed standard rodent chow or iron-rich diet for 2weeks, with or without daily injection of the antioxidant mito-TEMPOL.

RESULTS

In mouse hepatocytes, iron induced the nuclear translocation of NRF2 and the expression of cytoprotective genes in an NRF2-dependent manner. Moreover, Nrf2(-/-) hepatocytes were highly susceptible to iron-induced cell death. Wild-type and Nrf2(-/-) mice fed iron-rich diet accumulated similar amounts of iron in the liver and were equally able to increase the expression of hepatic hepcidin and ferritin. Nevertheless, in Nrf2-null mice the iron loading resulted in progressive liver injury, ranging from mild confluent necrosis to severe necroinflammatory lesions. Hepatocytic cell death was associated with gross ultrastructural damage to the mitochondria. Notably, liver injury was prevented in iron-fed animals that received mito-TEMPOL.

CONCLUSIONS

NRF2 protects the mouse liver against the toxicity of dietary iron overload by preventing hepatocytic cell death. We identify NRF2 as a potential modifier of liver disease in iron overload pathology and show the beneficial effect of the antioxidant mito-TEMPOL in a mouse model of dietary iron-induced liver injury.

Use of functional aerobic capacity based on stress testing to predict outcomes in normal, overweight, and obese patients

OBJECTIVE

To determine the poorly studied relationship between functional aerobic capacity (FAC) as measured by treadmill stress testing and mortality in normal, overweight, and obese patients.

PATIENTS AND METHODS

Patients were identified retrospectively from the stress testing database at Mayo Clinic in Rochester, Minnesota. We selected 5328 male nonsmokers (mean ± SD age, 51.8±11.5 years) without baseline cardiovascular disease who were referred for treadmill exercise testing between January 1, 1986, and December 31, 1991, and classified them by body mass index (BMI) into normal-weight (18.5-24.9 kg/m(2)), overweight (25.0-29.9 kg/m(2)), and obese (≥30 kg/m(2)) categories. Functional aerobic capacity was assessed by maximal exercise test results based on age- and sex-specific metabolic equivalents, and patients were stratified into fitness quintiles. Cox proportional hazards analysis was used to determine the relationship of all-cause mortality to fitness in each BMI category.

RESULTS

There were 322 deaths during 14 years of follow-up. After adjustment for age and exercise confounders, FAC predicted mortality in the 3 BMI groups. Hazard ratios for FAC less than 80% of predicted vs a reference group with normal BMI and fitness (FAC ≥100%) were 1.754 (95% CI, 0.874-3.522), 1.962 (1.356-2.837), and 1.518 (1.056-2.182) for the normal, overweight, and obese groups, respectively. The CIs of the hazard ratios overlapped with no statistically significant differences (P>.05).

CONCLUSION

A significant increase in mortality occurs with FAC below 80% of predicted for overweight and obese subjects and below 70% for normal weight subjects. Our results suggest that clinicians need not adjust the standard for low fitness in obese patients.

Transthyretin suppresses the toxicity of oligomers formed by misfolded proteins in vitro

Although human transthyretin (TTR) is associated with systemic amyloidoses, an anti-amyloidogenic effect that prevents Aβ fibril formation in vitro and in animal models has been observed. Here we studied the ability of three different types of TTR, namely human tetramers (hTTR), mouse tetramers (muTTR) and an engineered monomer of the human protein (M-TTR), to suppress the toxicity of oligomers formed by two different amyloidogenic peptides/proteins (HypF-N and Aβ42). muTTR is the most stable homotetramer, hTTR can dissociate into partially unfolded monomers, whereas M-TTR maintains a monomeric state. Preformed toxic HypF-N and Aβ42 oligomers were incubated in the presence of each TTR then added to cell culture media. hTTR, and to a greater extent M-TTR, were found to protect human neuroblastoma cells and rat primary neurons against oligomer-induced toxicity, whereas muTTR had no protective effect. The thioflavin T assay and site-directed labeling experiments using pyrene ruled out disaggregation and structural reorganization within the discrete oligomers following incubation with TTRs, while confocal microscopy, SDS-PAGE, and intrinsic fluorescence measurements indicated tight binding between oligomers and hTTR, particularly M-TTR. Moreover, atomic force microscopy (AFM), light scattering and turbidimetry analyses indicated that larger assemblies of oligomers are formed in the presence of M-TTR and, to a lesser extent, with hTTR. Overall, the data suggest a generic capacity of TTR to efficiently neutralize the toxicity of oligomers formed by misfolded proteins and reveal that such neutralization occurs through a mechanism of TTR-mediated assembly of protein oligomers into larger species, with an efficiency that correlates inversely with TTR tetramer stability.

Modulation of Dcytb (Cybrd 1) expression and function by iron, dehydroascorbate and Hif-2α in cultured cells

BACKGROUND

Duodenal cytochrome b (Dcytb) is a mammalian plasma ferric reductase enzyme that catalyses the reduction of ferric to ferrous ion in the process of iron absorption. The current study investigates the relationship between Dcytb, iron, dehydroascorbate (DHA) and Hif-2α in cultured cell lines.

METHODS

Dcytb and Hif-2α protein expression was analysed by Western blot technique while gene regulation was determined by quantitative PCR. Functional analyses were carried out by ferric reductase and (59)Fe uptake assays.

RESULTS

Iron and dehydroascorbic acid treatment of cells inhibited Dcytb mRNA and protein expression. Desferrioxamine also enhanced Dcytb mRNA level after cells were treated overnight. Dcytb knockdown in HuTu cells resulted in reduced mRNA expression and lowered reductase activity. Preloading cells with DHA (to enhance intracellular ascorbate levels) did not stimulate reductase activity fully in Dcytb-silenced cells, implying a Dcytb-dependence of ascorbate-mediated ferrireduction. Moreover, Hif-2α knockdown in HuTu cells led to a reduction in reductase activity and iron uptake.

CONCLUSIONS

Taken together, this study shows the functional regulation of Dcytb reductase activity by DHA and Hif-2α.

GENERAL SIGNIFICANCE

Dcytb is a plasma membrane protein that accepts electrons intracellularly from DHA/ascorbic acid for ferrireduction at the apical surface of cultured cells and enterocytes.