Secretin-stimulated amylase release into blood is impaired in type 1 diabetes mellitus

What is the clinical significance of low serum amylase? Systematic review of the conditions associated with low serum amylase

Objective

Most studies have assessed the impact of elevated serum amylase levels in clinical practice, but only a few have investigated the significance of low serum amylase. We therefore, aimed to review the literature to understand the conditions associated with low serum amylase and its clinical relevance.

Method

This systematic review was performed in accordance with the criteria established in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The search was conducted on Medline and Embase databases until November 2022. After identifying relevant titles, abstracts were read and data of eligible articles retrieved. The conditions associated with low serum amylase were evaluated. The quality of the studies was assessed using the Newcastle-Ottawa Score.

Results

Our search strategy identified 19 studies including a total of 15 097 patients for systematic review. All the studies were observational including two studies which used secretin-induced test. The main conditions associated with low serum amylase were diabetes mellitus (n=9), metabolic syndrome (n=3), chronic pancreatitis (CP) (n=3), non-alcoholic fatty liver disease (n=2) and obesity (n=1). Low serum amylase showed a high specificity (94%) with low sensitivity (38.7%-59%) in diagnosing chronic pancreatitis.

Conclusion

This systematic review revealed a unique insight into the relevance of low serum amylase in clinical practice. Low serum amylase can be a useful adjunct test in the assessment of patients with CP, pancreatic exocrine insufficiency, diabetes mellitus and metabolic syndrome.

Impaired exocrine pancreatic function in different stages of type 1 diabetes

INTRODUCTION

Aim of this study was to investigate the pancreatic exocrine function in patients with type 1 diabetes (T1D) by multiple non-invasive tests.

RESEARCH DESIGN AND METHODS

The study is a single-center, cross-sectional study of pancreatic exocrine function in adult patients with new-onset or long-standing T1D and healthy controls.

RESULTS

Healthy controls, new-onset T1D, and long-standing T1D were similar for age at the time of the study, gender and body mass index (BMI) categories. Age of onset of T1D patients with long-standing disease was younger than that of patients with new-onset T1D (p<0.001). As expected, the three groups differed for C-peptide and hemoglobin A1c (HbA1c) levels. Lipase activity measured by ¹³C-mixed triglyceride breath test was reduced progressively, although not significantly, from controls to recent-onset T1D and long-standing T1D participants. Fecal elastase-1 was significantly lower in participants with T1D, either new onset or long standing. Pancreatic amylase, lipase, retinol binding protein and prealbumin were significantly different across the groups, with a significant trend toward lower values in long-standing T1D and intermediate values in new-onset T1D, while no differences were observed for total amylase. The markers of impaired exocrine function tests (fecal elastase-1, serum pancreatic amylase and lipase) and of nutritional status (retinol binding protein and prealbumin levels) correlated with the reduction of fasting and urinary C-peptide.

CONCLUSIONS

Our results confirm that exocrine pancreatic impairment is a feature of T1D, with low fecal elastase-1, serum pancreatic amylase and lipase as specific markers, associated with reduced levels of nutritional indexes. Moreover, the evidence of more advanced insufficiency in long-standing disease reflects the chronic nature of this process, and its correlation with the residual β-cell function suggests parallel pathways for the impairment of the endocrine and exocrine pancreatic function.

Ketonuria may be associated with low serum amylase independent of body weight and glucose metabolism

CONTEXT

Ketonuria, which reflects a preferential combustion of lipids relative to carbohydrates, is often observed in lean rather than obese people. Clinical studies have shown that individuals with diabetes and/or obesity predispose to have low serum amylase (LSA).

OBJECTIVE

To investigate the association between ketonuria and LSA.

METHODS

We examined ketonuria assessed by dipstick urinalysis and clinical parameters including serum amylase in 3638 Japanese people aged 25-79 years who underwent a health-screening checkup.

RESULTS

There was an inverse relationship between body mass index (BMI) and serum amylase. The lowest serum amylase was observed in obese subjects (BMI ≥ 25.0 kg/m²) with positive ketonuria. Logistic regression analysis showed that ketonuria was significantly associated with LSA (<50 IU/L), which was not altered by the adjustments for relevant confounders including age, sex, BMI, and HbA1c.

