AMY1 Copy Number Research Articles

Influence of AMY1 gene copy number on salivary amylase activity changes induced by exercise in young adults.

Human salivary amylase secretion increases in response to stress; the activity has been reported to rise significantly with high-intensity exercise. The human salivary amylase gene (AMY1) has copy number variation, with the copy number correlating with salivary amylase activity. However, the relationship between individual AMY1 copy number and salivary amylase activity in response to exercise remains unclear. In this study, we investigated AMY1 copy number and fluctuations in amylase activity in 42 healthy university students (25 males and 17 females). Participants engaged in intermittent round-trip interval training on a basketball court. Saliva samples were collected pre- and post-exercise to measure amylase activity. DNA was extracted from the oral mucosa, and AMY1 copy number was quantified using RT-PCR. Results showed a significant increase in amylase activity postexercise. Additionally, amylase activity pre- and post-exercise was positively correlated with AMY1 copy number. The generalize linear model showed that the exercise-induced increase in amylase activity per AMY1 gene was negatively related to the AMY1 copy number and aerobic fitness. Gender has no effect on amylase activity. These results suggest a different mechanism for the constitutive and exercise-induced amylase secretion, while aerobic fitness may be independently involved in the secretion.

Effect of Aerobic Exercise in Chinese Adult Individuals at Risk for Type 2 Diabetes Mellitus (T2DM) with Low Salivary Amylase Gene (AMY1) Copy Number Variation.

Type 2 Diabetes mellitus (T2DM) has become a life-threatening health problem around the world. Studies have confirmed that aerobic exercise can prevent the risk of T2DM. Furthermore, recent research showed that salivary amylase gene (AMY1) copy number variation (CNV) could be one of the genetic factors that increased the risk of T2DM. To provide more evidence on how AMY1 CNV and exercise is correlated with the risk of T2DM, we designed this study to show the differences in postprandial carbohydrate metabolism between people with different AMY1 copy numbers, and how aerobic exercise can influence this process. Sixteen participants without cardiovascular disease were chosen, 8 with AMY1 CNV≥6 (High CNV group, HCNV), and 8 with AMY1 CNV ≤ 2 (Low CNV group, LCNV). All participants were Chinese, Han nationality, 18 to 40 years old, with fasting blood glucose lower than 6.1 mmol/L and normal blood pressure levels. They were asked to visit the laboratory in fasting state and drink a cup of solution with 75 grams of edible carbohydrate (glucose or starch). After carbohydrate intake, blood samples were taken at certain times at rest or after aerobic exercise. Blood glucose levels were tested with a portable blood glucose monitor, and insulin levels were tested with the enzyme-linked immunosorbent assay (ELISA). The LCNV group had significantly higher resting insulin levels and homeostatic model assessment of insulin resistance (HOMA-IR) than the HCNV group. Compared to the HCNV group, postprandial blood glucose levels and insulin levels were insensitive to starch intake in the LCNV group. However, this difference disappeared after aerobic exercise was added as an intervention. Lower AMY1 CNV could be associated with higher risk of T2DM and complex carbohydrate metabolism disorder, while aerobic exercise can reduce the risk by increasing the carbohydrate utilization rate.

Salivary amylase gene (AMY1) copy number variation has only a minor correlation with body composition in Chinese adults.

According to the WHO, about 39% of the global adult population were overweight or obese in 2016. Obesity has high heritability, with more than 1000 variants so far identified. There have been reports indicating that salivary amylase gene (AMY1) copy number was one of these variants, yet its association with obesity remains controversial. Our research aimed to provide more evidence on the relationship of AMY1 copy number variation (CNV) with body mass index (BMI) and body composition. We recruited 133 Chinese adults (65 males, 68 females, 18-25years old) with normal fasting blood glucose and blood pressure levels. 19 males were selected for a 10-week intervention to change body composition. After anthropometric measurements, BMI was calculated, and body composition was measured using dual energy X-ray absorptiometry (DEXA). For the 19 selected participants, we collected their height, weight, and body composition data one more time after intervention. All participants were required to leave their saliva samples and their AMY1 copy number was determined by real-time fluorescence quantitative PCR. We failed to find any significant difference in BMI and body composition between different copy number groups. Only a weak correlation was found between body muscle mass and body fat mass. After adjusted for height and weight, AMY1 CNV explained 4.83% of the variance and one single increase in AMY1 CNV can increase 0.214kg of the body muscle mass, while one single increase in AMY1 CNV can decrease 0.217kg of the body fat mass and explained 4.69% of the variance. As a genetic factor, the AMY1 gene copy number variation has only a minor correlation with BMI and body composition, and its effect can easily be hidden by other factors such as individual diet and exercise habit.

