Vaspin (visceral adipose tissue-derived serine protease inhibitor) was isolated for the first time from visceral adipose tissue in Otsuka Long-Evans Tokushima Fatty rats, which comprises an animal model of abdominal obesity, accompanied by type 2 diabetes mellitus (T2DM) [1]. Human vaspin mRNA has been found both in the visceral and in subcutaneous adipose tissue. It is coded by the gene SERPNA12 located on the long arm of chromosome 14 (14q32.13) and consists of five introns and six exons. According to the literature review, there is a positive association between the vaspin concentration in the blood serum and the indicators of obesity, T2DM, polycystic ovary syndrome (PCOS) and coronary artery disease (CAD) [1,2]. Feng
The commercially available PCR premix (PCR Mix Plus; A&A Biotechnology, Gdynia, Poland) was prepared according to the manufacturer's instructions. Briefly, 1 μL of each primer (10 ρmol/μL), 1 μL of template DNA (˜25 ng/μL), 12.5 μL of PCR Pre Mix and made up to 25 μL with DNAse-free water. The procedure of T-ARMS PCR was optimized and final conditions were: denaturation at 95 °C for 3 min., amplification for 30 cycles at 95 °C for 1 min., 60 °C for 1 min., and 72 °C for 1 min., and a final extension at 72 °C for 8 min. After DNA amplification, the gel documentation system (InGenius; Syngene, Cambridge, Cambridgeshire, UK) was used for product visualization. The specific genotypes were characterized, respectively: 174 and 378 bp for homozygous T, 248 and 378 bp for homozygous A, and 174, 248 and 378 bp for heterozygous TA (Figure 1).
The study involved 108 individuals with MetS and 110 participants representing the control group. The group with MetS was similar to the control group regarding sex and age. Participants with MetS were more often overweight (BMI >25.0 m/kg2), with abdominal obesity, elevated blood pressure, glucose and triglyceride (TG) concentration and decreased concentration of high density lipoprotein (HDL) cholesterol, compared to the control group (all
There was no statistically significant difference in distribution of alleles and genotypes of the vaspin rs2236242 polymorphism between individuals with MetS and controls (Table 1). The meta-analysis of genotype distribution in Egyptian, Iranian and Polish populations showed that the TT genotype was identified more frequently in MetS patients than in controls
Genolype and allele distribution of the vaspin rs2236242 polymorphism in the control group and MetS patients.
Genotypes | Total | Control Group | MetS Patients | χ2(df=2) | |
---|---|---|---|---|---|
TT | 86 (39.45) | 43 (39.10) | 43 (39.81) | ||
TA | 106 (48.62) | 50 (45.45) | 56 (51.86) | 2.783 | 0250 |
AA | 26 (11.93) | 17(15.45) | 9 (8.33) | ||
Alleles | χ2 (df = 1) | ||||
Τ | 278 (63.76) | 126 (61.82) | 142 (65.74) | 0.730 | 0.394 |
A | 158 (36.24) | 84 (38.18) | 74 (34.26) |
MetS: metabolic syndrome.
The meta-analysis of the the vaspin rs2236242 polymorphism in the MetS patients (
Genotypes | MetS Patients | Control Group | χ2(df=2) | |
---|---|---|---|---|
TT | 210 (44.78) | 149 (32.46) | ||
TA | 215 (45.84) | 240 (52.59) | 24.20 | <0.0001 |
AA | 34 (7.25) | 70 (15.25) | ||
Alleles | χ2(df=l) | |||
Τ | 635 (67.70) | 538 (58.61) | 33.21 | <0.0001 |
A | 283 (30.17) | 380 (41.39) |
MetS: metabolic syndrome.
However, a two-fold more frequent prevalence of the AA genotype in individuals from the control group compared to the group with MetS was found (15.45
The TA, AA and TA+AA genotypes showed no association with MetS when compared to the TT genotype 0 = 0.638;
Associations between the vaspin rs2236242 polymorphism a risk of MetS and its components [OR (95% CI)]. I: unadjusted model; II: model adjusted for gender, age, smoking, walking and interactions between the vaspin rs2236242 polymorphism and walking in relation to MetS and its components; III: model adjusted for gender, age, smoking, BMI, walking and interactions between the vaspin rs2236242 gene polymorphism and walking in relation to MetS or its components.
