The effects of intragastric balloons on metabolic and inflammatory parameters in obese patients

Abstract

Introduction: The prevalence of obesity worldwide has rapidly increased. One of the methods for treating obesity is endoscopic intragastric balloon (IGB) implantation. The aim of this study was to evaluate the effects of carbohydrate homeostasis and select cytokines in obese patients with a body mass index (BMI) ≥ 40 kg/m².

Material and methods: We analysed 68 obese subjects who underwent IGB. There were 19 females and 49 males in the study, their ages ranged from 23–65 years, their weights were 169.04 ± 33 kg, and their BMIs were 54.81 ± 7.8 kg/m². We measured carbohydrate parameters, including glucose, insulin and Homeostatic Model Assessment — Insulin Resistance (HOMA-IR), and cytokines, such as growth differentiation factor 15 (GDF15), human zinc-alpha-2-glycoprotein (ZAGa2), tumour necrosis factor alpha (TNF-α), and tumour necrosis factor weak inducer of apoptosis (TNFSF12/TWEAK). All parameters were measured before and at 6 months after the IGB was removed.

Results: Anthropometric parameters and carbohydrate homeostasis significantly changed 6 months after IGB implantation. We found significant decreases in body weight (p < 0.0001), BMI (p < 0.0001), glucose levels (p < 0.0001), insulin concentration (p < 0.0001), and HOMA-IR (p < 0.0001), regardless of sex. After 6 months, GDF15 (p < 0.0001), ZAGa2 (p < 0.0001) and TNFα (p < 0.0001) levels decreased. In contrast, the TNFSF12/TWEAK concentration increased (p < 0.0001). There was no difference between women and men in any of the parameters.

Conclusions: The results of this study indicate that IGB-induced weight loss leads to the normalization of metabolic parameters and inflammatory cytokines in obese individuals, regardless of sex.

Introduction

Excess body weight is an important risk factor for mortality due to the increased risk for cardiovascular diseases, diabetes, and some cancers [1, 2]. Epidemiological studies have shown that the incidence of obesity worldwide has almost doubled over the past four decades [3]. The worldwide age-standardized prevalence of obesity has increased from 6.4% to 12%, from 3.2% to 10.8% in men and from 6.4% to 14.9% in women [4]. One of the most common health consequences of obesity is carbohydrate metabolism disorders and type 2 diabetes (DM2). Insulin resistance is one of the factors responsible for the development of diabetes. The obesity-associated inflammatory response activates the immune system, playing a key role in the pathogenesis of the clinical complications of obesity, leading to the development of metabolic syndrome or hormonal disorders [5, 6]. Adipocytes produce cytokines such as tumor necrosis factor alpha (TNF-a), interleukin 6 (IL-6), the chemokine monocyte chemoattractant protein-1 (MCP-1), and tumour necrosis factor ligand superfamily member 12 (TNFSF12/TWEAK; also known as tumour necrosis factor weak inducer of apoptosis), which increase inflammation. In addition, they are also a source of specific adipokines, which increase the migration of inflammatory cells into adipose tissue [7, 8]. There is a relationship between the endocrine activity of adipocytes, inflammation, and insulin resistance, leading to an increased risk of DM2.

One of the methods for treating obesity is endoscopic intragastric balloon (IGB) insertion. It is usually not a stand-alone treatment method; it is mainly used as a bridging therapy before bariatric surgery in extremely obese patients with a body mass index (BMI) of ≥ 50 kg/m2 [9, 10]. IGB methods can also be used to reduce body weight before other surgical procedures, including heart transplantation [11].

The aim of this study was to evaluate the effects of IGB insertion on carbohydrate metabolism parameters and select cytokines in obese patients with a BMI ≥ 40 kg/m2.

Material and methods

We analysed 68 obese subjects. There were 19 (27.9%) females and 49 (72.1%) males in the study, with 65 years, a mean weight of 169.04 ± 33 kg and a mean BMI of 54.81 ± 7.8 kg/m2. The following three groups of patients were made according to their BMIs: Group I, including 22 (32.35%) patients with BMIs ranging from 40–49.9 kg/m2, Group II, including 27 (39.71%) patients with BMIs ranging from 50–59.9 kg/m2, and Group III, including 19 (27.94%) patients with BMIs ≥ 60 kg/m2.