Starch intake, amylase gene copy number variation, plasma proteins, and risk of cardiovascular disease and mortality

BackgroundSalivary amylase, encoded by the AMY1 gene, initiate the digestion of starch. Whether starch intake or AMY1 copy number is related to disease risk is currently rather unknown. The aim was to investigate the association between starch intake and AMY1 copy number and risk of cardiovascular disease (CVD) and mortality and whether there is an interaction. In addition, we aim to identify CVD-related plasma proteins associated with starch intake and AMY1 copy number.MethodsThis prospective cohort study used data from 21,268 participants from the Malmö Diet and Cancer Study. Dietary data were collected through a modified diet history method and incident CVD and mortality were ascertained through registers. AMY1 gene copy number was determined by droplet digital polymerase chain reaction, a risk score of 10 genetic variants in AMY1 was measured, and a total of 88 selected CVD-related proteins were measured. Cox proportional hazards regression was used to analyze the associations of starch intake and AMY1 copy number with disease risk. Linear regression was used to identify plasma proteins associated with starch intake and AMY1 copy number.ResultsOver a median of 23 years’ follow-up, 4443 individuals developed CVD event and 8125 died. After adjusting for potential confounders, a U-shape association between starch intake and risk of CVD (P-nonlinearity = 0.001) and all-cause mortality (P-nonlinearity = 0.03) was observed. No significant association was found between AMY1 copy number and risk of CVD and mortality, and there were no interactions between starch intake and AMY1 copy number (P interaction > 0.23). Among the 88 plasma proteins, adrenomedullin, interleukin-1 receptor antagonist protein, fatty acid-binding protein, leptin, and C-C motif chemokine 20 were associated with starch intake after adjusting for multiple testing.ConclusionsIn this large prospective study among Swedish adults, a U-shaped association between starch intake and risk of CVD and all-cause mortality was found. Several plasma proteins were identified which might provide information on potential pathways for such association. AMY1 copy number was not associated with CVD risk or any of the plasma proteins, and there was no interaction between starch intake and AMY1 copy number on disease risk.

Genetic factors associated with serum amylase in a Japanese population: combined analysis of copy-number and single-nucleotide variants

Amylase activity and levels in humans are heritable quantitative traits. Although many studies exist on the effects of copy-number variants (CNVs) in amylase genes (AMY) on human phenotypes, such as body mass index (BMI), the genetic factors controlling interindividual variation in amylase levels remain poorly understood. Here, we conducted a genome-wide association study (GWAS) of serum amylase levels (SAL) in 814 Japanese individuals to identify associated single-nucleotide variants (SNVs), after adjusting for non-genetic factors. Diploid copy numbers (CN) of AMY (AMY1, AMY2A, and AMY2B) were measured using droplet digital PCR to examine the association between each diploid CN and SAL. We further assessed the relative contribution of the GWAS-lead SNV and AMY CNVs to SAL. GWAS identified 14 significant SNVs (p < 5 × 10−8) within a linkage disequilibrium block near the AMY cluster on chromosome 1. The association analyses of AMY CNVs and SAL showed a significant association between AMY1 diploid CN and SAL (p = 1.89 × 10−19), while no significant association with SAL was found for AMY2A CN (p = 0.54) or AMY2B CN (p = 0.15). In a joint association analysis with SAL using the GWAS-lead SNV and AMY1 diploid CN, AMY1 CN remained significant (p = 5.4 ×10−13), while the association of the lead SNV was marginal (p = 0.08). We also found no association between AMY1 diploid CN and BMI (p = 0.14). Our results indicate that AMY1 CNV is the major genetic factor for Japanese SAL, with no significant association with BMI.

