Pes varus correction in dachshunds with mini hybrid external skeletal fixators.

AIM: To evaluate the clinical and radiographic outcome of pes varus deformity correction in dachshunds managed with acute medial opening wedge osteotomy of the distal tibia and stabilised with a mini hybrid external skeletal fixator (HESF). METHODS: Surgical correction involved a transverse osteotomy over the premeasured location at the distal tibia and application of a IMEX mini HESF. All corrections were evaluated using centre of rotation and angulation methodology. RESULTS: Medical records and radiographies of 20 dachshunds (28 pes varus corrections) were reviewed. All osteotomies healed and fixators were removed between 6 and 12 weeks. Lameness resolved in 18 dachshunds (90%) and significantly improved in two dachshunds (10%). Lateral patella luxation (LPL) was detected in 11/28 (39.2%) of the involved pelvic limbs, all of which resolved following pes varus correction. Mean frontal plane alignment (FPA) of the normal and abnormal tibiae were 12.3° valgus (range: 4°-18°) and 25° Varus (range: 16°-41°) respectively. Angular correction ranged between 30° and 50° (Mean: 39°) and the mean post-operative FPA was 13° valgus (range: 5°-21°). CLINICAL SIGNIFICANCE: Pes varus deformity in dachshunds can be corrected by medial opening wedge osteotomy of the distal tibia stabilised by HESF. Single-session bilateral pes varus corrections can also be performed with minimal morbidity. LPL was commonly detected in dogs with pes varus deformity and all resolved spontaneously following pes varus correction alone.

Prevalence and risk factors of peripheral artery disease in a population with chronic kidney disease in Australia: A systematic review and meta-analysis.

There is a lack of clarity and guidance for screening peripheral artery disease (PAD) in persons with chronic kidney disease (CKD) and end stage kidney disease (ESKD) despite this group being at excess risk of cardiovascular disease (CVD). In this current study, we performed a systematic review and meta-analysis to examine the prevalence and risk factors for PAD in persons with CKD in Australian cohorts. We used the inverse variance heterogeneity meta-analysis with double arcsine transformation to summarize the prevalence of PAD (with 95% CIs). Nine studies and 18 reports from the Australia and New Zealand dialysis and transplant registry with 36 cohorts were included in the review. We found a substantially higher PAD prevalence in cohorts based on an ankle-brachial index (ABI) or toe systolic pressure (TBI) than cohorts based on self-reported history. Higher PAD prevalence was observed in ESKD persons than CKD persons without dialysis (PAD diagnosis based on ABI or TBI: 31% in ESKD persons and 23% in CKD persons, PAD diagnosis based on self-reported history: 17% in ESKD persons and 10% in CKD persons). Older age, Caucasian race, cerebrovascular disease and haemodialysis were associated with the presence of PAD in ESKD persons. Our findings indicated a considerable proportion of PAD in CKD and ESKD persons particularly in those with ESKD. To develop and provide an adequate plan to clinically manage CKD patients with PAD, evidence of cost-effectiveness and clinical benefit of early detection of PAD in persons with CKD in Australia is recommended for future studies.

The effect of taking blood pressure lowering medication at night on cardiovascular disease risk. A systematic review.

To investigate the effect of night-time BP-lowering drug treatment on the risk of major CVD and mortality, we systematically reviewed randomized controlled trials comparing night-time versus morning dosing. Two studies were found relevant to the clinical question (the MAPEC and Hygia trials). They were similar in study design and population and were conducted by the same study group. As the Hygia trial had more power with a significantly larger sample size, we did not perform a meta-analysis. Both studies reported a reduction of ~50% in major CVD events and all-cause mortality with night-time dosing and a reduction of 60% in CVD mortality. The results from these studies support the implementation of night-time BP-lowering drug treatment in the prevention of CVD and mortality. However there is an on-going discussion on the validity and methodology of MAPEC and Hygia trials, the interpretation of the results should be cautious. Stronger evidence is needed prior to changing clinical practice. Questions that remain to be answered relate to the generalisability of the results across different populations at different levels of BP related risk and the importance of morning versus evening timing of medication on CVD prevention as determined though a well-designed randomised controlled trial.

