Incidence, Risk Factors, and Complications of Cholelithiasis in Patients with Home Parenteral Nutrition

Emerging drugs for the treatment of short bowel syndrome

INTRODUCTION

SBS is a rare and disabling condition. The standard management is based on diet optimization with parenteral supplementation. In addition, glucagon-like peptide-2 (GLP-2)analogs, have shown promising results as disease-modifying therapies for SBS.

AREAS COVERED

Short bowel syndrome (SBS) is defined as a reduction in functional intestinal length to less than 200 cm, leading to intestinal failure (IF) leading to malnutrition and parenteral support dependency. This review discusses the current management of SBS-CIFpatients, the place of GLP-2 analog treatment in terms of efficacy, safety and availability, and the new perspectives opened by the use of enterohormones.

EXPERT OPINION

Clinical trials and real-world experience demonstrated that Teduglutide   reduces dependence on parenteral support and has a place in the management of patients with SBS-CIF.  The use of Teduglutide should be discussed in patients stabilized after resection and its introduction requires the advice of an expert center capable of assessing the benefit-risk ratio. The complex, individualized management of SBS-C IF requires theexpertise of a specialized IF center which a multidisciplinary approach. The arrival of new treatments will call for new therapeutic strategies, and the question of how to introduce and monitor them will represent a new therapeutic challenge.

Co-Morbid Hypothyroidism and Liver Dysfunction: A Review

The liver and thyroid hormones interact at multiple levels to maintain homoeostasis. The liver requires large adequate amounts of thyroid hormones to execute its metabolic functions optimally, and deficiency of thyroid hormones may lead to liver dysfunction. Hypothyroidism has been associated with abnormal lipid metabolism, non-alcoholic fatty liver disease (NAFLD), hypothyroidism-induced myopathy, hypothyroidism-associated gallstones and occasionally, interferon-induced thyroid dysfunction. NAFLD remain an important association with hypothyroidism and further studies are needed that specifically compare the natural course of NAFLD secondary to hypothyroidism and primary NAFLD. Hepatic dysfunction associated with hypothyroidism is usually reverted by normalizing thyroid status. Large scale studies geared towards finding new and effective therapies, especially for NAFLD are needed. The clinician must be aware that there exists overlapping symptomatology between liver dysfunction and severe hypothyroidism which may make delay the diagnosis and treatment of hypothyroidism; this requires a high index of suspicion.

ESPEN guideline on chronic intestinal failure in adults - Update 2023

BACKGROUND & AIMS

In 2016, ESPEN published the guideline for Chronic Intestinal Failure (CIF) in adults. An updated version of ESPEN guidelines on CIF due to benign disease in adults was devised in order to incorporate new evidence since the publication of the previous ESPEN guidelines.

METHODS

The grading system of the Scottish Intercollegiate Guidelines Network (SIGN) was used to grade the literature. Recommendations were graded according to the levels of evidence available as A (strong), B (conditional), 0 (weak) and Good practice points (GPP). The recommendations of the 2016 guideline (graded using the GRADE system) which were still valid, because no studies supporting an update were retrieved, were reworded and re-graded accordingly.

RESULTS

The recommendations of the 2016 guideline were reviewed, particularly focusing on definitions, and new chapters were included to devise recommendations on IF centers, chronic enterocutaneous fistulas, costs of IF, caring for CIF patients during pregnancy, transition of patients from pediatric to adult centers. The new guideline consist of 149 recommendations and 16 statements which were voted for consensus by ESPEN members, online in July 2022 and at conference during the annual Congress in September 2022. The Grade of recommendation is GPP for 96 (64.4%) of the recommendations, 0 for 29 (19.5%), B for 19 (12.7%), and A for only five (3.4%). The grade of consensus is "strong consensus" for 148 (99.3%) and "consensus" for one (0.7%) recommendation. The grade of consensus for the statements is "strong consensus" for 14 (87.5%) and "consensus" for two (12.5%).

CONCLUSIONS

It is confirmed that CIF management requires complex technologies, multidisciplinary and multiprofessional activity, and expertise to care for the underlying gastrointestinal disease and to provide HPN support. Most of the recommendations were graded as GPP, but almost all received a strong consensus.

Short bowel syndrome: Complications and management

Short bowel syndrome (SBS) occurs when a patient loses bowel length or function significantly enough to cause malabsorption, oftentimes requiring lifelong parenteral support. In adults, this occurs most commonly in the setting of massive intestinal resection, whereas congenital anomalies and necrotizing enterocolitis predominate in children. Many patients with SBS develop long-term clinical complications over time related to their altered intestinal anatomy and physiology or to various treatment interventions such as parenteral nutrition and the central venous catheter through which it is administered. Identifying, preventing, and treating these complications can be challenging. This review will focus on the diagnosis, treatment, and prevention of several complications that can occur in this patient population, including diarrhea, fluid and electrolyte imbalance, vitamin and trace element derangements, metabolic bone disease, biliary disorders, small intestinal bacterial overgrowth, d-lactic acidosis, and complications of central venous catheters.

