Increases in regional brain volume across two native South American male populations.

Industrialized environments, despite benefits such as higher levels of formal education and lower rates of infections, can also have pernicious impacts upon brain atrophy. Partly for this reason, comparing age-related brain volume trajectories between industrialized and non-industrialized populations can help to suggest lifestyle correlates of brain health. The Tsimane, indigenous to the Bolivian Amazon, derive their subsistence from foraging and horticulture and are physically active. The Moseten, a mixed-ethnicity farming population, are physically active but less than the Tsimane. Within both populations (N = 1024; age range = 46-83), we calculated regional brain volumes from computed tomography and compared their cross-sectional trends with age to those of UK Biobank (UKBB) participants (N = 19,973; same age range). Surprisingly among Tsimane and Moseten (T/M) males, some parietal and occipital structures mediating visuospatial abilities exhibit small but significant increases in regional volume with age. UKBB males exhibit a steeper negative trend of regional volume with age in frontal and temporal structures compared to T/M males. However, T/M females exhibit significantly steeper rates of brain volume decrease with age compared to UKBB females, particularly for some cerebro-cortical structures (e.g., left subparietal cortex). Across the three populations, observed trends exhibit no interhemispheric asymmetry. In conclusion, the age-related rate of regional brain volume change may differ by lifestyle and sex. The lack of brain volume reduction with age is not known to exist in other human population, highlighting the putative role of lifestyle in constraining regional brain atrophy and promoting elements of non-industrialized lifestyle like higher physical activity.

What are the experiences of supportive care in people affected by brain cancer and their informal caregivers: A qualitative systematic review.

PURPOSE: To critically synthesise qualitative research to understand experiences of supportive care in people affected by brain cancer and their informal caregivers. METHODS: A qualitative systematic review was conducted according to the Joanna Briggs methodology and has been reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) Guidelines. Electronic databases were searched by an expert systematic review librarian for all qualitative studies irrespective of research design. All publications were double screened by two reviewers using a pre-determined exclusion and inclusion criteria. The review was managed using Covidence systematic review software. Methodological quality assessment and data extraction were performed. Qualitative findings accompanied by illustrative quotes from included studies were extracted and grouped into categories, which created the overall synthesised findings. RESULTS: A total of 33 studies were included which represented a total sample of 671 participants inclusive of 303 patients and 368 informal caregivers. There was a total of 220 individual findings included in this review, which were synthesised into two findings (1) caregivers and patients perceived supports which would have been helpful and (2) caregiver and patient experiences of unmet supportive care needs. CONCLUSION: This review highlighted the suffering and distress caused by brain cancer and associated treatments. Both patients and their informal caregivers experienced disconnect from themselves in renegotiating roles, and a profound sense of loneliness as the physical deterioration of the disease progressed. Both patients and informal caregivers reported similar unmet needs within the current service provision for brain cancer. However, what is apparent is that current cancer services are provided solely for patients, with little or no consideration to the support needs of both the patient and their informal caregiver. Service re-design is needed to improve care coordination with individualised informational support, implementation of holistic needs assessments for both the patients and their caregivers, better community support provision, improved opportunities for emotional care with early referral for palliative care services. IMPLICATIONS FOR CANCER SURVIVORS: It is recommended that members of the multidisciplinary brain cancer team reflect on these findings to target holistic needs assessments and develop shared self-management care plans for both the patient and the informal caregiver.

Brain volume, energy balance, and cardiovascular health in two nonindustrial South American populations.

