Medical devices for the treatment of obesity

Repeated photodynamic therapy using a chlorin e6-embedded device to prolong the therapeutic effects on obesity

OBJECTIVE

This study aimed to investigate the efficacy and safety of repeated photodynamic therapy (PDT) with a chlorin e6 (Ce6)-embedded intragastric satiety-inducing device (ISD) to maintain therapeutic effects of obesity in a juvenile pig.

METHODS

The Ce6-embedded ISD was fabricated with a dipping method. Twelve pigs were divided into four groups of three and were administered control, single, biweekly, or weekly PDT, respectively. The therapeutic effects were assessed by comparing the results of phototoxicity, endoscopy, fluoroscopy, hormone and weight changes, and histological examination.

RESULTS

The percentage of total body weight gain was significantly suppressed in PDT-treated pigs compared with control pigs (all p < 0.001). This suppression persisted in the repeated PDT groups, but percentage of total body weight gain gradually increased when PDT was stopped. Ghrelin levels in the PDT-treated groups were significantly lower and leptin levels were significantly higher than those in the control group (all p < 0.05). Inflammatory cell infiltration, collagen, TUNEL, and anti-ghrelin-positive deposition in the weekly group were significantly higher than those in the control, single, and biweekly groups (all p < 0.01).

CONCLUSIONS

Repeated and periodic PDT was technically feasible and safe and successfully maintained the therapeutic effects against obesity while eliminating the indwelling time and reducing ISD-related complications in pigs.

Long term outcomes of metabolic/bariatric surgery in adults

The prevalence of obesity continues to rise around the world, driving up the need for effective and durable treatments. The field of metabolic/bariatric surgery has grown rapidly in the past 25 years, with observational studies and randomized controlled trials investigating a broad range of long term outcomes. Metabolic/bariatric surgery results in durable and significant weight loss and improvements in comorbid conditions, including type 2 diabetes. Observational studies show that metabolic/bariatric surgery is associated with a lower incidence of cardiovascular events, cancer, and death. Weight regain is a risk in a fraction of patients, and an association exists between metabolic/bariatric surgery and an increased risk of developing substance and alcohol use disorders, suicidal ideation/attempts, and accidental death. Patients need lifelong follow-up to help to reduce the risk of these complications and other nutritional deficiencies. Different surgical procedures have important differences in risks and benefits, and a clear need exists for more long term research about less invasive and emerging procedures. Recent guidelines for the treatment of obesity and metabolic conditions have been updated to reflect this growth in knowledge, with an expansion of eligibility criteria, particularly people with type 2 diabetes and a body mass index between 30.0 and 34.9.

Adipose Tissue Targeting Ultra-Small Hybrid Nanoparticles for Synergistic Photodynamic Therapy and Browning Induction in Obesity Treatment

Photodynamic therapy (PDT), as a means of locally and rapidly inducing adipocyte death via light illumination, in combination with adipose browning induction, a more gradual and widespread effect that could transform white adipose tissue into thermogenic adipose tissue, manifests a promising approach to combat obesity. Herein, adipose-targeting ultra-small hybrid nanoparticles (Pep-PPIX-Baic NPs) composed of an adipose-targeting peptide, Fe3+ , a photosensitizer (protoporphyrin IX), and a browning agent (baicalin) are introduced. Pep-PPIX-Baic NPs have been designed to simultaneously enhance the photodynamic effect and induce browning. After intravenous injection in obese mice, the hybrid nanoparticles can specifically accumulate in white adipose tissues, especially those rich in blood supply, and drive adipose reduction owing to the synergy of the PDT effect and baicalin browning induction. Overall, Pep-PPIX-Baic NPs exhibited superior anti-obesity potential through PDT synergistic with adipose browning induction. The designed multifunctional adipose-targeting hybrid nanoparticles present a prospective nanoplatform for obesity treatment.