In silico studies, nitric oxide, and cholinesterases inhibition activities of pyrazole and pyrazoline analogs of diarylpentanoids.

A new series of pyrazole, phenylpyrazole, and pyrazoline analogs of diarylpentanoids (excluding compounds 3a, 4a, 5a, and 5b) was pan-assay interference compounds-filtered and synthesized via the reaction of diarylpentanoids with hydrazine monohydrate and phenylhydrazine. Each analog was evaluated for its anti-inflammatory ability via the suppression of nitric oxide (NO) on IFN-γ/LPS-activated RAW264.7 macrophage cells. The compounds were also investigated for their inhibitory capability toward acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), using a modification of Ellman's spectrophotometric method. The most potent NO inhibitor was found to be phenylpyrazole analog 4c, followed by 4e, when compared with curcumin. In contrast, pyrazole 3a and pyrazoline 5a were found to be the most selective and effective BChE inhibitors over AChE. The data collected from the single-crystal X-ray diffraction analysis of compound 5a were then applied in a docking simulation to determine the potential binding interactions that were responsible for the anti-BChE activity. The results obtained signify the potential of these pyrazole and pyrazoline scaffolds to be developed as therapeutic agents against inflammatory conditions and Alzheimer's disease.

Value of lipocalin 2 as a potential biomarker for bacterial meningitis.

OBJECTIVES: Central nervous system (CNS) infections are common causes of morbidity and mortality worldwide. We aimed to discover protein biomarkers that could rapidly and accurately identify the likely cause of the infections, essential for clinical management and improving outcome. METHODS: We applied liquid chromatography tandem mass spectrometry on 45 cerebrospinal fluid (CSF) samples from a cohort of adults with and without CNS infections to discover potential diagnostic biomarkers. We then validated the diagnostic performance of a selected biomarker candidate in an independent cohort of 364 consecutively treated adults with CNS infections admitted to a referral hospital in Vietnam. RESULTS: In the discovery cohort, we identified lipocalin 2 (LCN2) as a potential biomarker of bacterial meningitis (BM) other than tuberculous meningitis. The analysis of the validation cohort showed that LCN2 could discriminate BM from other CNS infections (including tuberculous meningitis, cryptococcal meningitis and virus/antibody-mediated encephalitis), with sensitivity of 0.88 (95% confident interval (CI), 0.77-0.94), specificity of 0.91 (95% CI, 0.88-0.94) and diagnostic odds ratio of 73.8 (95% CI, 31.8-171.4). LCN2 outperformed other CSF markers (leukocytes, glucose, protein and lactate) commonly used in routine care worldwide. The combination of LCN2, CSF leukocytes, glucose, protein and lactate resulted in the highest diagnostic performance for BM (area under the receiver operating characteristics curve, 0.96; 95% CI, 0.93-0.99). Data are available via ProteomeXchange with identifier PXD020510. CONCLUSIONS: LCN2 is a sensitive and specific biomarker for discriminating BM from a broad spectrum of other CNS infections. A prospective study is needed to assess the diagnostic utility of LCN2 in the diagnosis and management of CNS infections.

Legacy effect of delayed blood pressure lowering drug treatment in middle-aged adults with mildly elevated blood pressure: systematic review and meta-analysis.