CONCLUSIONS

Current results suggest a relative unavailability of carbohydrates for energy production in individuals with LSA.

Pancreatic Elastase Levels in Feces As A Marker of Exocrine Pancreatic Function in Patients With Diabetes Mellitus

OBJECTIVE

The measurement of pancreatic elastase (PE) in feces is used widely to screen for pancreatic exocrine insufficiency. The aim of our study was to evaluate the relationship of PE with residual beta cell secretion and metabolic control in patients with diabetes mellitus.

METHOD

We determined the presence of PE in specimens via enzyme-linked immunosorbent assay (ELISA), whereas serum fasting glucose, C-peptide, amylase, lipase, triglycerides, total 25(OH)-vitamin D, C-reactive protein (CRP), and hemoglobin A1c (HbA1c) concentrations were assayed using routine laboratory tests.

RESULTS

PE values in 48 patients with diabetes were significantly lower than in 24 healthy volunteers (P = 001). In one-third of participants with diabetes mellitus, PE were less than 200 µg per g, indicating pancreatic functional insufficiency. Among the patients in the cohort, PE correlated positively with C-peptide levels (P = 04), lipase (P = 009), CRP (P = 04), sex (P = 03), and BMI (P = 02) but not significantly with duration of diabetes (P = 81) or levels of HbA1c(P = 87), amylase (P = 06), total 25(OH)-vitamin D (P = 16), or triglycerides (P = 52).

CONCLUSION

Our results demonstrated a strong association of diabetes with low PE levels.

Evaluation of Biochemical Markers Serum Amylase and Serum Lipase for the Assessment of Pancreatic Exocrine Function in Diabetes Mellitus

INTRODUCTION

Diabetes mellitus (DM), a metabolic disorder characterized by hyperglycaemia, associated with deficiency or resistance to insulin indicates endocrinal abnormality of the pancreas. Amylase and lipase are enzymes secreted by the exocrine portion of the pancreas. Endocrinal derangement observed in diabetes may interfere with the exocrine function of the pancreas.

AIM

To estimate the levels of fasting blood sugar, serum lipase, serum amylase in patients of type 1 and type 2 DM. Than comparing them with healthy controls and to study the effect of type 1 and type 2 DM on pancreatic exocrine function using serum levels of amylase and lipase as biochemical marker.

MATERIALS AND METHODS

This study was conducted at GMERS Medical College and Hospital from Dec 2015 to July 2016. Thirty patients of type 1 DM and 30 patients of type 2 DM, who were already diagnosed and taking treatment, were included in this study. A total number of 30 apparently healthy individuals were recruited as the control group in our study. Fasting venous blood samples were collected from the cases as well as the controls and they were analysed by using semi auto analyser for blood glucose, serum amylase and serum lipase. The results were analysed statistically by using SPSS software. Values were expressed as means ± SD.

RESULTS

We found statistically significant (p<0.01) low values for serum amylase and serum lipase in patients with type 1 and type 2 DM as compared to healthy controls. Fasting blood sugar was significantly higher in cases as compared to controls. We found negative correlation of fasting blood sugar level with serum amylase and serum lipase and positive correlation of serum amylase with serum lipase in both type 1 and type 2 DM.

CONCLUSION

Our study clearly demonstrated that in type 1 and type 2 DM, there was increase in fasting blood sugar with decrease in serum amylase and serum lipase which signifies the derangement of endocrine-exocrine axis of the pancreas. Serum amylase and serum lipase can be used as biochemical markers for assessment of pancreatic exocrine function.

