Imaging in alveolar echinococcosis (AE): Comparison of Echinococcus multilocularis classification for computed-tomography (EMUC-CT) and ultrasonography (EMUC-US)

Circulating free DNA as a diagnostic marker for echinococcosis: a systematic review and meta-analysis

Introduction

Echinococcosis is a chronic zoonotic disease caused by tapeworms of the genus Echinococcus. The World Health Organization (WHO) has identified encapsulated disease as one of 17 neglected diseases to be controlled or eliminated by 2050. There is no accurate, early, non-invasive molecular diagnostic method to detect echinococcosis. The feasibility of circulating free DNA as a diagnostic method for echinococcosis has yielded inconclusive results in a number of published studies. However, there has been no systematic evaluation to date assessing the overall performance of these assays. We report here the first meta-analysis assessing the diagnostic accuracy of cfDNA in plasma, serum, and urine for echinococcosis.

Methods

We systematically searched PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), and WeiPu databases up to 17 January 2024, for relevant studies. All analyses were performed using RevMan 5.3, Meta-DiSc 1.4, Stata 17.0, and R 4.3.1 software. The sensitivity, specificity, and other accuracy indicators of circulating free DNA for the diagnosis of echinococcosis were summarized. Subgroup analyses and meta-regression were performed to identify sources of heterogeneity.

Results

A total of 7 studies included 218 patients with echinococcosis and 214 controls (156 healthy controls, 32 other disease controls (non-hydatid patients), and 26 non-study-targeted echinococcosis controls were included). Summary estimates of the diagnostic accuracy of cfDNA in the diagnosis of echinococcosis were as follows: sensitivity (SEN) of 0.51 (95% CI: 0.45-0.56); specificity (SPE) of 0.99 (95% CI: 0.97-0.99); positive likelihood ratio (PLR) of 11.82 (95% CI: 6.74-20.74); negative likelihood ratio (NLR) of 0.57 (95% CI: 0.41-0.80); diagnostic ratio (DOR) of 36.63 (95% CI: 13.75-97.59); and area under the curve (AUC) value of 0.98 (95% CI: 0.96-1.00).

Conclusion

Existing evidence indicates that the combined specificity of circulating cfDNA for echinococcosis is high. However, the combined sensitivity performance is unsatisfactory due to significant inter-study heterogeneity. To strengthen the validity and accuracy of our findings, further large-scale prospective studies are required.Systematic review registrationThe systematic review was registered in the International Prospective Register of Systematic Reviews PROSPERO [CRD42023454158]. https://www.crd.york.ac.uk/PROSPERO/.

Circulating Small RNA Profiling of Patients with Alveolar and Cystic Echinococcosis

Alveolar (AE) and cystic (CE) echinococcosis are two parasitic diseases caused by the tapeworms Echinococcus multilocularis and E. granulosus sensu lato (s. l.), respectively. Currently, AE and CE are mainly diagnosed by means of imaging techniques, serology, and clinical and epidemiological data. However, no viability markers that indicate parasite state during infection are available. Extracellular small RNAs (sRNAs) are short non-coding RNAs that can be secreted by cells through association with extracellular vesicles, proteins, or lipoproteins. Circulating sRNAs can show altered expression in pathological states; hence, they are intensively studied as biomarkers for several diseases. Here, we profiled the sRNA transcriptomes of AE and CE patients to identify novel biomarkers to aid in medical decisions when current diagnostic procedures are inconclusive. For this, endogenous and parasitic sRNAs were analyzed by sRNA sequencing in serum from disease negative, positive, and treated patients and patients harboring a non-parasitic lesion. Consequently, 20 differentially expressed sRNAs associated with AE, CE, and/or non-parasitic lesion were identified. Our results represent an in-depth characterization of the effect E. multilocularis and E. granulosus s. l. exert on the extracellular sRNA landscape in human infections and provide a set of novel candidate biomarkers for both AE and CE detection.

Diagnosis of echinococcosis by detecting circulating cell-free DNA and miRNA

INTRODUCTION

Diagnosis of echinococcosis is difficult and usually performed based on clinical findings, imaging, and serological test. However, all of them have limitations, especially in follow-up approaches.

AREAS COVERED

Detection of cell-free DNA (cfDNA) and micro-RNA (miRNA) is currently a hot topic for diagnosis of echinococcosis diseases. For detecting cell-free DNA in echinococcosis patient's samples such as sera, some techniques are based on next-generation sequencing (NGS), DNA-deep sequencing, some are based on PCR-based methods, and a few works related to the detection of miRNA for the diagnosis of human echinococcosis.