The patients were weighed, examined, and interviewed by the surgeon and blood was drawn for laboratory measurements. Blood from the basilic vein for biochemical tests was collected on an empty stomach, in the morning between 7.30 and 8.00 on the day of balloon implantation, and then 6 months later on the day of its removal. Blood samples were collected into Vacutainer tubes. Blood was collected on the clot (dry tube), in a volume of 5 ml of whole blood, respectively. Each sample was immediately centrifuged at 3000g for 30 min at 4°C. After separation of the morphotic elements, the obtained sera were frozen at –85°C until use.

The study protocol was approved by the ethical committee of the Medical University of Silesia, and all participants provided written consent (KNW/0022/KB1/137/16).

Laboratory measurements

Insulin, glucose and HOMA-IR

Insulin levels were measured via commercially available enzyme-linked immunosorbent assay kits purchased from DRG (DRG International, Inc., USA) according to the manufacturer’s instructions. Absorbance readings were obtained via the Universal Microplate Spectrophotometer-µQUANT apparatus by BIO-TEK INC (Bio-Tek World Headquarters, California, USA) at a wavelength of 580 nm, and the results were processed via the computer program KCJunior (Bio-Tek, USA). Glucose levels were measured via an enzymatic method with an Integra 400 Plus autoanalyzer (Roche Diagnostic, Mannheim, Germany). The Homeostatic Model Assessment — Insulin Resistance index (HOMA-IR) was determined based on the relationship between the concentrations of insulin and glucose in fasting peripheral blood according to the following formula:

Growth differentation factor 15 (GDF15) and zinc-alpha-2-glycoprotein (ZAGa2)

The growth differentation factor 15 (GDF15) concentrations in the serum were measured via an immunoenzymatic method with a kit purchased from BioVendor LLC (BioVendor — Laboratorní medicína a.s. The Czech Republic), according to the manufacturer’s instructions. The immunocomplexes were detected via a reaction with a polyclonal rabbit antibody against the human GDF15 molecule, conjugated with horseradish peroxidase, and then with TMB solution as a substrate (TMB substrate, slow kinetic, Sigma, USA).

Zinc-alpha-2-glycoprotein (ZAGa2) concentrations in the serum were measured via an immunoenzymatic method with a kit purchased from BioVendor LLC (BioVendor — Laboratorní medicína a.s. The Czech Republic), according to the manufacturer’s instructions. The immunocomplexes were detected via a reaction with a polyclonal rabbit antibody against the human ZAGa2 molecule conjugated with horseradish peroxidase and then with TMB solution as a substrate (TMB substrate, slow kinetic, Sigma, USA). The absorbance of both samples was measured via the Universal Microplate Spectrophotometer-µQUANT apparatus by BIO-TEK INC (Bio-Tek World Headquarters, California, USA) at a wavelength of 450 nm, and the results were processed via the computer program KCJunior (Bio-Tek, USA).

TNF-a and TNFSF12/TWEAK

Serum TNF-a levels were measured via commercially available enzyme-linked immunosorbent assay kits purchased from R&D (R&D Systems, Minneapolis, USA) according to the manufacturer’s instructions.

Serum TNFSF12/TWEAK levels were measured via commercially available enzyme-linked immunosorbent assay kits purchased from LSBIO (LifeSpan Biosciences, Inc., Seattle, USA) according to the manufacturer’s instructions. The absorbance of both samples was measured via the Universal Microplate Spectrophotometer-µQUANT apparatus by BIO-TEK INC (Bio-Tek World Headquarters, California, USA) at a wavelength of 450 nm, and the results were processed via the computer program KCJunior (Bio-Tek, USA).