Anti-Obesity Effect of Chlorin e6-Mediated Photodynamic Therapy on Mice with High-Fat-Diet-Induced Obesity

This study aimed to evaluate the efficacy of Chlorin e6 (Ce6)-based photodynamic therapy (PDT) for anti-obesity activities in high-fat-diet (HFD)-induced obesity mouse models. We induced obesity in C57BL/6 mice by HFD and administered Ce6 (2.5 or 5 mg/kg) orally with 3 h of incubation. The mice were then exposed to light of high fluence rate (4.96 mW/cm²) or low fluence rate (2.56 mW/cm²) in the designed LED mouse chamber 2-3 days a week for up to 8 weeks. The study also analyzed the pharmacokinetics and optimization of the drug by evaluating the absorption, distribution, metabolism, and excretion (ADME) of Ce6 in the rat models. Both low doses (2.5 mg/kg) and high doses (5 mg/kg) of Ce6 with high irradiation dose showed better anti-obesity effects than other groups with decreased body weight. The lipid accumulation in the liver and adipocyte size in epididymal adipose tissues were found to be decreased by Ce6-PDT in comparison to vehicle-treated HFD groups. We also observed increased levels of the lipidomic biomarkers, such as leptin and LDL cholesterol, while observing decreasing levels of total cholesterol and adiponectin in the Ce6-PDT-treated mice. These findings may provide valuable insight into Ce6-PDT as an alternative and non-invasive therapeutic methodology for obesity and obesity-related diseases.

Current treatment landscape for obesity in Singapore

The rising prevalence of obesity in Singapore is a harbinger for a corresponding increase in obesity-related complications such as type 2 diabetes mellitus (T2DM) and coronary heart disease. Obesity is a complex disease driven by multiple factors, and hence, treatment cannot follow a 'one-size-fits-all' approach. Lifestyle modifications involving dietary interventions, physical activity and behavioural changes remain the cornerstone of obesity management. However, similar to other chronic diseases such as T2DM and hypertension, lifestyle modifications are often insufficient on their own, hence the importance of other treatment modalities including pharmacotherapy, endoscopic bariatric therapy and metabolic-bariatric surgery. Weight loss medications currently approved in Singapore include phentermine, orlistat, liraglutide and naltrexone-bupropion. In recent years, endoscopic bariatric therapies have evolved as an effective, minimally invasive and durable therapeutic option for obesity. Metabolic-bariatric surgery remains the most effective and durable treatment for patients with severe obesity, with an average weight loss of 25%-30% after one year.

Sustained weight loss after duodenal-jejunal bypass liner treatment in patients with body mass index below, but not above 35 kg/m2 : A retrospective cohort study

Previous data from short term studies have shown an efficacy of the duodenal-jejunal bypass liner (DJBL) for weight loss. However, less data is available regarding weight change after device removal and possible predictors for weight loss. This is a retrospective chart review of all patients who had DJBL inserted at the University Hospital Zurich between December 2012 and June 2015. A total of 27 patients had DJBL insertion. The median BMI at baseline was 38.5 (34.0-42.2) kg/m² . In the 24 patients with DJBL treatment >3 months (failed implantation or early removal due to side effects in 3 patients), the mean duration of implantation was 42.9 ± 13.1 weeks. During the treatment, the mean total body weight loss (%TBWL) was 15.0 ± 8.3%. Fifteen patients had long-term follow-up data available (mean duration of follow-up 4.0 ± 0.9 years). The mean weight change was 12.7 ± 12.8 kg, corresponding with a mean % weight regain of 13.3 ± 13.3%. Five patients (33.3%) subsequently underwent bariatric surgery. In patients with class I obesity (BMI <35 kg/m² at baseline), 4 out of 6 (66.7%) had a stable weight or only a weight regain <7%. In contrast, no patient with BMI >35 kg/m² at baseline was able to keep weight regain below 7%. DJBL is an effective treatment for obesity, but substantial weight regain occurs during long-term follow up after the device removal, in particular in patients with BMI > 35 kg/m² .

