A systematic literature review of frequency of vaso-occlusive crises in sickle cell disease.

BACKGROUND AND PURPOSE: Sickle cell disease (SCD) is a collection of rare inherited blood disorders affecting approximately 100,000 people in the U.S. and 20-25 million people globally. Individuals with SCD experience recurrent episodes of severe and unpredictable pain that are caused by vaso-occlusive crises (VOCs), a hallmark of the disease. VOCs are the primary cause of hospitalization in SCD, result in missed workdays and school days, and decrease quality of life (QoL). Although VOCs cause significant burden in the lives of individuals with SCD, there is no synthesis on the frequency of VOCs in the real world. This systematic literature review sought to identify literature describing the frequency of VOCs experienced by individuals with SCD in real-world settings. METHODS: MEDLINE and 6 congresses were searched (date range: January 1, 2000 to June 30, 2020). Studies were reviewed independently by two researchers. Studies assessing frequency or prevalence of VOCs or VOC-related outcomes were included. RESULTS: Of 1438 studies identified in the search, 52 met pre-specified inclusion and exclusion criteria. Reported frequency of VOCs varied widely ranging from a mean or median of 0 VOCs/year to 18.2 VOCs/year. The proportion of patients experiencing ≥ 3 VOCs/year ranged from 4 to 67% and the proportion of patients experiencing ≥ 5 VOCs/year ranged from 18 to 59%. Measures of VOC severity were limited, with 13 studies considering frequency of complicated VOCs and only 1 study reporting duration of VOC episodes. CONCLUSIONS: This is the first study to systematically assess published evidence pertaining to VOCs in real-world settings. Reported VOC frequency in real-world settings varied widely, with a majority of studies only considering VOCs managed in an inpatient or outpatient setting. Studies that considered VOCs managed at home reported a higher frequency of VOCs, suggesting that many studies may underestimate the frequency of VOCs. This systematic literature review (SLR) highlights the need for consistent reporting of (1) self-reported VOCs, including those managed at home, (2) definitions of VOCs, (3) complicated VOCs, and (4) duration of VOC episodes in literature.

An Optogenetic Kindling Model of Neocortical Epilepsy.

Epileptogenesis is the gradual process by which the healthy brain develops epilepsy. However, the neuronal circuit changes that underlie epileptogenesis are not well understood. Unfortunately, current chemically or electrically induced epilepsy models suffer from lack of cell specificity, so it is seldom known which cells were activated during epileptogenesis. We therefore sought to develop an optogenetic variant of the classical kindling model of epilepsy in which activatable cells are both genetically defined and fluorescently tagged. We briefly optogenetically activated pyramidal cells (PCs) in awake behaving mice every two days and conducted a series of experiments to validate the effectiveness of the model. Although initially inert, brief optogenetic stimuli eventually elicited seizures that increased in number and severity with additional stimulation sessions. Seizures were associated with long-lasting plasticity, but not with tissue damage or astrocyte reactivity. Once optokindled, mice retained an elevated seizure susceptibility for several weeks in the absence of additional stimulation, indicating a form of long-term sensitization. We conclude that optokindling shares many features with classical kindling, with the added benefit that the role of specific neuronal populations in epileptogenesis can be studied. Links between long-term plasticity and epilepsy can thus be elucidated.

Assessment of Pregabalin Postapproval Trials and the Suggestion of Efficacy for New Indications: A Systematic Review.

