Clinical implications of pediatric biliary intraepithelial neoplasia diagnosed from a choledochal cyst specimen

BACKGROUND

Biliary intraepithelial neoplasia (BilIN), a noninvasive precursor of cholangiocarcinoma, can manifest malignant transformation. Since cholangiocarcinoma (CCA) may progress due to chronic inflammation in the bile ducts and gallbladder, choledochal cysts are considered a precursor to CCA. However, BilIN has rarely been reported in children, to date.

METHODS

We reviewed medical records of patients (< 18 years of age, n = 329) who underwent choledochal cyst excision at Asan Medical Center from 2008 to 2022. BilIN was diagnosed in 15 patients. Subsequent analyses were performed of the demographics, surgical procedures, clinical course, and outcomes in these patients. Subgroup analysis and multivariate logistic regression test were performed to identify factors influencing BilIN occurrence.

RESULTS

The mean age of the patients included in our study was 40.1 ± 47.6 months. In 15 patients, BilIN of various grades was diagnosed. Todani type I was prevalent in 80% of the patients. The median age at surgery was 17 months. During a mean follow-up of 63.3 ± 94.0 months, no adverse events such as stone formation in the remnant intrapancreatic common bile duct and intrahepatic duct or cholangiocarcinoma were observed, indicating a favorable outcome until now.

CONCLUSIONS

The potential progression of choledochal cysts to BilIN in children was demonstrated. These results could underscore the importance of early and comprehensive excision of choledochal cysts, including resection margins for associated lesions and more thorough postoperative surveillance in patients with or at risk of BilIN.

Photocobilins integrate B12 and bilin photochemistry for enzyme control

Photoreceptor proteins utilise chromophores to sense light and trigger a biological response. The discovery that adenosylcobalamin (or coenzyme B12) can act as a light-sensing chromophore heralded a new field of B12-photobiology. Although microbial genome analysis indicates that photoactive B12-binding domains form part of more complex protein architectures, regulating a range of molecular-cellular functions in response to light, experimental evidence is lacking. Here we identify and characterise a sub-family of multi-centre photoreceptors, termed photocobilins, that use B12 and biliverdin (BV) to sense light across the visible spectrum. Crystal structures reveal close juxtaposition of the B12 and BV chromophores, an arrangement that facilitates optical coupling. Light-triggered conversion of the B12 affects quaternary structure, in turn leading to light-activation of associated enzyme domains. The apparent widespread nature of photocobilins implies involvement in light regulation of a wider array of biochemical processes, and thus expands the scope for B12 photobiology. Their characterisation provides inspiration for the design of broad-spectrum optogenetic tools and next generation bio-photocatalysts.

Boosting the Cannabidiol Production in Engineered Saccharomyces cerevisiae by Harnessing the Vacuolar Transporter BPT1

Cannabidiol (CBD), the main nonpsychoactive cannabinoid in Cannabis sativa, has diverse applications in the pharmacological, food, and cosmetic industries. The long plantation period and the complex chemical structure of cannabidiol pose a great challenge on CBD supply. Here, we achieved de novo biosynthesis of cannabidiol in Saccharomyces cerevisiae. The CBD production was further enhanced by 2.53-fold through pushing the supply of precursors and fusion protein construction. Bile pigment transporter 1 (BPT1) was the most effective transporter for transferring cannabigerolic acid (CBGA) from the cytoplasm to the vacuole, which removed the physical barrier separating CBGA and its catalytic enzyme. The lowest binding energy of the CBGA-BPT1 complex confirmed a strong interaction between BPT1 and CBGA. A CBD yield of 6.92 mg/L was achieved, which was 100-fold higher than the yield generated by the starting strain. This study provides insights into high-level CBD-producing strain construction and lays the foundation for CBD supply.

