👤 David B Allison

Arterial stiffness is a contributor to cognitive decline. Pressure time constants (PTCs: PTC1, PTC2) are new measures of arterial compliance (inverse of stiffness) which are based on a Windkessel model of arterial pulse pressure waveforms. The methodology for PTCs is open-source and scalable. We evaluated the cross-sectional association between PTCs from radial artery pressure waveforms and cognitive performance: Global cognitive function (Cognitive Abilities Screening Instrument, CASI; score range 0-100); processing speed (Digit Symbol Coding, DSC; 0-133); and working memory (Digit Span, DS; 0-30). Among 3134 adults from 6 U.S. communities in 2010-2012 (aged 54-94 years; 47% male; 41% White, 25% Black, 23% Hispanic/Latino, 12% Chinese), the mean ± SD was 283 ± 127 ms for PTC1, 85 ± 31 ms for PTC2, 89 ± 8 for CASI, 51 ± 18 for DSC, and 15 ± 4 for DS. In the entire sample (after adjustment for community, race/ethnicity, and variables in the dementia score called "Cardiovascular Risk Factors, Aging, and Incidence of Dementia"), neither PTC1 nor PTC2 was associated with CASI, DSC, or DS. In exploratory analyses, after adjustment, one SD higher PTC2 was associated with a 1.4 (95% confidence interval: 0.4, 2.5; p = 0.004) higher mean DSC score among the subset with at least one APOE-ε4 allele (N = 828) and a 0.8 (0.1, 1.5; p = 0.03) higher mean DSC score among those 65 years and older (N = 2020). Higher radial artery PTC2 (lower arterial stiffness) was associated with faster processing speed among carriers of APOE-ε4 and older adults. Future work should investigate the association of PTCs with other indicators of brain health. Show less

Early-onset fetal growth restriction (FGR) is associated with prolonged fetoplacental hypoxia and altered brain development, including deficits in hippocampal structure and function. Neuroprotective actions of lactoferrin have been described, mediated via anti-inflammatory and antioxidant properties. Here, we investigated whether the antenatal administration of lactoferrin (1) improves hippocampal structure, (2) promotes neuronal growth, and (3) mitigates neuroinflammation in the hippocampus of fetal sheep with FGR. Early-onset FGR was induced by performing single umbilical artery ligation surgery on ovine fetuses at ~89 days gestational age (dGA; term ~148 dGA), compared with appropriate for gestational age (AGA) controls. Lactoferrin supplementation to the ewe commenced at 95 dGA (oral, 36 g/day) and continued until 127 dGA (fetal group) or birth (newborn group). Experimental fetal groups included control appropriate for gestational age (AGA; n = 8), FGR (n = 5), control + lactoferrin (AGA + Lacto; n = 6), and FGR + lactoferrin (FGR + Lacto; n = 6). In the fetal group, results showed that neither FGR nor lactoferrin altered hippocampal structure at 127 dGA. Lactoferrin exposure significantly increased neuronal abundance but also altered neuronal morphology. Lactoferrin increased the neurotrophic factor, brain-derived neurotrophic factor (BDNF) in the hippocampus. Lactoferrin exerted region-specific anti-inflammatory effects, with reduced total microglial cell count and resting microglia count in the Show less

Obesity is a major public health crisis associated with high mortality rates. Previous genome-wide association studies (GWAS) investigating body mass index (BMI) have largely relied on imputed data from European individuals. This study leveraged whole-genome sequencing (WGS) data from 88,873 participants from the Trans-Omics for Precision Medicine (TOPMed) Program, of which 51% were of non-European population groups. We discovered 18 BMI-associated signals (P < 5 × 10 Show less

Apolipoprotein C-III (apoC-III) proteoform composition shows distinct relationships with plasma lipids and cardiovascular risk. The present study tested whether apoC-III proteoforms are associated with risk of peripheral artery disease (PAD). ApoC-III proteoforms, i.e., native (C-III Higher baseline C-III We found associations of apoC-III proteoform composition with changes in ABI that were independent of other risk factors, including plasma lipids. Our data further support unique properties of apoC-III proteoforms in modulating vascular health that go beyond total apoC-III levels. Show less

Obesity is a major public health crisis associated with high mortality rates. Previous genome-wide association studies (GWAS) investigating body mass index (BMI) have largely relied on imputed data from European individuals. This study leveraged whole-genome sequencing (WGS) data from 88,873 participants from the Trans-Omics for Precision Medicine (TOPMed) Program, of which 51% were of non-European population groups. We discovered 18 BMI-associated signals ( Show less

