Transmembrane and coiled-coil 2 associates with Alzheimer's disease pathology in the human brain.

Transmembrane and coiled-coil 2 (TMCC2) is a human orthologue of the Drosophila gene dementin, mutant alleles of which cause neurodegeneration with features of Alzheimer's disease (AD). TMCC2 and Dementin further have an evolutionarily conserved interaction with the amyloid protein precursor (APP), a protein central to AD pathogenesis. To investigate if human TMCC2 might also participate in mechanisms of neurodegeneration, we examined TMCC2 expression in late onset AD human brain and age-matched controls, familial AD cases bearing a mutation in APP Val717, and Down syndrome AD. Consistent with previous observations of complex formation between TMCC2 and APP in the rat brain, the dual immunocytochemistry of control human temporal cortex showed highly similar distributions of TMCC2 and APP. In late onset AD cases stratified by APOE genotype, TMCC2 immunoreactivity was associated with dense core senile plaques and adjacent neuronal dystrophies, but not with Aß surrounding the core, diffuse Aß plaques or tauopathy. In Down syndrome AD, we observed in addition TMCC2-immunoreactive and methoxy-X04-positive pathological features that were morphologically distinct from those seen in the late onset and familial AD cases, suggesting enhanced pathological alteration of TMCC2 in Down syndrome AD. At the protein level, western blots of human brain extracts revealed that human brain-derived TMCC2 exists as at least three isoforms, the relative abundance of which varied between the temporal gyrus and cerebellum and was influenced by APOE and/or dementia status. Our findings thus implicate human TMCC2 in AD via its interactions with APP, its association with dense core plaques, as well as its alteration in Down syndrome AD.

Obesity does not alter vascular function and handgrip exercise hemodynamics in middle-aged patients with hypertension.

Lifestyle modification including exercise training is often the first line of defense in the treatment of obesity and hypertension (HTN), however, little is known regarding how these potentially compounding disease states impact vasodilatory and hemodynamic responses at baseline and exercise. Therefore, this study sought to compare the impact of obesity on vascular function and hemodynamics at baseline and during handgrip (HG) exercise among individuals with HTN. Non-obese (13M/7F, 56 ± 16 yr, 25 ± 4 kg/m2) and obese (17M/4F, 50 ± 7 yr, 35 ± 4 kg/m2) middle-aged individuals with HTN forwent antihypertensive medication use for ≥2 wk before assessment of vascular function by brachial artery flow-mediated dilation (FMD) and exercise hemodynamics during progressive HG exercise at 15-30-45% maximal voluntary contraction (MVC). FMD was not different between Non-Obese (4.1 ± 1.7%) and Obese (5.2 ± 1.9%, P = 0.11). Systolic blood pressure (SBP) was elevated by ∼15% during the supine baseline and during HG exercise in the obese group. The blood flow response to HG exercise at 30% and 45% MVC was ∼20% greater (P < 0.05) in the obese group but not different after normalizing for the higher, albeit, nonsignificant differences in workloads (MVC: obese: 24 ± 5 kg, non-obese: 21 ± 5 kg, P = 0.11). Vascular conductance and the brachial artery shear-induced vasodilatory response during HG were not different between groups (P > 0.05). Taken together, despite elevated SBP during HG exercise, obesity does not lead to additional impairments in vascular function and peripheral exercising hemodynamics in patients with HTN. Obesity may not be a contraindication when prescribing exercise for the treatment of HTN among middle-aged adults, however, the elevated SBP should be appropriately monitored.NEW & NOTEWORTHY This study examined vascular function and handgrip exercise hemodynamics in obese and nonobese individuals with hypertension. Obesity, when combined with hypertension, was neither associated with additional vascular function impairments at baseline nor peripheral hemodynamics and vasodilation during exercise compared with nonobese hypertension. Interestingly, systolic blood pressure and pulse pressure were greater in the obese group during supine baseline and exercise. These findings should not be ignored and may be particularly important for rehabilitation strategies.

A candidate locus in the renalase gene and susceptibility to blood pressure responses to the dietary salt.