Little is known about brain aging or dementia in nonindustrialized environments that are similar to how humans lived throughout evolutionary history. This paper examines brain volume (BV) in middle and old age among two indigenous South American populations, the Tsimane and Moseten, whose lifestyles and environments diverge from those in high-income nations. With a sample of 1,165 individuals aged 40 to 94, we analyze population differences in cross-sectional rates of decline in BV with age. We also assess the relationships of BV with energy biomarkers and arterial disease and compare them against findings in industrialized contexts. The analyses test three hypotheses derived from an evolutionary model of brain health, which we call the embarrassment of riches (EOR). The model hypothesizes that food energy was positively associated with late life BV in the physically active, food-limited past, but excess body mass and adiposity are now associated with reduced BV in industrialized societies in middle and older ages. We find that the relationship of BV with both non-HDL cholesterol and body mass index is curvilinear, positive from the lowest values to 1.4 to 1.6 SDs above the mean, and negative from that value to the highest values. The more acculturated Moseten exhibit a steeper decrease in BV with age than Tsimane, but still shallower than US and European populations. Lastly, aortic arteriosclerosis is associated with lower BV. Complemented by findings from the United States and Europe, our results are consistent with the EOR model, with implications for interventions to improve brain health.

Prevalence of dementia and mild cognitive impairment in indigenous Bolivian forager-horticulturalists.

INTRODUCTION: We evaluated the prevalence of dementia and mild cognitive impairment (MCI) in indigenous Tsimane and Moseten, who lead a subsistence lifestyle. METHODS: Participants from population-based samples ≥ 60 years of age (n = 623) were assessed using adapted versions of the Modified Mini-Mental State Examination, informant interview, longitudinal cognitive testing and brain computed tomography (CT) scans. RESULTS: Tsimane exhibited five cases of dementia (among n = 435; crude prevalence = 1.2%, 95% confidence interval [CI]: 0.4, 2.7); Moseten exhibited one case (among n = 169; crude prevalence = 0.6%, 95% CI: 0.0, 3.2), all age ≥ 80 years. Age-standardized MCI prevalence was 7.7% (95% CI: 5.2, 10.3) in Tsimane and 9.8% (95% CI: 4.9, 14.6) in Moseten. Cognitive impairment was associated with visuospatial impairments, parkinsonian symptoms, and vascular calcification in the basal ganglia. DISCUSSION: The prevalence of dementia in this cohort is among the lowest in the world. Widespread intracranial medial arterial calcifications suggest a previously unrecognized, non-Alzheimer's disease (AD) dementia phenotype.

The Indigenous South American Tsimane Exhibit Relatively Modest Decrease in Brain Volume With Age Despite High Systemic Inflammation.

Brain atrophy is correlated with risk of cognitive impairment, functional decline, and dementia. Despite a high infectious disease burden, Tsimane forager-horticulturists of Bolivia have the lowest prevalence of coronary atherosclerosis of any studied population and present few cardiovascular disease (CVD) risk factors despite a high burden of infections and therefore inflammation. This study (a) examines the statistical association between brain volume (BV) and age for Tsimane and (b) compares this association to that of 3 industrialized populations in the United States and Europe. This cohort-based panel study enrolled 746 participants aged 40-94 (396 males), from whom computed tomography (CT) head scans were acquired. BV and intracranial volume (ICV) were calculated from automatic head CT segmentations. The linear regression coefficient estimate ß^T of the Tsimane (T), describing the relationship between age (predictor) and BV (response, as a percentage of ICV), was calculated for the pooled sample (including both sexes) and for each sex. ß^T was compared to the corresponding regression coefficient estimate ß^R of samples from the industrialized reference (R) countries. For all comparisons, the null hypothesis ß T = ß R was rejected both for the combined samples of males and females, as well as separately for each sex. Our results indicate that the Tsimane exhibit a significantly slower decrease in BV with age than populations in the United States and Europe. Such reduced rates of BV decrease, together with a subsistence lifestyle and low CVD risk, may protect brain health despite considerable chronic inflammation related to infectious burden.

Income disparity in school readiness and the mediating role of perinatal maternal mental health: a longitudinal birth cohort study.