Understanding the neural components modulating feeding-related behavior and energy expenditure is crucial to combating obesity and its comorbidities. Neurons within the paraventricular nucleus of the hypothalamus (PVH) are a key component of the satiety response; activation of the PVH decreases feeding and increases energy expenditure, thereby promoting negative energy balance. In contrast, PVH ablation or silencing in both rodents and humans leads to substantial obesity. Recent studies have identified genetically-defined PVH subpopulations that control discrete aspects of energy balance (e.g. oxytocin (OXT), neuronal nitric oxide synthase 1 (NOS1), melanocortin 4-receptor (MC4R), prodynorphin (PDYN)). We previously demonstrated that non-OXT NOS1 Show less

Genome-wide association studies (GWAS) have identified >250 loci for body mass index (BMI), implicating pathways related to neuronal biology. Most GWAS loci represent clusters of common, noncoding variants from which pinpointing causal genes remains challenging. Here we combined data from 718,734 individuals to discover rare and low-frequency (minor allele frequency (MAF) < 5%) coding variants associated with BMI. We identified 14 coding variants in 13 genes, of which 8 variants were in genes (ZBTB7B, ACHE, RAPGEF3, RAB21, ZFHX3, ENTPD6, ZFR2 and ZNF169) newly implicated in human obesity, 2 variants were in genes (MC4R and KSR2) previously observed to be mutated in extreme obesity and 2 variants were in GIPR. The effect sizes of rare variants are ~10 times larger than those of common variants, with the largest effect observed in carriers of an MC4R mutation introducing a stop codon (p.Tyr35Ter, MAF = 0.01%), who weighed ~7 kg more than non-carriers. Pathway analyses based on the variants associated with BMI confirm enrichment of neuronal genes and provide new evidence for adipocyte and energy expenditure biology, widening the potential of genetically supported therapeutic targets in obesity. Show less

The apolipoproteins (APOA1/C3/A4/A5) are key components in modulating lipoprotein metabolism. It is unknown whether variants at the APOA1/C3/A4/A5 gene cluster are associated with lipid response to pharmacologic intervention. Plasma triglycerides (TGs) and high-density lipoprotein (HDL) levels were measured in 861 Genetics of Lipid-Lowering Drugs and Diet Network study participants who underwent a 3-week fenofibrate trial. We examined 18 common single nucleotide polymorphisms (SNPs) spanning the APOA1/C3/A4/A5 genes to investigate the effects of variants at the gene cluster on lipid response to fenofibrate treatment. We found that the minor alleles of the SNPs rs3135506 (APOA5_S19W), rs5104 (APOA4_N147S), rs4520 (APOC3_G34G), and rs5128 (APOC3₃U386) were associated with enhanced TG response to fenofibrate treatment (P= 0.0004-0.018). The minor allele of SNP rs2854117 (APOC3_M482) was associated with reduced rather than enhanced TG response (P= 0.026). The SNP rs3135506 (APOA5_S19W) was associated with HDL response, with minor allele related to reduced HDL response to fenofibrate (P= 0.002). Association analyses on haplotype provided corroborative evidence to single SNP association analyses. The common haplotypes H2, H3, and H5 were significantly associated with reduced TG response to fenofibrate. The genetic variants at APOA1/C3/A4/A5 gene cluster may be useful markers to predict response of lipid-lowering therapy with fenofibrate. Further studies to replicate/confirm our findings are warranted. Show less

The synaptic protein PSD-95/SAP90 binds to and clusters a variety of membrane proteins via its two N-terminal PDZ domains. We report a novel protein, CRIPT, which is highly conserved from mammals to plants and binds selectively to the third PDZ domain (PDZ3) of PSD-95 via its C terminus. While conforming to the consensus PDZ-binding C-terminal sequence (X-S/T-X-V-COOH), residues at the -1 position and upstream of the last four amino acids of CRIPT determine its specificity for PDZ3. In heterologous cells, CRIPT causes a redistribution of PSD-95 to microtubules. In brain, CRIPT colocalizes with PSD-95 in the postsynaptic density and can be coimmunoprecipitated with PSD-95 and tubulin. These findings suggest that CRIPT may regulate PSD-95 interaction with a tubulin-based cytoskeleton in excitatory synapses. Show less