Salivary Amylase: Digestion and Metabolic Syndrome

Salivary amylase is a glucose-polymer cleavage enzyme that is produced by the salivary glands. It comprises a small portion of the total amylase excreted, which is mostly made by the pancreas. Amylases digest starch into smaller molecules, ultimately yielding maltose, which in turn is cleaved into two glucose molecules by maltase. Starch comprises a significant portion of the typical human diet for most nationalities. Given that salivary amylase is such a small portion of total amylase, it is unclear why it exists and whether it conveys an evolutionary advantage when ingesting starch. This review will consider the impact of salivary amylase on oral perception, nutrient signaling, anticipatory metabolic reflexes, blood sugar, and its clinical implications for preventing metabolic syndrome and obesity.

Serum Amylase Levels in Relation to Islet β Cell Function in Patients with Early Type 2 Diabetes

Objective

The insulin-pancreatic acinar axis may play a major role in pancreatic function. Amylase is an exocrine enzyme that is produced by pancreatic acinar cells, and low serum amylase levels may be associated with endocrine diseases, such as metabolic syndrome and diabetes. We hypothesized that low serum amylase levels may be associated with impaired islet β cell function in type 2 diabetes. Therefore, we investigated the relationship between the serum amylase levels and islet β cell function in patients with early type 2 diabetes.

Methods

The cross-sectional study recruited 2327 patients with a mean of 1.71±1.62 years since their diagnosis of type 2 diabetes, and all participants were treated with lifestyle intervention alone. Serum amylase levels, the 75-g oral glucose tolerance test (OGTT) and metabolic risk factors were examined in all participants. The insulin sensitivity index (Matsuda index, ISI_Matsuda) and insulin secretion index (ratio of total area-under-the-insulin-curve to glucose-curve, AUC_ins/glu) were derived from the OGTT. Integrated islet β cell function was assessed by the Insulin Secretion-Sensitivity Index-2 (ISSI-2) (ISI_Matsuda multiplied by AUC_ins/glu).

Results

Serum amylase levels in the normal range were significantly correlated with ISI_Matsuda, AUC_ins/glu and ISSI-2 (r = 0.203, 0.246 and 0.413, respectively, p<0.001). The association of the serum amylase levels with ISSI-2 (adjusted r = 0.363, p<0.001) was closer than the association with ISI_Matsuda (adjusted r = 0.191, p<0.001) and AUC_ins/glu (adjusted r = 0.174, p<0.001) after adjusting for the anthropometric indices, time since the diagnosis of diabetes, lipid profiles, uric acid levels, estimated glomerular filtration rate, HbA1c levels, smoking and drinking using the partial correlation test. After adjusting for these metabolic risk factors in the multivariate regression analysis with the amylase levels as the dependent variable, ISSI-2 was the major independent contributor to the serum amylase levels (β = 0.416, t = 21.72, p<0.001). Meanwhile, in a comparison of the groups with the highest and lowest quartiles of serum amylase levels, the mean difference in logISSI-2 was 0.902 (95% CI 0.823 to 0.982), and after adjusting for metabolic risk factors, the mean difference in logISSI-2 was 0.610 (0.537 to 0.683).

Conclusions

Serum amylase levels in the normal range are positively associated with integrated islet β cell function in patients with early type 2 diabetes, as assessed by ISSI-2.

Pancreatic proteome profiling of type 1 diabetic mouse: Differential expression of proteins involved in exocrine function, stress response, growth, apoptosis and metabolism

Type 1 diabetes (T1D) is a chronic autoimmune disease in which the pancreatic β-cells fail to produce insulin. In addition to such change in the endocrine function, the exocrine function of the pancreas is altered as well. To understand the molecular basis of the changes in both endocrine and exocrine pancreatic functions due to T1D, the proteome profile of the pancreas of control and diabetic mouse was compared using two dimensional gel electrophoresis (2D-GE) and the differentially expressed proteins identified by electrospray ionization liquid chromatography-tandem mass spectrometry (ESI-LC-MS/MS). Among several hundred protein spots analyzed, the expression levels of 27 protein spots were found to be up-regulated while that of 16 protein spots were down-regulated due to T1D. We were able to identify 23 up-regulated and 9 down-regulated protein spots and classified them by bioinformatic analysis into different functional categories: (i) exocrine enzymes (or their precursors) involved in the metabolism of proteins, lipids, and carbohydrates; (ii) chaperone/stress response; and (iii) growth, apoptosis, amino acid metabolism or energy metabolism. Several proteins were found to be present in multiple forms, possibly resulting from proteolysis and/or post-translational modifications. Succinate dehydrogenase [ubiquinone] flavoprotein subunit, which is the major catalytic subunit of succinate dehydrogenase (SDH), was found to be one of the proteins whose expression was increased in T1D mouse pancreata. Since altered expression of a protein can modify its functional activity, we tested and observed that the activity of SDH, a key metabolic enzyme, was increased in the T1D mouse pancreata as well. The potential role of the altered expression of different proteins in T1D associated pathology in mouse is discussed.