Importance: After a drug receives regulatory approval, researchers often pursue small, underpowered trials, called exploratory trials, aimed at testing additional indications. If favorable early findings from exploratory trials are not promptly followed by confirmatory trials, then physicians, patients, and payers can be left uncertain about a drug's clinical value (clinical agnosticism). Such findings may encourage the off-label use of ineffective drugs. Objective: To characterize the relationship between exploratory and confirmatory postapproval trials for the blockbuster drug, pregabalin (Lyrica). Evidence Review: Ovid MEDLINE and Embase databases were used to identify clinical trials published prior to January 2018 and that tested the efficacy of pregabalin for nonapproved indications. Indications, trial outcomes, publication dates, and trial design elements were recorded. Time elapsed was calculated between the generation of clinical agnosticism about pregabalin (ie, publications reporting positive or inconclusive evidence of efficacy on a primary endpoint) and it being addressed (publication of at least 1 confirmatory trial in the same indication, regardless of outcome). Findings: There were 238 trials identified that tested the efficacy of pregabalin in at least 33 indications; 5 indications eventually received European Medicines Agency and/or US Food and Drug Administration marketing approval. Sixty-seven percent (22 of 33) of first publications for new indications may have generated clinical agnosticism. Of those indications with at least 5 years of follow-up, 63% (17 of 27) may have generated agnosticism that was not addressed in confirmatory trials within 5 years. As pregabalin development expanded from indications that received regulatory approval to other indications, the linkage of exploratory to confirmatory trial publication diminished. Conclusions and Relevance: After initial approval, exploratory evidence suggesting the value of pregabalin for new indications often went unconfirmed for extended periods of time. Poor coordination between exploratory and confirmatory testing may represent an important vehicle through which off-label prescription is recommended in clinical practice guidelines and encouraged in the absence of confirmatory trial evidence.

A Systems Biology Approach Using Transcriptomic Data Reveals Genes and Pathways in Porcine Skeletal Muscle Affected by Dietary Lysine.

Nine crossbred finishing barrows (body weight 94.4 ± 6.7 kg) randomly assigned to three dietary treatments were used to investigate the effects of dietary lysine on muscle growth related metabolic and signaling pathways. Muscle samples were collected from the longissimus dorsi of individual pigs after feeding the lysine-deficient (4.30 g/kg), lysine-adequate (7.10 g/kg), or lysine-excess (9.80 g/kg) diet for five weeks, and the total RNA was extracted afterwards. Affymetrix Porcine Gene 1.0 ST Array was used to quantify the expression levels of 19,211 genes. Statistical ANOVA analysis of the microarray data showed that 674 transcripts were differentially expressed (at p ≤ 0.05 level); 60 out of 131 transcripts (at p ≤ 0.01 level) were annotated in the NetAffx database. Ingenuity pathway analysis showed that dietary lysine deficiency may lead to: (1) increased muscle protein degradation via the ubiquitination pathway as indicated by the up-regulated DNAJA1, HSP90AB1 and UBE2B mRNA; (2) reduced muscle protein synthesis via the up-regulated RND3 and ZIC1 mRNA; (3) increased serine and glycine synthesis via the up-regulated PHGDH and PSPH mRNA; and (4) increased lipid accumulation via the up-regulated ME1, SCD, and CIDEC mRNA. Dietary lysine excess may lead to: (1) decreased muscle protein degradation via the down-regulated DNAJA1, HSP90AA1, HSPH1, and UBE2D3 mRNA; and (2) reduced lipid biosynthesis via the down-regulated CFD and ME1 mRNA. Collectively, dietary lysine may function as a signaling molecule to regulate protein turnover and lipid metabolism in the skeletal muscle of finishing pigs.

Effects of dietary lysine levels on plasma free amino acid profile in late-stage finishing pigs.