AIMS: There is compelling evidence for gradient effects of household income on school readiness. Potential mechanisms are described, yet the growth curve trajectory of maternal mental health in a child's early life has not been thoroughly investigated. We aimed to examine the relationships between household incomes, maternal mental health trajectories from antenatal to the postnatal period, and school readiness. METHODS: Prospective data from 505 mother-child dyads in a birth cohort in Singapore were used, including household income, repeated measures of maternal mental health from pregnancy to 2-years postpartum, and a range of child behavioural, socio-emotional and cognitive outcomes from 2 to 6 years of age. Antenatal mental health and its trajectory were tested as mediators in the latent growth curve models. RESULTS: Household income was a robust predictor of antenatal maternal mental health and all child outcomes. Between children from the bottom and top household income quartiles, four dimensions of school readiness skills differed by a range of 0.52 (95% Cl: 0.23, 0.67) to 1.21 s.d. (95% CI: 1.02, 1.40). Thirty-eight percent of pregnant mothers in this cohort were found to have perinatal depressive and anxiety symptoms in the subclinical and clinical ranges. Poorer school readiness skills were found in children of these mothers when compared to those of mothers with little or no symptoms. After adjustment of unmeasured confounding on the indirect effect, antenatal maternal mental health provided a robust mediating path between household income and multiple school readiness outcomes (χ2 126.05, df 63, p < 0.001; RMSEA = 0.031, CFI = 0.980, SRMR = 0.034). CONCLUSIONS: Pregnant mothers with mental health symptoms, particularly those from economically-challenged households, are potential targets for intervention to level the playing field of their children.

Tablet-based electroencephalography diagnostics for patients with epilepsy in the West African Republic of Guinea.

BACKGROUND AND PURPOSE: Epilepsy is most common in lower-income settings where access to electroencephalography (EEG) is generally poor. A low-cost tablet-based EEG device may be valuable, but the quality and reproducibility of the EEG output are not established. METHODS: Tablet-based EEG was deployed in a heterogeneous epilepsy cohort in the Republic of Guinea (2018-2019), consisting of a tablet wirelessly connected to a 14-electrode cap. Participants underwent EEG twice (EEG1 and EEG2), separated by a variable time interval. Recordings were scored remotely by experts in clinical neurophysiology as to data quality and clinical utility. RESULTS: There were 149 participants (41% female; median age 17.9 years; 66.6% ≤21 years of age; mean seizures per month 5.7 ± SD 15.5). The mean duration of EEG1 was 53 ± 12.3 min and that of EEG2 was 29.6 ± 12.8 min. The mean quality scores of EEG1 and EEG2 were 6.4 [range, 1 (low) to 10 (high); both medians 7.0]. A total of 44 (29.5%) participants had epileptiform discharges (EDs) at EEG1 and 25 (16.8%) had EDs at EEG2. EDs were focal/multifocal (rather than generalized) in 70.1% of EEG1 and 72.5% of EEG2 interpretations. A total of 39 (26.2%) were recommended for neuroimaging after EEG1 and 22 (14.8%) after EEG2. Of participants without EDs at EEG1 (n = 53, 55.8%), seven (13.2%) had EDs at EEG2. Of participants with detectable EDs on EEG1 (n = 23, 24.2%), 12 (52.1%) did not have EDs at EEG2. CONCLUSIONS: Tablet-based EEG had a reproducible quality level on repeat testing and was useful for the detection of EDs. The incremental yield of a second EEG in this setting was ~13%. The need for neuroimaging access was evident.

Brain Segmentation From Computed Tomography of Healthy Aging and Geriatric Concussion at Variable Spatial Resolutions.