BACKGROUND: High dietary salt confers a risk of elevating blood pressure (BP) and the development of hypertension. BP to salt intake may be determined in part by individual genetic predisposition. Identifying these genetic underpinnings will enhance our understanding of the biological mechanisms of BP regulation. This study aims to assess the genetic association with salt sensitivity of BP (SSBP) within two well-phenotyped multinational cohorts. METHODS: A total of 720 white participants from the HyperPATH consortium program were selected and genotyped using a multiethnic genotyping array. Individuals consumed two study diets containing high (>200 mEq/day) and low (<10 mEq/day) sodium content, after which SSBP, aldosterone, and plasma renin activity (PRA) were assessed in a controlled inpatient research setting. RESULTS: A top signal (rs10887801; beta = 4.57, P  = 5.03E - 07) at the renalase gene ( RNLS ) region was significantly associated with SSBP. We also identified seven single nucleotide variants with linkage disequilibrium to the top signal at this region that comprised a significant haplotype (TCTTAGTT, P  = 0.00081). Homozygous carriers of the T-risk allele of the key single nucleotide variant had higher SSBP ( P  ≤ 0.00001) and lower PRA ( P  = 0.0076) compared with the nonrisk allele. CONCLUSION: We identified significant associations between genetic variants of the RNLS gene and BP responses to dietary salt intervention and PRA that suggest susceptibility to volume-driven hypertension. These findings may contribute to a better understanding of the genetic mechanisms underlying BP regulation, support the role of RNLS in the pathogenesis of SSBP, and identify individuals who may be at risk from excess dietary salt intake.

Structural basis of tankyrase activation by polymerization.

The poly-ADP-ribosyltransferase tankyrase (TNKS, TNKS2) controls a wide range of disease-relevant cellular processes, including WNT-ß-catenin signalling, telomere length maintenance, Hippo signalling, DNA damage repair and glucose homeostasis1,2. This has incentivized the development of tankyrase inhibitors. Notwithstanding, our knowledge of the mechanisms that control tankyrase activity has remained limited. Both catalytic and non-catalytic functions of tankyrase depend on its filamentous polymerization3-5. Here we report the cryo-electron microscopy reconstruction of a filament formed by a minimal active unit of tankyrase, comprising the polymerizing sterile alpha motif (SAM) domain and its adjacent catalytic domain. The SAM domain forms a novel antiparallel double helix, positioning the protruding catalytic domains for recurring head-to-head and tail-to-tail interactions. The head interactions are highly conserved among tankyrases and induce an allosteric switch in the active site within the catalytic domain to promote catalysis. Although the tail interactions have a limited effect on catalysis, they are essential to tankyrase function in WNT-ß-catenin signalling. This work reveals a novel SAM domain polymerization mode, illustrates how supramolecular assembly controls catalytic and non-catalytic functions, provides important structural insights into the regulation of a non-DNA-dependent poly-ADP-ribosyltransferase and will guide future efforts to modulate tankyrase and decipher its contribution to disease mechanisms.

Persistent vascular dysfunction following an acute nonpharmacological reduction in blood pressure in hypertensive patients.

BACKGROUND: Vascular dysfunction, an independent risk factor for cardiovascular disease, often persists in patients with hypertension, despite improvements in blood pressure control induced by antihypertensive medications. METHODS: As some of these medications may directly affect vascular function, this study sought to comprehensively examine the impact of reducing blood pressure, by a nonpharmacological approach (5 days of sodium restriction), on vascular function in 22 hypertensive individuals (14 men/8 women, 50 ±â€Š10 years). Following a 2-week withdrawal of antihypertensive medications, two 5-day dietary phases, liberal sodium (liberal sodium, 200 mmol/day) followed by restricted sodium (restricted sodium, 10 mmol/day), were completed. Resting blood pressure was assessed and vascular function, at both the conduit and microvascular levels, was evaluated by brachial artery flow-mediated dilation (FMD), reactive hyperemia, progressive handgrip exercise, and passive leg movement (PLM). RESULTS: Despite a sodium restriction-induced fall in blood pressure (liberal sodium: 141 ±â€Š14/85 ±â€Š9; restricted sodium 124 ±â€Š12/79 ±â€Š9 mmHg, P < 0.01 for both SBP and DBP), FMD (liberal sodium: 4.6 ±â€Š1.8%; restricted sodium: 5.1 ±â€Š2.1%, P = 0.27), and reactive hyperemia (liberal sodium: 548 ±â€Š201; restricted sodium: 615 ±â€Š206 ml, P = 0.08) were not altered. Similarly, brachial artery vasodilation during handgrip exercise was not different between conditions (liberal sodium: Δ0.36 ±â€Š0.19 mm; restricted sodium: Δ0.42 ±â€Š0.18 mm, P = 0.16). Lastly, PLM-induced changes in peak blood flow (liberal sodium: 5.3 ±â€Š2.5; restricted sodium: 5.8 ±â€Š3.6 ml/min per mmHg, P = 0.30) and the total vasodilatory response [liberal sodium: 2 (0.9-2.5) vs. restricted sodium: 1.7 (1.1-2.6) ml/min per mmHg; P = 0.5] were also not different between conditions. CONCLUSION: Thus vascular dysfunction, at both the conduit and microvascular levels, persists in patients with hypertension even when blood pressure is acutely reduced by a nonpharmacological approach.