Low serum amylase and obesity, diabetes and metabolic syndrome: A novel interpretation

For the last decade, low serum amylase (hypoamylasemia) has been reported in certain common cardiometabolic conditions such as obesity, diabetes (regardless of type), and metabolic syndrome, all of which appear to have a common etiology of insufficient insulin action due to insulin resistance and/or diminished insulin secretion. Some clinical studies have shown that salivary amylase may be preferentially decreased in obese individuals, whereas others have revealed that pancreatic amylase may be preferentially decreased in diabetic subjects with insulin dependence. Despite this accumulated evidence, the clinical relevance of serum, salivary, and pancreatic amylase and the underlying mechanisms have not been fully elucidated. In recent years, copy number variations (CNVs) in the salivary amylase gene (AMY1), which range more broadly than the pancreatic amylase gene (AMY2A and AMY2B), have been shown to be well correlated with salivary and serum amylase levels. In addition, low CNV of AMY1, indicating low salivary amylase, was associated with insulin resistance, obesity, low taste perception/satiety, and postprandial hyperglycemia through impaired insulin secretion at early cephalic phase. In most populations, insulin-dependent diabetes is less prevalent (minor contribution) compared with insulin-independent diabetes, and obesity is highly prevalent compared with low body weight. Therefore, obesity as a condition that elicits cardiometabolic diseases relating to insulin resistance (major contribution) may be a common determinant for low serum amylase in a general population. In this review, the novel interpretation of low serum, salivary, and pancreas amylase is discussed in terms of major contributions of obesity, diabetes, and metabolic syndrome.

Metabolic effects of secretin

Secretin (Sct), traditionally a gastrointestinal hormone backed by a century long research, is now beginning to be recognized also as a neuroactive peptide. Substantiation by recent evidence on the functional role of Sct in various regions of the brain, especially on its potential neurosecretion from the posterior pituitary, has revealed Sct's physiological actions in regulating water homeostasis. Recent advances in understanding the functional roles of central and peripheral Sct has been made possible by the development of Sct and Sct receptor (SctR) knockout animal models which have led to novel approaches in research on the physiology of this brain-gut peptide. While research on the role of Sct in appetite regulation and fatty acid metabolism has been initiated recently, its role in glucose homeostasis is unclear. This review focuses mainly on the metabolic role of Sct by discussing data from the last century and recent discoveries, with emphasis on the need for revisiting and elucidating the role of Sct in metabolism and energy homeostasis.

Independent association between low serum amylase and non-alcoholic fatty liver disease in asymptomatic adults: a cross-sectional observational study

OBJECTIVES

Low serum amylase (LSA) was reported to be associated with obesity, metabolic syndrome (MetS) and diabetes. However, it is unknown as to whether LSA is associated with non-alcoholic fatty liver disease (NAFLD), a hepatic manifestation of MetS and insulin resistance. Therefore, we performed a clinical epidemiological study to investigate this potential association.

DESIGN

A cross-sectional observational study with multivariate analysis.

SETTING

Subjects were recruited in a healthcare centre in Saitama, an eastern district of Japan, near Tokyo.

PARTICIPANTS

A total of 1475 asymptomatic adults aged 30-79 years who underwent detailed medical check-ups and who regularly consumed small amounts of alcohol (<20 g/day).