Obesity and type 2 diabetes mellitus: connections in epidemiology, pathogenesis, and treatments

The prevalence of obesity and diabetes mellitus (DM) has been consistently increasing worldwide. Sharing powerful genetic and environmental features in their pathogenesis, obesity amplifies the impact of genetic susceptibility and environmental factors on DM. The ectopic expansion of adipose tissue and excessive accumulation of certain nutrients and metabolites sabotage the metabolic balance via insulin resistance, dysfunctional autophagy, and microbiome-gut-brain axis, further exacerbating the dysregulation of immunometabolism through low-grade systemic inflammation, leading to an accelerated loss of functional β-cells and gradual elevation of blood glucose. Given these intricate connections, most available treatments of obesity and type 2 DM (T2DM) have a mutual effect on each other. For example, anti-obesity drugs can be anti-diabetic to some extent, and some anti-diabetic medicines, in contrast, have been shown to increase body weight, such as insulin. Meanwhile, surgical procedures, especially bariatric surgery, are more effective for both obesity and T2DM. Besides guaranteeing the availability and accessibility of all the available diagnostic and therapeutic tools, more clinical and experimental investigations on the pathogenesis of these two diseases are warranted to improve the efficacy and safety of the available and newly developed treatments.

Medication-induced weight gain and advanced therapies for the child with overweight and obesity: An Obesity Medicine Association (OMA) Clinical Practice Statement 2022

Background

This Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) details medication-induced weight gain and advanced therapies for the child with overweight or obesity.

Methods

The scientific information and clinical guidance in this CPS are based on scientific evidence, supported by the medical literature, and derived from the clinical perspectives of the authors.

Results

This OMA Clinical Practice Statement addresses medication-induced weight gain and advanced therapies for the child with overweight or obesity.

Conclusions

This OMA Clinical Practice Statement on medication induced-weight gain and advanced therapies for the child with overweight or obesity is an overview of current recommendations. These recommendations provide a roadmap to the improvement of the health of children and adolescents with obesity, especially those with metabolic, physiological, and psychological complications. This CPS also addresses treatment recommendations. This section is designed to help the provider with clinical decision making.

Endoscopic bariatrics: current therapies and future directions

Endoscopic bariatric therapies (EBTs) are endoscopic procedures indicated for weight loss in the obese population. They are shown to be safe and effective for patients who do not quality for bariatric surgery. There are currently no randomized controlled studies comparing bariatric surgery with EBTs. However, EBTs are more cost effective and have fewer complications. This review will examine currently available EBTs with published data.

Photodynamic Methylene Blue-Embedded Intragastric Satiety-Inducing Device to Treat Obesity

Bariatric surgery is the most effective treatment for weight recidivism, and endoscopic bariatric treatment has been developed for a similar effect without anatomical modification. An intragastric satiety-inducing device (ISD) is a minimally invasive approach to induce satiety by continuously pressing the stomach and stimulating ghrelin-producing cells. To enhance the therapeutic effects of ISD, photodynamic therapy (PDT) can be combined by generating singlet oxygen under laser irradiation. Methylene blue (MB), as a photosensitizer (PS), was coated on the ISD surface for singlet oxygen production to stimulate or destroy cells. Ghrelin-producing cells effectively inhibited ghrelin secretion and induced gastrointestinal satiety signals compared with the MB-uncoated device via PDT. Herein, MB-embedded ISDs were developed, and their photoresponsive abilities were demonstrated in the device itself and in vitro. PDT with an MB-embedded ISD was successfully performed in a porcine model, which had 2-fold reduced body weight gain (12% in PDT vs 24% in control) and 2-fold reduced ghrelin levels (21.2 pg/mL in PDT vs 45.1 pg/mL in control) at the first week postprocedure. The simple and unique operation extends the point of view in PDT and is expected to be a novel endoscopic bariatric therapy.