IGB insertion procedure

All patients had one type of intragastric balloon, the Orbera Balloon Intragastric System (Apollo Endosurgery Inc. Austin, USA), inserted. The balloon was implanted via the OLYMPUS GIF Q 165 Video Gastroscope. The balloon was inserted into the stomach under sedoanalgesia after gastroscopy was previously performed, and the balloon was filled with saline to a volume of approximately 700 cm3 (650–700 cm3). The valve was closed with negative pressure using a syringe. The position of the balloon was determined using ultrasound. The balloon was removed endoscopically 6 months after implantation. After puncture, the fluid was sucked out and then the balloon was removed using endoscopic forceps. There were no complications related to procedure, both during insertion and follow-up.

Statistics

Continuous variables are presented as the means ± standard deviations (SDs) or the median with the interquartile range if they were not normally distributed. Categorical variables are presented as absolute numbers and percentages. The Shapiro-Wilk test was used for all continuous variables to test for their normal distribution. The chi-square (X2) test was performed to compare differences among the categorical data. Differences were determined via the unpaired Student’s t-test and the Mann-Whitney U test for nonnormally distributed data. Paired Student’s t-tests were performed to compare the differences in the data before and 6 months after balloon implantation, and the Kruskal-Wallis test was used for nonnormally distributed data. Comparisons of each dependent variable before and 6 months after balloon implantation were performed via paired Student’s t- test and the paired Wilcoxon nonparametric test for nonnormally distributed data. Differences in each variable among the three patient groups were calculated via ANOVA followed by Tukey’s post hoc test or Scheffe’s post hoc test for nonnormally distributed data. A p value < 0.05 was considered to indicate statistical significance. This statistical analysis was performed via Statistica 12 (StatSoft Inc., Tulsa, OK, USA).

Results

Anthropometric parameters and carbohydrate metabolism decreased significantly at 6 months after IGB implantation. A significant decrease in body weight was observed from 169.04 ± 33 kg to 143.5 ± 31.5 kg (p < 0.0001), and BMI decreased from 54.81 kg/m2 to 46.46 ± 7.6 kg/m2 (p < 0.0001), regardless of sex (Tab. 1). The median weight and BMI loss after IGB were 24 (17.5–32.2) kg and 8 (5.9–10) kg/m2, which were 15.4% and 15.2%, respectively. There was no difference between the female and male groups (p = 0.978 and p = 0.811, respectively). The percentage of excess weight lost (%EWL) decreased by an average of 26% and was dependent on baseline BMI. The best result was noted in the group of patients with the lowest initial BMI (Group I), with a 37% decrease in %EWL, compared with patients with a BMI ≥ 60 kg/m2, where a 20% decrease in %EWL was observed (Tab. 2).

Table 1. Effects of intragastric balloon (IGB) on anthropometric and metabolic changes at 6 months

	All patients		Female		Male
	0	6 months	0	6 months	0	6 months
N	68	68	19	19	49	49
Weight [kg]	169.04 ± 33.1	143.5 ± 1.5	146.15 ± 25.6	124 ± 26.7	177.9 ± 31.3	151.1 ± 30.1
	p < 0.0001		p < 0.0001		p < 0.0001
			p = 0.0002
				p = 0.0017
BMI [kg/m2]	54.8 ± 7.8	46.46 ± 7.6	54.2 ± 7.24	45.87 ± 7.6	55.05 ± 8.1	46.7 ± 7.65
	p < 0.0001		p < 0.0001		p < 0.0001
			p = 0.688
				p = 0.693
%EWL (%)		26.3 (18.5–37.5)		25.9 (19–37.5)		26.3 (18–37.4)
				p = 0.935
Glucose [mg/dL]	114 (105–123)	91 (102–85)	111 (94–117)	94 (91–98)	115 (106–124)	96 (92–105)
	p < 0.0001		p < 0.0001		p < 0.0001
			p = 0.059
				p = 0.145
Insulin [μlU/mL]	16.28 ± 4.04	9.86 ± 2.73	14.95 ± 3.88	9.31 ± 3.67	16.8 ± 4.02	10.07 ± 2.29
	p < 0.0001		p < 0.0001		p < 0.0001
			p = 0.091
				p = 0.31
HOMA-IR	4.6 ± 1.48	2.38 ± 0.73	4.03 ± 1.37	2.2 ± 0.93	4.83 ± 1.47	2.46 ± 0.63
	p < 0.0001		p < 0.0001		p < 0.0001
			p = 0.0454
				p = 0.191