OUTCOME MEASURES

Serum amylase, cardiometabolic risk factors, NAFLD determined by ultrasound, MetS determined by Adult Treatment Panel-III criteria and diabetes were assessed.

RESULTS

The prevalence of NAFLD increased significantly from 22.5% to 42.4% (all grades) and from 9.2% to 24.0% (moderate or severe grade) from the highest to the lowest quartile of serum amylase. Multiple logistic regression analysis showed that, compared with the highest quartile of serum amylase, the lowest quartile of serum amylase was significantly associated with any-grade NAFLD and with moderate-to-severe NAFLD, even after adjusting for MetS or diabetes. The association between LSA and any-grade NAFLD disappeared after further adjustment for body mass index or waist circumference, whereas the association between LSA and moderate or severe NAFLD remained statistically significant (ORs (95%CI), 2.01 (1.07 to 3.78) and 2.06 (1.09 to 3.87), respectively, both p=0.01).

CONCLUSIONS

Our results suggest that LSA may be associated with moderate or severe NAFLD in asymptomatic adults independent of MetS, diabetes and obesity. These results warrant confirmation in further studies.

Low serum pancreatic enzyme levels predict mortality and are associated with malnutrition-inflammation-atherosclerosis syndrome in patients with chronic kidney disease

PURPOSE

Serum levels of amylase and lipase are frequently increased in patients with chronic kidney disease (CKD). Relatively low serum pancreatic enzyme levels in CKD may represent a state of pancreatic insufficiency and may contribute to protein-energy wasting (PEW). We aimed to investigate the relationships of serum pancreatic enzyme levels with PEW, inflammation, and mortality in CKD patients.

METHODS

Two hundred and thirty CKD patients (male/female: 144/86; mean age, 59 ± 16 years) were enrolled. Serum total α-amylase and lipase activities were measured by enzymatic colorimetric assays. Mean follow-up time was 18 ± 10 months. Forty-seven patients (20 %) died during this period.

RESULTS

Serum amylase levels were increased in 95 patients (41 %) and serum lipase levels were increased in 71 patients (30 %) out of the 230 patients. Diabetic patients had significantly lower serum amylase levels than non-diabetic ones (86 ± 46 vs. 111 ± 60 IU/L, p < 0.0001). Patients with ischemic heart disease also had significantly lower serum amylase (82 ± 37 vs. 108 ± 60 IU/L, p < 0.0001) and lipase levels (39 ± 36 vs. 57 ± 57 IU/L, p = 0.007). Serum amylase and lipase levels were directly correlated with serum creatinine (r = 0.173, p = 0.009 and r = 0.374, p < 0.0001) and albumin (r = 0.410, p < 0.0001 and 0.287, p < 0.0001), and inversely correlated with CRP (r = -0.223, p = 0.001 and r = -0.147, p = 0.027). The Kaplan-Meier analysis revealed survival advantages for both high-amylase and high-lipase groups in end-stage renal disease (ESRD) (CKD stage 5) patients (log rank, p < 0.001 and p = 0.02, respectively). In the Cox regression analysis, serum amylase was found to be an independent predictor for mortality.

CONCLUSION

Serum amylase activity was found to be an independent predictor of mortality in ESRD patients. Relatively low serum pancreatic enzyme levels in CKD may be regarded as a novel component of the malnutrition-inflammation-atherosclerosis syndrome.

Revisiting the cardiometabolic relevance of serum amylase

Background

The pancreas has dual functions as a digestive organ and as an endocrine organ, by secreting digestive enzymes and endocrine hormones. Some early studies have revealed that serum amylase levels are lower in individuals with chronic pancreatitis, severe long-term type 2 diabetes or type 1 diabetes. Regarding this issue, we recently reported that low serum amylase levels were associated with metabolic syndrome and diabetes in asymptomatic adults. In the light of this, we further investigated the fundamental relationship between serum amylase and cardiometabolic aspects by reanalyzing previous data which comprised subjects without diabetes treatment with oral hypoglycemic drugs or insulin (n = 2,344).