When properly implemented and processed, anatomic T 1-weighted magnetic resonance imaging (MRI) can be ideal for the noninvasive quantification of white matter (WM) and gray matter (GM) in the living human brain. Although MRI is more suitable for distinguishing GM from WM than computed tomography (CT), the growing clinical use of the latter technique has renewed interest in head CT segmentation. Such interest is particularly strong in settings where MRI is unavailable, logistically unfeasible or prohibitively expensive. Nevertheless, whereas MRI segmentation is a sophisticated and technically-mature research field, the task of automatically classifying soft brain tissues from CT remains largely unexplored. Furthermore, brain segmentation methods for MRI hold considerable potential for adaptation and application to CT image processing. Here we demonstrate this by combining probabilistic, atlas-based classification with topologically-constrained tissue boundary refinement to delineate WM, GM and cerebrospinal fluid (CSF) from head CT images. The feasibility and utility of this approach are revealed by comparison of MRI-only vs. CT-only segmentations in geriatric concussion victims with both MRI and CT scans. Comparison of the two segmentations yields mean Sørensen-Dice coefficients of 85.5 ± 4.6% (WM), 86.7 ± 5.6% (GM) and 91.3 ± 2.8% (CSF), as well as average Hausdorff distances of 3.76 ± 1.85 mm (WM), 3.43 ± 1.53 mm (GM) and 2.46 ± 1.27 mm (CSF). Bootstrapping results suggest that the segmentation approach is sensitive enough to yield WM, GM and CSF volume estimates within ~5%, ~4%, and ~3% of their MRI-based estimates, respectively. To our knowledge, this is the first 3D segmentation approach for CT to undergo rigorous within-subject comparison with high-resolution MRI. Results suggest that (1) standard-quality CT allows WM/GM/CSF segmentation with reasonable accuracy, and that (2) the task of soft brain tissue classification from CT merits further attention from neuroimaging researchers.

The first pilot study of expanded newborn screening for inborn errors of metabolism and survey of related knowledge and opinions of health care professionals in Hong Kong.

INTRODUCTION: Newborn screening is important for early diagnosis and effective treatment of inborn errors of metabolism (IEM). In response to a 2008 coroners' report of a 14-year-old boy who died of an undiagnosed IEM, the OPathPaed service model was proposed. In the present study, we investigated the feasibility of the OPathPaed model for delivering expanded newborn screening in Hong Kong. In addition, health care professionals were surveyed on their knowledge and opinions of newborn screening for IEM. METHODS: The present prospective study involving three regional hospitals was conducted in phases, from 1 October 2012 to 31 August 2014. The 10 steps of the OPathPaed model were evaluated: parental education, consent, sampling, sample dispatch, dried blood spot preparation and testing, reporting, recall and counselling, confirmation test, treatment and monitoring, and cost-benefit analysis. A fully automated online extraction system for dried blood spot analysis was also evaluated. A questionnaire was distributed to 430 health care professionals by convenience sampling. RESULTS: In total, 2440 neonates were recruited for newborn screening; no true-positive cases were found. Completed questionnaires were received from 210 respondents. Health care professionals supported implementation of an expanded newborn screening for IEM. In addition, there is a substantial need of more education for health care professionals. The majority of respondents supported implementing the expanded newborn screening for IEM immediately or within 3 years. CONCLUSION: The feasibility of OPathPaed model has been confirmed. It is significant and timely that when this pilot study was completed, a government-led initiative to study the feasibility of newborn screening for IEM in the public health care system on a larger scale was announced in the Hong Kong Special Administrative Region Chief Executive Policy Address of 2015.

Resistance to HSP90 inhibition involving loss of MCL1 addiction.

Inhibition of the chaperone heat-shock protein 90 (HSP90) induces apoptosis, and it is a promising anti-cancer strategy. The mechanisms underpinning apoptosis activation following HSP90 inhibition and how they are modified during acquired drug resistance are unknown. We show for the first time that, to induce apoptosis, HSP90 inhibition requires the cooperation of multi BH3-only proteins (BID, BIK, PUMA) and the reciprocal suppression of the pro-survival BCL-2 family member MCL1, which occurs via inhibition of STAT5A. A subset of tumour cell lines exhibit dependence on MCL1 expression for survival and this dependence is also associated with tumour response to HSP90 inhibition. In the acquired resistance setting, MCL1 suppression in response to HSP90 inhibitors is maintained; however, a switch in MCL1 dependence occurs. This can be exploited by the BH3 peptidomimetic ABT737, through non-BCL-2-dependent synthetic lethality.