BMI — body mass index; %EWL — percentage of excess weight loss; HOMA-IR — Homeostasis Model Assessment-Estimated Insulin Resistance index

Table 2. Effects of intragastric balloon (IGB) on anthropometric and metabolic changes across body mass index (BMI) groups

	Group I (BMI = 40–49.9 kg/m2)		Group II (BMI = 50–59.9 kg/m2)		Group III (BMI ≥ 60 kg/m2)
	0	6 months	0	6 months	0	6 months
N	22	22	27	27	19	19
Weight (kg)	137.68 ± 17.9	113.5 ± 16.4	170.5 ± 20.4	148.2 ± 24.1	203.2 ± 25.1	171.6 ± 23.8
	p < 0.0001		p < 0.0001		p < 0.0001
BMI (kg/m2)	46.38 ± 2.3	38.53 ± 3.5	54.62 ± 2.74	47.37 ± 4.5	64 (61.7–68)	55.5 (51–58)
	p < 0.0001		p < 0.0001		p < 0.0001
%EWL (%)		37.6 ± 14		24.4 ± 9.6		20 (14.4–30.4)
		p < 0.0001
				p = 0.128
Glucose (mg/dl)	120.5 (106–124)	97 (93–106)	111 (105–121)	95 (91–101)	112 (102–119)	94 (91–99)
	p = 0.0013		p < 0.0001		p < 0.0001
	p = 0.119
		p = 0.163
Insulin (μlU/ml)	16.24 ± 3.6	9.85 ± 2.1	16.94 ± 4.2	10.25 ± 2.9	15.4 ± 4.1	9.31 ± 3.09
	p < 0.0001		p < 0.0001		p < 0.001
	p = 0.678
		p = 0.588
HOMA-IR	4.73 ± 1.42	2.41 ± 0.66	4.75 ± 1.56	2.49 ± 0.77	4.24 ± 1.44	2.21 ± 0.75
	p < 0.0001		p < 0.0001		p < 0.0001
	p = 0.461
		p = 0.587

%EWL — percentage of excess weight loss; HOMA-IR — Homeostasis Model Assessment-Estimated Insulin Resistance index

Glucose levels decreased significantly from 114 mg/dl to 95 mg/dl (p < 0.0001), both in women (p < 0.0001) and men (p < 0.0001; Tab. 1). There was no significant difference in glucose levels between women and men after IGB removal (p = 0.1455), although men had significantly higher glucose levels before IGB implantation (p = 0.592). The insulin concentration decreased from 16.28 ± 4.04 μlU/mL to 9.86 ± 2.73 μlU/mL (p < 0.0001), and the HOMA-IR decreased from 4.6 ± 1.48 to 2.38 ± 0.73 (p < 0.0001), regardless of sex (Tab. 1). There was no significant difference in insulin concentration between women and men before implantation (p = 0.0913) or after IGB removal (p = 0.31). The HOMA-IR before IGB implantation in women was lower than that in men (p = 0.0454), whereas no such difference was found after balloon removal (p = 0.191; Tab. 1).

The mean decreases in glucose, insulin and HOMA-IR were 18 mg/dl, 5.8 μlU/ml and 2, which were 14.7%, 38.7% and 46.8%, respectively. There was no difference in the percentage decrease in glucose (p = 0.516), insulin (p = 0.072) or HOMA-IR (p = 0.073) between women and men (Fig. 1ABC, respectively).

Figure 1. Effect of weight loss on percentage changes in glucose (A), insulin (B) and Homeostatic Model Assessment — Insulin Resistance (HOMA-IR) (C). BMI — body mass index

Significant reductions in both body weight and BMI were observed in each group across the BMI classes (Tab. 2). Glucose and insulin levels and HOMA-IR decreased in each patient subgroup across BMIs (Tab. 2). There were no differences across BMI groups in the percentage reductions in glucose (p = 0.624), insulin (p = 0.98), or HOMA-IR (p = 0.73; Fig. 1).