EXPERT OPINION

In the detection of cell-free DNA in echinococcosis patient' samples, NGS and DNA-deep sequencing have shown high level of sensitivity, but are not suitable for routine clinical examination as they are expensive and inaccessible in the majority of endemic areas. However, PCR-based methods have shown a sensitivity of about 20-25%. To improve the sensitivity of these tests, improving the DNA extraction method, designing appropriate primers for detecting short-length fragments of circulating DNA, using a higher volume of a serum sample, and application of more sensitive PCR methods are recommended. In the field of miRNA detection, further works are recommended.

Robotic Liver Surgery for Alveolar Echinococcosis: A Single-Centre Experience

Alveolar echinococcosis (AE) is a rare disease caused by Echinococcosis multilocularis, which usually requires multidisciplinary management including surgery as the only curative approach. In recent years, minimally invasive strategies have been increasingly adopted for liver surgery. In particular, robotic surgery enables surgeons to perform even complex liver resections using a minimally invasive approach. However, there are only a few reports on robotic liver surgery for AE. Consecutive patients undergoing robotic liver surgery for AE were analysed based on the prospective database of the Interdisciplinary Robotic Centre of Ulm University Hospital. Between January 2021 and August 2022, a total of 16 patients with AE underwent robotic hepatectomy at our institution. Median age was 55.5 years (23−73), median body mass index (BMI) was 25.8 kg/m2 (20.2−36.8) and 12 patients (75%) were female. Anatomic resections were performed in 14 patients (87.5%), of which 4 patients (25%) underwent major hepatectomies (i.e., resection of >3 segments) including two right hemihepatectomies, one left hemihepatectomy and one extended right hemihepatectomy performed as associating liver partition with portal vein ligation staged (ALPPS) hepatectomy. There was no 90-day mortality, no postoperative bile leakage and no posthepatectomy haemorrhage. One patient developed posthepatectomy liver failure grade B after extended right hemihepatectomy using an ALPPS approach. One patient had to be converted to open surgery and developed an organ-space surgical site infection, for which he was re-admitted and underwent intravenous antibiotic therapy. Median length of postoperative hospital stay was 7 days (4−30). To our knowledge, this is the largest series of robotic liver surgeries for AE. The robotic approach seems safe with promising short-term outcomes in this selected cohort for both minor as well as major resections.

Stage-Oriented CT Classification and Intermodal Evolution Model in Hepatic Alveolar Echinococcosis

Background

Alveolar echinococcosis (AE) is one of the most dangerous human parasitoses. The main site of disease manifestation is the liver (about 98 %). The Echinococcus Multilocularis Ulm Classification for Computed Tomography (EMUC-CT), presented in 2016, was the first compilation of CT morphological criteria of hepatic AE. Studies based on EMUC-CT made it possible to draw conclusions about the development of the lesions in the course of disease beyond purely diagnostic typing. Among the most important findings of these precursor studies was that EMUC-CT type IV presented as an initial lesion, whereas EMUC-CT type III lesions were mostly associated with an advanced disease constellation. An intermodal view of image morphological criteria provides further multi-layered indications for lesion evolution.

Method

With the “Alveolar Echinococcosis Ulm Classification” (AEUC), a revision of the previous EMUC-CT was carried out with stage-oriented reorganization of the primary morphologies. Furthermore, an intermodal classification scheme for the evolution of hepatic AE lesions based on AEUC, MRI Kodama classification, and aspects of ultrasound could be outlined.

Results

The first stage-oriented CT classification of hepatic AE “AEUC” is based with respect to its lesion characterization on the separate consideration of two classification pillars, the five “primary morphologies”, AEUC I–V (AEUC II–IV with subcriteria) and the five “patterns of calcification”. In addition, an intermodal classification scheme presents five stages of lesion evolution: “initial stage”, “progressive stage”, “advanced stage”, “transitional stage” and “regressive stage”.

Conclusion

The imaging modalities differ with respect to their visualization of lesion criteria. This underlines the need for unimodal classification systems. Staging of an AE lesion can be done more accurately by evaluating different modalities.

Key Points:

Citation Format

Primary pulmonary cystic Echinococcus in an immunocompetent patient

A 60-year-old man was referred to the interventional pulmonology clinic with a large right-sided intraparenchymal lung mass and a second, smaller lesion in the left lower lobe, accompanied by intermittent haemoptysis, fever, chills, productive cough of white phlegm as well as dizziness and weakness. He had presented previously and was being evaluated for the possibility of malignancy. Investigations had revealed 'hooklets' (protoscolices) of hydatid cysts, most likely representing the parasite Echinococcus Successful surgical excision of the affected lobe, lung decortication, partial pleurectomy and pneumolysis of the adhesions was performed, along with long-term antiparasitic therapy. The initial differential diagnosis for this patient was challenging and required multimodal investigations. The patient made good recovery and continued to be followed by infectious disease specialists for management of antiparasitic therapy.

