Cissus Quadrangularis enhances UCP1 mRNA, indicative of white adipocyte browning and decreases central obesity in humans in a randomized trial

Obesity is associated with the growth and expansion of adipocytes which could be decreased via several mechanisms. Cissus Quadrangularis (CQ) extract has been shown to reduce obesity in humans; however, its effect on human white adipocytes (hWA) has not been elucidated. This study aimed to investigate the effects of CQ on obesity, lipolysis, and browning of hWA. CQ treatment in obese humans significantly decreased waist circumference at week 4 and week 8 when compared with the baseline values (p < 0.05 all) and significantly decreased hip circumference at week 8 when compared with the baseline and week 4 values (p < 0.05 all). Serum leptin levels of the CQ-treated group were significantly higher at week 8 compared to baseline levels (p < 0.05). In hWA, glycerol release was reduced in the CQ-treated group when compared with the vehicle-treated group. In the browning experiment, pioglitazone, the PPAR-γ agonist, increased UCP1 mRNA when compared to vehicle (p < 0.01). Interestingly, 10, 100, and 1000 ng/ml CQ extract treatment on hWA significantly enhanced UCP1 expression in a dose-dependent manner when compared to pioglitazone treatment (p < 0.001 all). In conclusion, CQ decreased waist and hip circumferences in obese humans and enhanced UCP1 mRNA in hWA suggestive of its action via browning of hWA.

Epigallocatechin gallate decreases plasma triglyceride, blood pressure, and serum kisspeptin in obese human subjects

Obesity is one of major risk factors increasing chronic diseases including type II diabetes, cardiovascular diseases, and hypertension. The effects of epigallocatechin gallate (EGCG), the major active compound in green tea, on reduced obesity and improved metabolic profiles are still controversial. Furthermore, the effects of EGCG on human adipocyte lipolysis and browning of white adipocytes have not been elucidated. This study aimed to investigate the effects of EGCG on obesity, lipolysis, and browning of human white adipocytes. The results showed that, when compared to the baseline values, EGCG significantly decreased fasting plasma triglyceride levels (P < 0.05), systolic blood pressure (P < 0.05), diastolic blood pressure (P < 0.05), and serum kisspeptin levels (P < 0.05) after 8 weeks of supplement. On the other hand, supplement of EGCG in obese human subjects for 4 or 8 weeks did not decrease body weight, body mass index, waist and hip circumferences, nor total body fat mass or percentage when compared to their baseline values. The study in human adipocytes showed that EGCG did not increase the glycerol release when compared to vehicle, suggesting that it had no lipolytic effect. Furthermore, treatment of EGCG did not enhance uncoupling protein 1 (UCP1) mRNA expression in human white adipocytes when compared with treatment of pioglitazone, the peroxisome proliferator-activated receptor γ (PPAR-γ) agonist, suggesting that EGCG did not augment the browning effect of PPAR-γ on white adipocytes. This study revealed that EGCG reduced 2 metabolic risk factors which are triglyceride and blood pressure in the human experiment. We also showed a novel evidence that EGCG decreased kisspeptin levels. However, EGCG had no effects on obesity reduction in humans, lipolysis, nor browning of human white adipocytes.

Placental expressions and serum levels of adiponectin, visfatin, and omentin in GDM

AIMS

Adiponectin, visfatin, and omentin have been shown to be associated with insulin sensitivity and might have a role in the pathophysiology of gestational diabetes mellitus (GDM). This study aimed to (1) compare adiponectin, visfatin, and omentin mRNA expressions in placenta and their serum levels between normal pregnancy (NP) and GDM class A1 (GDMA1) pregnancy and (2) determine correlations between placental gene expressions as well as serum levels with maternal and neonatal clinical parameters in all, NP, and GDM subjects.

METHODS

NP subjects (n = 37), who had normal medical history during their pregnancies without diagnosis of any abnormalities and GDMA1 subjects (n = 37), who were diagnosed since they had antenatal care, were recruited when they were in labor with a gestational age of at least 34 weeks. Clinical parameters and serum adiponectin, visfatin, and omentin levels were measured in the delivery room.

RESULTS

GDMA1 subjects had higher serum visfatin and plasma glucose levels, but lower serum omentin levels (p  < 0.05 all) compared to controls, with comparable levels of placental adiponectin, visfatin, and omentin expressions, plasma insulin, and indices of insulin sensitivity and insulin resistance. Serum visfatin was negatively correlated with neonatal weight and length in the GDM group (p  < 0.05 all). Serum omentin was negatively correlated with pre-pregnancy body mass index and waist circumference only in the NP group (p  < 0.05 all). Serum adiponectin was negatively correlated with maternal age and HOMA-IR in the NP group (p  < 0.05 all) and with placental weight and serum omentin in the GDM group (p  < 0.05 all).

CONCLUSIONS

In conclusion, in GDMA1, increased serum visfatin, which has insulin-mimetic effect, might be associated with a compensatory mechanism that improves the impaired insulin function. Decreased serum omentin in GDMA1, which is normally found in visceral obesity, might lead to insulin resistance and contribute to the pathophysiology of GDM.

