Nicotinamide Adenine Dinucleotide Augmentation in Overweight or Obese Middle-Aged and Older Adults: A Physiologic Study.

CONTEXT: Nicotinamide adenine dinucleotide (NAD) levels decline with aging and age-related decline in NAD has been postulated to contribute to age-related diseases. OBJECTIVE: We evaluated the safety and physiologic effects of NAD augmentation by administering its precursor, ß-nicotinamide mononucleotide (MIB-626, Metro International Biotech, Worcester, MA), in adults at risk for age-related conditions. METHODS: Thirty overweight or obese adults, ≥ 45 years, were randomized in a 2:1 ratio to 2 MIB-626 tablets each containing 500 mg of microcrystalline ß-nicotinamide mononucleotide or placebo twice daily for 28 days. Study outcomes included safety; NAD and its metabolome; body weight; liver, muscle, and intra-abdominal fat; insulin sensitivity; blood pressure; lipids; physical performance, and muscle bioenergetics. RESULTS: Adverse events were similar between groups. MIB-626 treatment substantially increased circulating concentrations of NAD and its metabolites. Body weight (difference -1.9 [-3.3, -0.5] kg, P = .008); diastolic blood pressure (difference -7.01 [-13.44, -0.59] mmHg, P = .034); total cholesterol (difference -26.89 [-44.34, -9.44] mg/dL, P = .004), low-density lipoprotein (LDL) cholesterol (-18.73 [-31.85, -5.60] mg/dL, P = .007), and nonhigh-density lipoprotein cholesterol decreased significantly more in the MIB-626 group than placebo. Changes in muscle strength, muscle fatigability, aerobic capacity, and stair-climbing power did not differ significantly between groups. Insulin sensitivity and hepatic and intra-abdominal fat did not change in either group. CONCLUSIONS: MIB-626 administration in overweight or obese, middle-aged and older adults safely increased circulating NAD levels, and significantly reduced total LDL and non-HDL cholesterol, body weight, and diastolic blood pressure. These data provide the rationale for larger trials to assess the efficacy of NAD augmentation in improving cardiometabolic outcomes in older adults.

Design and assembly of new nonviral RNAi delivery agents by microwave-assisted quaternization (MAQ) of tertiary amines.

RNA interference (RNAi) is a gene-silencing phenomenon whereby double-stranded RNA (dsRNA) triggers the sequence-specific degradation of homologous mRNA. RNAi has been quickly and widely applied to discover gene functions and holds great potential to provide a new class of therapeutic agents. However, new chemistry and delivery approaches are greatly needed to silence disease-causing genes without toxic effects. We reasoned that conjugation of the cholesterol moiety to cationic lipids would enhance RNAi efficiencies and lower the toxic effects of lipid-mediated RNAi delivery. Here, we report the first design and synthesis of new cholesterol-conjugated cationic lipids for RNAi delivery using microwave-assisted quaternization (MAQ) of tertiary amines. This strategy can be employed to develop new classes of nonviral gene delivery agents under safe and fast reaction conditions.

Design and creation of new nanomaterials for therapeutic RNAi.

RNA interference is an evolutionarily conserved gene-silencing phenomenon that shows great promise for developing new therapies. However, the development of small interfering RNA (siRNA)-based therapies needs to overcome two barriers and be able to (i) identify chemically stable and effective siRNA sequences and (ii) efficiently silence target genes with siRNA doses that will be clinically feasible in humans. Here, we report the design and creation of interfering nanoparticles (iNOPs) as new systemic gene-silencing agents. iNOPs have two subunits: (i) a well-defined functionalized lipid nanoparticle as a delivery agent and (ii) a chemically modified siRNA for sustained silencing in vivo. When we injected iNOPs containing only 1-5 mg kg(-1) siRNA into mice, an endogenous gene for apolipoprotein B (apoB) was silenced in liver, plasma levels of apoB decreased, and total plasma cholesterol was lowered. iNOP treatment was nontoxic and did not induce an immune response. Our results show that these iNOPs can silence disease-related endogenous genes in clinically acceptable and therapeutically affordable doses.

A mutation in the LDL receptor-related protein 5 gene results in the autosomal dominant high-bone-mass trait.

Osteoporosis is a complex disease that affects >10 million people in the United States and results in 1.5 million fractures annually. In addition, the high prevalence of osteopenia (low bone mass) in the general population places a large number of people at risk for developing the disease. In an effort to identify genetic factors influencing bone density, we characterized a family that includes individuals who possess exceptionally dense bones but are otherwise phenotypically normal. This high-bone-mass trait (HBM) was originally localized by linkage analysis to chromosome 11q12-13. We refined the interval by extending the pedigree and genotyping additional markers. A systematic search for mutations that segregated with the HBM phenotype uncovered an amino acid change, in a predicted beta-propeller module of the low-density lipoprotein receptor-related protein 5 (LRP5), that results in the HBM phenotype. During analysis of >1,000 individuals, this mutation was observed only in affected individuals from the HBM kindred. By use of in situ hybridization to rat tibia, expression of LRP5 was detected in areas of bone involved in remodeling. Our findings suggest that the HBM mutation confers a unique osteogenic activity in bone remodeling, and this understanding may facilitate the development of novel therapies for the treatment of osteoporosis.

High throughput analysis of differential gene expression.

Elucidation of the changes in gene expression associated with biological processes is a central problem in biology. Advances in molecular and computational biology have led to the development of powerful, high-thoughput methods for the analysis of differential gene expression. These tools have opened up new opportunities in disciplines ranging from cell and developmental biology to drug development and pharmacogenomics. In this review, the attributes of five commonly used differential gene expression methods are discussed: expressed sequence tag (EST) sequencing, cDNA microarray hybridization, subtractive cloning, differential display, and serial analysis of gene expression (SAGE). The application of EST sequencing and microarray hybridization is illustrated by the discovery of novel genes associated with osteoblast differentiation. The application of subtractive cloning is presented as a tool to identify genes regulated in vivo by the transcription factor pax-6. These and other examples illustrate the power of genomics for discovering novel genes that are important in biology and which also represent new targets for drug development. The central theme of the review is that each of the approaches to identifying differentially expressed genes is useful, and that the experimental context and subsequent evaluation of differentially expressed genes are the critical features that determine success. J. Cell. Biochem. Suppls. 30/31:286-296, 1998. © 1998 Wiley-Liss, Inc.