Effect of niacin on triglyceride-rich lipoprotein apolipoprotein B-48 kinetics in statin-treated patients with type 2 diabetes

AIM

To investigate the effects of extended-release (ER) niacin on apolipoprotein B-48 (apoB-48) kinetics in statin-treated patients with type 2 diabetes (T2DM).

METHODS

A total of 12 men with T2DM were randomized to rosuvastatin or rosuvastatin plus ER niacin for 12 weeks and then crossed to the alternate therapy. Postprandial metabolic studies were performed at the end of each treatment period. D3-leucine tracer was administered as subjects consumed a high-fat liquid meal. ApoB-48 kinetics were determined using stable isotope tracer kinetics with fractional catabolic rates (FCRs) and secretion rates derived using a non-steady-state compartmental model. Area-under-the-curve (AUC) and incremental AUC (iAUC) for plasma triglyceride and apoB-48 were also calculated over the 10-h period after ingestion of the fat meal.

RESULTS

In statin-treated patients with T2DM, apoB-48 concentration was lower with ER niacin (8.24 ± 1.98 vs 5.48 ± 1.14 mg/l, p = 0.03) compared with statin alone. Postprandial triglyceride and apoB-48 AUC were also significantly lower on ER niacin treatment (-15 and -26%, respectively; p < 0.05), without any change to triglyceride and apoB-48 iAUC. ApoB-48 secretion rate in the basal state (3.21 ± 0.34 vs 2.50 ± 0.31 mg/kg/day; p = 0.04) and number of apoB-48-containing particles secreted in response to the fat load (1.35 ± 0.19 vs 0.84 ± 0.12 mg/kg; p = 0.02) were lower on ER niacin. ApoB-48 FCR was not altered with ER niacin (8.78 ± 1.04 vs 9.17 ± 1.26 pools/day; p = 0.79).

CONCLUSIONS

ER niacin reduces apoB-48 concentration by lowering fasting and postprandial apoB-48 secretion rate. This effect may be beneficial for lowering atherogenic postprandial lipoproteins and may provide cardiovascular disease risk benefit in patients with T2DM.

Abstract P6-13-22: Pharmacodynamics and consequences of PI3K inhibition in ER+ breast tumors

PI3K inhibitors have shown promise for the treatment of anti-estrogen-resistant ER+ breast cancers. Current PI3K inhibitor treatment regimens may incompletely and transiently inhibit the pathway in carcinomas, and are accompanied by significant adverse effects in patients. We hypothesized that short-term, complete inhibition of PI3K will have a greater anti-tumor effect and reduce systemic toxicity compared to chronic, partial inhibition.

Pharmacokinetic analysis of the orally available pan-PI3K inhibitor GDC-0941 at low (100 mg/kg) and high (800 mg/kg) doses in mice revealed that plasma levels peaked after 15-30 min, and decreased below the limit of detection within 24 h (low dose) and 72 h (high dose), respectively. Administering 2 doses at 100 mg/kg 12 h apart provided continuous drug exposure. Drug pharmacokinetics in MCF-7 tumors was similar.

Mice bearing s.c. MCF-7 tumors were treated with the anti-estrogen fulvestrant (fulv; 5 mg/wk) three days before GDC-0941 treatment to assess pharmacodynamic effects. Phospho-AKT and -S6 levels (markers of PI3K and mTORC1 activities, respectively) were inversely correlated with tumor drug concentrations. Mice bearing MCF-7, fulv-resistant T47D/FR, or HCC-003 patient-derived xenografts were treated with vehicle, fulv, GDC-0941 (100 mg/kg QD 5 d/wk; 100 mg/kg BID 3 d on/4 d off; 800 mg/kg QW), or combinations. Tumor growth curves indicated that different schedules of PI3K inhibition with fulv similarly induced tumor regression. Molecular analysis of MCF-7 tumors showed that fulv plus GDC-0941 QW induced 30.14% apoptosis (assessed by TUNEL) at 48 h, which dropped to baseline (2.72%) at 72 h. Fulv plus GDC-0941 BID induced 18.27% apoptosis at 24 h, and maintained apoptosis rate near 10% until 96 h (when GDC-0941 washed out), which is a rate similar to that observed with fulv plus GDC-0941 QD. Fulv plus GDC-0941 QW decreased cell proliferation (assessed by geminin and Ki67 staining) from 34.89% (baseline) to 11.46%, which rebounded to 60.54% at the time of GDC-0941 washout (at 96 h). Fulv plus GDC-0941 QD or BID modestly decreased cell proliferation to 28.84% and 24.32%, respectively, after 24 h, which returned to baseline after 36 h and 72 h, respectively, then maintained the level for a week. Temporal analysis of PI3K signaling revealed that fulv plus GDC-0941 QW and BID maximally decreased phospho-AKT levels after 3 h, which returned to baseline within 48 h and 72 h, respectively. With fulv + GDC-0941 QD, phospho-AKT levels decreased after 3 h, but rebounded to baseline within 24 h. These results indicate that 2 approaches to PI3K inhibition provide similar anti-tumor efficacy: 1) complete/intermittent (QW) PI3K inhibition induces a burst of apoptosis with a rebound in cell proliferation after drug clearance; and 2) metronomic/repeated (QD) PI3K inhibition repeatedly induces a smaller amount of apoptosis without significantly affecting cell proliferation. These findings may inform clinical testing of PI3K inhibitors to maximize therapeutic index.