Short Bowel Syndrome in Adults

Short bowel syndrome (SBS) is a rare disorder characterized by severe intestinal dysfunction leading to malabsorption of macronutrients and micronutrients that often results in permanent need of parenteral nutrition support. Patients can develop SBS because of massive intestinal resection or loss of intestinal function and consequently experience significant morbidity and increased healthcare utilization. The remaining anatomy and length of bowel after intestinal resection have important prognostic and therapeutic implications. Because patients with SBS constitute a heterogenous group, management is complex and multifaceted, involving nutrition support, fluid and electrolyte management, and pharmacologic therapies in particular to control diarrhea. Surgical interventions including intestinal transplantation may be considered in selected individuals. Successful care of these patients is best accomplished by a multidisciplinary team that is experienced in the management of this syndrome.

Prevalence, Risk Factors, and Complications of Cholelithiasis in Adults With Short Bowel Syndrome: A Longitudinal Cohort Study

Background: Patients with short bowel syndrome (SBS) are at a high risk of cholestasis or cholelithiasis. This study aimed to determine the incidence, risk factors, and clinical consequences of cholelithiasis in adults with SBS over an extended period.

Methods: All eligible adults diagnosed with SBS and admitted to a tertiary hospital center between January 2010 and December 2019 were retrospectively identified from the hospital records database. Kaplan–Meier analysis was used to estimate the cumulative incidence of SBS during the 10-year period. For assessment the risk factors for cholelithiasis, we used multivariate Cox proportional hazards model with estimation of hazard ratio (HR) with 95% confidence intervals (95 %CI).

Results: This study enrolled 345 eligible patients with SBS. Kaplan–Meier analysis revealed that 72 patients (20.9%) developed cholelithiasis during the 10-year observation period. In multivariate analyses using the Cox proportional hazard model revealed that the remnant jejunum (HR = 2.163; 95% confidence interval [CI]: 1.156–4.047, p = 0.016) and parenteral nutrition dependence (HR = 1.783; 95% CI: 1.077–2.952, p = 0.025) were independent risk factors for cholelithiasis in adults with SBS. Twenty-eight patients developed symptoms and/or complications in the cholelithiasis group. Proportions of acute cholecystitis or cholangitis and acute pancreatitis were significantly increased in the cholelithiasis group compared with the non-cholelithiasis group (31.9 vs. 7.7%, p < 0.01; and 6.9 vs. 1.1%, p = 0.003, respectively).

Conclusion: Because of the adverse clinical consequences of cholelithiasis, adult patients with SBS should be closely monitored, and preventive interventions should be considered.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT04867538.

Intravenous Lipid Emulsions in the Prevention and Treatment of Liver Disease in Intestinal Failure

The development of intestinal failure-associated liver disease (IFALD) in pediatric and adult patients on parenteral nutrition is usually multifactorial in nature due to nutritional and non-nutritional causes. The role of lipid therapy as a contributing cause is well-established with the pathophysiological pathways now better understood. The review focuses on risk factors for IFALD development, biological effects of lipids, lipid emulsions and the mechanisms of lipid toxicity observed in laboratory animals followed by a synopsis of clinical studies in pediatric and adult patients. The introduction of fish oil-based lipid emulsions that provide partial or complete lipid replacement therapy has resulted in resolution of IFALD that had been associated with soybean oil-based therapy. Based on case reports and cohort studies in pediatric and adult patients who were at risk or developed overt liver disease, we now have more evidence that an early switch to partial or complete fish oil-based lipid therapy should be implemented in order to successfully halt and reverse IFALD.

Understanding short bowel syndrome: Current status and future perspectives

Short bowel syndrome (SBS) is a rare malabsorptive disorder as a result of the loss of bowel mass mostly secondary to surgical resection of the small intestine. Other causes are vascular diseases, neoplasms or inflammatory bowel disease. The spectrum of the disease is widely variable from single micronutrient malabsorption to complete intestinal failure, depending on the remaining length of the small intestine, the anatomical portion of intestine and the function of the remnant bowel. Over the last years, the management of affected patients has remarkably improved with the increase in patients' quality of life and survival, mainly thanks to advances in home-based parenteral nutrition (PN). In the last ten years new treatment strategies have become available together with increasing experience and the encouraging results with new drugs, such as teduglutide, have added a new dimension to the management of SBS. This review aims to summarize the knowledge available in the current literature on SBS epidemiology, pathophysiology, and its surgical (including intestinal lengthening procedures and intestinal transplantation) and medical management with emphasis on the recent advances. Moreover, this review attempts to provide the new understanding and recent approaches to SBS complications such as sepsis, catheter thrombosis, and intestinal failure-associated liver disease.