Placental Neuropeptide Y ( NPY) and NPY receptors expressions and serum NPY levels in preeclampsia

IMPACT STATEMENT

Neuropeptide Y (NPY) has been reported as a vasoconstrictive substance which might be associated with preeclampsia. The novel findings of this study were that Y1R, Y2R, and Y5R expressions were significantly lower in the PE than the NP group. Moreover, the NPY receptor expression ratio between the PE/NP groups was lowest for Y2R (0.27) compared to Y1R (0.42) and Y5R (0.40) suggestive of a reduction of this receptor in the preeclampsia group. Our results suggested that decreased Y2R mRNA in the PE group might be associated with abnormalities of placental angiogenesis which probably contributes to the pathophysiology of preeclampsia.

Adipose Y5R mRNA is higher in obese than non-obese humans and is correlated with obesity parameters

Neuropeptide Y is mainly expressed in the central nervous system to regulate food intake via its receptors, Y receptors, and in various peripheral tissues including adipose tissue. The objectives of this study were to compare Y5R mRNA and adipocyte parameters consisting of area, width, height, and perimeter either between obese and non-obese subjects or between subcutaneous and visceral fat as well as to compare between NPY, Y1R, Y2R, and Y5R mRNA expressions in subcutaneous and visceral adipose tissues. In subcutaneous and visceral adipose tissues, Y5R was greater in obese than in non-obese humans (both P < 0.05). Y1R mRNA expression was highest followed by Y5R, Y2R, and NPY mRNA expressions, respectively, in subcutaneous and visceral adipose tissues. Visceral Y5R mRNA had positive correlations with body weight, body mass index, waist circumference, hip circumference (R ≍ 0.4), and visceral Y1R mRNA (R = 0.773), but had a negative correlation with the quantitative insulin sensitivity check index (R=-0.421) (all P < 0.05). Subcutaneous and visceral adipocyte parameters were positively correlated with body weight, waist circumference, hip circumference, and waist-to-hip ratio, with greater values of correlation coefficient shown in visceral (R ≍ 0.5-0.8) than in subcutaneous adipocytes (R ≍ 0.4-0.6, all P < 0.05). The parameters of visceral adipocytes had positive correlations with serum NPY levels (R ≍ 0.4, all P < 0.05). Y5R mRNA in visceral adipose tissue is related to increased obesity and reduced insulin sensitivity. The dominant Y receptors in subcutaneous and visceral adipose tissue might be the Y1R and Y5R. Visceral adipocytes show higher correlations with obesity parameters than subcutaneous adipocytes, suggestive of an increased risk of metabolic syndrome in visceral obesity. Y1R and Y5R in visceral adipose tissue might be targets of drug development in prevention or treatment of adiposity. Impact statement Obesity, defined as excess fat accumulation, has been increasingly diagnosed worldwide causing adverse health consequences. The novel findings of this study were that Y5R mRNA expression in both subcutaneous and visceral fat was higher in obese than non-obese subjects. Furthermore, Y5R only in visceral fat, not subcutaneous fat, was positively correlated with visceral Y1R and obesity parameters but it was negatively correlated with the QUICKI. Moreover, we found that Y1R expression was highest followed by Y5R and Y2R, respectively, in both subcutaneous and visceral fat. Our results suggested that Y5R in visceral fat was associated with increased obesity and decreased insulin sensitivity. Y1R and Y5R might be the dominant receptors that mediate the effect of NPY-induced fat accumulation in both subcutaneous and visceral adipose tissues. Y1R and Y5R in visceral adipose tissue might be targets of drug development in prevention or treatment of obesity.

Interactions between adiponectin, visfatin, and omentin in subcutaneous and visceral adipose tissues and serum, and correlations with clinical and peripheral metabolic factors

Adiponectin, visfatin, and omentin are adipokines involved in insulin sensitivity. This study aimed to determine interactions between these adipokines in subcutaneous and visceral fat and in serum, and their associations with clinical factors. Adiponectin was present at the highest levels in subcutaneous and visceral fat and serum. Subcutaneous adiponectin showed positive correlations with serum adiponectin and the quantitative insulin sensitivity check index (QUICKI). Serum adiponectin correlated positively with QUICKI and serum omentin-1 but negatively with body weight, BMI, and homeostasis model assessment of insulin resistance (HOMA-IR). Subcutaneous omentin correlated positively with QUICKI but negatively with waist and hip circumferences. Serum omentin-1 correlated positively with QUICKI but negatively with body weight, BMI, waist and hip circumferences, weight gain, and HOMA-IR. Serum visfatin correlated positively with serum omentin-1 and negatively with weight gain. Serum peptide YY (PYY) levels were correlated positively with subcutaneous visfatin but negatively with visceral visfatin. Positive correlations were observed between subcutaneous expression of adiponectin, visfatin, and omentin and visceral expression of these genes. Multiple linear regression analysis showed that serum adiponectin was associated with BMI and QUICKI. Serum omentin-1 could be predicted from BMI, QUICKI, and weight gain. Weight gain, serum adiponectin, omentin-1, and DBP could be used to predict serum visfatin. In conclusion, adiponectin and omentin from subcutaneous fat displayed correlations with decreased obesity and increased insulin sensitivity while visfatin showed an association with serum PYY and weight gain. The expressions of these adipokines were correlated within each type of fat but not between different fat depots.