To investigate if there is evidence for a 'legacy effect' for blood pressure (BP) lowering treatment, that is, worse health outcomes from not initiating drug treatment at a systolic BP threshold of 140 mmHg in middle-age adults. We systematically reviewed studies comparing the effects of delayed BP treatment (placebo/untreated during the trial or no previous treatment at trial entry) vs. early treatment (actively treated during the trial or previous BP treatment at trial entry) on mortality in the short term (5-year in-trial period) and long term (≥10 years in total period). The data were pooled using Peto ORs. A subgroup analysis by 10-year Framingham risk score was performed. Three studies (ALLHAT, Oslo and PREVEND-IT) involving 4746 participants were included. The results were heavily influenced by the ALLHAT trial. We found no significant difference in all-cause mortality between 'delayed BP' and 'early treatment' in the short-term OR 0.95 (95% CI 0.68-1.32) or long-term OR 0.90 (95% CI 0.78-1.04), with similar results for mortality from cardiovascular disease (CVD). The effects of delayed BP lowering treatment on long-term all-cause and CVD mortality did not vary with baseline risk of CVD. The review showed no clinically adverse 'legacy effect' on mortality or major CVD event from not treating middle-aged adults at a systolic BP threshold of 140 mmHg or over. The results were consistent for all CVD risk subgroups. Although these studies are non-randomised post-hoc analyses, they may allay concerns that early treatment of elevated systolic BP is necessary to prevent CVD events in primary prevention populations.

Lack of a significant legacy effect of baseline blood pressure 'treatment naivety' on all-cause and cardiovascular mortality in the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial.

OBJECTIVES: To investigate legacy effects at 14-year follow-up of all-cause and cardiovascular disease (CVD) mortality in 'treatment-naive' or 'previous treatment' groups based on blood pressure (BP)-lowering treatment status at baseline. METHODS: A post-hoc observational study of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial. We excluded participants with a previous history of CVD events. Cox proportional hazard model and 95% confidence interval were used to estimate the effects of treatment naive on mortality outcomes. Moreover, a subgroup analysis by estimated 10-year Framingham risk score was performed. RESULTS: In multivariable models adjusting for baseline and in-trial characteristics (BP values and number of BP medications as time-dependent variables), there was no statistically significant difference in 5 and 14-year all-cause mortality with a hazard ratio of 0.93 (95% confidence interval 0.80-1.09) and hazard ratio 0.95 (0.88-1.03) and in 5 and 14-year CVD mortality hazard ratio 0.94 (0.72-1.23) and hazard ratio 0.93 (0.80-1.08). In subgroup by absolute CVD risk, no heterogeneity of the association between treatment naive and short-term or long-term all-cause or CVD mortality were found. All comparisons are between the treatment-naive and previous treatment groups. CONCLUSION: Physicians are concerned about 'legacy effects' of not treating individuals with a BP of 140 mmHg or over and low absolute risk. When treatment intensification was taken into consideration in the primary prevention population in this study, no adverse legacy effect as a result of baseline BP 'treatment naivety' was evident in 14 years of follow-up. The nonsignificant associations were consistent across the CVD risk subgroups. However, the results may be biased due to unobserved residual confounding and therefore should be interpreted with caution.

Short- and long-term association of lipid-lowering drug treatment and cardiovascular disease by estimated absolute risk in the Second Australian National Blood Pressure study.

BACKGROUND: There is currently insufficient evidence to support the use of lipid-lowering drug treatment (LLT) for primary prevention of cardiovascular disease (CVD) in the elderly. OBJECTIVES: We examined the relationship of early initiation of LLT with short- and long-term all-cause and CVD mortality in persons older than 65 years in this post hoc study from the Second Australian National Blood Pressure study (ANBP2). METHODS: This was an in- and post-trial observational study. About 4257 hypertensive participants aged 65 to 84 years within Australian family practices were randomized to an angiotensin-converting enzyme inhibitor or a diuretic treatment group. After excluding participants with a prior history of CVD, the cohort was stratified into "LLT" and "no LLT" subgroups based on LLT status at randomization. RESULTS: At randomization, the participants had a mean age of 72 years, average blood pressure of 168/91 mm Hg and estimated 5-year CVD risk of 18.7 ± 8.3%. In the overall study population, the association of LLT with long-term (11-years) all-cause and non-CVD mortality was significant (hazard ratio [HR] 0.78 [95% confidence interval {CI} 0.66-0.92, P = .003] and HR 0.70 [95% CI 0.54-0.90, P = .006], respectively). Magnitudes of the association of LLT with long-term mortality and the association with short-term mortality were similar; however, no statistically significant association with short-term mortality was observed. In the subgroup analysis by baseline 5-year CVD risk, LLT participants in the highest risk tertile had a substantially lower relative risk for short-term all-cause mortality (HR 0.31, 95% CI 0.13-0.71, P for interaction .02) compared to those with lower estimated CVD risk. All analyses were adjusted for baseline and in-trial characteristics. CONCLUSION: Our study showed a strong association between LLT and reduced long-term all-cause mortality. Thus, our findings support recommendations of the use of LLT in patients over 65 years, particularly those with high CVD risk who were more likely to obtain additional benefits in the short term. The findings also suggested that mortality benefits of LLT for the elderly may take longer to become evident.