Citation Format: Yang W, Bean J, Hosford S, Lloye D, Liu S, Salphati L, Pang J, Zhang X, Nannini M, Miller TW. Pharmacodynamics and consequences of PI3K inhibition in ER+ breast tumors. [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 P6-13-22.

Restoration of miR-101 suppresses lung tumorigenesis through inhibition of DNMT3a-dependent DNA methylation

The deregulation of miR-101 and DNMT3a has been implicated in the pathogenesis of multiple tumor types, but whether and how miR-101 silencing and DNMT3a overexpression contribute to lung tumorigenesis remain elusive. Here we show that miR-101 downregulation associates with DNMT3a overexpression in lung cancer cell lines and patient tissues. Ectopic miR-101 expression remarkably abrogated the DNMT3a 3′-UTR luciferase activity corresponding to the miR-101 binding site and caused an attenuated expression of endogenous DNMT3a, which led to a reduction of global DNA methylation and the re-expression of tumor suppressor CDH1 via its promoter DNA hypomethylation. Functionally, restoration of miR-101 expression suppressed lung cancer cell clonability and migration, which recapitulated the DNMT3a knockdown effects. Interestingly, miR-101 synergized with decitabine to downregulate DNMT3a and to reduce DNA methylation. Importantly, ectopic miR-101 expression was sufficient to trigger in vivo lung tumor regression and the blockage of metastasis. Consistent with these phenotypes, examination of xenograft tumors disclosed an increase of miR-101, a decrease of DNMT3a and the subsequent DNA demethylation. These findings support that the loss or suppression of miR-101 function accelerates lung tumorigenesis through DNMT3a-dependent DNA methylation, and suggest that miR-101-DNMT3a axis may have therapeutic value in treating refractory lung cancer.

Hybrid monitor for both beam position and tilt of pulsed high-current beams

A Hybrid beam monitor, integrated with both azimuthal and axial B-dot probes, was designed for simultaneous measurement of both beam position and beam angle for pulsed high-current beams at the same location in beam pipe. The output signals of axial B-dot probes were found to be mixed with signals caused by transverse position deviation. In order to eliminate the unwanted signals, an elimination method was developed and its feasibility tested on a 50-Ω coaxial line test stand. By this method, a waveform, shape-like to that of input current and proportional to the tilt angle, was simulated and processed by following integration step to achieve the tilt angle. The tests showed that the measurement error of displacement and tilt angle less than 0.3 mm and 1.5 mrad, respectively. The latter error could be reduced with improved probes by reducing the inductance of the axial B-dot probe, but the improvement reached a limit due to some unknown systemic mechanism.

EIF5A2 predicts outcome in localised invasive bladder cancer and promotes bladder cancer cell aggressiveness in vitro and in vivo

BACKGROUND

EIF5A2, eukaryotic translation initiation factor 5A2, is associated with several human cancers. In this study, we investigated the role of EIF5A2 in the metastatic potential of localised invasive bladder cancer (BC) and its underlying molecular mechanisms were explored.

METHODS

The expression pattern of EIF5A2 in localised invasive BC was determined by immunohistochemistry. In addition, the function of EIF5A2 in BC and its underlying mechanisms were elucidated with a series of in vitro and in vivo assays.