Salt Sensitivity of Blood Pressure and Aldosterone: Interaction Between the Lysine-specific Demethylase 1 Gene, Sex, and Age.

CONTEXT: Salt sensitivity of blood pressure (SSBP) is associated with increased cardiovascular risk, especially in individuals of African descent, although the underlying mechanisms remain obscure. Lysine-specific demethylase 1 (LSD1) is a salt-sensitive epigenetic regulator associated with SSBP and aldosterone dysfunction. An LSD1 risk allele in humans is associated with SSBP and lower aldosterone levels in hypertensive individuals of African but not European descent. Heterozygous knockout LSD1 mice display SSBP and aldosterone dysregulation, but this effect is modified by age and biological sex. This might explain differences in cardiovascular risk with aging and biological sex in humans. OBJECTIVE: This work aims to determine if LSD1 risk allele (rs587618) carriers of African descent display a sex-by-age interaction with SSBP and aldosterone regulation. METHODS: We analyzed 297 individuals of African and European descent from the HyperPATH cohort. We performed multiple regression analyses for outcome variables related to SSBP and aldosterone. RESULTS: LSD1 risk allele carriers of African (but not European) descent had greater SSBP than nonrisk homozygotes. Female LSD1 risk allele carriers of African descent had greater SSBP, mainly relationship-driven by women with low estrogen (postmenopausal). There was a statistically significant LSD1 genotype-sex interaction in aldosterone response to angiotensin II stimulation in individuals aged 50 years or younger, with female carriers displaying decreased aldosterone responsiveness. CONCLUSION: SSBP associated with LSD1 risk allele status is driven by women with a depleted estrogen state. Mechanisms related to a resistance to develop SSBP in females are uncertain but may relate to an estrogen-modulating effect on mineralocorticoid receptor (MR) activation and/or LSD1 epigenetic regulation of the MR.

Genetic Predictors of Salt Sensitivity of Blood Pressure: The Additive Impact of 2 Hits in the Same Biological Pathway.

[Figure: see text].

The Role of Thyroid in Renovascular Function: Independent Association of Serum TSH With Renal Plasma Flow.

CONTEXT: There are well-established interactions between the thyroid and the kidney. Thyroid hypofunction is associated with reduced renal plasma flow (RPF), and hypothyroidism is highly prevalent in chronic kidney disease; however, less is known about the thyroid-kidney axis in the euthyroid state. OBJECTIVE: This work aimed to study the association of thyroid function with renovascular parameters in a well-phenotyped cohort of euthyroid normotensive and hypertensive individuals. METHODS: This cross-sectional, multicenter study of the HyperPATH Consortium took place in 5 US and European academic institutions. A total of 789 individuals, aged 18 to 65 years, with serum thyrotropin (TSH) 0.4 to 5.5 mIU/L, participated; individuals with uncontrolled or secondary hypertension or on medication affecting the hypothalamus-pituitary-thyroid axis were excluded. Hemodynamic parameters including RPF, thyroid function testing, and the Thr92Ala deiodinase 2 (D2) polymorphism were assessed in the setting of a liberal and restricted salt diet. We searched for associations between thyroid function and renovascular parameters and accounted for confounding factors, such as older age, hypertension, and diabetes. RESULTS: Serum TSH was inversely associated with RPF assessed in the setting both of liberal and restricted salt diets. This association remained significant and independent when accounting for confounding factors, whereas free thyroxine index (fTI) and the Thr92Ala polymorphism, associated with lower D2 catalytic activity and disrupted thyroid hormone tissue availability, were not independently associated with RPF. Serum TSH remained an independent predictor of RPF on a liberal salt diet when the analysis was restricted to healthy young individuals. CONCLUSION: Serum TSH levels, but not fTI nor the Thr92Ala D2 polymorphism, were independently inversely associated with RPF in individuals of the HyperPATH Consortium. These findings suggest a direct interconnection between TSH and renovascular dynamics even with TSH within reference range, warranting further investigation.