The ups and downs of caloric restriction and fasting: from molecular effects to clinical application

Age-associated diseases are rising to pandemic proportions, exposing the need for efficient and low-cost methods to tackle these maladies at symptomatic, behavioral, metabolic, and physiological levels. While nutrition and health are closely intertwined, our limited understanding of how diet precisely influences disease often precludes the medical use of specific dietary interventions. Caloric restriction (CR) has approached clinical application as a powerful, yet simple, dietary modulation that extends both life- and healthspan in model organisms and ameliorates various diseases. However, due to psychological and social-behavioral limitations, CR may be challenging to implement into real life. Thus, CR-mimicking interventions have been developed, including intermittent fasting, time-restricted eating, and macronutrient modulation. Nonetheless, possible side effects of CR and alternatives thereof must be carefully considered. We summarize key concepts and differences in these dietary interventions in humans, discuss their molecular effects, and shed light on advantages and disadvantages.

Bile reflux after one anastomosis gastric bypass surgery: A review study

Background

Recently the performance rate of one anastomosis gastric bypass (OAGB) bariatric surgery has increased. Bile reflux is on of common considered complication of OAGB challenging surgeon.

Methods

We searched English full text with keyword "bile reflux" AND "OAGB" OR "one anastomosis gastric bypass" OR "SAGB" OR "single anastomosis gastric bypass" that published from January 1st, 2000 to December 31st, 2020 in PubMed, EMBASE, Google scholar and Cochrane Library. We included prospective or retrospective systematic review, review, clinical, and meta-analysis human article that its full text was available and focused on bile reflux after OAGB/SAGB as the fundamental performed bariatric surgery.

Results

A total of 1259 articles were analyzed, of which 5 were included. Analysis of number articles by year revealed that 2019 and 2020 was the highest number of published articles (n = 232; 68%). Study type analysis revealed that review studies and clinical research (n = 62; 18.2%) were the most frequent study types. Reported data on bile reflux after OAGB had diversity. Implicitly, postoperative incidence of bile reflux differed from 7.8 to 55.5%. General consensus was not existed among authors to consider the OAGB as the first suspect leading to postoperative bile reflux among other bariatric surgery types.

Conclusion

Although surgeons prefer to conduct OAGB procedure because of its easier surgical approach needing just one anastomosis formation it is not virtually clear that is the procedure costly benefitted regarding bile reflux outcomes.

Intragastric satiety-inducing device reduces food intake and suppresses body weight gain in a rodent model

BACKGROUND

An intragastric satiety-inducing device (ISD) (Full Sense Device; Baker, Foote, Kemmeter, Walburn, LLC, Grand Rapids, MI) is a novel weight-loss device, which may induce satiety by applying continuous pressure on the gastric cardia. This study investigated the effect of the ISD on food intake and body weight gain in a rodent model.

METHODS

Thirty-two male Sprague-Dawley rats (weight, 250-300 g) were randomly divided into four groups of eight individuals. Single-disk (SD) and double-disk (DD) group animals underwent peroral placement of a single- or double-disk ISD, respectively, under fluoroscopic guidance. The ISD comprised a 4 mm × 1.5 cm nitinol stent placed in the lower esophagus and one (single-disk) or two (double-disk) 2.5-cm-diameter star-shaped nitinol disks placed in the gastric fundus. Esophageal stent (ES) and sham-operated (SO) group animals underwent peroral placement of the ES part of the ISD and a sham operation, respectively.

RESULTS

Food intake was significantly different among the four groups over the 4-week study period (P < 0.001); food intake was significantly lower in the SD and DD groups than in the SO group (P = 0.016 and P = 0.002, respectively) but was not significantly different between the SD and DD groups (P > 0.999) and between the ES and SO groups (P = 0.677). Body weight was significantly different among the four groups by the end of the study period (P < 0.001); body weight was significantly lower in the DD group than in the SD, ES, and SO groups (P = 0.010, P < 0.001, and P < 0.001, respectively) and in the SD group than in the SO group (P = 0.001), but it was not significantly different between the ES and SO groups (P = 0.344).

CONCLUSION

ISD reduced food intake and suppressed body weight gain in a rodent model.