Association of author's financial conflict of interest with characteristics and outcome of rheumatoid arthritis randomized controlled trials.

OBJECTIVE: To examine the prevalence, types and temporal trends of reported financial conflicts of interest (FCOIs) among authors of drug therapy randomized controlled trials (RCTs) for RA and their association with study outcomes. METHODS: We identified original, non-phase 1, parallel-group, drug therapy RA RCTs published in the years 2002-03, 2006-07, and 2010-11. Two investigators independently obtained trial characteristics data. Authors' FCOIs were classified as honoraria/consultation fees receipt, employee status, research grant, and stock ownership. Multivariable logistic regression was performed to identify whether FCOIs were independently associated with study outcome. RESULTS: A total of 146 eligible RCTs were identified. Of these, 83 (58.4%) RCTs had at least one author with an FCOI [employee status: 63 (43.2%), honoraria/consultation fees receipt: 49 (33.6%), research grant: 30 (20.5%), and stock ownership: 28 (19.2%)]. A remarkable temporal increase in reporting of honoraria/consultation fees receipt, research grant, and stock ownership was seen. The reporting of any FCOI itself was not associated with positive outcome [50/73 (68.5%) with author FCOI vs 36/52 (69.2%) without author FCOI, P = 0.93]. However, honoraria/consulting fees receipt was independently associated with increased likelihood of a positive outcome [adjusted odds ratio (95% CI) of 3.24 (1.06-9.88)]. In general, trials with FCOIs were significantly more likely to be multicentre, have larger enrolment, use biologic or a small molecule as the experimental intervention, and have better reporting of some methodological quality measures. CONCLUSION: FCOI reporting in RA drug RCT authors is common and temporally increasing. Receipt of honoraria/consulting fees was independently associated with a positive study outcome.

Blockade of Eosinophil-Induced Bronchial Epithelial-Mesenchymal Transition with a Geranyl Acetophenone in a Coculture Model.

Epithelial-mesenchymal transition (EMT) is currently recognized as the main cellular event that contributes to airway remodeling. Eosinophils can induce EMT in airway epithelial cells via increased transforming growth factor (TGF)-ß production. We assessed the effect of synthetic 2,4,6-trihydroxy-3-geranyl acetophenone (tHGA) upon eosinophil-induced EMT in a cellular model. The human eosinophil cell line EoL-1 was used to induce EMT in BEAS-2B human bronchial epithelial cells. The induction of EMT was dose-dependently suppressed following tHGA treatment in which the epithelial morphology and E-cadherin expression were not altered. Protein and mRNA expression of vimentin, collagen I and fibronectin in eosinophil-induced epithelial cells were also significantly suppressed by tHGA treatment. Following pathway analysis, we showed that tHGA suppressed eosinophil-induced activator protein-1-mediated TGF-ß production by targeting c-Jun N-terminal kinase and phosphoinositide 3-kinase signaling pathways. These findings corroborated previous findings on the ability of tHGA to inhibit experimental murine airway remodeling.