Characterizing a Common CERS2 Polymorphism in a Mouse Model of Metabolic Disease and in Subjects from the Utah CAD Study.

CONTEXT: Genome-wide association studies have identified associations between a common single nucleotide polymorphism (SNP; rs267738) in CERS2, a gene that encodes a (dihydro)ceramide synthase that is involved in the biosynthesis of very-long-chain sphingolipids (eg, C20-C26) and indices of metabolic dysfunction (eg, impaired glucose homeostasis). However, the biological consequences of this mutation on enzyme activity and its causal roles in metabolic disease are unresolved. OBJECTIVE: The studies described herein aimed to characterize the effects of rs267738 on CERS2 enzyme activity, sphingolipid profiles, and metabolic outcomes. DESIGN: We performed in-depth lipidomic and metabolic characterization of a novel CRISPR knock-in mouse modeling the rs267738 variant. In parallel, we conducted mass spectrometry-based, targeted lipidomics on 567 serum samples collected through the Utah Coronary Artery Disease study, which included 185 patients harboring 1 (n = 163) or both (n = 22) rs267738 alleles. RESULTS: In-silico analysis of the amino acid substitution within CERS2 caused by the rs267738 mutation suggested that rs267738 is deleterious for enzyme function. Homozygous knock-in mice had reduced liver CERS2 activity and enhanced diet-induced glucose intolerance and hepatic steatosis. However, human serum sphingolipids and a ceramide-based cardiac event risk test 1 score of cardiovascular disease were not significantly affected by rs267738 allele count. CONCLUSIONS: The rs267738 SNP leads to a partial loss-of-function of CERS2, which worsened metabolic parameters in knock-in mice. However, rs267738 was insufficient to effect changes in serum sphingolipid profiles in subjects from the Utah Coronary Artery Disease Study.

Carbohydrate and fat intake associated with risk of metabolic diseases through epigenetics of CPT1A.

BACKGROUND: Epigenome-wide association studies identified the cg00574958 DNA methylation site at the carnitine palmitoyltransferase-1A (CPT1A) gene to be associated with reduced risk of metabolic diseases (hypertriglyceridemia, obesity, type 2 diabetes, hypertension, metabolic syndrome), but the mechanism underlying these associations is unknown. OBJECTIVES: We aimed to elucidate whether carbohydrate and fat intakes modulate cg00574958 methylation and the risk of metabolic diseases. METHODS: We examined associations between carbohydrate (CHO) and fat (FAT) intake, as percentages of total diet energy, and the CHO/FAT ratio with CPT1A-cg00574958, and the risk of metabolic diseases in 3 populations (Genetics of Lipid Lowering Drugs and Diet Network, n = 978; Framingham Heart Study, n = 2331; and REgistre GIroní del COR study, n = 645) while adjusting for confounding factors. To understand possible causal effects of dietary intake on the risk of metabolic diseases, we performed meta-analysis, CPT1A transcription analysis, and mediation analysis with CHO and FAT intakes as exposures and cg00574958 methylation as the mediator. RESULTS: We confirmed strong associations of cg00574958 methylation with metabolic phenotypes (BMI, triglyceride, glucose) and diseases in all 3 populations. Our results showed that CHO intake and CHO/FAT ratio were positively associated with cg00574958 methylation, whereas FAT intake was negatively correlated with cg00574958 methylation. Meta-analysis further confirmed this strong correlation, with ß = 58.4 ± 7.27, P = 8.98 x 10-16 for CHO intake; ß = -36.4 ± 5.95, P = 9.96 x 10-10 for FAT intake; and ß = 3.30 ± 0.49, P = 1.48 x 10-11 for the CHO/FAT ratio. Furthermore, CPT1A mRNA expression was negatively associated with CHO intake, and positively associated with FAT intake, and metabolic phenotypes. Mediation analysis supports the hypothesis that CHO intake induces CPT1A methylation, hence reducing the risk of metabolic diseases, whereas FAT intake inhibits CPT1A methylation, thereby increasing the risk of metabolic diseases. CONCLUSIONS: Our results suggest that the proportion of total energy supplied by CHO and FAT can have a causal effect on the risk of metabolic diseases via the epigenetic status of CPT1A.Study registration at https://www.clinicaltrials.gov/: the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN)-NCT01023750; and the Framingham Heart Study (FHS)-NCT00005121.