Prevotella abundance and salivary amylase gene copy number predict fat loss in response to wholegrain diets

BackgroundSalivary amylase (AMY1) gene copy number (CN) and Prevotella abundance in the gut are involved in carbohydrate digestion in the upper and lower gastrointestinal tract, respectively; and have been suggested as prognostic biomarkers for weight loss among overweight individuals consuming diets rich in fiber and wholegrains.ObjectiveWe hypothesized that Prevotella abundance would be linked to greater loss of body fat after wholegrain consumption among individuals with low AMY1 CN, but not in those with high AMY1 CN.MethodsWe reanalyzed data from two independent randomized ad libitum wholegrain interventions (fiber intake ∼33 g/d for 6–8 weeks), to investigate the relationship between baseline Prevotella abundance and body fat loss among healthy, overweight participants stratified into two groups by median AMY1 CN. Individuals with no detected Prevotella spp. were excluded from the main analysis.ResultsIn both studies, individuals with low AMY1 CN exhibited a positive correlation between baseline Prevotella abundance and fat loss after consuming the wholegrain diet (r > 0.5, P < 0.05), but no correlation among participants with high AMY1 CN (P ≥ 0.6). Following consumption of the refined wheat control diets, there were no associations between baseline Prevotella abundance and changes in body fat in any of the AMY1 groups.ConclusionThese results suggest that Prevotella abundance together with AMY1 CN can help predict fat loss in response to ad libitum wholegrain diets, highlighting the potential of these biomarkers in personalized obesity management.

Association of Serum Amylase Activity and the Copy Number Variation of AMY1/2A/2B with Metabolic Syndrome in Chinese Adults.

PurposeLow serum amylase activity and copy number (CN) variation (CNV) of the salivary amylase gene (AMY1) are reportedly associated with obesity and abnormal glucose metabolism; however, this association remains controversial. We aimed to clarify the relationship between serum amylase activity and the CNV of AMY1/2A/2B with the occurrence of metabolic syndrome (MetS) in Chinese adults.Patients and MethodsAnthropometry, metabolic risk factors, and serum amylase activity were assessed in 560 subjects (260 MetS patients; 300 healthy controls). AMY1/2A/2B CNs were evaluated using the highly sensitive droplet digital PCR.ResultsThe serum total, pancreatic, and salivary amylase activity, but not the AMY1/2A/2B CNs, was significantly lower in MetS patients than that in the control subjects. Patients <45 y had a lower AMY1 CN, compared to that in healthy controls. Low serum amylase activity was significantly associated with high MetS prevalence (p < 0.001). In the receiver operating characteristic curve analysis, serum amylase activity was a significant diagnostic indicator for MetS. The diagnostic value of total amylase was second only to that of γ-glutamyl transpeptidase; it was higher than that of alanine aminotransferase and uric acid.ConclusionLow serum amylase activity was significantly associated with increased risk of MetS in Chinese adults. Therefore, amylase could be a potential biomarker for predicting MetS.

Effect of AMY1 copy number variation and various doses of starch intake on glucose homeostasis: data from a cross-sectional observational study and a crossover meal study