Findings

Serum amylase was inversely correlated with body mass index independently of age. Higher serum amylase levels were noted in older subjects aged 55 years old or more (n = 1,114) than in younger subjects (P < 0.0001, ANOVA), probably due to lower kidney function. It was likely that serum amylase may act similarly to other cardiometabolic protective factors such as high-density lipoprotein cholesterol. However, serum amylase levels were significantly lower in drinkers, particularly daily drinkers (n = 746, P < 0.0001, ANOVA). Meanwhile, despite of consistent inverse relationship between serum amylase and fasting plasma glucose, the relationship between serum amylase and HbA1c may be rather complicated in individuals with normal or mildly impaired glucose metabolism (up to HbA1c 6.0% (NGSP)).

Conclusions

Revisiting the cardiometabolic relevance of serum amylase may yield novel insight not only into glucose homeostasis and metabolic abnormalities related to obesity, but also possibly carbohydrate absorption in the gut.

Serum amylase and risk of the metabolic syndrome in Korean adults

BACKGROUND

Serum amylase has recently been shown to be associated with ghrelin and adiponectin as well as obesity. We investigated the relationship between total amylase and metabolic syndrome in adults.

METHODS

4495 adults were enrolled. All subjects denied any medical history or status of a disorder that could influence their serum amylase. Anthropometry, metabolic risk factors and total amylase concentration were measured. Each participant was categorized into one of 4 subgroups according to their total amylase concentration. Multiple logistic regression analysis was used to assess the independent association between amylase concentration and metabolic syndrome. Receiver-operating characteristics (ROC) curves analyses were used for comparison of the diagnostic value of amylase and other biomarkers for metabolic syndrome.

RESULTS

The prevalence of metabolic syndrome by the National Cholesterol Education Program criteria was 13.4%, 15.3%, 19.3%, and 24.2% of those in the fourth, third, second, and lowest quartile of amylase concentration (P for trend <0.001). After adjusting for age, sex, and body mass index, the odds ratios of the lower quartiles were significantly higher compared to the fourth quartile for the presence of metabolic syndrome. In ROC curve analysis, amylase was similar to uric acid as a significant diagnostic indicator for metabolic syndrome, but it had lower diagnostic value than alanine aminotransferase, γ-glutamyltransferase or C-reactive protein.

CONCLUSIONS

Lower amylase concentration is associated with an increased prevalence of metabolic syndrome. Amylase may contribute to identifying metabolic syndrome, although further research is needed to understand the mechanism behind these associations.

Low serum amylase in association with metabolic syndrome and diabetes: A community-based study

Background

Low serum amylase levels may reflect impaired exocrine-endocrine relationship in the pancreas. However, few clinical studies have addressed this issue. Therefore, in this epidemiological study, we investigated whether low serum amylase was associated with the pathogenesis of impaired insulin action: metabolic syndrome (MetS) and diabetes.

Research Design and Methods

Serum amylase, cardiometabolic risk factors, MetS (Adult Treatment Panel III criteria), and diabetes were examined in 2,425 asymptomatic subjects aged 30-80 years who underwent medical checkups recently (April 2009-March 2010) and 5 years ago.

Results

Clinical variables, except for age and estimated glomerular filtration rate (eGFR), shifted favorably with increasing serum amylase levels. Plasma glucose levels at 1- and 2-hr during OGTT increased significantly with decreasing serum amylase levels. Multiple logistic analyses showed that, compared with highest quartile of serum amylase, lowest quartile was associated with increased risk for MetS and diabetes after adjustment for confounding factors [odds ratio (95% CI), 2.07 (1.39-3.07) and 2.76 (1.49-5.11), respectively]. In subjects who underwent checkups 5 years ago (n = 571), lower amylase at the previous checkup were associated with larger numbers of metabolic abnormalities at the recent checkup. The fluctuation over time in serum amylase levels in subjects with low serum amylase at the previous checkup was slight and was unaffected by kidney dysfunction.

Conclusions

Our results indicate that low serum amylase is associated with increased risk of metabolic abnormalities, MetS and diabetes. These results suggest a pancreatic exocrine-endocrine relationship in certain clinical conditions.