Muscle growth requires a constant supply of amino acids (AAs) from the blood. Therefore, plasma AA profile is a critical factor for maximizing the growth performance of animals, including pigs. This research was conducted to study how dietary lysine intake affects plasma AA profile in pigs at the late production stage. Eighteen crossbred (Large White × Landrace) finishing pigs (nine barrows and nine gilts; initial BW 92.3 ± 6.9 kg) were individually penned in an environment controlled barn. Pigs were assigned randomly to one of the three dietary treatments according to a randomized complete block design with sex as block and pig as experiment unit (6 pigs/treatment). Three corn- and soybean meal-based diets contained 0.43 % (lysine-deficient, Diet I), 0.71 % (lysine-adequate, Diet II), and 0.98 % (lysine-excess, Diet III) l-lysine, respectively. After a 4-week period of feeding, jugular vein blood samples were collected from the pigs and plasma was obtained for AA analysis using established HPLC methods. The change of plasma lysine concentration followed the same pattern as that of dietary lysine supply. The plasma concentrations of threonine, histidine, phenylalanine, isoleucine, valine, arginine, and citrulline of pigs fed Diet II or III were lower (P < 0.05) than that of pigs fed Diet I. The plasma concentrations of alanine, glutamate, and glycine of pigs fed Diet II or III were higher (P < 0.05) than that of pigs fed Diet I. The change of plasma leucine and asparagine concentrations followed the patterns similar to that of plasma lysine. Among those affected AAs, arginine was decreased (P < 0.05) in the greatest proportion with the lysine-excess diet. We suggest that the skeletal muscle growth of finishing pigs may be further increased with a lysine-excess diet if the plasma concentration of arginine can be increased through dietary supplementation or other practical nutritional management strategies.

Proteome Differences in Placenta and Endometrium between Normal and Intrauterine Growth Restricted Pig Fetuses.

Uteroplacental tissue plays a key role in substance exchanges between maternal and fetal circulation, and, therefore, in the growth and development of fetuses. In this study, proteomics and western blotting were applied to investigate the changes of proteome in the placenta and endometrium of normal and intrauterine growth restriction (IUGR) porcine fetuses during mid to late pregnancy (D60, 90, and 110 of gestation). Our results showed that proteins participating in cell structure, energy metabolism, stress response, cell turnover, as well as transport and metabolism of nutrients were differentially expressed in placenta and endometrium between normal and IUGR fetuses. Analysis of functions of these proteins suggests reductions in ATP production and nutrients transport, increases in oxidative stress and apoptosis, and impairment of cell metabolism in IUGR fetuses. Collectively, our findings aid in understanding of the mechanisms responsible for uteroplacental dysfunction in IUGR fetus, and are expected to provide new strategies to reduce fetal growth restriction in pigs and other mammals.

Lysine nutrition in swine and the related monogastric animals: muscle protein biosynthesis and beyond.

Improving feed efficiency of pigs with dietary application of amino acids (AAs) is becoming increasingly important because this practice can not only secure the plasma AA supply for muscle growth but also protect the environment from nitrogen discharge with feces and urine. Lysine, the first limiting AA in typical swine diets, is a substrate for generating body proteins, peptides, and non-peptide molecules, while excess lysine is catabolized as an energy source. From a regulatory standpoint, lysine is at the top level in controlling AA metabolism, and lysine can also affect the metabolism of other nutrients. The effect of lysine on hormone production and activities is reflected by the change of plasma concentrations of insulin and insulin-like growth factor 1. Lysine residues in peptides are important sites for protein post-translational modification involved in epigenetic regulation of gene expression. An inborn error of a cationic AA transporter in humans can lead to a lysinuric protein intolerance condition. Dietary deficiency of lysine will impair animal immunity and elevate animal susceptibility to infectious diseases. Because lysine deficiency has negative impact on animal health and growth performance and it appears that dietary lysine is non-toxic even at a high dose of supplementation, nutritional emphasis should be put on lysine supplementation to avoid its deficiency rather than toxicity. Improvement of muscle growth of monogastric animals such as pigs via dietary lysine supply may be due to a greater increase in protein synthesis rather than a decrease in protein degradation. Nevertheless, the underlying metabolic and molecular mechanisms regarding lysine effect on muscle protein accretion merits further clarification. Future research undertaken to fully elucidate the metabolic and regulatory mechanisms of lysine nutrition could provide a sound scientific foundation necessary for developing novel nutritional strategies to enhance the muscle growth and development of meat animals.

Temporal proteomic analysis reveals defects in small-intestinal development of porcine fetuses with intrauterine growth restriction.