BackgroundCopy number (CN) variation (CNV) of the salivary amylase gene (AMY1) influences the ability to digest starch and may influence glucose homeostasis, obesity and gut microbiota composition. Hence, the aim was to examine the association of AMY1 CNV with fasting glucose, BMI, and gut microbiota composition considering habitual starch intake and to investigate the effect of AMY1 CNV on the postprandial response after two different starch doses.MethodsThe Malmö Offspring Study (n = 1764, 18–71 years) was used to assess interaction effects between AMY1 CNV (genotyped by digital droplet polymerase chain reaction) and starch intake (assessed by 4-day food records) on fasting glucose, BMI, and 64 gut bacteria (16S rRNA sequencing). Participants with low (≤ 4 copies, n = 9) and high (≥ 10 copies, n = 10) AMY1 CN were recruited for a crossover meal study to compare postprandial glycemic and insulinemic responses to 40 g and 80 g starch from white wheat bread.ResultsIn the observational study, no overall associations were found between AMY1 CNV and fasting glucose, BMI, or gut microbiota composition. However, interaction effects between AMY1 CNV and habitual starch intake on fasting glucose (P = 0.03) and BMI (P = 0.05) were observed, suggesting inverse associations between AMY1 CNV and fasting glucose and BMI at high starch intake levels and positive association at low starch intake levels. No associations with the gut microbiota were observed. In the meal study, increased postprandial glucose (P = 0.02) and insulin (P = 0.05) were observed in those with high AMY1 CN after consuming 40 g starch. This difference was smaller and nonsignificant after consuming 80 g starch.ConclusionsStarch intake modified the observed association between AMY1 CNV and fasting glucose and BMI. Furthermore, depending on the starch dose, a higher postprandial glucose and insulin response was observed in individuals with high AMY1 CN than in those with low AMY1 CN.Trial registrationClinicalTrials.gov, NCT03974126. Registered 4 June 2019—retrospectively registered.

Reduced odds of diabetes associated with high plasma salivary \u03b1-amylase activity in Qatari women: a cross-sectional study

The association of salivary α-amylase activity (SAA) activity or low copy number of its coding gene AMY1 with diabetes remains controversial. We aimed to reinvestigate the association of these factors with diabetes in Qatar, where diabetes prevalence is about 16%. We obtained cross-sectional data of 929 Qataris (age > 18 years) from the Qatar Biobank. We estimated AMY1 copy number variants (CNV) from whole-genome data, and quantified the SAA activity in plasma (pSAA). We used adjusted logistic regression to examine the association between pSAA activity or AMY1 CNV and diabetes odds. We found a significant association between high pSAA activity, but not AMY1 CNV, and reduced odds of diabetes in Qatari women. The OR per pSAA activity unit was 0.95 [95% CI 0.92, 0.98] (p = 0.002) (pSAA activity range: 4.7 U/L to 65 U/L) in women. The association is driven largely by the highest levels of pSAA activity. The probability of having diabetes was significantly lower in the fifth pSAA activity quintile relative to the first (0.21 ± 0.03 (Q1) versus 0.82 ± 0.02 (Q5)), resulting in significantly reduced diabetes prevalence in Q5 in women. Our study indicates a beneficial effect of high pSAA activity, but not AMY1 CN, on diabetes odds in Qatari women, and suggests pSAA activity levels as a potential marker to predict future diabetes in Qatari women.

Recent advances in understanding the adaptive evolution of metabolic genes and traits.

This review summarizes the recent advances in understanding the adaptive evolution of metabolic genes and traits, providing insights into gene-diet interactions in human evolution and health. The rapid accumulation of ancient DNA across time and geography illuminates unprecedented details of some well-established examples of genetic adaptation to diet, such as the LCT and FADS genes. Novel cases of thrifty genes were identified, especially a microRNA at the LCT locus that controls energy expenditure and glucose homeostasis, connecting the historical adaptation to present-day metabolic disorders. A new example of gene-diet-microbiota interactions was established among the AMY1 copy number, starchy diets, and resistant-starch-digesting Ruminococcus. The explosion of genome-wide association studies in large cohorts unravels the present-day health implications of historically adaptive genetic variants. It also enables studies into the polygenic adaptation of metabolic traits, revealing intriguing adaptive signals for increased bone mineral density, blood pressure, and risk of type 2 diabetes, but decreased body mass index and HbA1c. The rapid accumulation of ancient and modern DNA has fueled the characterization of novel and existing cases of genetic adaptation. However, transferring these evolutionary insights into genome-informed precision nutrition requires extensive mechanistic studies and genotype-aware clinical trials.