Activation of the insulin-signaling pathway in sciatic nerve and hippocampus of type 1 diabetic rats.

Peripheral neuropathy is a major complication associated with diabetes and central neuropathy characterized by Alzheimer's disease-like features in the brain is associated with increased dementia risk for patients with diabetes. Although glucose uptake into the cells of the nervous system is insulin-independent, contribution of impaired insulin support is clearly recognized to play a role, however not yet fully understood, in the development of neuropathy. In this study, we assessed the direct role of insulin on the peripheral nervous system (PNS) and central nervous system (CNS) of insulin-dependent type 1 diabetic rats. Fresh sciatic nerve and hippocampus from control and diabetic rats were incubated with varied ex vivo concentrations of insulin and phosphorylation levels of insulin receptor and glycogen synthase kinase-3 (GSK3ß) were assessed by Western blot analysis. Both the sciatic nerve and hippocampus from type 1 diabetic rats were highly responsive to exogenous insulin with a significantly increased phosphorylation of insulin receptor and GSK3 compared to tissues from control rats. Further, sustained in vivo insulin delivery, not sufficient to restore normal blood glucose, normalized the activation of both insulin receptor and GSK3 in both PNS and CNS tissues. These results suggest that the insulin-signaling pathway is responsive to exogenous insulin in the nervous system of insulin-deficient type 1 diabetic rats and that constant insulin delivery restore normal nerve function and may protect PNS and CNS from damage.

SAA1 polymorphisms are associated with variation in antiangiogenic and tumor-suppressive activities in nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is a cancer that occurs in high frequency in Southern China. A previous functional complementation approach and the subsequent cDNA microarray analysis have identified that serum amyloid A1 (SAA1) is an NPC candidate tumor suppressor gene. SAA1 belongs to a family of acute-phase proteins that are encoded by five polymorphic coding alleles. The SAA1 genotyping results showed that only three SAA1 isoforms (SAA1.1, 1.3 and 1.5) were observed in both Hong Kong NPC patients and healthy individuals. This study aims to determine the functional role of SAA1 polymorphisms in tumor progression and to investigate the relationship between SAA1 polymorphisms and NPC risk. Indeed, we have shown that restoration of SAA1.1 and 1.3 in the SAA1-deficient NPC cell lines could suppress tumor formation and angiogenesis in vitro and in vivo. The secreted SAA1.1 and SAA1.3 proteins can block cell adhesion and induce apoptosis in the vascular endothelial cells. In contrast, the SAA1.5 cannot induce apoptosis or inhibit angiogenesis because of its weaker binding affinity to αVß3 integrin. This can explain why SAA1.5 has no tumor-suppressive effects. Furthermore, the NPC tumors with this particular SAA1.5/1.5 genotype showed higher levels of SAA1 gene expression, and SAA1.1 and 1.3 alleles were preferentially inactivated in tumor tissues that were examined. These findings further strengthen the conclusion for the defective function of SAA1.5 in suppression of tumor formation and angiogenesis. Interestingly, the frequency of the SAA1.5/1.5 genotype in NPC patients was ~2-fold higher than in the healthy individuals (P=0.00128, odds ratio=2.28), which indicates that this SAA1 genotype is significantly associated with a higher NPC risk. Collectively, this homozygous SAA1.5/1.5 genotype appears to be a recessive susceptibility gene, which has lost the antiangiogenic function, whereas SAA1.1 and SAA1.3 are the dominant alleles of the tumor suppressor phenotype.

Importance of baseline specification in evaluating conservation interventions and achieving no net loss of biodiversity.