The effects of IGB implantation on changes in the concentrations of cytokines are presented in Figure 2. The GDF15 concentration decreased from 588.7 (313.4–647.8) pg/dL to 524.9 (486.4–585.3) pg/dL (p < 0.0001; Fig. 2A), the ZAGa2 concentration decreased from 38.9 ± 5.5 mg/dL to 33.06 ± 5.2 mg/dL (p < 0.0001; Fig. 2B), and the TNFa concentration decreased from 5.94 ± 0.66 pg/dL to 5.38 ± 0.7 pg/dL (p < 0.0001; Fig. 2C). In contrast, the TNFSF12/TWEK concentration increased from 239.2 (201.8–261) pg/dL to 300 (258.2–308.9) pg/dL (p < 0.0001; Fig. 2D). There was no difference between women and men in any of the parameters.

Figure 2. Effect of weight loss on cytokine changes: growth differentiation factor 15 (GDF15) (A), zinc-alpha-2-glycoprotein (ZAGa2) (B), tumor necrosis factor alpha (TNF-a) (C), tumour necrosis factor weak inducer of apoptosis (TNFSF12/TWEAK) (D)

Discussion

Intensive lifestyle changes in obese patients is associated with a 5% to 8% body weight loss [12], whereas bariatric surgery is associated with significantly greater and lasting weight loss and improvement in cardiovascular risk factor remission, including hypertension [13], DM2 [14, 15] and dyslipidaemia [16]. Compared with a dietary program, the use of an IGB results in greater weight loss and is a safe and well-tolerated procedure [17, 18]. Several studies have assessed the safety and efficacy of IGB implantation [19, 20]. These methods significantly reduce body weight, BMI, %EWL [19, 20], and biochemical parameters [20] and improve lung function parameters [21], with a low percentage of complications associated with the procedure. Five years after the use of IGB combined with lifestyle changes in patients with a BMI > 50, a reduction in BMI of 3.8% and a decrease in the %EWL of 10% were observed [22]. In our study, we found significant reductions in body weight, BMI and %EWL, regardless of sex. %EWL decreased by an average of 26% and was dependent on baseline BMI. The best result was noted in the group of patients with the lowest initial BMI, with a 37% decrease in %EWL, compared with patients with a BMI ≥ 60 kg/m2, where a 20% decrease in %EWL was observed. The metabolic parameters were also normalized. Glucose, insulin, and HOMA-IR decreased independently of sex and BMI. Our results are consistent with the results of other studies confirming the beneficial effect of IGB implantation on carbohydrate haemostasis [23]. According to our observations, patients with a lower initial BMI achieved better results [24]. In another study, better results in insulin normalization after IGB were also observed in patients with a BMI < 40 kg/m2 than in those with a BMI > 40 kg/m2 [25]. In the meta-analysis, no sex differences were found in the incidence of comorbidities or short-term complications after bariatric treatment, whereas women were twice as likely to develop long-term complications [26]. This a meta-analysis was conducted to assess the effect of sex on weight loss and co-morbidity remission upon bariatric procedures. Of the studies included, 4 were related to sleeve gastrectomy (SG), 4 to IGB, 2 to biliopancreatic diversion (BPD), 1 to laparoscopic adjustable gastric banding (LAGB), and 1 to Roux-en-Y gastric bypass (RYGB) and SG. Upon subgroup analysis based on bariatric procedure, women were more likely to be successful in terms of %EWL upon IGB placement. ZAGa2 is an adipokine that was initially identified in cancer cachexia patients. It is involved in the regulation of carbohydrate and lipid metabolism, exerting a beneficial effect on reducing obesity and improving glucose tolerance and insulin sensitivity, both in humans and animal models [27]. The effects of bariatric surgery on the ZAGa2 concentration are not clear. Morse et al. conducted a study in a group of obese patients to assess the effects of weight loss after RYGB surgery and a very-low-calorie diet (VLCD) on the plasma ZAGa2 concentration [28]. They reported a decrease in ZAGa2 levels in both groups, but significant changes occurred only after RYGB. In another study, an increase in ZAGa2 levels was observed after sleeve gastrectomy at 1 and 12 months after surgery [29]. In our study, there was a decrease in the ZAGa2 level after IGB removal, regardless of sex. It seems that ZAGa2 changes after bariatric procedures may differ and depend on the type of procedure, and the mechanism of alteration may depend on obesity-associated comorbidities.