Acetylation is essential for nuclear heme oxygenase-1-enhanced tumor growth and invasiveness.

Overexpression of heme oxygenase-1 (HO-1), an endoplasmic reticulum-anchored enzyme, is observed in many cancers. HO-1 nuclear translocation has been shown to correlate with progression of several cancers. We recently reported that HO-1 is susceptible to intramembrane proteolysis and translocates to the nucleus to promote cancer growth and invasiveness without depending on its enzymatic activity. In the present study, we show that the HO-1 lacking C-terminal transmembrane segment (t-HO-1) was susceptible to acetylation by p300 and CREB-binding protein (CBP) histone acetyltransferase in the nucleus. Mass spectrometry analysis of HO-1 isolated from human embryonic kidney cells 293T (HEK293T) cells overexpressing CBP and t-HO-1 revealed two acetylation sites located at K243 and K256. Mutation of both lysine residues to arginine (R) abolished t-HO-1-enhanced tumor cell growth, migration and invasion. However, mutation of the lysine residues to glutamine (Q), a mimic of acetylated lysine, had no significant effect on t-HO-1-mediated tumorigenicity. Mechanistic studies demonstrated that transcriptional factor JunD interacted with wild-type (WT) t-HO-1 and mutant carrying K243/256Q but not K243/256 R mutation. Moreover, JunD-induced AP-1 transcriptional activity was significantly enhanced by coexpression with WT and acetylation-mimic but not acetylation-defective t-HO-1. Consistent with the in vitro observations, the implication of K243/256 acetylation in t-HO-1-enhanced tumorigenicity was also demonstrated in xenograft models. Immunohistochemistry performed with a specific antibody against acetyl-HO-1 showed the positive acetyl-HO-1 nuclear staining in human lung cancer tissues but not in the corresponding non-tumor tissues, supporting its clinical significance. Collectively, our findings highlight the importance of nuclear HO-1 post-translational modification in the induction of cancer progression.

Signal peptide peptidase-mediated nuclear localization of heme oxygenase-1 promotes cancer cell proliferation and invasion independent of its enzymatic activity.

Heme oxygenase-1 (HO-1) is a heme-degrading enzyme anchored in the endoplasmic reticulum by a carboxyl-terminal transmembrane segment (TMS). HO-1 is highly expressed in various cancers and its nuclear localization is associated with the progression of some cancers. Nevertheless, the mechanism underlying HO-1 nuclear translocation and its pathological significance remain elusive. Here we show that the signal peptide peptidase (SPP) catalyzes the intramembrane cleavage of HO-1. Coexpression of HO-1 with wild-type SPP, but not a dominant-negative SPP, promoted the nuclear localization of HO-1 in cells. Mass spectrometry analysis of cytosolic HO-1 isolated from HeLa cells overexpressing HO-1 and SPP revealed two adjacent intramembrane cleavage sites located after S275 and F276 within the TMS. Mutations of S275F276 to A275L276 significantly hindered SPP-mediated HO-1 cleavage and nuclear localization. Nuclear HO-1 was detected in A549 and DU145 cancer cell lines expressing high levels of endogenous HO-1 and SPP. SPP knockdown or inhibition significantly reduced nuclear HO-1 localization in A549 and DU145 cells. The positive nuclear HO-1 stain was also evident in lung cancer tissues expressing high levels of HO-1 and SPP. Overexpression of a truncated HO-1 (t-HO-1) lacking the TMS in HeLa and H1299 cells promoted cell proliferation and migration/invasion. The effect of t-HO-1 was not affected by a mutation in the catalytic site. However, blockade of t-HO-1 nuclear localization abolished t-HO-1-mediated effect. The tumorigenic effect of t-HO-1 was also demonstrated in the mouse model. These findings disclose that SPP-mediated intramembrane cleavage of HO-1 promotes HO-1 nuclear localization and cancer progression independent of HO-1 enzymatic activity.

The rolC gene increases caffeoylquinic acid production in transformed artichoke cells.