Cardiovascular responses to rhythmic handgrip exercise in heart failure with preserved ejection fraction.

Although the contribution of noncardiac complications to the pathophysiology of heart failure with preserved ejection fraction (HFpEF) have been increasingly recognized, disease-related changes in peripheral vascular control remain poorly understood. We utilized small muscle mass handgrip exercise to concomitantly evaluate exercising muscle blood flow and conduit vessel endothelium-dependent vasodilation in individuals with HFpEF (n = 25) compared with hypertensive controls (HTN) (n = 25). Heart rate (HR), stroke volume (SV), cardiac output (CO), mean arterial pressure (MAP), brachial artery blood velocity, and brachial artery diameter were assessed during progressive intermittent handgrip (HG) exercise [15-30-45% maximal voluntary contraction (MVC)]. Forearm blood flow (FBF) and vascular conductance (FVC) were determined to quantify the peripheral hemodynamic response to HG exercise, and changes in brachial artery diameter were evaluated to assess endothelium-dependent vasodilation. HR, SV, and CO were not different between groups across exercise intensities. However, although FBF was not different between groups at the lowest exercise intensity, FBF was significantly lower (20-40%) in individuals with HFpEF at the two higher exercise intensities (30% MVC: 229 ± 8 versus 274 ± 23 ml/min; 45% MVC: 283 ± 17 versus 399 ± 34 ml/min, HFpEF versus HTN). FVC was not different between groups at 15 and 30% MVC but was ∼20% lower in HFpEF at the highest exercise intensity. Brachial artery diameter increased across exercise intensities in both HFpEF and HTN, with no difference between groups. These findings demonstrate an attenuation in muscle blood flow during exercise in HFpEF in the absence of disease-related changes in central hemodynamics or endothelial function.NEW & NOTEWORTHY The current study identified, for the first time, an attenuation in exercising muscle blood flow during handgrip exercise in individuals with heart failure with preserved ejection fraction (HFpEF) compared with overweight individuals with hypertension, two of the most common comorbidities associated with HFpEF. These decrements in exercise hyperemia cannot be attributed to disease-related changes in central hemodynamics or endothelial function, providing additional evidence for disease-related vascular dysregulation, which may be a predominant contributor to exercise intolerance in individuals with HFpEF.

No benefit of HDL mimetic CER-001 on carotid atherosclerosis in patients with genetically determined very low HDL levels.

BACKGROUND AND AIMS: Infusion of high-density lipoprotein (HDL) mimetics failed to induce regression of atherosclerosis in recent randomized clinical trials. However, patients in these previous trials had normal levels of HDL-cholesterol, which potentially limited efficacy. Patients with very low levels of HDL-cholesterol and impaired cholesterol efflux capacity can be expected to derive the most potential benefit from infusion of HDL mimetics. This randomized clinical trial evaluated the efficacy of infusions of the HDL mimetic CER-001 in patients with genetically determined very low levels of HDL cholesterol. METHODS: In this multicenter, randomized clinical trial, we recruited patients with familial hypoalphalipoproteinemia (due to ABCA1 and/or APOA1 loss-of-function variants). Participants were randomized to intravenous infusions of 8 mg/kg CER-001 or placebo (2:1 ratio), comprising 9 weekly infusions followed by infusions every two weeks. Patients underwent repeated 3T-MRI to assess mean vessel wall area and 18F-FDG PET/CT to quantify arterial wall inflammation. RESULTS: A total of 30 patients with a mean age of 52.7 ± 7.4 years and HDL-cholesterol of 0.35 ± 0.25 mmol/L were recruited. After 24 weeks, the absolute change in mean vessel wall area was not significantly different in the CER-001 group compared with placebo (n = 27; treatment difference: 0.77 mm2, p = 0.21). Furthermore, there was no significant difference in carotid arterial wall inflammation (n = 24, treatment difference: 0.10 target-to-background ratio of the most diseased segment, p = 0.33) after 24 weeks. CONCLUSION: In patients with genetically determined very low HDL-cholesterol, 24 weeks of treatment with HDL mimetic CER-001 did not reduce carotid vessel wall dimensions or arterial wall inflammation, compared with placebo.

