UEG Week 2016 Poster Presentations

Prospects of polyglycolic acid sheets for the treatment of esophageal stricture after esophageal endoscopic submucosal dissection

Esophageal cancer is the seventh most common type of cancer and the sixth leading cause of cancer -related mortality worldwide. Endoscopic submucosal dissection (ESD) is widely used for the resection of early esophageal cancer. However, post-ESD esophageal stricture is a common long-term complication, which requires attention. Patients with post-ESD esophageal stricture often experience dysphagia and require multiple dilatations, which greatly affects their quality of life and increases healthcare costs. Therefore, to manage post-ESD esophageal stricture, researchers are actively exploring various strategies, such as pharmaceutical interventions, endoscopic balloon dilation, and esophageal stenting. Although steroids-based therapy has achieved some success, steroids can lead to complications such as osteoporosis and infection. Meanwhile, endoscopic balloon dilatation is effective in the short term, but is prone to recurrence and perforation. Additionally, esophageal stenting can alleviate the stricture, but is associated with discomfort during stenting and the complication of easy displacement also present challenges. Tissue engineering has evolved rapidly in recent years, and hydrogel materials have good biodegradability and biocompatibility. A novel type of polyglycolic acid (PGA) sheets has been found to be effective in preventing esophageal stricture after ESD, with the advantages of a simple operation and low complication rate. PGA membranes act as a biophysical barrier to cover the wound as well as facilitate the delivery of medications to promote wound repair and healing. However, there is still a lack of multicenter, large-sample randomized controlled clinical studies focused on the treatment of post-ESD esophageal strictures with PGA membrane, which will be a promising direction for future advancements in this field.

New Alternative? Self-Assembling Peptide in Gastrointestinal Bleeding: A Systematic Review and Meta-Analysis

BACKGROUND

Gastrointestinal bleeding (GIB) is a common and potentially fatal condition with all-cause mortality ranging from 3 to 10%. Endoscopic therapy traditionally involves mechanical, thermal, and injection therapies. Recently, self-assembling peptide (SAP) has become increasingly available in the United States. When applied to an affected area, this gel forms an extracellular matrix-type structure allowing for hemostasis. This is the first systematic review and meta-analysis to assess the safety and efficacy of this modality in GIB.

METHODS

We performed a comprehensive literature search of major databases from inception to Nov 2022. The primary outcomes assessed were the success of hemostasis, rebleeding rates, and adverse events. The secondary outcomes assessed were successful hemostasis with monotherapy with SAP and combined therapy, which may include mechanical, injection, and thermal therapies. Pooled estimates were calculated using random-effects models with a 95% confidence interval (CI).

RESULTS

The analysis included 7 studies with 427 patients. 34% of the patients were on anticoagulation or antiplatelet agents. SAP application was technically successful in all patients. The calculated pooled rate of successful hemostasis was 93.1% (95% confidence interval (CI) 84.7-97.0, I2 = 73.6), and rebleeding rates were 8.9% (95% CI 5.3-14.4, I2 = 55.8). The pooled rates of hemostasis with SAP monotherapy and combined therapy were similar. No adverse events were noted related to SAP.

CONCLUSION

SAP appears to be a safe and effective treatment modality for patients with GIB. This modality provides an added advantage of improved visualization over the novel spray-based modalities. Further, prospective, or randomized controlled trials are needed to validate our findings.

Rifaximin for prevention and treatment of hepatic encephalopathy in people with cirrhosis

BACKGROUND

Hepatic encephalopathy describes the spectrum of neuropsychiatric changes that may complicate the course of cirrhosis and detrimentally affect outcomes. Ammonia plays a key role in its development. Rifaximin is a non-absorbable antibiotic that inhibits urease-producing bacteria and reduces absorption of dietary and bacterial ammonia.

OBJECTIVES

To evaluate the beneficial and harmful effects of rifaximin versus placebo, no intervention, or non-absorbable disaccharides for: (i) the prevention of hepatic encephalopathy, and (ii) the treatment of minimal and overt hepatic encephalopathy, in people with cirrhosis, both when used alone and when combined with a non-absorbable disaccharide.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Clinical Trials Register, CENTRAL, MEDLINE, Embase, three other databases, the reference lists of identified papers, and relevant conference proceedings. We wrote to authors and pharmaceutical companies for information on other published, unpublished, or ongoing trials. Searches were performed to January 2023.