Functional Nanomaterials Based on Self-Assembly of Endogenic NIR-Absorbing Pigments for Diagnostic and Therapeutic Applications

Endogenic pigments derived from hemoglobin have been successfully applied in the clinic for both imaging and therapy based on their inherent photophysical and photochemical properties, including light absorption, fluorescence emission, and producing reactive oxygen species. However, the clinically approved endogenic pigments can be excited only by UV/vis light, restricting the penetration depth of in vivo applications. Recently, endogenic pigments with NIR-absorbing properties have been explored for constructing functional nanomaterials. Here, the overview of NIR-absorbing endogenic pigments, mainly bile pigments, and melanins, as emerging building blocks for supramolecular construction of diagnostic and therapeutic nanomaterials is provided. The endogenic origins, synthetic pathways, and structural characteristics of the NIR-absorbing endogenic pigments are described. The self-assembling approaches and noncovalent interactions in fabricating the nanomaterials are emphasized. Since bile pigments and melanins are inherently photothermal agents, the resulting nanomaterials are demonstrated as promising candidates for photoacoustic imaging and photothermal therapy. Integration of additional diagnostic and therapeutic agents by the nanomaterials through chemical conjugation or physical encapsulation toward synergetic effects is also included. Especially, the degradation behaviors of the nanomaterials in biological environments are summarized. Along with the challenges, future perspectives are discussed for accelerating the ration design and clinical translation of NIR-absorbing nanomaterials.

Photophysics of faecal pigments stercobilin and urobilin in aliphatic alcohols: introduction of a sensitive method for their detection using solvent phase extraction and fluorometry

Faecal pigments (FPs) are ubiquitous in the environment and are a primary contaminant in groundwater and surface water. This article presents a new analytical paradigm by a fluorescence coupled extraction-based method involving FP fluorescence enhancement and minimization of background fluorescence for high sensitivity detection. FPs show higher fluorescence intensity in aliphatic alcohols due to the breaking down of higher-order H-aggregates into lower-order H-aggregates (dimers). DFT studies using the B3LYP functional and LANL2DZ basis set show π-π stacking and hydrogen-bonding contributions towards forming H-aggregated dimers of FPs in the implicit and explicit solvent environments of 1-hexanol. This study is the first report on the extractability of FPs using 1-hexanol as an efficient extraction medium in comparison to higher-order aliphatic alcohols (1-butanol, 1-hexanol and 1-octanol). Furthermore, FP-Zn(II) complexes in 1-hexanol medium significantly enhance the fluorescence emission intensity (∼14-17 times), and the emission intensity remains stable over time. This further helps to increase the detection limit of FPs in the picomolar to sub-picomolar concentration range. This study proposes a protocol involving extraction of FPs by 1-hexanol followed by the complexation of FPs with Zn(II) in the alcohol media and subsequent fluorimetric detection of the FP-Zn(II) complex with a high level of sensitivity, enabled by reduced interference from the background fluorescence of humic acid. The complexation behaviour of FPs with various metal salts was also examined, which provided an understanding of the fluorescence behaviour of FPs with various other metal ions commonly present in natural environmental water. The proposed analytical method has been further validated using real water samples.

Near-infrared emitting dual-stimuli-responsive carbon dots from endogenous bile pigments