There is an urgent need to improve the evaluation of conservation interventions. This requires specifying an objective and a frame of reference from which to measure performance. Reference frames can be baselines (i.e., known biodiversity at a fixed point in history) or counterfactuals (i.e., a scenario that would have occurred without the intervention). Biodiversity offsets are interventions with the objective of no net loss of biodiversity (NNL). We used biodiversity offsets to analyze the effects of the choice of reference frame on whether interventions met stated objectives. We developed 2 models to investigate the implications of setting different frames of reference in regions subject to various biodiversity trends and anthropogenic impacts. First, a general analytic model evaluated offsets against a range of baseline and counterfactual specifications. Second, a simulation model then replicated these results with a complex real world case study: native grassland offsets in Melbourne, Australia. Both models showed that achieving NNL depended upon the interaction between reference frame and background biodiversity trends. With a baseline, offsets were less likely to achieve NNL where biodiversity was decreasing than where biodiversity was stable or increasing. With a no-development counterfactual, however, NNL was achievable only where biodiversity was declining. Otherwise, preventing development was better for biodiversity. Uncertainty about compliance was a stronger determinant of success than uncertainty in underlying biodiversity trends. When only development and offset locations were considered, offsets sometimes resulted in NNL, but not across an entire region. Choice of reference frame determined feasibility and effort required to attain objectives when designing and evaluating biodiversity offset schemes. We argue the choice is thus of fundamental importance for conservation policy. Our results shed light on situations in which biodiversity offsets may be an inappropriate policy instrument.

Reciprocal longitudinal associations between pain and depressive symptoms in adolescents.

BACKGROUND: Elevated depressive symptoms are common in youth with chronic pain, and pain symptoms are frequent in adolescents with depressive disorders. While studies have identified concurrent associations between pain and depression over time in youth, it is unclear how change in one symptom impacts change in the other symptom. METHODS: This three-time point 12-month longitudinal study examined reciprocal associations among pain and depression in a clinical sample of adolescents (12-18) diagnosed with chronic pain (n = 55) or a depressive disorder (n = 40). Mixed-effects multivariate models were used to test if changes over a preceding time interval predicted symptom severity at subsequent time points. Study group, age, sex, race, baseline pain intensity and baseline depressive symptoms were included as covariates. RESULTS: Generalized estimating equations revealed that pain and depressive symptoms were significantly associated over time (ß = 1.54; p < 0.001). As hypothesized, changes in pain were associated with subsequent depressive symptoms (ß = 1.16; p < 0.001). Conversely, changes in depressive symptoms predicted subsequent pain (ß = 0.026; p < 0.05), but with a weaker association. In the model predicting pain, an interaction between depressive symptoms and study group emerged (ß = -0.02; p < 0.05), with change in depressive symptoms having the greatest impact on pain in the depressed sample. CONCLUSIONS: Findings extend previous adult research to an adolescent sample showing changes in pain intensity are predictive of subsequent depressive symptoms. In comparison to adult data, changes in depressive symptoms had less impact on subsequent pain in youth. Future research can examine how targeting persistent pain may also aid the treatment of depressive symptoms in adolescents.

Anti-angiogenic and tumor-suppressive roles of candidate tumor-suppressor gene, Fibulin-2, in nasopharyngeal carcinoma.

Fibulin-2 (FBLN2) has been identified as a candidate tumor-suppressor gene in nasopharyngeal carcinoma (NPC). Originally identified through a chromosome 3 NotI genomic microarray screen, it shows frequent deletion or methylation in NPC. FBLN2 is located on chromosome 3p25.1 and is associated with tumor development through its important interactions with the extracellular matrix (ECM) proteins. FBLN2 encodes two isoforms. The short isoform (FBLN2S) is expressed abundantly in normal tissues, but is dramatically downregulated in NPC, while the long isoform (FBLN2L) is either not detectable or is expressed only at low levels in both normal and tumor tissues. Reintroduction of this FBLN2S inhibited cell proliferation, migration, invasion and angiogenesis in vitro. Furthermore, in vivo studies in nude mice show its expression is associated with tumor and angiogenesis suppression. FBLN2-associated angiogenesis occurs via concomitant downregulation of vascular endothelial growth factor and matrix metalloproteinase 2. This study provides compelling evidence that FBLN2S has an important tumor-suppressive and anti-angiogenic role in NPC.