SELECTION CRITERIA

We included randomised clinical trials assessing prevention or treatment of hepatic encephalopathy with rifaximin alone, or with a non-absorbable disaccharide, versus placebo/no intervention, or a non-absorbable disaccharide alone.

DATA COLLECTION AND ANALYSIS

Six authors independently searched for studies, extracted data, and validated findings. We assessed the design, bias risk, and participant/intervention characteristics of the included studies. We assessed mortality, serious adverse events, health-related quality of life, hepatic encephalopathy, non-serious adverse events, blood ammonia, Number Connection Test-A, and length of hospital stay.

MAIN RESULTS

We included 41 trials involving 4545 people with, or at risk for, developing hepatic encephalopathy. We excluded 89 trials and identified 13 ongoing studies. Some trials involved participants with more than one type of hepatic encephalopathy or more than one treatment comparison. Hepatic encephalopathy was classed as acute (13 trials), chronic (7 trials), or minimal (8 trials), or else participants were considered at risk for its development (13 trials). The control groups received placebo (12 trials), no/standard treatment (1 trial), or a non-absorbable disaccharide (14 trials). Eighteen trials assessed rifaximin plus a non-absorbable disaccharide versus a non-absorbable disaccharide alone. We classified 11 trials as at high risk of overall bias for mortality and 28 for non-mortality outcomes, mainly due to lack of blinding, incomplete outcome data, and selective reporting. Compared to placebo/no intervention, rifaximin likely has no overall effect on mortality (risk ratio (RR) 0.83, 95% confidence interval (CI) 0.50 to 1.38; P = 48, I2 = 0%; 13 trials, 1007 participants; moderate-certainty evidence), and there may be no overall effect when compared to non-absorbable disaccharides (RR 0.99, 95% CI 0.49 to 1.97; P = 0.97, I2 = 0%; 10 trials, 786 participants; low-certainty evidence). However, there is likely a reduction in the overall risk of mortality when comparing rifaximin plus a non-absorbable disaccharide to a non-absorbable disaccharide alone (RR 0.69, 95% CI 0.55 to 0.86; number needed to treat for an additional beneficial outcome (NNTB) = 22; P = 0.001, I2 = 0%; 14 trials, 1946 participants; moderate-certainty evidence). There is likely no effect on the overall risk of serious adverse events when comparing rifaximin to placebo/no intervention (RR 1.05, 95% CI 0.83 to 1.32; P = 68, I2 = 0%; 9 trials, 801 participants; moderate-certainty evidence) and there may be no overall effect when compared to non-absorbable disaccharides (RR 0.97, 95% CI 0.66 to 1.40; P = 85, I2 = 0%; 8 trials, 681 participants; low-certainty evidence). However, there was very low-certainty evidence that use of rifaximin plus a non-absorbable disaccharide may be associated with a lower risk of serious adverse events than use of a non-absorbable disaccharide alone (RR 0.66, 95% CI 0.45 to 0.98; P = 0.04, I2 = 60%; 7 trials, 1076 participants). Rifaximin likely results in an overall effect on health-related quality of life when compared to placebo/no intervention (mean difference (MD) -1.43, 95% CI -2.87 to 0.02; P = 0.05, I2 = 81%; 4 trials, 214 participants; moderate-certainty evidence), and may benefit health-related quality of life in people with minimal hepatic encephalopathy (MD -2.07, 95% CI -2.79 to -1.35; P < 0.001, I2 = 0%; 3 trials, 176 participants). The overall effect on health-related quality of life when comparing rifaximin to non-absorbable disaccharides is very uncertain (MD -0.33, 95% CI -1.65 to 0.98; P = 0.62, I2 = 0%; 2 trials, 249 participants; very low-certainty evidence). None of the combined rifaximin/non-absorbable disaccharide trials reported on this outcome. There is likely an overall beneficial effect on hepatic encephalopathy when comparing rifaximin to placebo/no intervention (RR 0.56, 95% CI 0.42 to 0.77; NNTB = 5; P < 0.001, I2 = 68%; 13 trials, 1009 participants; moderate-certainty evidence). This effect may be more marked in people with minimal hepatic encephalopathy (RR 0.40, 95% CI 0.31 to 0.52; NNTB = 3; P < 0.001, I2 = 10%; 6 trials, 364 participants) and in prevention trials (RR 0.71, 95% CI 0.56 to 0.91; NNTB = 10; P = 0.007, I2 = 36%; 4 trials, 474 participants). There may be little overall effect on hepatic encephalopathy when comparing rifaximin to non-absorbable disaccharides (RR 0.85, 95% CI 0.69 to 1.05; P = 0.13, I2 = 0%; 13 trials, 921 participants; low-certainty evidence). However, there may be an overall beneficial effect on hepatic encephalopathy when comparing rifaximin plus a non-absorbable disaccharide to a non-absorbable disaccharide alone (RR 0.58, 95% CI 0.48 to 0.71; NNTB = 5; P < 0.001, I2 = 62%; 17 trials, 2332 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