Amylase Alpha 1 Gene (AMY1) Copy Number Variation and Dental Caries Experience: A Pilot Study among Adults in Lithuania

Introduction: Genetic biomarkers have the potential to be used in personalised dentistry for improved prevention and decision-making in caries management. The amylase alpha 1 gene (AMY1) encodes salivary α-amylase and may be one such biomarker. We examined the association between AMY1 copy number variation (CNV) and dental caries experience in adults. Materials and Methods: A stratified random sample of 193 participants from the Lithuanian National Oral Health Survey (LNOHS) agreed to provide saliva samples and were included in this analysis (age 35–44 years; participation rate 43%). Information on socio-demographic and behavioural characteristics was taken from the LNHOS, which used the self-administered World Health Organisation (WHO) questionnaire. Data on fluoride levels in drinking water at the recruitment areas was recorded based on information provided by water suppliers. Dental caries experience was recorded at a surface level (smooth-surface and occlusal-surface decayed, missing, filled surfaces [D₃MFS] score) by one trained and calibrated examiner using WHO criteria, and subsequently dichotomised for the statistical analyses. DNA extracted from saliva samples was used to investigate AMY1 CNV using the QX200 droplet digital PCR system. Bivariate and multivariable statistical analyses were employed. Results: When compared to participants with an AMY1 copy number (CN) of 2–3, higher odds of smooth-surface D₃MFS >14 was observed for participants with a CN of 4–5 (OR 13.3, 95% CI 2.1–86.3), 6–9 (OR 7.0, 95% CI 1.4–34.1), and 10–16 (OR 5.8, 95% CI 1.2–32.2). Female sex was independently associated with a smooth-surface D₃MFS >14 (OR 5.7, 95% CI 1.9–17.2). Conclusions: Our study demonstrated an association between AMY1 CNV and high smooth-surface caries experience. Studies with larger sample sizes are needed to validate this association.

Ethnic-specific association of amylase gene copy number with adiposity traits in a large Middle Eastern biobank

Studies assessing the impact of amylase genes copy number (CN) on adiposity report conflicting findings in different global populations, likely reflecting the impact of ancestral and ethnic-specific environment and lifestyle on selection at the amylase loci. Here, we leverage population size and detailed adiposity measures from a large population biobank to resolve confounding effects and determine the relationship between salivary (AMY1) and pancreatic (AMY2A) amylase genes CN and adiposity in 2935 Qatari individuals who underwent whole-genome sequencing (WGS) as part of the Qatar Genome Programme. We observe a negative association between AMY1 CNs and trunk fat percentage in the Qatari population (P = 7.50 × 10−3) and show that Qataris of Arab descent have significantly lower CN at AMY1 (P = 1.32 × 10−10) as well as less favorable adiposity and metabolic profiles (P < 1.34 × 10−8) than Qataris with Persian ancestry. Indeed, lower AMY1 CN was associated with increased total and trunk fat percentages in Arabs (P < 4.60 × 10−3) but not in Persians. Notably, overweight and obese Persians reported a significant trend towards dietary restraint following weight gain compared to Arabs (P = 4.29 × 10−5), with AMY1 CN showing negative association with dietary self-restraint (P = 3.22 × 10−3). This study reports an association between amylase gene CN and adiposity traits in a large Middle Eastern population. Importantly, we leverage rich biobank data to demonstrate that the strength of this association varies with ethnicity, and may be influenced by population-specific behaviors that also contribute to adiposity traits.

Interaction Effect Between Copy Number Variation in Salivary Amylase Locus (AMY1) and Starch Intake on Glucose Homeostasis in the Malmö Diet and Cancer Cohort.

Salivary amylase initiates the digestion of starch and it has been hypothesized that salivary amylase may play a role in the development of insulin resistance and type 2 diabetes. The aim was to examine the interaction between copy number variation in the salivary amylase gene AMY1 and starch intake. We studied 3,624 adults without diabetes or elevated blood glucose in the Malmö Diet Cancer cohort. We assessed the associations and interactions between starch intake, AMY1 copies and glucose homeostasis traits (i.e., fasting plasma glucose, insulin and HOMA-IR) and risk of type 2 diabetes over an average of 18 follow-up years. AMY1 copy number was not associated with glucose, insulin or HOMA-IR. We observed a significant interaction between starch intake and AMY1 copies on insulin and HOMA-IR after adjusting for potential confounders (p < 0.05). The inverse association between starch intake and insulin and HOMA-IR was stronger in the group with 10 or more copies (Ptrend < 0.001). In addition, we observed an inverse association between starch intake and type 2 diabetes in the group with 10 or more copies (ptrend = 0.003), but not in the other groups. This cross-sectional observational study suggests that AMY1 copy numbers might interact with starch intake on glucose homeostasis traits. Interventional studies are required to determine whether individuals with high AMY1 copy numbers may benefit from a high starch intake.