Components of MetS | AA (TTref.) | TA (TT ret) | TA+AA (TTref.) | AA (TT+TAref.) | |||||
---|---|---|---|---|---|---|---|---|---|
MetS | I | 0.54 (0.22-1.35) | 0.187 | 0.15 (0.65-2.02) | 0.638 | 0.99 (0.58-1.71) | 0.979 | 0.50(0.21-1.18) | 0.115 |
II | 1.24(0.31-4.97) | 0.759 | 2.54 (1.07-60.5)a | 0.035 | 2.14 (0.96-4.77)· | 0.064 | 0.75 (0.20-2.83) | 0.674 | |
III | 0.91 (0.19-4.36 | 0.911 | 2.96 (1.07-7.40)a | 0.020 | 2.37 (1.01-5.57)· | 0.047 | 0.60 (0.14-2.48) | 0.480 | |
Abdominal obesity | I | 0.80 (0.32-2.04) | 0.647 | 1.13 (0.60-2.12) | 0.699 | 1.05 (0.58-1.91) | 0.861 | 0.75 (0.32-1.79) | 0.521 |
II | 1.61 (0.28-9.36) | 0.593 | 0.91 (0.34-2.43) | 0.846 | 1.02 (0.40-2.62) | 0.961 | 1.41 (0.26-7.72) | 0.695 | |
III | 1.21 (0.11-12.77) | 0.874 | 1.84 (0.45-7.57) | 0.398 | 1.59 (0.43-5.09) | 0.483 | 0.50 (0.07-3.78) | 0.506 | |
Elevated BP | I | 0.71 (0.26-1.94) | 0.503 | 0.89 (0.45-1.78) | 0.744 | 0.85 (0.44-1.64) | 0.627 | 0.75 (0.30-1.92) | 0.554 |
II | 0.60 (0.20-1.77) | 0.356 | 1.88 (0.64-5.52)b | 0.251 | 2.38 (0.84-6.77)» | 0.103 | 0.61 (0.23-1.64) | 0.332 | |
III | 0.44 (0.13-1.49) | 0.187 | 1.86 (0.63-7.04)b | 0.265 | 2.42 (0.83-7.04)» | 0.104 | 0.62 (0.22-1.72) | 0.360 | |
Increased glucose | I | 0.80(0.31-2.06) | 0.648 | 1.14 (0.63-2.05) | 0.663 | 1.07 (0.61-1.87) | 0.823 | 0.75 (0.41-1.80) | 0.517 |
concentration | II | 1.02 (0.24-4.33) | 0.978 | 0.41 (0.60-3.30) | 0.424 | 1.30 (0.58-2.91) | 0.527 | 0.76 (0.19-2.97) | 0.696 |
III | 0.78 (0.17-3.58) | 0.748 | 1.46 (0.61-3.47) | 0.395 | 1.29 (0.56 (2.96) | 0.544 | 0.65 (0.16-2.62) | 0.546 | |
Decreased HDL | I | 0.56 (0.19-1.64) | 0.290 | 1.06 (0.57-1.96) | 0.852 | 0.95 (0.52-1.172) | 0.861 | 0.54 (0.19-1.50) | 0.238 |
concentration | II | 1.44(0.31-4.78) | 0.642 | 1.84 (0.74-4.60) | 0.189 | 1.72 (0.72-4.11) | 0.219 | 1.10 (0.26-4.67) | 0.899 |
III | 1.26 (0.25-6.21) | 0.778 | 1.91 (0.76-4.79) | 0.170 | 1.72 (0.71-4.16) | 0.224 | 0.99 (0.22-4.36) | 0.990 | |
Increased TG | I | 0.60 (0.22-1.66) | 0.324 | 1.42 (0.79-2.56) | 0.245 | 1.22 (0.69-2.15) | 0.493 | 0.49 (0.19-1.28) | 0.148 |
concentration | II | 2.34 (0.57-9.64)c | 0.237 | 2.02 (0.854.78) | 0.110 | 2.09 (0.92-4.75) | 0.076 | 1.66 (0.44-6.24)c | 0.456 |
III | 1.92 (0.42-8.09)c | 0.399 | 2.12 (0.88-5.11) | 0.095 | 2.15 (0.93-5.00) | 0.075 | 1.49 (0.37-5.97)c | 0.569 |
MetS: metabolic syndrome; OR (95% CI): odds ratio (95% confidence interval); BMI: body mass index; BP: blood pressure;
HDL: high density lipoprotein; TG: triglycerides.
a Statistically significant interaction gene x walking, in relation to MetS.
b Statistically significant interaction gene x walking, in relation to blood pressure.
c Statistically significant interaction gene x walking, in relation to TG concentration.