Compared to placebo/no intervention, rifaximin likely improves health-related quality of life in people with minimal hepatic encephalopathy, and may improve hepatic encephalopathy, particularly in populations with minimal hepatic encephalopathy and when it is used for prevention. Rifaximin likely has no overall effect on mortality, serious adverse events, health-related quality of life, or hepatic encephalopathy compared to non-absorbable disaccharides. However, when used in combination with a non-absorbable disaccharide, it likely reduces overall mortality risk, the risk of serious adverse events, improves hepatic encephalopathy, reduces the length of hospital stay, and prevents the occurrence/recurrence of hepatic encephalopathy. The certainty of evidence for these outcomes is very low to moderate; further high-quality trials are needed.

Comparing outcomes from tailored meta-analysis with outcomes from a setting specific test accuracy study using routine data of faecal calprotectin testing for inflammatory bowel disease

Background

Meta-analyses of test accuracy studies may provide estimates that are highly improbable in clinical practice. Tailored meta-analysis produces plausible estimates for the accuracy of a test within a specific setting by tailoring the selection of included studies compatible with a specific setting using information from the target setting. The aim of this study was to validate the tailored meta-analysis approach by comparing outcomes from tailored meta-analysis with outcomes from a setting specific test accuracy study.

Methods

A retrospective cohort study of primary care electronic health records provided setting-specific data on the test positive rate and disease prevalence. This was used to tailor the study selection from a review of faecal calprotectin testing for inflammatory bowel disease for meta-analysis using the binomial method and the Mahalanobis distance method. Tailored estimates were compared to estimates from a study of test accuracy in primary care using the same routine dataset.

Results

Tailoring resulted in the inclusion of 3/14 (binomial method) and 9/14 (Mahalanobis distance method) studies in meta-analysis. Sensitivity and specificity from tailored meta-analysis using the binomial method were 0.87 (95% CI 0.77 to 0.94) and 0.65 (95% CI 0.60 to 0.69) and 0.98 (95% CI 0.83 to 0.999) and 0.68 (95% CI 0.65 to 0.71), respectively using the Mahalanobis distance method. The corresponding estimates for the conventional meta-analysis were 0.94 (95% CI 0.90 to 0.97) and 0.67 (95% CI 0.57 to 0.76) and for the FC test accuracy study of primary care data 0.93 (95%CI 0.89 to 0.96) and 0.61 (95% CI 0.6 to 0.63) to detect IBD at a threshold of 50 μg/g. Although the binomial method produced a plausible estimate, the tailored estimates of sensitivity and specificity were not closer to the primary study estimates than the estimates from conventional meta-analysis including all 14 studies.

Conclusions

Tailored meta-analysis does not always produce estimates of sensitivity and specificity that lie closer to the estimates derived from a primary study in the setting in question. Potentially, tailored meta-analysis may be improved using a constrained model approach and this requires further investigation.

Impact of Food-Based Weight Loss Interventions on Gut Microbiome in Individuals with Obesity: A Systematic Review

The observation that the gut microbiota is different in healthy weight as compared with the obese state has sparked interest in the possible modulation of the microbiota in response to weight change. This systematic review investigates the effect of food-based weight loss diets on microbiota outcomes (α-diversity, β-diversity, relative bacterial abundance, and faecal short-chain fatty acids, SCFAs) in individuals without medical comorbidities who have successfully lost weight. Nineteen studies were included using the keywords ‘obesity’, ‘weight loss’, ‘microbiota’, and related terms. Across all 28 diet intervention arms, there were minimal changes in α- and β-diversity and faecal SCFA concentrations following weight loss. Changes in relative bacterial abundance at the phylum and genus level were inconsistent across studies. Further research with larger sample sizes, detailed dietary reporting, and consistent microbiota analysis techniques are needed to further our understanding of the effect of diet-induced weight loss on the gut microbiota.