Validation of a food frequency questionnaire to measure intakes of inulin and oligofructose.

BACKGROUND AND OBJECTIVES: Inulin and oligofructose are prebiotic carbohydrates associated with numerous health benefits. The aim of this study was to accurately measure inulin and oligofructose intakes and to develop and validate a food frequency questionnaire (FFQ). SUBJECTS AND METHODS: A 7-d semi-weighed food diary (FD) was used to measure intakes in 66 healthy subjects. A 23-item FFQ was developed to measure short-term inulin and oligofructose intakes over the same 7 days and was completed twice on 2 separate days. RESULTS: There were no significant differences in inulin intake (4.0 ± 1.3 vs 4.0 ± 1.4 g/d, P = 0.646) or oligofructose intake (3.8 ± 1.2 vs 3.8 ± 1.3 g/d, P = 0.864) when measured using the 7-d FD or the FFQ. Bland-Altman analysis demonstrated low mean differences between the FD and FFQ in measuring intakes of inulin (-0.09 g/d) and oligofructose (-0.03 g/d). The FFQ categorised 89% of subjects into the same or adjacent tertiles of intakes as the 7-d FD. For the majority of food items, kappa values indicated 'substantial' or 'almost perfect' agreement for assignment of 'portion size' and 'frequency of consumption' between the FFQs completed on separate days. CONCLUSIONS: The FFQ is a valid and reliable method for measuring short-term inulin and oligofructose intakes for use in dietary surveys and clinical trials.

Differences between amyloid toxicity in alpha and beta cells in human and mouse islets and the role of caspase-3.

AIMS/HYPOTHESIS: Type 2 diabetes is characterised by decreased beta cell mass and islet amyloid formation. Islet amyloid formed by aggregation of human islet amyloid polypeptide (hIAPP) is associated with beta cell apoptosis. We used human and transgenic mouse islets in culture to examine whether deletion of caspase-3 protects islets from apoptosis induced by endogenously produced and exogenously applied hIAPP and compared hIAPP toxicity in islet alpha and beta cells. METHODS: Human and wild-type or caspase-3 knockout mouse islet cells were treated with hIAPP. Rat insulinoma INS-1 cells were similarly cultured with hIAPP and the amyloid inhibitor Congo Red or caspase-3 inhibitor. Human and hIAPP-expressing caspase-3 knockout mouse islets were cultured to form amyloid fibrils and assessed for beta and alpha cell apoptosis, beta cell function and caspase-3 activation. RESULTS: hIAPP-treated INS-1 cells had increased caspase-3 activation and apoptosis, both of which were reduced by inhibitors of amyloid or caspase-3. Similarly, hIAPP-treated human and mouse islet beta cells had elevated active caspase-3- and TUNEL-positive cells, whereas mouse islet cells lacking caspase-3 had markedly lower beta cell but comparable alpha cell apoptosis. During culture, human islets that formed amyloid had higher active caspase-3- and TUNEL-positive beta cells than those without detectable amyloid. Finally, cultured hIAPP-expressing mouse islets lacking caspase-3 had markedly lower beta cell apoptosis than those expressing caspase-3, associated with an increase in islet beta cell/alpha cell ratio, insulin content and glucose response. CONCLUSIONS/INTERPRETATION: Prevention of caspase-3 activation protects islet beta cells from apoptosis induced by fibrillogenesis of endogenously secreted and exogenously applied hIAPP. Islet beta cells are more susceptible to hIAPP toxicity than alpha cells cultured under the same conditions.