High plasma salivary \u03b1-amylase, but not high AMY1 copy number, associated with low obesity rate in Qatari adults: cross-sectional study

The relationship between salivary α-amylase activity (psAAa) or AMY1 copy number and the risk of obesity remains controversial. We aimed to assess this relationship in a cohort from Qatar, where obesity affects 43% of adults. The relationship was investigated cross-sectionally in 923 Qatari adults from the Qatar biobank cohort. AMY1 CN was estimated form whole genome sequencing data. The associations with obesity prevalence were assessed by linear and logistic regressions. We found no difference in AMY1 CN between obese and normal-weight individuals. However, the psAAa was significantly lower in obese individuals. Significant inverse correlations were found between adiposity markers and psAAa in both sexes, but were marginally stronger in men. A significant effect of high psAAa, but not AMY1 CN, on reduced obesity rates was identified in men (OR per psAAa unit 0.957 [95% CI 0.937–0.977], p < 0.001, with psAAa ranging between 5 to 66 U/L). A significantly higher prevalence of obesity was observed in the lowest quartile of psAAa in men (75% (Q1) vs. 36% (Q4), p < 0.001) and women (74% (Q1) vs 56% (Q4), p = 0.009). Our findings suggest that high psAAa, but not AMY1 CN, has a potential positive benefit against obesity in the Qatari population.

AMY1 Gene Copy Number Correlates With Glucose Absorption and Visceral Fat Volume, but Not with Insulin Resistance.

The human amylase gene (AMY1) has a broad copy number (CN) variation that may associate with body mass index. Deoxyribonucleic acid was extracted from urine (n = 74) and serum (n = 6) samples (Protein, Fiber and Metabolic Syndrome [ProFiMet] cohort), and buccal (n = 17) samples (Oral Starch Challenge [OSC] cohort), and assessed for AMY1 CN by droplet digital polymerase chain reaction. The association of AMY1 CN with comprehensive markers of metabolic status (ProFiMet cohort) were analyzed with Pearson's correlation coefficient (CC). For the healthy, euglycemic OSC cohort, glycemic response to OSC was analyzed with independent sample t-tests (subgroups: high AMY1 CN 9-12, n = 10; low AMY1 CN 4-6, n = 7). There were significant inverse correlations of AMY1 CN with total visceral fat volume (CC -0.33; P = 0.004) and positive correlations of AMY1 CN with oral glucose insulin sensitivity score (derived from an oral glucose tolerance test, CC 0.26; P = 0.02), serum HDL-cholesterol (CC 0.325; P = 0.003), and serum adiponectin (CC 0.249; P = 0.026). Linear regression multivariate analysis (adiponectin as dependent variable), showed independent association of adiponectin with AMY1 CN (Beta = 0.29; P = 0.03). There were no significant associations between AMY1 CN and clamp-derived M-value, homeostasis model assessment of insulin resistance (IR), hepatic endogenous glucose production, fecal floral signature, or macronutrient dietary preference. Delta (mean) change in blood glucose concentration (fasting to 30-minutes post-OSC) was significantly greater in the high versus low AMY1 CN subgroups (mean 1.7 mmol/l [SEM 0.6] vs 0.9 mmol/l [SEM 0.9], respectively; P = 0.016). High AMY1 CN associates with a favorable metabolic profile (lower visceral fat volume, higher serum adiponectin, enhanced glucose absorption following oral glucose, and OSC), but not with whole-body or hepatic IR.

AMY1 diploid copy number among end-stage renal disease patients.