Carbon dots are biocompatible nanoparticles suitable for a variety of biomedical applications. Careful selection of carbon dot precursors and surface modification techniques has allowed for the development of carbon dots with strong near-infrared fluorescence emission. However, carbon dots that provide strong fluorescence contrast would prove even more useful if they were also responsive to stimuli. In this work, endogenous bile pigments bilirubin (BR) and biliverdin (BV) were used for the first time to synthesize stimuli-responsive carbon dots (BR-CDots and BV-CDots respectively). The precursor choice lends these carbon dots spectroscopic characteristics that are enzyme-responsive and pH-responsive without the need for surface modifications post-synthesis. Both BV- and BR-CDots are water-dispersible and provide fluorescence contrast, while retaining the stimuli-responsive behaviors intrinsic to their precursors. Nanoparticle Tracking Analysis revealed that the hydrodynamic size of the BR-CDots and BV-CDots decreased with exposure to bilirubin oxidase and biliverdin reductase, respectively, indicating potential enzyme-responsive degradation of the carbon dots. Fluorescence spectroscopic data demonstrate that both BR-CDots and BV-CDots exhibit changes in their fluorescence spectra in response to changes in pH, indicating that these carbon dots have potential applications in pH sensing. In addition, BR-CDots are biocompatible and provide near-infrared fluorescence emission when excited with light at wavelengths of 600 nm or higher. This work demonstrates the use of rationally selected carbon sources for obtaining near-infrared fluorescence and stimuli-responsive behavior in carbon dots that also provide strong fluorescence contrast.

Understanding the photophysics of stercobilin-Zn(II) and urobilin-Zn(II) complexes towards faecal pigment analysis

A detailed photophysical study of two faecal pigments (FPs), Urobilin (UB) and Stercobilin (SB), and their zinc complexes [FP-Zn(II)] was carried out. The enhancement of UB and SB fluorescence resulting from the formation of their Zn(II) complexes was attributed to the complexation-induced rigidity of the chromophoric units, and the corresponding decrease of nonradiative decay rate constants of the excited singlet states (k_nr). The effect of various physicochemical environments was also studied in detail in order to understand the fluorescence behaviour of the Zn(II) complexes. FP-Zn(II) complexes have a lower solubility in water that results in the formation of molecular aggregates. The aggregation-induced loss of fluorescence of FP-Zn(II) complexes could be overcome by using the appropriate mixture of ethanol and water (70:30). Molecular orbital calculations on the FP-Zn(II) complexes provided a good idea of the geometry of the complexes and helped rationalise the enhancement of fluorescence after complexation. This study could pave the way towards developing a convenient non-extraction aqueous phase analytical procedure for detection of FPs using Zn(II) complexation method.

Early Detection of High-grade Biliary Intraepithelial Neoplasia (BilIN-3) in the Cystic Duct Visualized by SpyGlass DS Cholangioscopy

An 84-year-old man was admitted with epigastralgia. Computed tomography showed contrast-enhanced wall thickness in the cystic duct. An endoscopic examination revealed short irregular stricture in the cystic duct, and per-oral cholangioscopy revealed a reddish papillary tumor at the stricture site. Surgical resection revealed high-grade biliary intraepithelial neoplasia (BilIN) at the stricture site of the cystic duct. To our knowledge, this is the first case of a solitary high-grade BilIN epithelium in the cystic duct detected by per-oral cholangioscopy.

Chemical characterization of Cuban propolis by HPLC-PDA, HPLC-MS, and NMR: the brown, red, and yellow Cuban varieties of propolis

Sixty-five samples of propolis were collected from eleven regions of Cuba; methanolic extracts of propolis were prepared from all samples, and a classification method was developed using a combination of NMR, HPLC-PDA, and HPLC-ESI/MS techniques. The analysis of (1)H and (13)C NMR spectra and chromatographic profiles of all propolis extracts allowed the definition of three main types of Cuban propolis directly related to their secondary metabolite classes: brown Cuban propolis (BCP), rich in polyisoprenylated benzophenones, red Cuban propolis (RCP), containing isoflavonoids as the main constituents, and yellow Cuban propolis (YCP), probably with aliphatic compounds. Subsequently, the principal compounds of the brown and red types were characterized by HPLC-ESI/MS analysis. Instrumental techniques used are complementary; NMR was shown to be a quick and informative tool for the rapid analysis of crude propolis polar extracts and allowed the identification of the main class of secondary metabolites, while LC-PDA and LC-MS techniques were useful tools for qualitative and quantitative analysis of marker compounds of Cuban propolis.