Meta-analysis of vonoprazan and proton pump inhibitors in preventing delayed bleeding and facilitating ulcer healing after gastric endoscopic submucosal dissection

BACKGROUND

Vonoprazan (VPZ) is a novel potassium-competitive acid blocker that has been widely used in Japan for Helicobacter pylori eradication and for treatment of gastroeasophageal reflux disease and peptic ulcer. Compared with proton pump inhibitors (PPIs), VPZ can inhibit acid secretion more stably and effectively. Based on the results of previous studies, we speculated that compared with PPIs, VPZ is more effective in preventing delayed bleeding and facilitating ulcer healing after gastric endoscopic submucosal dissection (ESD).

AIM

To compare the efficacy of VPZ and PPIs in preventing delayed bleeding and facilitating ulcer healing after gastric ESD.

METHODS

We collected randomized controlled trials (RCTs) or cohort studies on the effectiveness of VPZ and PPIs in ESD-induced ulcer and delayed bleeding from electronic datasets including PubMed, EMBASE, Cochrane Library, Google Scholar, CNKI database, Wanfang database, and VIP database. The Cochrane Risk of Bias Tool and Newcastle Ottawa Quality Assessment Scale were applied to evaluate the quality of the articles included. Meta-analysis was performed using software Revman 5.2. Publication bias was assessed and Begg's graphs were drawn using Stata 14.0. Trim and fill analysis was performed when the publication bias was significant.

RESULTS

Nineteen studies were included in this Meta-analysis. The overall risk ratio (RR) of VPZ relative to PPIs for delayed bleeding was 0. 86 (P = 0. 38; 95%CI: 0.61-1.21). The RR in the subgroup of antithrombotic patientes was 1.35 (P = 0.54; 95%CI: 0.52-3.48), while the RR in the subgroup of non-antithrombotic patients was 0.68 (P = 0.12; 95%CI: 0.41-1.10). The RR of VPZ relative to PPIs was 1.37 (P = 0.02; 95%CI: 1.06-1.77) at 4 wk and 1.02 (P = 0.60; 95%CI: 0.95-1.09) at 8 wk. After excluding three studies with combination treatment, the RRs for delayed bleeding, ulcer healing at 4 wk, and ulcer healing at 8 wk were 0.90 (P = 0.56), 1.34 (P = 0.04), and 1. 02 (P = 0.60), respectively.

CONCLUSION

During the first 4 wk after gastric ESD, VPZ promotes ulcer healing faster than PPIs. At the end of the 8th weeks after ESD, there is no significant difference between VPZ and PPIs for ulcer healing. In the postoperative population with or without using antithrombotic drugs, compared with PPIs, VPZ does not exhibit any superiority in preventing delayed bleeding.

An update on efficacy and safety considerations for the latest drugs used to treat irritable bowel syndrome

INTRODUCTION

Irritable bowel syndrome (IBS), globally affecting 11.2% of the population and imposing a direct annual cost of $1.7bn-$10bn in the US, is one of the today's major therapeutic challenges. Therefore, there is urgent need to address this issue through reviewing the tolerability and efficacy of available medications.

AREAS COVERED

Over the past decade, related experiments were cited through Clinicaltrials.gov, PubMed, WHO ICTRP, and Cochrane library. Pharmacological parameters of approved medications available in the USFDA, EMA, TGA and PMDA were also stated.

EXPERT OPINION

Anti-spasmodics are used as the first-line treatment in pain-predominant IBS and IBS-D, among which calcium channel blockers and neurokinin-type 2 receptor antagonists seem to replace anti-cholinergic drugs. As second-line treatments, rifaximin is considered to be the best for IBS-D though it has lower efficacy than alosetron and eluxadoline. For IBS-C, linaclotide is the most effective and the safest second-line therapy, following laxatives/fibers, which may be replaced by tenapanor, in the future. When moderate to severe IBS is associated with severe pain or comorbid psychological disorders, gut-brain neuromodulators could also be prescribed. Regarding all this, there is still a paramount need to conduct careful clinical studies on efficacy, safety and cost-effectiveness of current approved and non-approved treatments.