TNFSF12/TWEAK is a cytokine that has potentially protective effects on obesity and insulin resistance. We found a significant increase in the TNFSF12/TWEAK concentration 6 months after IGB removal. This result is consistent with a study evaluating the effect of a two-year intervention program including dietary treatment and exercise, which also reported an increase in the TNFSF12/TWEK score [30]. Furthermore, TNFSF12/TWEAK levels were greater in patients who achieved weight loss than in patients without significant weight loss.

Growth differentiation factor 15 (GDF15) is a cellular stress-responsive cytokine that is considered a central regulator of appetite and metabolism and participates in the pathogenesis of several disease processes. In humans, plasma concentrations are increased in several diseases, including most types of cancer, chronic inflammatory diseases, and serious infections, and are increased in response to metabolic stress in conditions such as obesity, starvation, insulin resistance, and diabetes [31]. Studies indicate that relatively small changes in serum GDF15 levels can lead to reduced body weight and adiposity and improved metabolism, suggesting that GDF15 likely plays a role in the pathophysiology of obesity [32]. Serum GDF15 levels are elevated in obese individuals and correlate with the degree of obesity and its metabolic complications, especially type 2 diabetes. RYGB leads to weight loss and, paradoxically, increases GDF15 levels [33, 34], which correlates with weight loss after surgery [34]. This effect may be specific to restrictive and malabsorption procedures, such as Roux-en-Y bypass, because weight loss following restrictive procedures, such as sleeve gastrectomy, in mice is not modified by deletion of the germline GDF15 gene. The results of our study indicate that body weight reduction induced by IGBs significantly reduces the GDF15 concentration. IGB insertion is a restrictive procedure that limits the ability to absorb food without affecting the function of the gastrointestinal tract. It appears that changes in GDF15 may involve different mechanisms depending on the weight loss induced by the bariatric procedure. Three mechanisms of action of GDF15 are considered. In the adaptive model, GDF15-induced metabolic changes help normalize the stress response through increased GDF15 expression, and serum levels subsequently return to normal. In the incompletely adaptive model, GDF15 is induced as part of the disease process, and the metabolic changes it causes help to keep the process under partial control but are insufficient to return to normal. Circulating GDF15 levels often remain elevated.

In the maladaptive model, the disease process induces a marked increase in circulating GDF15, but the disease process is not significantly influenced by GDF15. Its circulating levels increase even further with advancing disease, causing severe anorexia and eventually cachexia. This suggests that elevated levels are an attempt to restore homeostasis, but in the context of severe disease, this may be ineffective, suboptimal, or at times maladaptive and harmful.

Conclusions

The results of the present study indicate that IGB-induced weight loss leads to the normalization of metabolic syndrome parameters and inflammatory cytokines in obese individuals, regardless of sex. Further studies are needed, especially in the field of the role of GDF15 and its changes after obesity treatment.

Data availability statement

Data sharing is not applicable to this article (Any datasets generated during and/or analyzed during the current study are not publicly available, available upon reasonable request).

Ethics statement

The study protocol was approved by the ethical committee of the Medical University of Silesia, and all participants provided written consent (KNW/0022/KB1/137/16).

Author contributions

M.W. — conception and design, analysis and interpretation of data, draft of the manuscript; A.K. — acquisition of data, project administration; E.Ś. — acquisition of data, analysis and interpretation of data; H.W. — acquisition of data; J.P.Jr — acquisition of data; J.P. — conception and design, revised the manuscript critically for important intellectual content

Funding

The authors declare no Funding of manuscript.

Conflict of interest

Authors declare no conflicts of interest for this article.