Non-Invasive Luciferase Imaging of Type I Interferon Induction in a Transgenic Mouse Model of Biomaterial Associated Bacterial Infections: Microbial Specificity and Inter-Bacterial Species Interactions

The performance of biomaterials is often compromised by bacterial infections and subsequent inflammation. So far, the conventional analysis of inflammatory processes in vivo involves time-consuming histology and biochemical assays. The present study employed a mouse model where interferon beta (IFN-β) is monitored as a marker for non-invasive rapid detection of inflammation in implant-related infections. The mouse model comprises subcutaneous implantation of morphologically modified titanium, followed by experimental infections with four taxonomically diverse oral bacteria: Streptococcus oralis, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Treponema denticola (as mono culture or selected mixed-culture). IFN-β expression increased upon infections depending on the type of pathogen and was prolonged by the presence of the implant. IFN-β expression kinetics reduced with two mixed species infections when compared with the single species. Histological and confocal microscopy confirmed pathogen-specific infiltration of inflammatory cells at the implant-tissue interface. This was observed mainly in the vicinity of infected implants and was, in contrast to interferon expression, higher in infections with dual species. In summary, this non-invasive mouse model can be used to quantify longitudinally host inflammation in real time and suggests that the polymicrobial character of infection, highly relevant to clinical situations, has complex effects on host immunity.

A new algorithm for drift compensation in multi-unit recordings of action potentials in peripheral autonomic nerves over time

BACKGROUND

Peripheral autonomic nerves control visceral organs and convey information regarding their functional states and are, therefore, potential targets for new therapeutic and diagnostic approaches. Conventionally recorded multi-unit nerve activity in vivo undergoes slow differential drift of signal and noise amplitudes, making accurate monitoring of nerve activity for more than tens of minutes problematic.

NEW METHOD

We describe an on-line drift compensation algorithm that utilizes recursive least-squares to estimate the relative change in spike amplitude due to changes in the nerve-electrode interface over time.

RESULTS

We tested and refined our approach using simulated data and in vivo recordings from nerves supplying the small intestine under control conditions and in response to gut inflammation over several hours. The algorithm is robust to changes in recording conditions and signal-to-noise ratio and applicable to both single and multi-unit recordings. In uncompensated records, drift prevented "spike families" and single units from being discriminated accurately over hours. After rescaling, these were successfully tracked throughout recordings (up to 3 h).

COMPARISON WITH EXISTING METHODS

Existing methods are subjective or compensate for drift using spatial information and spike shape data which is not practical in multi-unit peripheral nerve recordings. In contrast, this method is objective and applicable to data from a single differential multi-unit recording. In comparisons using simulated data the algorithm performed as well as or better than existing methods.

CONCLUSIONS

Results suggest our drift compensation algorithm is widely applicable and robust, though conservative, when differentiating prolonged responses from drift in signal. Extracellular nerve recordings; drift compensation; chronic nerve recordings; closed-loop; multi-unit activity; spike discrimination; recursive least squares; real-time.

Obesity: Pathophysiology and Management

Obesity continues to be among the top health concerns across the globe. Despite our failure to contain the high prevalence of obesity, we now have a better understanding of its pathophysiology, and how excess adiposity leads to type 2 diabetes, hypertension, and cardiovascular disease. Lifestyle modification is recommended as the cornerstone of obesity management, but many patients do not achieve long-lasting benefits due to difficulty with adherence as well as physiological and neurohormonal adaptation of the body in response to weight loss. Fortunately, 5 drug therapies-orlistat, lorcaserin, liraglutide, phentermine/topiramate, and naltrexone/bupropion-are available for long-term weight management. Additionally, several medical devices are available for short-term and long-term use. Bariatric surgery yields substantial and sustained weight loss with resolution of type 2 diabetes, although due to the high cost and a small risk of serious complications, it is generally recommended for patients with severe obesity. Benefit-to-risk balance should guide treatment decisions.