RESULTS

Overexpression of EIF5A2 was an independent predictor for poor metastasis-free survival of localised invasive BC patients treated with radical cystectomy. Knockdown of EIF5A2 inhibited BC cell migratory and invasive capacities in vitro and metastatic potential in vivo and reversed epithelial-mesenchymal transition (EMT), whereas overexpression of EIF5A2 promoted BC cells motility and invasiveness in vitro and metastatic potential in vivo and induced EMT. In addition, we found that EIF5A2 might activate TGF-β1 expression to induce EMT and drive aggressiveness in BC cells. EIF5A2 stabilized STAT3 and stimulated nuclear localisation of STAT3, which resulted in increasing enrichment of STAT3 onto TGF-β1 promoter to enhance the transcription of TGF-β1.

CONCLUSIONS

EIF5A2 overexpression predicts tumour metastatic potential in patients with localised invasive BC treated with radical cystectomy. Furthermore, EIF5A2 elevated TGF-β1 expression through STAT3 to induce EMT and promotes aggressiveness in BC.

Megaesophagus in a line of transgenic rats: a model of achalasia

Megaesophagus is defined as the abnormal enlargement or dilatation of the esophagus, characterized by a lack of normal contraction of the esophageal walls. This is called achalasia when associated with reduced or no relaxation of the lower esophageal sphincter (LES). To date, there are few naturally occurring models for this disease. A colony of transgenic (Pvrl3-Cre) rats presented with megaesophagus at 3 to 4 months of age; further breeding studies revealed a prevalence of 90% of transgene-positive animals having megaesophagus. Affected rats could be maintained on a total liquid diet long term and were shown to display the classic features of dilated esophagus, closed lower esophageal sphincter, and abnormal contractions on contrast radiography and fluoroscopy. Histologically, the findings of muscle degeneration, inflammation, and a reduced number of myenteric ganglia in the esophagus combined with ultrastructural lesions of muscle fiber disarray and mitochondrial changes in the striated muscle of these animals closely mimic that seen in the human condition. Muscle contractile studies looking at the response of the lower esophageal sphincter and fundus to electrical field stimulation, sodium nitroprusside, and L-nitro-L-arginine methyl ester also demonstrate the similarity between megaesophagus in the transgenic rats and patients with achalasia. No primary cause for megaesophagus was found, but the close parallel to the human form of the disease, as well as ease of care and manipulation of these rats, makes this a suitable model to better understand the etiology of achalasia as well as study new management and treatment options for this incurable condition.

Ovariectomy induces osteoporosis in the maxillary alveolar bone: an in vivo micro-CT and histomorphometric analysis in rats

OBJECTIVE

To investigate whether porotic changes occur in maxillary alveolar bone in ovariectomized rats.

METHODS

Thirty-two 6-week-old female Sprague-Dawley rats were divided into an ovariectomy group (OVX) and a sham-ovariectomy group (sham). Twelve weeks after surgery, maxillae of 16 rats (eight OVX and eight sham) were analyzed by micro-CT. Inter-radicular alveolar bone of the maxillary first molar was reconstructed and analyzed. The remaining 16 maxillae were used for histochemistry, including hematoxylin-eosin staining and tartrate-resistant acid phosphatase enzyme staining.

RESULTS

Three-dimensional reconstructed images of the irregular alveolar bone showed an intuitive view of porotic changes in the OVX group. The alveolar bone in OVX rats had a porous microarchitecture including lower bone mass and a looser structure of more widely separated trabeculae. Bone mineral density (BMD), bone volume fraction (BV/TV), and trabecular thickness (Tb.Th.) were significantly lower in the OVX group than those in the sham group (P < 0.05). Trabecular separation (Tb.Sp.) increased significantly in the OVX rats compared to the sham rats (P < 0.05). Histomorphometric analysis of alveolar bone also revealed porotic changes in the OVX rats. Bone area ratio significantly decreased in the OVX group compared with the sham group (P < 0.01). There were also more osteoclasts present in the alveolar bone of OVX rats compared to sham rats (P < 0.05).

CONCLUSION

Ovariectomy induces osteoporosis in maxillary alveolar bone in rats, which may be related to the increased number of osteoclasts.

Provider use of and attitudes towards an active clinical alert: a case study in decision support

BACKGROUND

In a previous study, we reported on a successful clinical decision support (CDS) intervention designed to improve electronic problem list accuracy, but did not study variability of provider response to the intervention or provider attitudes towards it. The alert system accurately predicted missing problem list items based on health data captured in a patient's electronic medical record.

OBJECTIVE

To assess provider attitudes towards a rule-based CDS alert system as well as heterogeneity of acceptance rates across providers.