Interplay Between Statins, Cav1 (Caveolin-1), and Aldosterone.

Statin use is associated with lower aldosterone levels. We hypothesized that caveolin-1 may be important for the uptake of statins into the adrenal gland and would affect statin's aldosterone-lowering effects. The aim of this study was to test whether the caveolin-1 risk allele (rs926198) would affect aldosterone levels associated with statin use. The Hypertensive Pathotype database includes healthy and hypertensive individuals who have undergone assessment of adrenal hormones. Individuals were studied off antihypertensive medications but were maintained on statins if prescribed by their personal physician. Adrenal hormones were measured at baseline and after 1 hour of angiotensin II stimulation on both high- and low-sodium diets. A mixed-model repeated-measures analysis was employed with a priori selected covariates of age, sex, body mass index, and protocol (low versus high sodium, baseline versus angiotensin II stimulated aldosterone). A total of 250 individuals were included in the study; 31 individuals were taking statins (12.4%) and 219 were not. Among statin users, carrying a caveolin-1 risk allele resulted in a 25% (95% CI, 1-43.2) lower aldosterone level (P=0.04). However, among nonstatin users, carrying a caveolin-1 risk allele resulted in no significant effect on aldosterone levels (P=0.38). Additionally, the interaction between caveolin-1 risk allele and statin use on aldosterone levels was significant (P=0.03). These findings suggest caveolin-1 risk allele carrying individuals are likely to receive the most benefit from statin's aldosterone-lowering properties; however, due to the observational nature of this study, these findings need further investigation.

The Unrecognized Prevalence of Primary Aldosteronism: A Cross-sectional Study.

BACKGROUND: Primary aldosteronism is a nonsuppressible renin-independent aldosterone production that causes hypertension and cardiovascular disease. OBJECTIVE: To characterize the prevalence of nonsuppressible renin-independent aldosterone production, as well as biochemically overt primary aldosteronism, in relation to blood pressure. DESIGN: Cross-sectional study. SETTING: 4 U.S. academic medical centers. PARTICIPANTS: Participants with normotension (n = 289), stage 1 hypertension (n = 115), stage 2 hypertension (n = 203), and resistant hypertension (n = 408). MEASUREMENTS: Participants completed an oral sodium suppression test, regardless of aldosterone or renin levels, as a confirmatory diagnostic for primary aldosteronism and to quantify the magnitude of renin-independent aldosterone production. Urinary aldosterone was measured in participants in high sodium balance with suppressed renin activity. Biochemically overt primary aldosteronism was diagnosed when urinary aldosterone levels were higher than 12 µg/24 h. RESULTS: Every blood pressure category had a continuum of renin-independent aldosterone production, where greater severity of production was associated with higher blood pressure, kaliuresis, and lower serum potassium levels. Mean adjusted levels of urinary aldosterone were 6.5 µg/24 h (95% CI, 5.2 to 7.7 µg/24 h) in normotension, 7.3 µg/24 h (CI, 5.6 to 8.9 µg/24 h) in stage 1 hypertension, 9.5 µg/24 h (CI, 8.2 to 10.8 µg/24 h) in stage 2 hypertension, and 14.6 µg/24 h (CI, 12.9 to 16.2 µg/24 h) in resistant hypertension; corresponding adjusted prevalence estimates for biochemically overt primary aldosteronism were 11.3% (CI, 5.9% to 16.8%), 15.7% (CI, 8.6% to 22.9%), 21.6% (CI, 16.1% to 27.0%), and 22.0% (CI, 17.2% to 26.8%). The aldosterone-renin ratio had poor sensitivity and negative predictive value for detecting biochemically overt primary aldosteronism. LIMITATION: Prevalence estimates rely on arbitrary and conventional thresholds, and the study population may not represent nationwide demographics. CONCLUSION: The prevalence of primary aldosteronism is high and largely unrecognized. Beyond this categorical definition of primary aldosteronism, there is a prevalent continuum of renin-independent aldosterone production that parallels the severity of hypertension. These findings redefine the primary aldosteronism syndrome and implicate it in the pathogenesis of "essential" hypertension. PRIMARY FUNDING SOURCE: National Institutes of Health.

Salivary AMY1 Copy Number Variation Modifies Age-Related Type 2 Diabetes Risk.