Endoscopic bariatric and metabolic therapies: Another tool for the management of diabetes and obesity

Endoscopic bariatric and metabolic therapies (EBMTs) have sparked significant interest as minimally invasive therapeutic options for weight loss. Although bariatric surgery remains an effective option for sustained weight loss and improvement in the metabolic syndrome, access and utilization are limited. Various EBMTs have been designed to emulate the physiologic effects of established surgical interventions, including space-occupying and non-space-occupying gastric therapies, gastric remodeling procedures, and small bowel therapies. This review discusses the safety and efficacy of available US Food and Drug Administration-approved minimally invasive endoscopic bariatric interventions, as well as those currently under investigation. In addition, the role of endoscopic revision after failed surgical intervention is discussed.

Bioelectric neuromodulation for gastrointestinal disorders: effectiveness and mechanisms

The gastrointestinal tract has extensive, surgically accessible nerve connections with the central nervous system. This provides the opportunity to exploit rapidly advancing methods of nerve stimulation to treat gastrointestinal disorders. Bioelectric neuromodulation technology has considerably advanced in the past decade, but sacral nerve stimulation for faecal incontinence currently remains the only neuromodulation protocol in general use for a gastrointestinal disorder. Treatment of other conditions, such as IBD, obesity, nausea and gastroparesis, has had variable success. That nerves modulate inflammation in the intestine is well established, but the anti-inflammatory effects of vagal nerve stimulation have only recently been discovered, and positive effects of this approach were seen in only some patients with Crohn's disease in a single trial. Pulses of high-frequency current applied to the vagus nerve have been used to block signalling from the stomach to the brain to reduce appetite with variable outcomes. Bioelectric neuromodulation has also been investigated for postoperative ileus, gastroparesis symptoms and constipation in animal models and some clinical trials. The clinical success of this bioelectric neuromodulation therapy might be enhanced through better knowledge of the targeted nerve pathways and their physiological and pathophysiological roles, optimizing stimulation protocols and determining which patients benefit most from this therapy.

Food Intake and Eating Behavior After Bariatric Surgery

Obesity is an escalating global chronic disease. Bariatric surgery is a very efficacious treatment for obesity and its comorbidities. Alterations to gastrointestinal anatomy during bariatric surgery result in neurological and physiological changes affecting hypothalamic signaling, gut hormones, bile acids, and gut microbiota, which coalesce to exert a profound influence on eating behavior. A thorough understanding of the mechanisms underlying eating behavior is essential in the management of patients after bariatric surgery. Studies investigating candidate mechanisms have expanded dramatically in the last decade. Herein we review the proposed mechanisms governing changes in eating behavior, food intake, and body weight after bariatric surgery. Additive or synergistic effects of both conditioned and unconditioned factors likely account for the complete picture of changes in eating behavior. Considered application of strategies designed to support the underlying principles governing changes in eating behavior holds promise as a means of optimizing responses to surgery and long-term outcomes.

IFSO Worldwide Survey 2016: Primary, Endoluminal, and Revisional Procedures

BACKGROUND AND AIM

The International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO), being a Federation of 62 national societies, is the ideal network to monitor the number and type of procedures at a global level. The IFSO survey, enriched with a special section on revisional procedures, aims to report the number and types of bariatric procedures performed worldwide in 2016 and analyzes the surgical trends from 2008 to 2016.

METHODS

The 2016 IFSO Survey form was emailed to all IFSO societies. Each Society was requested to indicate the number and type of bariatric procedures performed in the country. Trend analyses from 2008 to 2016 were also performed.

RESULTS

The total number of bariatric/metabolic procedures performed in 2016 was 685,874; 634,897 (92.6%) of which were primary and 50,977 were revisional (7.4%). Among the primary interventions, 609,897 (96%) were surgical and 25,359 (4%) were endoluminal. The most performed primary surgical bariatric/metabolic procedure was sleeve gastrectomy (SG) (N = 340,550; 53.6%), followed by Roux-en-Y gastric bypass (N = 191,326; 30.1%), and one-anastomosis gastric bypass (N = 30,563; 4.8%).

CONCLUSIONS

In 2016, there was an increase in the total number both of surgical and endoluminal bariatric/metabolic procedures. Revisional procedures represent about 7% of the total bariatric interventions. SG remains the most performed surgical procedure in the world.