Can tailored nanoceria act as a prebiotic? Report on improved lipid profile and gut microbiota in obese mice

BACKGROUND

Microbiome modulation is a pillar intervention to treat metabolic syndrome, prestages, and cascade of related pathologies such as atherosclerosis, among others. Lactobacillus and Bifidobacterium probiotic strains demonstrate efficacy to reduce obesity, dyslipidemia, and improve metabolic health. Novel prebiotic substances composed with known probiotics may strongly synergize health benefits to the host. The aim of this study was to evaluate beneficial effects of Lactobacillus and Bifidobacterium strains (probiotics) if composed with nanoceria (potential prebiotic) to reduce cholesterol levels and restore gut microbiota in obese mice.

MATERIALS AND METHODS

Two lines of mice were used in the study: BALB/c mice (6-8 weeks, 18-24 g) and CBA mice (11-12 months, 20-26 g); experimental animals were fed by fat-enriched diet 3 weeks before the evaluation. Animals were divided into groups to test probiotic strains and nanoceria. All groups received probiotic strains orally and cerium dioxide orally or intravenously in various composition. A group of untreated animals was used as a control. Cholesterol level and gut microbiota of mice were studied.

RESULTS

Cerium dioxide nanoparticles, probiotic strain L. casei ІМV В-7280, and composition B. animalis VKB/B. animalis VKL applied separately and in different combinations all reduced at different levels free and bound cholesterol in blood serum of mice fed by fat-enriched diet. The combination of 0.01 M nanoceria and probiotic strain L. casei ІМV В-7280 resulted in the fastest cholesterol level decrease in both young and mature animals. Oral administration of CeO2 applied alone reduced the number of microscopic fungi in the gut of mice and Gram-positive cocci (staphylococci and/or streptococci). Application of L. casei IMV B-7280 as a probiotic strain increased most significantly the number of lactobacilli and bifidobacteria in the gut of mice. The most significant normalization of gut microbiota was observed after oral administration of alternatively either L. casei IMV B-7280 + 0.1 M CeO2 or L. casei IMV B-7280 + 0.01 M CeO2.

CONCLUSION

Dietary application of nanoceria combined with probiotic strains L. casei IMV B-7280, B. animalis VKB, and B. animals VKL has significantly reduced both free and bound cholesterol levels in serum. Simultaneous administration of probiotics and cerium nanoparticles as a prebiotic, in various combinations, significantly enhanced positive individual effects of them on the gut microbiota spectrum. The presented results provide novel insights into mechanisms behind nutritional supplements and open new perspectives for application of probiotics combined with substances demonstrating prebiotic qualities benefiting, therefore, the host health. Follow-up translational measures are discussed to bring new knowledge from lab to the patient. If validated in a large-scale clinical study, this approach might be instrumental for primary and secondary prevention in obese individual and patients diagnosed with diabetes. To this end, individualized prediction and treatments tailored to the person are strongly recommended to benefit the health condition of affected individuals.

Systematic review and meta-analysis: assessment of factors affecting disability in inflammatory bowel disease and the reliability of the inflammatory bowel disease disability index

BACKGROUND

The Inflammatory Bowel Disease Disability Index (IBD-DI) has recently been developed for patients with Crohn's disease (CD) and ulcerative colitis (UC).

AIM

To assess the severity of disability and associated factors using the IBD-DI, and review the validity of the IBD-DI as a tool.

METHOD

Systematic review of cross-sectional studies. Patients included had UC or CD and were classified as active, in remission, or needing surgery, biological and/or steroid treatment. We included studies assessing disability using the IBD-DI and that were captured by electronic and manual searches (January 2017). The possibility of bias was evaluated with the Newcastle-Ottawa Scale.