Role of intestinal barrier in pathogenesis of pigment gallstone in a guinea pig model

BACKGROUND

The function of the intestinal barrier has drawn more and more attention from researchers in recent years for its important role in many diseases such as burns, wounds, and pancreatitis. In our experimental studies on pigment gallstone, we found potential relationships between the function of the intestinal barrier and pigment gallstone formation. This study was undertaken to investigate the possible action and mechanism of the function of the intestinal barrier in the pathogenesis of pigment gallstone.

METHODS

Eighty guinea pigs were divided into a normal group (CON), a pigment gallstone group (PS) and an intestinal mucosa protection group (GLN). Normal forage, pigment gallstone-forming forage and pigment gallstone-forming forage with supplemental intestinal mucosa protector (glutamine) were given to each group. In the gallstone-forming rate, morphology of intestinal mucosa, intestinal permeability, serum endotoxin and biliary beta-glucuronidase were assessed after 8 weeks.

RESULTS

The rate of gallstone-formation was 73.9% in the PS group. Damage of intestinal mucosa, endotoxemia (from 77+/-43 X 10(-6) EU/L to 1,367+/-525 X 10(-6) EU/L, P<0.01) and increased activity of biliary beta-glucuronidase (endogenous beta-glucuronidase from 122.1+/-39.5 to 209.8+/-47.5 Fishman Unit, P<0.01, and exogenous beta-glucuronidase from 573.5+/-476.9 to 2,206.6+/-983.9 Fishman Unit, P<0.01) were observed in the PS group compared with the CON group. The rate gallstone-formation decreased significantly to 44.4% and the other indices except beta-glucuronidase were lower in the GLN group than in the PS group.

CONCLUSIONS

The function of the intestinal barrier is correlated with pigment gallstone formation. Dysfunction of the intestinal barrier function may promote pigment gallstone formation through bacterial translocation, endotoxemia, and biliary beta-glucuronidase.

An animal model of black pigment gallstones caused by nanobacteria

Black pigment gallstones are often founded in gallbladder, but their pathogenesis is unclear. The present study was undertaken to study the role of nanobacteria in pigment gallstone formation in Japanese white rabbits. Nanobacteria were successfully cultured from 3 of 7 cholecystolithiasis patients gallbladder (without acute cholecystitis) bile samples and affirmed by Hoechst 33258 staining and specific immunostaining using monoclonal antibody. Nanobacteria were injected into rabbits' gallbladder. After 2 weeks follow-up, the incidence of black pigment gallstones in rabbits was significantly greater in nanobacteria-injected group (8/10) than that in DMEM-injected group (2/10) and that in hydroxyapatite-injected group (2/10). This study indicates that nanobacteria exists in gallbladder bile of cholelithiasis patients and causes the formation of black pigment gallstones in rabbits. For the first time, we successfully established an animal model of black pigment gallstones caused by nanobacteria. This will be helpful in further delineating the pathogenesis of black pigment gallstones.

Surgical practice in symptomatic and asymptomatic gallstone disease

AIMS

To determine the surgical practice in individuals with symptomatic and asymptomatic gallstone disease using a questionnaire survey.

METHODS

A questionnaire was sent to 724 patients with gallstone disease. Details of symptoms, duration of illness, nature of treatment including surgery, color of gallstones retrieved and postoperative follow-up particulars were obtained.

RESULTS

The study group included 225 (54%) men; there was a rising trend of prevalence of gallstones in men with increasing age (p<0.05). A third of the patients (142 [34%]) were symptomatic. The mean duration of symptoms was 12.1 months. One hundred and ninety seven patients (48%), including 90 asymptomatic ones, underwent cholecystectomy. Most patients (92.5% of those symptomatic and 76.6% of those asymptomatic) underwent cholecystectomy within one year of diagnosis. Eight asymptomatic patients underwent surgery 3 years or more after diagnosis. The predominant color of stones retrieved was black or brown (57%) or mixed (39%).

