ABSTRACT
Background: The concept insulin resistance as the basis for a series of metabolic alterations and diseases was introduced by Gerald Reaven in 1988, when he described a cluster of alterations that named syndrome X. Aim: To review and discuss the present information about insulin resistance (IR) and metabolic syndrome (MS). Material and methods: The IR concept is defined,the affected metabolic ways, its consequences and relationship with different diseases are presented. The importance of central obesity with its metabolic, inflammatory and prothrombotic consequences playing a key role in cardiovascular risk, is discussed. The cluster of factors focused on cardiovascular disease and eventually diabetes is named MS. Several definitions of MS are analyzed and compared. A proposition is made about the definition to be used in the Chilean population. Differences between IR syndrome and MS are discussed. Diagnostic methods of IR and MS are presented, recommendations are made about their usefulness and reliability. Non pharmacological and pharmacological treatments of IR and MS are analyzed. Other related diseases, such as polycystic ovary syndrome, non alcoholic steatohepatitis and sleep apnea are discussed. Conclusions. Until further studies are made to define a local waist circumference cut-off associated with high risk, the ATPIII MS definition is preferred. A clinical approach is recommended for diagnosis. A search for all components of the MS is important. There is no evidence about the benefits of MS treatment on the prevention of cardiovascular diseases or diabetes. Evidence supports the use of lifestyle changes and some drugs, such as metformin on the prevention of diabetes in prediabetic states.
Subject(s)
Humans , Metabolic Syndrome/diagnosis , Metabolic Syndrome/therapy , Insulin ResistanceABSTRACT
BACKGROUND: Tumor necrosis factor-alpha (TNF-alpha) has an increased expression in the adipose tissue of obese subjects and is involved in insulin resistance. AIM: To screen for associations between -308G/A, -238G/A, -376G/A and -163G/A genetic variants of the TNF-alpha gene, diabetes and obesity-related variables. MATERIAL AND METHODS: A group of 263 elderly women aged 60-90 years were recruited. Among them, an oral glucose tolerance test was performed and serum lipids measured in 100 women. TNF-alpha genotypes were determined by polymerase chain reaction (PCR) and analysis of restriction fragment length polymorphisms. RESULTS: No significant differences were found when comparing allele frequencies in TNF-alpha polymorphisms of normal subjects with those having impaired glucose tolerance or type 2 diabetes. After excluding patients with previous diagnosis of diabetes, no significant differences by polymorphism carrier status were found for plasma levels of lipids, glucose and insulin. Additionally, no significant differences were found for the association between variables related to adiposity and the -308G/A polymorphisms. CONCLUSIONS: It is unlikely that polymorphisms in the promoter region of the TNF-alpha gene have a major influence in obesity and diabetes phenotypes in Chilean elderly women.
Subject(s)
Diabetes Mellitus, Type 2/genetics , Obesity/genetics , Polymorphism, Genetic/genetics , Promoter Regions, Genetic , Tumor Necrosis Factor-alpha/genetics , Adult , Aged , Blood Glucose , Body Mass Index , Chile , Cross-Sectional Studies , Female , Gene Frequency , Genotype , Glucose Tolerance Test , Humans , Insulin Resistance , Lipids/blood , Middle Aged , Polymerase Chain Reaction , Polymorphism, Restriction Fragment LengthABSTRACT
Background : Tumor necrosis factor-alpha (TNF-alpha) has an increased expression in the adipose tissue of obese subjects and is involved in insulin resistance. Aim: To screen for associations between -308G/A, -238G/A, -376G/A and -163G/A genetic variants of the TNF-alpha gene, diabetes and obesity-related variables. Material and methods: A group of 263 elderly women aged 60-90 years were recruited. Among them, an oral glucose tolerance test was performed and serum lipids measured in 100 women. TNF-alpha genotypes were determined by polymerase chain reaction (PCR) and analysis of restriction fragment lenght polymorphisms. Results: No significant differences were found when comparing allele frequencies in TNF-alpha polymorphisms of normal subjects with those having impaired glucose tolerance or type 2 diabetes. After excluding patients with previous diagnosis of diabetes, no significant differences by polymorphism carrier status were found for plasma levels of lipids, glucose and insulin. Additionally, no significant differences were found for the association between variables related to adiposity and the ¡308G/A polymorphisms. Conclusions: It is unlikely that polymorphisms in the promoter region of the TNF-alpha gene have a major influence in obesity and diabetes phenotypes in Chilean elderly women.