The salivary amylase gene (AMY1) copy number variation (CNV) is increased as a human adaptation to starch-enriched nutritional patterns. The purpose of this study was to evaluate the relationship between AMY1 CNV, dietary starch consumption, and anthropometric indices among a known population with elevated cardiovascular risk, beingend-stage renal disease (ESRD) patients. A total of 43 ESRD patients were recruited based on the following inclusion criteria: being (1) adults, (2) on hemodialysis for more than 3months, (3) able to communicate effectively, and (4) willing to participate. Anthropometric measurements were performed, dietary intake was recorded via food-frequency questionnaires, and AMY1 CNV was quantified in blood samples DNA via real-time PCR. Median AMY1 CNV was 4.0 (2.0-17.0). A total of 21 patients had an even, and 22 had an odd AMY1 copy number (CN). Independent samples t tests revealed that AMY1-odd diploid CN is associated with increased body weight, waist and hip circumferences, and fat mass compared to the respective even diploid CN carrier group. No differences were observed for BMI or nutritional intake. Multiple regression analysis revealed that AMY1-odd diploid CN was positively associated with increased hip circumference (ß= 7.87, 95% CI = 0.34 to 15.39) and absolute fat mass (ß= 6.66, 95% CI = 0.98 to 12.34); however, after applying the Bonferroni correction for multiplicity, all regression analyses lost their significance. AMY1-odd diploid CN appears to be associated with selected adiposity variables among hemodialysis patients. However, more research is needed to verify this finding in this population with known increased cardiovascular risk.

Salivary Amylase Gene Copy Number Is Associated with the Obesity and Inflammatory Markers in Children.

BackgroundWe have recently shown that the copy number of salivary amylase (AMY1) gene was significantly decreased, and the obesity-related salivary biomarkers resistin, MCP-1, TNF-α, IL-6, and CRP were significantly increased in overweight/obese children compared to normal weight. This study aimed to evaluate the association of AMY1 copy number variant (CNV) with obesity and inflammatory markers. Seventy-six participants aged between 6 and 10 years have participated, and the saliva samples were collected along with the anthropometric measurements.MethodsAMY1 copy number was analyzed by 3D digital PCR, and obesity-related biomarkers were performed with a Bioplex multiplex analyzer.ResultsThe mean AMY1 copy number was higher in normal weight (7.90 ± 0.38) compared to the overweight/obese group (6.20 ± 0.29). The association of AMY1 CNV with obesity and inflammatory markers showed significant negative correlation [CRP, β = −0.238 (p < 0.05); resistin, β = −0.25 (p < 0.05); MCP-1, β = −0.304 (p < 0.01)] except for complement factor D, TNF α and IL-6. The anti-inflammatory cytokine, IL-10 reported a positive correlation with AMY1 copy number with a β = 0.268 (p < 0.05). The multivariable model adjusted with age and gender depicted a similar correlation with obesity markers.ConclusionOur results report that AMY1 CNV is associated with obesity and inflammatory biomarkers in children’s saliva sample.

Salivary amylase gene copy number and its association with fasting and postprandial glucose response

AbstractIntroductionWhen compared to other primates, humans elicit a large variation in the copy number for the salivary amylase gene, AMY1. This variation can range from 2 to 17 copies. The AMY1 gene is responsible for coding for salivary amylase, an enzyme needed to catalyze the hydrolysis of starch molecules into smaller sugars. AMY1 copy number correlates with the amount and activity of salivary amylase. Few studies have investigated the effect of amylase copy number on fasting and postprandial glucose levels. The aim was first to investigate the association between AMY1 copy numbers and fasting glucose in an observational study, and secondly to investigate the difference in postprandial effect of high-starch meals in individuals with either high or low AMY1 copy numbers.Materials and methodsFor the observational study, we used data from 436 participants from the Malmö Offspring Study (MOS) cohort whom have been genotyped for AMY1. For the meal study (conducted during May 2019), we used genotype-based-recall to recruit 24 participants from the observational study of the MOS cohort: 12 with low AMY1 copy number (from the lowest 20%) and 12 with high AMY1 copy numbers (from the highest 20%). Each subject will be served a breakfast meal of white wheat bread on two separate test days: one containing 40 g and the other containing 80 g of carbohydrates (mainly starch). Blood samples will then be taken at various time points to investigate postprandial glucose and insulin responses.ResultsWhen using linear regression analyses adjusting for age and sex, no significant association between AMY1 copy number and fasting glucose was observed (p = 0.23). However, there was a difference (p = 0.05) in fasting glucose levels between the lowest (2–4 copy numbers: 5.31 mmol/L; 95% CI: 5.13–5.50) and highest (10–16 copy numbers: 5.57 mmol/L; 95% CI: 5.39–5.75) copy number groups. The results for the meal study will be obtained in June 2019 and be presented at the conference.DiscussionOur findings of higher fasting glucose among the group with more than 10 AMY1 copy numbers is the first study to find this and needs to be replicated in other populations.