CONCLUSIONS

A majority of patients with gallstone disease had cholecystectomy within one year of diagnosis. Black or brown pigment stones were the dominant types of gallstones.

Brown pigment stones in the common bile duct: reduced bilirubinate diconjugate in bile

BACKGROUND

Bilirubin is the main component of most common bile duct stones. Normally, almost all bilirubin in bile is conjugated to glucuronic acid or some other sugar moiety. These conjugates are unstable and liable to deconjugation. Unconjugated bilirubin is insoluble and may precipitate as the calcium salt found in brown pigment stones. The pattern of bilirubin conjugates in common duct bile of patients with choledocholithiasis has been unknown.

METHODS

In a clinical series of 55 patients with choledocholithiasis common-duct bile was aspirated, and the bilirubin conjugates analyzed with high-performance liquid chromatography. One stone from each patient was analyzed for cholesterol and bilirubin content to determine stone type.

RESULTS

Sixteen patients had cholesterol stones, 38 patients had brown pigment stones, and 1 patient had a black stone. Patients with pigment stones had a lower percentage of bilirubin diglucuronide (median, 60.3%; interquartile range, 49.7%-67.3%) than patients with cholesterol stones (64.0%; 60.2%-73.3%) (Mann-Whitney, P=0.015). No significant difference was found for the other bilirubin conjugates, total bilirubin, or biliary pH when pigment and cholesterol stone patients were compared. The time of bile sampling in relation to papillotomy and treatment of cholestasis was not associated with the low percentage of bilirubin diglucuronide. The observation of reduced values for bilirubin diglucuronide could not be ascribed to duodenal diverticula or Billroth-II gastric resection.

CONCLUSION

The percentage of the main bilirubinate conjugate, bilirubin diglucuronide, is decreased in the common duct bile of patients with pigmented compared with cholesterol stones.

Inflammatory properties of bile from dogs with pigment gallstones

BACKGROUND

Gallbladder inflammation and mucus hypersecretion are prominent features of cholesterol and pigment gallstones in humans and animals. The factors leading to inflammation and mucus hypersecretion are poorly understood. These studies examine the inflammatory potential of bile from dogs with pigment gallstones.

METHODS

Dogs fed a methionine-deficient diet that produces pigment gallstones by 6 weeks were compared to normal dogs. Mucus layer thickness, myeloperoxidase activity, and interleukin-1-like activities were measured in canine gallbladder. The inflammatory potential of canine bile was determined by measuring mucus layer thickness, sodium absorption, myeloperoxidase activity and interleukin-1-like activity in guinea pig gallbladders exposed to normal and lithogenic canine bile for 4 hours.

RESULTS

Mean mucus layer thickness, myeloperoxidase, and interleukin-1 activity were significantly greater in canine gallbladders containing pigment gallstones. Bile from dogs with pigment gallstones markedly increased mucus layer thickness, myeloperoxidase activity, and interleukin-1 activity and decreased sodium absorption in normal guinea pig gallbladder. These effects were not eliminated by centrifuging bile to remove crystals and gallstones.

CONCLUSIONS

Canine bile from dogs with pigment gallstones contains soluble factors capable of causing inflammation in the gallbladder wall.

The ability of bile to scavenge superoxide radicals and pigment gallstone formation in guinea pigs

After partial ligation of the common bile duct (CBD) of guinea pigs, 14 of 16 animals developed pigment gallstones within one week (S group). Intraperitoneal injection of Vit. E and C, each 10 mg/kg daily from 3 days before CBD ligation to one week after the operation (S+V group), decreased the gallstone incidence to 5/14 (exact probability < 0.01). The gallstone incidence in the control group, that only received laparotomy without ligation of the CBD, was 0/15. Biochemical analysis of the gallbladder bile showed that stricture of the CBD was associated with a significant increase in levels of unconjugated bilirubin (UCB) and Ca2+ (p < 0.05 and < 0.01). Simultaneously the scavenging rate (SR) of superoxide radical in bile significantly decreased (p < 0.05). Comparing S+V group with S group, the effect of Vit. E and C on the concentrations of UCB and Ca2+ in bile was not significant (both p > 0.05), but Vit. E and C normalized the SR, and the difference between S group and S+V group was significant (p < 0.05). These results suggested that Vit. E and C, known as antioxidants, enhanced the ability to scavenge oxygen radical in S+V group; and that in addition to the increases of UCB and Ca2+ concentrations, the participation of oxygen radicals might be of importance for pigment gallstone formation induced by bile duct obstruction.