Epoxyeicosatrienoic acid prevents postischemic electrocardiogram abnormalities in an isolated heart model.

Cytochrome P450 epoxygenases metabolize arachidonic acid (AA) to epoxyeicosatrienoic acids (EETs) which are in turn converted to dihydroxyeicosatrienoic acids (DHETs) by soluble epoxide hydrolase (sEH). The main objective of this study was to investigate the protective effects of EETs following ischemic injury using an ex vivo electrocardiogram (EKG) model. Hearts from C57Bl/6, transgenic mice with cardiomyocyte-specific overexpression of CYP2J2 (Tr) and wildtype (WT) littermates were excised and perfused with constant pressure in a Langendorff apparatus. Electrodes were placed superficially at the right atrium and left ventricle to assess EKG waveforms. In ischemic reperfusion experiments hearts were subjected to 20 min of global no-flow ischemia followed by 20 min of reperfusion (R20). The EKG from C57Bl/6 hearts perfused with 1 microM 14,15-EET showed less QT prolongation (QTc) and ST elevation (STE) (QTc=41+/-3, STE=2.3+/-0.3; R20: QTc=42+/-2 ms, STE=1.2+/-0.2mv) than control hearts (QTc=36+/-2, STE=2.3+/-0.2; R20: QTc=53+/-3 ms; STE=3.6+/-0.4mv). Similar results of reduced QT prolongation and ST elevation were observed in EKG recording from CYP2J2 Tr mice (QTc=35+/-1, STE=1.9+/-0.1; R20: QTc=38+/-4 ms, STE=1.3+/-0.2mv) compared to WT hearts. The putative epoxygenase inhibitor MS-PPOH (50 microM) and EET antagonist 14,15-EEZE (10 microM) both abolished the cardioprotective response, implicating EETs in this process. In addition, separate exposure to the K(ATP) channel blockers glibenclamide (1 microM) and HMR1098 (10 microM), or the PKA protein inhibitor H89 (50 nM) during reperfusion abolished the improved repolarization in both the models. Consistent with a role of PKA, CYP2J2 Tr mice had an enhanced activation of the PKAalpha regulatory II subunit in plasma membrane following IR injury. The present data demonstrate that EETs can enhance the recovery of ventricular repolarization following ischemia, potentially by facilitating activation of K(+) channels and PKA-dependent signaling.

Inactivation of the mouse adenylyl cyclase 3 gene disrupts male fertility and spermatozoon function.

Mammalian spermatids and spermatozoa express functional G protein-coupled receptors. However, bicarbonate-regulated soluble adenylyl cyclase (AC), the major AC present in these cells, is not directly coupled to G proteins. To understand how G protein-coupled receptors signal in spermatozoa, we investigated whether a conventional transmembrane cyclase is present and biologically active in these cells. Here, we provide evidence for expression of type 3 AC (AC3) in male germ cells and describe the effects of disruption of the AC3 gene on fertility and function of mouse spermatozoa. As previously reported in rat, AC3 mRNA is expressed in mouse testes and localized, together with soluble AC mRNA, mainly in postmeiotic germ cells. AC3 protein was detected by immunolocalization in round and elongating spermatids in a region corresponding to the developing acrosome and was retained in the mature spermatozoa of the epididymis. Forskolin caused a small increase in cAMP production in mouse spermatozoa, but this increase could not be detected in the AC3(-/-) mice. Inactivation of the AC3 gene did not have overt effects on spermatogenesis; however, AC3(-/-) males were subfertile with only three litters generated by 11 males over a period of 6 months. When used in in vitro fertilization, spermatozoa from these AC3(-/-) mice produced few embryos, but their fertilizing ability was restored after removal of the zona pellucida. Despite an apparently normal structure, these spermatozoa had decreased motility and showed an increase in spontaneous acrosome reactions. These data support the hypothesis that AC3 is required for normal spermatid or spermatozoa function and male fertility.