Caffeoylquinic acids are found in artichokes, and they are currently considered important therapeutic or preventive agents for treating Alzheimer's disease and diabetes. We transformed artichoke [the cultivated cardoon or Cynara cardunculus var. altilis DC (Asteraceae)] with the rolC gene, which is a known inducer of secondary metabolism. High-performance liquid chromatography with UV and high-resolution mass spectrometry (HPLC-UV-HRMS) revealed that the predominant metabolites synthesized in the transgenic calli were 1,5-dicaffeoylquinic acid, 3,4-dicaffeoylquinic acid, and chlorogenic acid. The rolC-transformed calli contained 1.5% caffeoylquinic acids by dry weight. The overall production of these metabolites was three times higher than that of the corresponding control calli. The enhancing effect of rolC remained stable over long-term cultivation.

TRC8 suppresses tumorigenesis through targeting heme oxygenase-1 for ubiquitination and degradation.

The TRC8 gene, which was previously shown to be disrupted by a 3;8 chromosomal translocation in hereditary kidney cancer, encodes for an endoplasmic reticulum-resident E3 ligase. Studies have shown that TRC8 exhibits a tumor-suppressive effect through its E3-ligase activity. Therefore, the identification of its physiological substrates will provide important insights into the molecular mechanism underlying TRC8-mediated tumor suppression. Here we show that TRC8 targets heme oxygenase-1 (HO-1), an antioxidant enzyme highly expressed in various cancers, for ubiquitination and degradation. Ectopic TRC8 expression suppresses HO-1-induced cancer cell growth and migration/invasion. Conversely, HO-1 depletion reduced the tumorigenic and invasive capacities promoted by TRC8 knockdown. HO-1 downregulation in renal carcinoma cells induces a mitotic delay at G2/M phase by increasing the intracellular reactive oxygen species and the DNA-damage-induced checkpoint activation. These results highlight the tumorigenic role of HO-1 and the importance of TRC8-mediated HO-1 degradation in the control of cancer growth.

A food restriction protocol that increases drug reward decreases tropomyosin receptor kinase B in the ventral tegmental area, with no effect on brain-derived neurotrophic factor or tropomyosin receptor kinase B protein levels in dopaminergic forebrain regions.

Food restriction (FR) decreases brain-derived neurotrophic factor (BDNF) expression in hypothalamic and hindbrain regions that regulate feeding and metabolic efficiency, while increasing expression in hippocampal and neocortical regions. Drugs of abuse alter BDNF expression within the mesocorticolimbic dopamine (DA) pathway, and modifications of BDNF expression within this pathway alter drug-directed behavior. Although FR produces a variety of striatal neuroadaptations and potentiates the rewarding effects of abused drugs, the effects of FR on BDNF expression and function within the DA pathway are unknown. The primary purpose of the present study was to examine the effect of FR on protein levels of BDNF and its tropomyosin receptor kinase B (TrkB) receptor in component structures of the mesocorticolimbic pathway. Three to four weeks of FR, with stabilization of rats at 80% of initial body weight, did not alter BDNF or TrkB levels in nucleus accumbens, caudate-putamen, or medial prefrontal cortex. However, FR decreased TrkB levels in the ventral tegmental area (VTA), without change in levels of BDNF protein or mRNA. The finding that FR also decreased TrkB levels in substantia nigra, with elevation of BDNF protein, suggests that decreased TrkB in VTA could be a residual effect of increased BDNF during an earlier phase of FR. Voltage-clamp recordings in VTA DA neurons indicated decreased glutamate receptor transmission. These data might predict lower average firing rates in FR relative to ad libitum fed subjects, which would be consistent with previous evidence of decreased striatal DA transmission and upregulation of postsynaptic DA receptor signaling. However, FR subjects also displayed elevated VTA levels of phospho-ERK1/2, which is an established mediator of synaptic plasticity. Because VTA neurons are heterogeneous with regard to neurochemistry, function, and target projections, the relationship(s) between the three changes observed in VTA, and their involvement in the augmented striatal and behavioral responsiveness of FR subjects to drugs of abuse, remains speculative.

