Featured Reagent – Adiponectin
Adiponectin (ADPN) (adipocyte complement-related protein of 30kDa (Acrp30)) is an adipokine (protein hormone) produced and secreted by the adipose tissue, an endocrine organ 1. ADPN acts as a messenger in the communication of adipose tissue and metabolic organs. In doing so, ADPN suppresses the production of glucose in the liver through inhibiting the genes involved in glucose production and enhances fatty acid oxidation in skeletal muscle 2.
Consequently, ADPN is a strong protector against several pathological events in various cells through inhibiting inflammation, suppressing cell death and enhancing cell survival 2.
ADPN has been identified as having pleiotropic functions widely associated with anti-atherogenic, anti-diabetic, cardioprotective and anti-inflammatory effects. ADPN levels inversely correlate with insulin levels, BMI, triglyceride levels, insulin resistance (IR), glucose, and most importantly, visceral fat accumulation 3. Moreover, physiological functions of adiponectin have also been observed in inflammation and cardiovascular disease (CVD), especially in atherosclerosis 2.
Fig. 1. Proposed salutary effects of adiponectin 1
Latex Enhanced Immunoturbidimetric Method
The automated latex enhanced immunoturbidimetric method produces results in as little as ten minutes, facilitating faster patient diagnosis and treatment plan implementation compared to traditional ELISA based testing.
A correlation coefficient of r=0.989 was displayed when compared to commercially available methods.
Extensive measuring range
The healthy range for adiponectin is 2 – 22μg/ml. The Randox adiponectin assay can comfortably detect levels outside of the healthy range, measuring between 0.32 – 23.8μg/ml.
Liquid ready-to-use assay
The Randox adiponectin assay is available in a liquid ready-to-use format for convenience and ease-of-use.
The Randox adiponectin assay is stable to expiry date when stored at +2 to +8°C and has an onboard stability of 28 days when stored at +10oC.
Applications are available
Applications are available detailing instrument-specific settings for the convenient use of the Randox adiponectin assay on a variety of clinical chemistry analysers. Contact us to enquire about your specific analyser.
APDN has an inverse correlation with abdominal visceral fat (AVF). Low levels of ADPN increases the risk of metabolic abnormalities. Furthermore, excess adipose tissue, especially visceral adipose tissue (VAT) is an important risk factor for IR, correlating with an increased risk of CVD 5.
The most commonly utilised methods for the assessment of AVF are waist circumference and BMI. Waist circumference does not measure total AVF reliably as the visceral fat / subcutaneous fat ratios vary by gender and ethnicity 6 and BMI cannot distinguish between muscle and fat and so classes those with high muscle and low fat mass as being overweight. Moreover, BMI also cannot distinguish between visceral fat and fat that sits beneath the skin 7.
Adiponectin levels are inversely correlated with AVF, proving to be a reliable indicator of at-risk patients.
The traditional biomarkers utilised in the assessment of T2DM risk include: oral glucose tolerance test (OGTT), fasting plasma glucose (FPG) and HbA1c. However, each of these tests are inadequate and a superior biomarker for T2DM risk assessment is vital.
1. JAMA (2009): Adiponectin levels and risk of type 2 diabetes: A systematic review and meta-analysis 8
Higher ADPN levels are associated with a lower risk of T2DM across diverse populations and is currently the strongest and most consistent biomarker of T2DM risk assessment.
2. BMJ Open Diabetes Research & Care (2016): Adiponectin levels predict prediabetes risk: The pathobiology in a biracial cohort (POP-ABC) study 9
Baseline ADPN levels were inversely related to the risk of pre-diabetes among the healthy African Americans and European Americans with a parental history of T2DM enrolled on the POP-ABC study. Despite gender and ethnic difference, this predictive relationship was evident.
The most commonly observed component of metabolic syndrome (MetS) is abdominal obesity. MetS encompasses several conditions
including: hypercholesterolemia, triglyceridemia, glycaemia, hypertension, abdominal obesity and dyslipidaemia. The prevalence of MetS is 31% and is associated with a 1.5-fold increased risk of all-cause mortality, a 2-fold increased risk of coronary heart disease (CHD) and cerebrovascular accident (CVA), and a 5-fold increased risk of T2DM 10, 11, 12.
Adiponectin has been identified as a glucose regulator and lipid homeostasis through its insulin sensitising properties which are associated with MetS.
1. Nutrition and Diabetes (2011): Serum adiponectin level is not only decreased in metabolic syndrome but also in borderline metabolic abnormalities 13
Decreasing ADPN levels begins at an early stage before the onset of hypertension, diabetes, MetS or dyslipidaemia. Moreover, in those with metabolic abnormalities / physiological abnormalities, adiponectin is an important biomarker for the risk assessment of atherosclerosis, both independently and as a reflection of the accumulation of AVF.