The fetus/neonate with intrauterine growth restriction (IUGR) has a high perinatal mortality and morbidity rate, as well as reduced efficiency for nutrients utilization. Our previous studies showed alterations of intestinal proteome in IUGR piglets both at birth and during the nursing period. Considering the potential long-term impacts of fetal programming and substantial increases in amounts of amniotic fluid nutrients from mid-gestation in pigs, the present study involved IUGR porcine fetuses from days 60 to 110 of gestation (mid to late gestation). We identified 59 differentially expressed proteins in the fetal small intestine that are related to intestinal growth, development and reprogramming. Our results further indicated increased abundances of proteins and enzymes associated with oxidative stress, apoptosis and protein degradation, as well as decreased abundances of proteins that are required for maintenance of cell structure and motility, absorption and transport of nutrients, energy metabolism, and protein synthesis in the fetal gut. Moreover, IUGR from middle to late gestation was associated with reduced expression of intestinal proteins that participate in regulation of gene expression and signal transduction. Collectively, these findings provide the first evidence for altered proteomes in the small intestine of IUGR fetuses, thereby predisposing the gut to metabolic defects during gestation and neonatal periods.

IUGR alters muscle fiber development and proteome in fetal pigs.

Intrauterine growth restriction (IUGR) may have permanent stunting effects on muscle growth and development of the progeny. However, underlying mechanisms are largely unknown. Recent studies comparing muscle fiber development and proteomes in IUGR and normal-body-weight (NBW) fetal pigs indicated that muscle fiber diameter were smaller in IUGR fetal pigs than in NBW fetal pigs on all three stages (d 60, d 90 and d 110) of gestation. Although the number of primary fibers did not differ between these two fetal groups on d 60 of gestation, the total number of muscle fibers in IUGR fetal pigs was lower on d 90 and 110 of gestation, when compared with NBW fetal pigs. Further proteomic analysis has shown that 37 proteins involved in energy supply and protein metabolism, structure and type of muscle fibers, proliferation and differentiation of muscle fibers, nutrient transport, intracellular environment, and tissue integrity were differentially expressed between IUGR and NBW fetal pigs. These novel findings provide some implications on the mechanisms of reduced growth and impaired development of skeletal muscle in IUGR piglets.

Intrauterine growth restriction alters the hepatic proteome in fetal pigs.

Intrauterine growth restriction (IUGR) is a major problem in both humans and animals. The IUGR fetus has abnormal metabolism of nutrients in the liver. This study was conducted with comparative proteomic approach and biochemical analyses to test the hypothesis that IUGR alters the hepatic proteome in the fetal liver. Livers were obtained from IUGR and normal-weight fetal pigs at Day 110 of gestation. Twenty-two differentially expressed proteins in the liver were identified between IUGR and normal fetal pigs. These proteins participate in the intermediary metabolism of nutrients (including glucose, amino acids, protein, lipids, vitamins and minerals), oxidative stress, as well as cell structure and growth. Of particular interest, the IUGR fetus had a higher activity of glutamate oxaloacetate transaminase and a lower activity of lipoprotein lipase than the normal ones. These results indicate altered metabolism of nutrients, abnormal ammonia utilization, and reduced capacity for detoxification in the liver of IUGR fetus. Collectively, the findings have important implication for explaining low food efficiency and understanding the mechanism responsible for impaired growth in IUGR neonates.

Biomarkers for optimal requirements of amino acids by animals and humans.

Amino acids are building blocks of proteins and key regulators of nutrient metabolism in cells. However, excessive intake of amino acids can be toxic to the body. Therefore, it is important to precisely determine amino acid requirements by organisms. To date, none of the methods is completely satisfactory to generate comprehensive data on amino acid requirements of animals or humans. Because of many influencing factors, amino acid requirements remain a complex and controversial issue in nutrition that warrants further investigations. Benefiting from the rapid advances in the emerging omics technologies and bioinformatics, biomarker discovery shows great potential in obtaining in-depth understanding of regulatory networks in protein metabolism. This review summarizes the current approaches to assess amino acid requirements of animals and humans, as well as the recent development of biomarkers as potentially functional parameters for recommending requirements of individual amino acids in health and disease. Identification of biomarkers in plasma or serum, which is a noninvasive approach, holds great promise in rapidly advancing the field of protein nutrition.