Cholestatic jaundice and congenital hypopituitarism

OBJECTIVE

The prevalence of cholestatic jaundice as a presenting feature of congenital hypopituitarism is assessed.

METHODOLOGY

A retrospective case record analysis of the presenting features in all patients diagnosed as having congenital hypopituitarism between 1973-93.

RESULTS

Seven of the 20 patients with congenital hypopituitarism presented with cholestatic jaundice as the major initial manifestation of the disorder. Liver biopsy findings in three revealed intracellular bile pigment accumulation and variable giant cell formation.

CONCLUSION

Cholestatic jaundice was the major manifestation of congenital hypopituitarism in 35% of patients presenting in the neonatal or early infancy period.

Cholelithiasis with common bile duct obstruction in a 20-week-old infant

Formation of bile calculi in the common bile duct is a rare event in early infancy. The following article describes the case of a 20-week-old infant with anal atresia and a deep rectovaginal fistula who presented with recurrent jaundice due to a single calculus in the common bile duct that led to intermittent obstruction of the papilla Vateri. Diagnosis was proven by endoscopically performed retrograde cholangiography and the concretion was successfully removed after transduodenal papillotomy using a Dormia basket.

[Relation between pigment gallstone formation and the ability of bile to scavenge superoxide radicals]

Operative stenosis of common bile duct (CBD) (S group) induced pigment gallstones in 14 of 16 guinea pigs one week after operation. If Vit E and Vit C were given intraperitoneally 10 mg/kg daily from 3 days before to one week after the operation (S+V group), the gallstone incidence decreased to 5/14 (P < 0.01). In comparison with control group (C), unconjugated bilirubin (UCB) and Ca2+ concentration in gallbladder bile of S group increased significantly (P < 0.05 and P < 0.01 respectively), while the scavenge rate (SR) of superoxide radical (O2-.) in bile decreased significantly (P < 0.05). Comparing S+V group with S group showed that the differences of UCB and Ca2+ concentration were not significant (P < 0.05 both); only the SR rose significantly (P < 0.05) and reached the level of C group. It is suggested that besides the increase of UCB and Ca2+ concentration, the participation of oxygen radicals may be needed in formation of pigment gallstones induced by bile duct obstruction.

Characterization of mucin in the hepatic bile of patients with intrahepatic pigment stones

To investigate the relationship between biliary mucin and ductular stone formation, mucin was isolated from hepatic bile using gel filtration on Sepharose CL-4B. The bile was obtained from 14 patients with stones in various sites of the biliary tract. The hexose content in the excluded fraction was significantly higher in patients with intrahepatic ductular stones (68.7 +/- 20.5 micrograms/mL; mean +/- s.d.) than in those with gall-bladder stones or extrahepatic ductular stones (23.8 +/- 8.1 micrograms/mL, 33.3 +/- 9.5 micrograms/mL; P less than 0.05), suggesting a higher concentration of mucin in the bile of patients with intrahepatic ductular stones. Ion-exchange chromatography on DEAE-Sephacel showed that most mucin from each material was negatively charged and electrophoretic studies indicated that it was composed mainly of high molecular weight (greater than 10(6)), sulfated glycoprotein. These results suggested that the mucin content of hepatic bile might have an important relation to the development of intrahepatic ductular stones.