BACKGROUND: Copy number variation (CNV) in the salivary amylase gene (AMY1) modulates salivary α-amylase levels and is associated with postprandial glycemic traits. Whether AMY1-CNV plays a role in age-mediated change in insulin resistance (IR) is uncertain. METHODS: We measured AMY1-CNV using duplex quantitative real-time polymerase chain reaction in two studies, the Boston Puerto Rican Health Study (BPRHS, n = 749) and the Genetics of Lipid-Lowering Drug and Diet Network study (GOLDN, n = 980), and plasma metabolomic profiles in the BPRHS. We examined the interaction between AMY1-CNV and age by assessing the relationship between age with glycemic traits and type 2 diabetes (T2D) according to high or low copy numbers of the AMY1 gene. Furthermore, we investigated associations between metabolites and interacting effects of AMY1-CNV and age on T2D risk. RESULTS: We found positive associations of IR with age among subjects with low AMY1-copy-numbers in both studies. T2D was marginally correlated with age in participants with low AMY1-copy-numbers but not with high AMY1-copy-numbers in the BPRHS. Metabolic pathway enrichment analysis identified the pentose metabolic pathway based on metabolites that were associated with both IR and the interactions between AMY1-CNV and age. Moreover, in older participants, high AMY1-copy-numbers tended to be associated with lower levels of ribonic acid, erythronic acid, and arabinonic acid, all of which were positively associated with IR. CONCLUSIONS: We found evidence supporting a role of AMY1-CNV in modifying the relationship between age and IR. Individuals with low AMY1-copy-numbers tend to have increased IR with advancing age.

Application of mild hypothermia successfully mitigates neural injury in a 3D in-vitro model of traumatic brain injury.

Therapeutic hypothermia (TH) is an attractive target for mild traumatic brain injury (mTBI) treatment, yet significant gaps in our mechanistic understanding of TH, especially at the cellular level, remain and need to be addressed for significant forward progress to be made. Using a recently-established 3D in-vitro neural hydrogel model for mTBI we investigated the efficacy of TH after compressive impact injury and established critical treatment parameters including target cooling temperature, and time windows for application and maintenance of TH. Across four temperatures evaluated (31.5, 33, 35, and 37°C), 33°C was found to be most neuroprotective after 24 and 48 hours post-injury. Assessment of TH administration onset time and duration showed that TH should be administered within 4 hours post-injury and be maintained for at least 6 hours for achieving maximum viability. Cellular imaging showed TH reduced the percentage of cells positive for caspases 3/7 and increased the expression of calpastatin, an endogenous neuroprotectant. These findings provide significant new insight into the biological parameter space that renders TH effective in mitigating the deleterious effects of cellular mTBI and provides a quantitative foundation for the future development of animal and preclinical treatment protocols.

Efficacy and Safety of Alirocumab in Patients With Autosomal Dominant Hypercholesterolemia Associated With Proprotein Convertase Subtilisin/Kexin Type 9 Gain-of-Function or Apolipoprotein B Loss-of-Function Mutations.

Autosomal dominant hypercholesterolemia results from mutations affecting the low-density lipoprotein receptor pathway, including proprotein convertase subtilisin/kexin type 9 (PCSK9) gain-of-function mutations (GoFm) and apolipoprotein B (APOB) loss-of-function mutations (LoFm). This study examined the long-term efficacy and safety of alirocumab in patients with PCSK9 GoFm and APOB LoFm who participated in the open-label extension to a Phase 2 double-blind study (NCT01604824). Of the 23 patients who completed the 14-week double-blind period and 8-week follow-up, 21 opted to continue in the open-label extension (PCSK9 GoFm, n = 15; APOB LoFm, n = 6). Patients received alirocumab 150 mg every 2 weeks from week 32 up to 3 years for PCSK9 GoFm and 2 years for APOB LoFm. Mean duration of alirocumab exposure was 129 weeks (median: 144 weeks). After initiation of alirocumab treatment, low-density lipoprotein cholesterol (LDL-C) decreased in both groups. At week 80, mean percent reduction in LDL-C from baseline was 58.0% and 47.1% for PCSK9 GoFm and APOB LoFm groups, respectively. Treatment-emergent adverse events were reported in 19 patients (90.5%); no patients discontinued treatment due to treatment-emergent adverse events. In patients with autosomal dominant hypercholesterolemia and elevated LDL-C levels despite receiving maximally tolerated lipid-lowering therapies, alirocumab 150 mg every 2 weeks resulted in clinically meaningful reductions in LDL-C, sustained through to 3 years and 2 years for patients with PCSK9 GoFm and APOB LoFm, respectively. Alirocumab was generally well tolerated with no unexpected safety concerns.