Association of Salivary Amylase (AMY1) Gene Copy Number with Obesity in Alabama Elementary School Children.

Salivary amylase (AMY1) is the most abundant enzyme in human saliva, responsible for the hydrolysis of α-1,4 glycosidic linkages that aids in the digestion of starch. Recently studies have shown that the copy number of AMY1 is associated with obesity; however, the data varies with location. One-third of children are overweight/obese in Alabama. In this study, we aim to determine the relationship between the copy number of AMY1 gene and obesity measurements in children from Alabama. One hundred twenty-seven children aged between 6 to 10 years participated in this study. Anthropometric measurements were measured using WHO recommendations. Genomic DNA was extracted from saliva, and the copy number of the AMY1 gene was estimated by digital PCR. The association between AMY1 copy number and obesity measurements was analyzed by linear regression. The mean AMY1 copy number significantly decreased in overweight/obese (6.21 ± 1.48) compared to normal weight (7.97 ± 2.35) children. AMY1 copy number inversely associated with the obesity measurements. African Americans had a stronger association between low AMY1 copy number and obesity compared to white/European Americans. Our findings suggest that overweight/obese children have a low AMY1 copy number and the effect is more prominent in African Americans.

Understanding Determinants of Carbohydrate Metabolism and Their Contribution to Metabolic Health; The Impact of AMY1 CNV (P21-015-19)

ObjectivesSalivary α- amylase (AMY1) is responsible for the breakdown of starch into oligosaccharides, tri and di-saccharides giving a start to the starch digestion in the oral cavity on food consumption. Several studies recently reported contradicting results regarding the link between AMY1 copy numbers (CNs) and obesity and type 2 diabetes.Objective: We investigated whether CN in the AMY1 gene was associated with differential anthropometrics and glycaemic outcomes in obese individuals who underwent a dietary plan varying in macronutrient intake, as a part of weight loss and weight maintenance program. We also investigated whether there existed an interaction between nutrient intakes and AMY1 CNs and if AMY1 CNs have influence on body weight, body composition and glycemic trajectories during dietary interventions. MethodsUsing the Paralogue Ratio Test, we accurately measured the AMY1 CNs in 761 obese individuals from the Diogenes study. Subjects underwent first an 8-week low-caloric diet (LCD, at 800 kcal/d) and those achieving >8% weight loss were then randomized to a 6-month weight maintenance dietary (WMD) intervention. The association between AMY1 CNs and weight- and glycemic- parameters was tested at baseline and following each intervention phase (LCD, WMD) with the use of linear mixed effect models adjusting for gender, age, center and total energy intake. ResultsAt baseline, a modest association between AMY1 CN and BMI (P = 0.04) was observed. AMY1 CN was not associated with baseline glycemic variables. Additionally, AMY1 CN was not associated with anthropometric or glycemic-outcomes following either LCD or WMD. Interaction analyses between AMY1 CN and nutrient intake did not reveal significant association with any clinical parameters (at baseline and following LCD or WMD) or when testing gene x WMD interactions during the WMD phase ConclusionsIn the absence of association with weight trajectories or glycemic improvements, the AMY1 CN cannot be considered as an important biomarker for response to a clinical weight loss and weight maintenance programs in overweight/obese subjects. Funding SourcesEuropean Commission, Food Quality and Safety Priority of the Sixth Framework Program (FP6-2005-513946), Nestlé Institute of Health Sciences. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.