In the model adjusted for age, gender, smoking and total PA, no statistically significant correlations have been found between the vaspin rs2236242 gene polymorphism and the risk of MetS and its components (data not shown). The differences of PA between MetS-subjects and the control group resulted mainly from the differences of walking time. The group of variables of small linkage distances included all MetS components, some demographic variables and lifestyle elements, along with walking time (Figure 2). Total PA and moderate-to-vigorous PA were characterized by greater Euclidean distances than the others. Taking this fact into consideration, in subsequent models walking time instead of total PA was used as a modifying variable. In the model adjusted for age, gender, smoking and walking (model II), there were also no significant associations between the vaspin rs2236242 polymorphism and MetS components. However, it was noted that having the TA genotype was related to a greater risk of MetS, compared to the TT genotype. The analysis of interaction 'genotype x walking time' showed that a longer walking time (>60 min./day) statistically significantly decreased the risk of
MetS in the TA genotype carriers (OR = 0.24;
Including BMI in the model did not significantly change the obtained scores (model III). Similar to the previous model, it was observed that longer walking time (>60 min./day) significantly decreased the risk of MetS in TA and TA+AA genotype carriers (OR
In our study, the possible association between the vaspin rs2236242 gene polymorphism and the risk of developing MetS in a group of Polish men and women was investigated. To the best of our knowledge, this is the first time such an association has been studied in the Polish population. Both in the unadjusted and adjusted models, there have been no statistically significant association between the vaspin rs2236242 polymorphism and the risk of the occurrence of individual components of MetS. However, in the model adjusted for known confounders (smoking, BMI, walking), it was noted that carrying the TA genotype was related to a greater risk of MetS, compared to the TT genotype.
Results of other studies are ambiguous in this respect. Hashemi
In the Iranian population, the analysis of the associations between the vaspin rs2236242 gene polymorphism and health conditions such as obesity, PCOS and T2DM, showed ambiguous results. Kohan
It has been shown that lifestyle factors, such as physical activity, can modify associations between variants of several genes and the risk of developing obesity, T2DM and cardiovascular disease in various populations [14,15,16]. Metabolic syndrome is also treated as a result of interactions between genetic factors and unhealthy lifestyle. It is thought that despite the significant role of genetic factors, a lack of regular PA and obesity are the main causes of the increase of occurrence of metabolic disorders, especially in developed countries [17,18]. According to our current knowledge, none of the previously published studies on the relationship between the vaspin rs2236242 polymorphism and the risk of MetS included PA or walking. Thus, our study provides the first vaspin rs2236242 gene polymorphism x ΡΑ/walking time interaction data on MetS and its components. Studies of the influence of other genes and PA on adiposity and metabolic characteristics provide diverse results. Brito
The analysis of interactions revealed that in our study population, longer walking (>60 min./day) lowered the risk of MetS and elevated blood pressure in the TA and TA+ AA genotype carriers and the risk of increased TG concentration in the AA genotype carriers, results were statistically significant. Walking is the most frequent form of physical activity. Results of several studies show that despite its low intensity, it is associated with lower risks of cardiovascular disease, T2DM and all cause mortality in men and women [21,22]. In a prospective study of Japanese workers aged 30-69, walking less than 60 min./ day comprised one of the crucial lifestyle elements increasing the risk of MetS, during 1 year of observation [23]. A decrease of MetS occurrence related to longer walking time, was also observed in several cross-sectional studies [24] and meta-analysis of cohort studies [25].
The strength of the conducted study is the inclusion of confounding factors in statistical analysis, which may have a modifying effect on the risk of MetS occurrence and its components. The limitations are considered to be the small number of participants and the fact that PA was assessed with the use of questionnaires, which are prone to bias and errors.
Conclusions. In the unadjusted model, no associations between the vaspin rs2236242 polymorphism and the risk of MetS and its components have been observed. Only the tendency to a decreased risk of MetS and its components in the AA genotype carriers has been noted, but the result was statistically insignificant. The results of the conducted study suggest that any unfavorable effect of the TA genotype of the vaspin rs2236242 polymorphism can be essentially reduced, or even reversed, in a case of individuals walking longer than 60 min. The analysis of interaction between the vaspin rs2236242 gene polymorphism and walking has revealed that walking time longer than 60 min./day considerably reduces the risk of MetS, elevated blood pressure and TG concentration. It is necessary to conduct further studies on a bigger group of participants, which will allow us to determine whether these results will be useful in MetS prophylaxis.