Machine learning reveals serum sphingolipids as cholesterol-independent biomarkers of coronary artery disease.

BACKGROUNDCeramides are sphingolipids that play causative roles in diabetes and heart disease, with their serum levels measured clinically as biomarkers of cardiovascular disease (CVD).METHODSWe performed targeted lipidomics on serum samples from individuals with familial coronary artery disease (CAD) (n = 462) and population-based controls (n = 212) to explore the relationship between serum sphingolipids and CAD, using unbiased machine learning to identify sphingolipid species positively associated with CAD.RESULTSNearly every sphingolipid measured (n = 30 of 32) was significantly elevated in subjects with CAD compared with measurements in population controls. We generated a novel sphingolipid-inclusive CAD risk score, termed SIC, that demarcates patients with CAD independently and more effectively than conventional clinical CVD biomarkers including serum LDL cholesterol and triglycerides. This new metric comprises several minor lipids that likely serve as measures of flux through the ceramide biosynthesis pathway rather than the abundant deleterious ceramide species that are included in other ceramide-based scores.CONCLUSIONThis study validates serum ceramides as candidate biomarkers of CVD and suggests that comprehensive sphingolipid panels should be considered as measures of CVD.FUNDINGThe NIH (DK112826, DK108833, DK115824, DK116888, and DK116450); the Juvenile Diabetes Research Foundation (JDRF 3-SRA-2019-768-A-B); the American Diabetes Association; the American Heart Association; the Margolis Foundation; the National Cancer Institute, NIH (5R00CA218694-03); and the Huntsman Cancer Institute Cancer Center Support Grant (P30CA040214).

Pharmacokinetic and pharmacodynamic assessment of alirocumab in patients with familial hypercholesterolemia associated with proprotein convertase subtilisin/kexin type 9 gain-of-function or apolipoprotein B loss-of-function mutations.

BACKGROUND: Familial hypercholesterolemia is characterized by high levels of low-density lipoprotein cholesterol (LDL-C), and causes of familial hypercholesterolemia include apolipoprotein B (APOB) loss-of-function mutations (LOFm) and proprotein convertase subtilisin/kexin type 9 (PCSK9) gain-of-function mutations (GOFm). OBJECTIVE: The aim of this study was to compare the pharmacokinetics and pharmacodynamics of alirocumab between patients with APOB LOFm vs PCSK9 GOFm. METHODS: Patients (6 APOB LOFm and 17 PCSK9 GOFm carriers) with LDL-C ≥70 mg/dL on maximally tolerated lipid-lowering therapies received alirocumab 150 mg at Weeks 0, 2, 4, and 6, placebo at Week 8, alirocumab at Week 10, placebo at Weeks 12 and 14, then completed a follow-up period at Week 22. RESULTS: At Week 8, mean ± standard error (SE) alirocumab concentration was lower in APOB LOFm carriers compared with PCSK9 GOFm carriers (12.12 ± 1.81 vs 16.74 ± 2.53 mg/L). APOB LOFm carriers had higher mean ± SE total PCSK9 (6.56 ± 0.73 mg/L) and lower mean ± SE free PCSK9 (0.025 ± 0.016 mg/L) at Week 8 compared with PCSK9 GOFm carriers (4.21 ± 0.35 and 0.11 ± 0.035 mg/L for total and free PCSK9, respectively). Despite this observed greater PCSK9 suppression, mean ± SE percent LDL-C reduction was lower in APOB LOFm (55.3 ± 1.0%) compared with PCSK9 GOFm carriers (73.1 ± 0.9%). Treatment-emergent adverse events occurred in 16 patients (94.1%) in the PCSK9 GOFm group and 5 patients (83.3%) in the APOB LOFm group. CONCLUSIONS: Overall, PCSK9 inhibition with alirocumab results in clinically meaningful reductions in LDL-C in both APOB LOFm and PCSK9 GOFm carriers, although reductions were greater in the PCSK9 GOFm carriers. The results indicate a possible underlying contributor to hypercholesterolemia other than PCSK9 in patients with APOB LOFm. CLINICAL TRIAL REGISTRATION: NCT01604824; clinicaltrials.gov.