METHODS

We conducted a by-provider analysis of alert logs from the previous study. In addition, we assessed provider opinions of the intervention via an email survey of providers who received the alerts (n = 140).

RESULTS

Although the alert acceptance rate was 38.1%, individual provider acceptance rates varied widely, with an interquartile range (IQR) of 14.8%-54.4%, and many outliers accepting none or nearly all of the alerts they received. No demographic variables, including degree, gender, age, assigned clinic, medical school or graduation year predicted acceptance rates. Providers' self-reported acceptance rate and perceived alert frequency were only moderately correlated with actual acceptance rates and alert frequency.

CONCLUSIONS

Acceptance of this CDS intervention among providers was highly variable but this heterogeneity is not explained by measured demographic factors, suggesting that alert acceptance is a complex and individual phenomenon. Furthermore, providers' self-reports of their use of the CDS alerting system correlated only modestly with logged usage.

Carbon trading for phosphorus gain: the balance between rhizosphere carboxylates and arbuscular mycorrhizal symbiosis in plant phosphorus acquisition

Two key plant adaptations for phosphorus (P) acquisition are carboxylate exudation into the rhizosphere and mycorrhizal symbioses. These target different soil P resources, presumably with different plant carbon costs. We examined the effect of inoculation with arbuscular mycorrhizal fungi (AMF) on amount of rhizosphere carboxylates and plant P uptake for 10 species of low-P adapted Kennedia grown for 23 weeks in low-P sand. Inoculation decreased carboxylates in some species (up to 50%), decreased plant dry weight (21%) and increased plant P content (23%). There was a positive logarithmic relationship between plant P content and the amount of rhizosphere citric acid for inoculated and uninoculated plants. Causality was indicated by experiments using sand where little citric acid was lost from the soil solution over 2 h and citric acid at low concentrations desorbed P into the soil solution. Senesced leaf P concentration was often low and P-resorption efficiencies reached >90%. In conclusion, we propose that mycorrhizally mediated resource partitioning occurred because inoculation reduced rhizosphere carboxylates, but increased plant P uptake. Hence, presumably, the proportion of plant P acquired from strongly sorbed sources decreased with inoculation, while the proportion from labile inorganic P increased. Implications for plant fitness under field conditions now require investigation.

Functionalized mesoporous silica particles for application in drug delivery system

In these years, ordered mesoporous silica materials have shown promising applications in drug delivery system as drug carriers. These carriers with stable mesoporous structure, large surface area, good biocompatibility and tailored size of mesopores exhibit significant property of higher drug loading. However, silica-based mesoporous materials cannot control the release of the loaded drug without modifications. In this paper, we review the recent research work discussing functionalization of mesoporous materials by various components and methods for application in drug delivery systems. All the examples show that these functionalized mesoporous silica-based systems have great potential for a variety of drug delivery applications, specifically in the fields of the drug targeted and controlled delivery systems.

Vitreous surgery for macular hole-related retinal detachment after phacoemulsification cataract extraction: 10-year retrospective review

PURPOSE

To evaluate the visual and anatomical results of surgery for macular hole-related retinal detachment (MHRD) after phacoemulsification cataract extraction.

METHODS

Data for all patients who underwent surgery for MHRD after phacoemulsification cataract extraction from 1 December 1998 to 30 September 2008 in one hospital were evaluated. Patient characteristics, best-corrected visual acuity (VA) preoperatively and at last examination, surgical technique, anatomical success, and follow-up period were extracted and analysed statistically.

RESULTS

A total of 13 625 eyes of 10 076 patients who had phacoemulsification cataract surgery were included. In the follow-up period, 10 cases of MHRD in nine patients were observed, of which seven eyes had high myopia. The mean axial length was 30.97 ± 1.36 mm (29.19, 32.97) and mean myopia was-19.35 ± 1.93 (-7.5,-3.5) dioptres. Overall anatomical success was achieved in 90% (9 out of 10 eyes). There was no statistically significant difference (P=0.240) between the logarithm of the MAR VA before the phacoemulsification cataract extraction and after MHRD surgical repair. VA increased in three eyes but decreased in the other seven after MHRD surgery.

CONCLUSIONS

As a primary procedure, vitreous surgery combined with other necessary adjunct procedures such as membrane peeling and retinal tamponade seems to be successful in achieving anatomical success. However, VA improvement is dependent on the type of macular lesion and not the surgical procedure.