RESULTS

Nine studies were included with 3167 patients. Comparatively, patients with active disease had higher disability rates than those in remission (SMD [CI95] = 1.49[1.11, 1.88], I²  = 94%, P<.01), while patients on biological treatment had lower disability rates than those receiving corticosteroid treatment (SMD [CI95] = -0.22[-0.36, -0.08], I²  = 0%, P<.01). Disease activity and unemployment were found to be associated factors. The IBD-DI scored "good" for internal consistency, "fair" to "excellent" for intra-rater reliability and "excellent" for inter-rater reliability. Construct validity was "moderately strong" to "very strong" and structural validity was found to be mainly unidimensional. The IBD-DI had excellent responsiveness, while its interpretability was only useful on a group level.

CONCLUSIONS

This systematic review and meta-analysis found a significant association between disease activity, treatment received and disability; although significant heterogeneity was found. The IBD-DI is reliable and valid, but further studies are needed to measure its interpretability.

Comparative study of probiotic effects of Lactobacillus and Bifidobacteria strains on cholesterol levels, liver morphology and the gut microbiota in obese mice

BACKGROUND

Microbiome-modulating interventions are promising for treatment and prevention of metabolic syndrome. The number of probiotic strains demonstrated ability to decrease cholesterol level in vivo, however, it was poorly confirmed in a clinical setting. The aim was to study the effects of L. acidophilus IMV B-7279, L. casei IMV B-7280, B. animalіs VKL and B. animalіs VKB separately and in various compositions on the level of serum cholesterol, gut microbiota contents and liver morphology on a high-calorie-induced obesity model in BALB/c mice.

MATERIALS AND METHODS

We used for the study female BALB/c mice 6-8 weeks old (18-24 g). Experimental animals were fed by a fat-enriched diet (FED), and 8 experimental groups were formed (12 mice in each group) to test strains of probiotic bacteria L. delbrueckii subsp. bulgaricus IMV B-7281, L. casei IMV B-7280, B. animalіs VKL and B. animalіs VKB and compositions. We used ultrasound for in vivo assessment of the liver and visceral (mesenteric) fat size. In the blood serum of the obese mice, the level of cholesterol was estimated. The liver morphology and gut microbiota of obese mice were studied.

RESULTS

We revealed that after treatment with all of the studied probiotic bacteria and compositions of B. animalis VKL/B. animalis VKB/L. casei IMV B-7280, the weight of obese mice decreased, and cholesterol and its fraction levels in serum were reduced. The size of the liver slightly decreased after treatment with L. delbrueckii subsp. bulgaricus IMV B-7281, B. аnimalis VKB or probiotic compositions; we observed reduction of the mesenteric fat size after injection of all these probiotic bacteria (separately) and probiotic compositions. We defined the strain-dependent effects on serum lipid profiles, liver morphology and the gut microbiota. The B. animalis VKL/B. animalis VKB/L. casei IMV B-7280 composition effectively recovered the liver morphological structure of obese mice. The number of Lactobacillus spp., Bifidobacterium spp. and coliform bacteria increased, the number of staphylococci and streptococci reduced, and the number of microscopic fungi significantly decreased in the gut of obese mice after treatment with L. casei IMV B-7280, L. delbrueckii subsp. bulgaricus IMV B-7281, B. animalis (separately) or their compositions.

CONCLUSION

L. casei IMV B-7280 (separately) and a composition of B. animalis VKL/B. animalis VKB/L. casei IMV B-7280 are effective at decreasing the weight of obese mice, decreasing cholesterol level, restoring the liver morphology and beneficially modulating the gut microbiome in high-calorie-induced obesity.

Small Bowel Motility

PURPOSE OF REVIEW

Small bowel motility disorders constitute a relatively small but important segment of clinical gastroenterology. Presenting features encompass a broad range of symptom manifestations and severity: from chronic functional-type complaints to life-threatening nutritional impairment. Diagnostic assessment of patients with suspected intestinal motility disorders is often hampered by the complexity of measuring intestinal contractile activity in humans. In this review, we describe and critically comment the main current and forthcoming methodologies.

RECENT FINDINGS

Beyond conventional small bowel manometry, radiological methods, and intestinal transit tests that have been available for several decades, now we focus on novel methodologies such as high-resolution manometry, magnetic resonance methodology, and endoluminal capsule image analysis. Gradual introduction of new approaches to diagnostic investigation of patients with suspected intestinal motility disorders should facilitate a less invasive and more accurate characterization of disturbed motor function. Enhanced understanding of the pathophysiological basis of clinical conditions should allow better application of therapeutic approaches that are also highlighted in this review.