2. Cardiovascular Diabetology (2015): Role of adiponectin and free fatty acids on the association between abdominal visceral fat and insulin resistance 14
Subjects with high AVF or low ADPN had a 3-fold increased risk of IR. The combination of low ADPN with high AVF doubled this probability.
It has been recognised that mRNA expression of the ADPN gene and the section of high molecular weight (HMW) oligomeric ADPN are impaired in adipose tissue of obese patients. Epidemiological studies undertaken in different ethnic groups established that low ADPN levels, especially in HMW oligomer, is an independent risk factor for CVD 15. Fig. 2 illustrates the pleiotropic role of adiponectin in the cardiovascular system.
1. PLOS ONE (2013): Adiponectin provides additional information to conventional cardiovascular risk factors for assessing the risk of atherosclerosis in both genders 16
The risk of carotid intima media thickness (CIMT) inversely correlates with ADPN levels in both genders. Adiponectin testing is a significant marker of atherosclerosis and can provide additional information in the assessment of atherosclerotic risk in both genders, independent of conventional cardiovascular risk factors.
2. European Journal of Preventive Cardiology (2015): Adiponectin, type 2 diabetes and cardiovascular risk 17
Increasing ADPN levels in plasma is associated with a decreased risk of T2DM and subsequently, a reduced risk of CVD.
Fig. 2. The pleiotropic role of adiponectin in the cardiovascular system 15
Excess body fat is not only associated with T2DM and CVD, but also with various types of malignancies. Many cancer cell lines express ADPN receptors, and adiponectin in vitro limits cell proliferation and induces apoptosis. Evidence exists supporting adiponectin as a novel risk marker in the diagnosis and prognosis of cancer 17. Fig. 3 illustrates the association between obesity, low levels of adiponectin and cancer progression.
1. Medicine (2018): Serum adiponectin in breast cancer: A meta – analysis 19
The meta-analysis indicates an intriguing association between low levels of ADPN and an increased risk of breast cancer (BC). Furthermore, APDN has the potential to serve as a biomarker of BC risk and aid in the identification of those at a high risk of developing BC.
Fig. 3. The association between obesity, low adiponectin levels and cancer progression 18
2. International Brazilian Journal of Urology (2019): Role of adiponectin in prostate cancer 20
Oxidative stress has been identified as a key event in the initiation, development and progression of PC. ADPN increased cellular anti-oxidative defence mechanisms and inhibited oxidative stress through increasing the NADPH oxidase NOX2 and NOX4 expressions in human 22Rv1 and DU – 145 PC cell lines. The review support ADPN as a protective and safe factor to prevent the progression of PC.
Obesity: The Risk Factor
Obesity, a major global health epidemic that burdens on healthcare systems, has increased at an alarming rate with 39% of adults (18+) classed as overweight and 13% classed as obese in 2016. Moreover, in the same year, 340 million children aged between 5 and 16 were identified as overweight or obese and 41 million children under 5 years of age were also classed as overweight or obese. Worldwide, obesity prevalence rates have almost tripled between 1975 and 2016 21, 22.
The main reason obesity is a massive health problem is because of the secondary diseases that develop due to obesity. Obesity has contributed to 23% of ischaemic heart disease cases, 7 – 41% of specific cancer cases and 44% of diabetes cases. Obesity is now no longer confined to developed countries. As the industrialisation of developing countries continues to emerge, high calorie diets and subsequently obesity increases 23.
Obesity reduces the number of disease free years. It was uncovered that those who were mildly obese lost 3 – 4 more disease – free years and those who were severely obese lost 7-8 more disease free years than non-obese individuals. Consequently, at least 2.8 million deaths per year are attributed to obesity 24, 25.
Obesity is a major risk factor for T2DM, IR, CVD and various types of malignancies. These secondary health-related problems cost the economy “$2 trillion annually and roughly 2.8% of the global gross domestic product (GDP)”. Moreover, childhood obesity costs the economy $14.1 billion annually 26, 27, 23. Whilst there are numerous parties involved to aid in the prevention of obesity, urgent actions are required to prevent obesity and the subsequent secondary health – related problems.
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 Sifferlin, Alexandra.Why BMI isn’t the Best Measure for Weight (or Health). Time. [Online] August 26, 2013. [Cited: May 21, 2019.] http://healthland.time.com/2013/08/26/why-bmi-isnt-the-best-measure-for-weight-or-health/.
 Nath, Trevir. The Economic Cost Of An Obese Society. Investopedia. [Online] June 25, 2019. [Cited: July 18, 2019.] https://www. investopedia.com/articles/personal – finance/041715/economic – cost – obese – society.asp.