Transgenic expression of haem oxygenase-1 in pancreatic beta cells protects non-obese mice used as a model of diabetes from autoimmune destruction and prolongs graft survival following islet transplantation.

AIMS/HYPOTHESIS: Haem oxygenase 1 (HO-1) has strong anti-apoptotic, anti-inflammatory and antioxidative effects that help protect cells against various forms of immune attack. We investigated whether transgenic expression of Ho-1 (also known as Hmox1) in pancreatic beta cells would protect NOD mice from autoimmune damage and prolong graft survival following islet transplantation. METHODS: To evaluate the protective effect of beta cell-specific HO-1 in autoimmune diabetes, we used an insulin promoter-driven murine Ho-1 construct (pIns-mHo-1) to generate a transgenic NOD mouse. Transgene expression, insulitis and the incidence of diabetes in mice were characterised. Lymphocyte composition, the development of T helper (Th)1, Th2 and T regulatory (Treg) cells, T cell proliferation and lymphocyte-mediated disease transfer were analysed. The potential effects of transgenic islets and islet transplantation on apoptosis, inflammation and the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) were evaluated. RESULTS: Transgenic mice showed less severe insulitis and a lower incidence of diabetes than non-transgenic control littermates. Lymphocyte composition and functions were not affected. Islets from transgenic mice expressed lower levels of proinflammatory cytokines/chemokines, proapoptotic gene expression and amounts of ROS/RNS, and were more resistant to TNF-α- and IFN-γ-induced apoptosis. Islet grafts from transgenic mice also survived longer in diabetic recipients than control islets. CONCLUSIONS/INTERPRETATION: Transgenic overexpression of Ho-1 in beta cells protected NOD mice from diabetes and delayed the autoimmune destruction of islet grafts, providing valuable insight into the development of better strategies for clinical islet transplantation in patients with type 1 diabetes.

AMPA receptor subunit GluR1 downstream of D-1 dopamine receptor stimulation in nucleus accumbens shell mediates increased drug reward magnitude in food-restricted rats.

Previous findings suggest that neuroadaptations downstream of D-1 dopamine (DA) receptor stimulation in nucleus accumbens (NAc) are involved in the enhancement of drug reward by chronic food restriction (FR). Given the high co-expression of D-1 and GluR1 AMPA receptors in NAc, and the regulation of GluR1 channel conductance and trafficking by D-1-linked intracellular signaling cascades, the present study examined effects of the D-1 agonist, SKF-82958, on NAc GluR1 phosphorylation, intracranial electrical self-stimulation reward (ICSS), and reversibility of reward effects by a polyamine GluR1 antagonist, 1-NA-spermine, in ad libitum fed (AL) and FR rats. Systemically administered SKF-82958, or brief ingestion of a 10% sucrose solution, increased NAc GluR1 phosphorylation on Ser845, but not Ser831, with a greater effect in FR than AL rats. Microinjection of SKF-82958 in NAc shell produced a reward-potentiating effect that was greater in FR than AL rats, and was reversed by co-injection of 1-NA-spermine. GluR1 abundance in whole cell and synaptosomal fractions of NAc did not differ between feeding groups, and microinjection of AMPA, while affecting ICSS, did not exert greater effects in FR than AL rats. These results suggest a role of NAc GluR1 in the reward-potentiating effect of D-1 DA receptor stimulation and its enhancement by FR. Moreover, GluR1 involvement appears to occur downstream of D-1 DA receptor stimulation rather than reflecting a basal increase in GluR1 expression or function. Based on evidence that phosphorylation of GluR1 on Ser845 primes synaptic strengthening, the present results may reflect a mechanism via which FR normally facilitates reward-related learning to re-align instrumental behavior with environmental contingencies under the pressure of negative energy balance.