Comprehensive characterization of plasma cell-free Echinococcus spp. DNA in echinococcosis patients using ultra-high-throughput sequencing

Background

Echinococcosis is a life-threatening parasitic disease caused by Echinococcus spp. tapeworms with over one million people affected globally at any time. The Echinococcus spp. tapeworms in the human body release DNA to the circulatory system, which can be a biomarker for echinococcosis. Cell-free DNA (cfDNA) is widely used in medical research and has been applied in various clinical settings. As for echinococcosis, several PCR-based tests had been trialed to detect cell-free Echinococcus spp. DNA in plasma or serum, but the sensitivity was about 20% to 25%. Low sensitivity of PCR-based methods might be related to our limited understanding of the features of cell-free Echinococcus spp. DNA in plasma, including its concentration, fragment pattern and release source. In this study, we applied ultra-high-throughput sequencing to comprehensively investigate the characteristics of cell-free Echinococcus spp. DNA in plasma of echinococcosis patients.

Methodology/Principal findings

We collected plasma samples from 23 echinococcosis patients. Total plasma cfDNA was extracted and sequenced with a high-throughput sequencing platform. An average of 282 million read pairs were obtained for each plasma sample. Sequencing data were analyzed with bioinformatics workflow combined with Echinococcus spp. sequence database. After identification of cell-free Echinococcus spp. reads, we found that the cell-free Echinococcus spp. reads accounted for 1.8e-5 to 4.0e-9 of the total clean reads. Comparing fragment length distribution of cfDNA between Echinococcus spp. and humans showed that cell-free Echinococcus spp. DNA of cystic echinococcosis (CE) had a broad length range, while that of alveolar echinococcosis (AE) had an obvious peak at about 135 bp. We found that most of the cell-free Echinococcus spp. DNA reads were from the nuclear genome with an even distribution, which might indicate a random release pattern of cell-free Echinococcus spp. DNA.

Conclusions/Significance

With ultra-high-throughput sequencing technology, we analyzed the concentration, fragment length, release source, and other characteristics of cell-free Echinococcus spp. DNA in the plasma of echinococcosis patients. A better understanding of the characteristics of cell-free Echinococcus spp. DNA in plasma may facilitate their future application as a biomarker for diagnosis.

Echinococcosis is one of the most neglected tropical diseases caused by the metacestodes of Echinococcus spp. tapeworms, which affect both humans and livestock. Plasma cell-free DNA (cfDNA) consists of nucleic acid fragments found extracellularly and may contain DNA released from the parasites. Research shows that a variety of parasites can be detected from plasma cfDNA. Cell-free Echinococcus spp. DNA in plasma or serum had been tested with PCR-based methods, but these PCR methods had low sensitivity ranged from 20% to 25%. Low sensitivity may be due to our limited understanding of cell-free Echinococcus spp. DNA in plasma. Here, we take advantage of high-throughput sequencing to get a comprehensive characterization of cell-free Echinococcus spp. DNA. Our results showed that with high-throughput sequencing we could detect cell-free Echinococcus spp. DNA in all samples, though at a very low level. Based on the sequencing data, we found that cell-free Echinococcus spp. DNA in plasma had a different fragment length distribution to cell-free human DNA, and fragment length distribution of cell-free Echinococcus spp. DNA is also different between cystic echinococcosis (CE) and alveolar echinococcosis (AE). The sequencing data can also help trace the release source of cell-free Echinococcus spp. DNA from the genome. According to the mapping results of cell-free Echinococcus spp. DNA reads, we found that most of them were from the nuclear genome rather than the mitochondrial genome, and their release position showed an even distribution on the genome. These characteristics of cell-free Echinococcus spp. DNA in echinococcosis patients’ plasma could facilitate their future application in research or clinical settings.

Surgical approaches for definitive treatment of hepatic alveolar echinococcosis: results of a survey in 178 patients

Hepatic alveolar echinococcosis (HAE) is a potentially fatal disease caused by the larval growth of Echinococcus multilocularis. We analysed the clinical data of 178 consecutive HAE patients treated with definitive radical surgery at our institution. According to the surgical approach: group A patients underwent direct radical hepatic resection; group B patients first underwent percutaneous puncture external drainage, followed by radical hepatic resection 2 months later; group C patients underwent a two-step hepatic resection; and group D patients underwent liver transplantation. The baseline characteristics, mortality, postoperative complications and recurrence rates were evaluated. Symptoms were present in 79.8% (142/178) patients. Bi-lobar lesion was found in 34 (19.1%, 34/178) patients, 47.2% (84/178) of whom had ⩾2 lesions each. There were no intraoperative deaths. The postoperative mortality was 2.29% in group A, 8.62% in group D and 0% in groups B and C. The main cause of death was a serious postoperative complication (Clavien–Dindo grades III–V). Patients were followed-up systematically for a median of 35.8 months (8–72) without recurrence. Active HAE should be treated by radical liver resection, and the complicated alveolar echinococcosis of the liver has been managed whenever possible using principles of radical liver resection by experienced hepatic surgeons.