Hepatobiliary Complications of Chronic Intestinal Failure

Intestinal failure-associated liver disease is a multifactorial process that may occur in patients with chronic intestinal failure on long-term home parenteral nutrition. A very short gut, the lack of enteral feeding, recurrent sepsis, and parenteral overfeeding are major risk factors. Histologic changes include steatosis, steatohepatitis, cholestasis, fibrosis, and cirrhosis. Chronic cholestasis is common, but does not always progress to fibrosis and/or cirrhosis. Preventing harmful factors may dramatically decrease the risk of intestinal failure-associated liver disease. Advanced liver disease is an indication for intestinal and/or multivisceral transplantation. Biliary stone formation is frequent and mainly due to a lack of enteral feeding.

Cholelithiasis and Related Morbidity in Chronic Intestinal Failure: a Longitudinal Cohort Study from a National Specialized Centre

BACKGROUND

Short-term studies have shown that patients with type III intestinal failure often develop gallstones and have recommended prophylactic cholecystectomy. In this retrospective cohort study, we aimed to define the incidence and clinical consequences of cholelithiasis over an extended time period, in order to refine the role of prophylactic cholecystectomy in type III intestinal failure.

METHODS

Data were retrospectively collected from a prospectively maintained audit. Patients with intestinal failure for 5 years or more were included. Kaplan-Meier analysis was used to estimate cumulative incidence over time. Predictors of cholelithiasis were evaluated by Cox regression.

RESULTS

Between 1 January 1983 and 1 December 2008, 81 patients were commenced on parenteral support lasting 5 years or more. Of 63 patients with no pre-existing gallstones on imaging, 17 (27%) developed gallstones during a median observation period of 133 months. On Kaplan-Meier analysis, the incidence at 10 years was 21%; at 20 years, 38%; and at 30 years, 47%. Thirteen of the 17 had symptoms and ten required surgical and/or endoscopic intervention. Increased weekly calorific content (P 0.003) and the provision of parenteral lipids (P 0.003) were predictors of cholelithiasis on univariable Cox regression.

CONCLUSION

Many patients with long-term intestinal failure develop gallstones over time, with a 20-year incidence of 38%. The majority of those have symptoms or complications and require intervention. Therefore, prophylactic en-passant cholecystectomy is justified when gallstones are present in type III intestinal failure, supporting routine pre-operative imaging of the gallbladder prior to abdominal surgery.

Frequency of symptoms associated with gallstone disease: a hospital-based cross sectional study

This study investigated the likely outcomes of gallstone disease and frequency of symptoms associated with this. This cross sectional study was performed at the Aliebn Abitaleb hospital in Rafsanjan over a period of twelve months from 2000 to 2001. A total sample of 70 individuals were included in the study, interviewing them using of a questionnaire covering data in terms of demographic features and medical history.The majority of patients belonged to the age group of 41 to 60 years (44.3% of all patients), while the lowest frequency was in the age group of 20 years or less. Frequency of females was higher than males. The frequency of female patients increased with the number of child birth, the highest being in women who had more than 5 child births. The most common complaint of pain was revealed as upper right abdominal quadrant (RUQ), which accounted for 95.7% of cases. Vomiting was observed in 52.9% of patients. In addition, the frequency of patients with chronic pain initiation was more than those with acute pain initiation. Among women, 17.5% had oral contraceptive pill constipation. It is worth noting that ultrasonography was the best diagnostic tool for evaluating patients. It is noteworthy that the most common symptom was right upper quadrant tenderness. Our data indicate that diabetes was the most common illness associated with gallstone disease and that 8.6% of patients had a family history of gallstone disease.

Telocytes: New Players in Gallstone Disease

Cholesterol gallstone disease is highly prevalent in Western countries, particularly in women and some specific ethnic groups. The mechanisms behind the formation of gallstones are not clearly understood, but gallbladder dysmotility seems to be a key factor that triggers the precipitation of cholesterol microcrystals from supersaturated lithogenic bile.Given that newly described interstitial cells, telocytes, are present in the gallbladder and they are located in close vicinity of smooth muscle cell and neural fibers possibly interfering with gallbladder motility or contractility, authors are trying to summarize the current knowledge on the role of telocytes with respect to disturbed gallbladder function in gallstone disease.

Parenteral Nutrition and Intestinal Failure

Severe short bowel syndrome (SBS) is a major cause of chronic (Type 3) intestinal failure (IF) where structural and functional changes contribute to malabsorption and risk of micronutrient deficiencies. Chronic IF may be reversible, depending on anatomy and intestinal adaptation, but most patients require long-term nutritional support, generally in the form of parenteral nutrition (PN). SBS management begins with dietary changes and pharmacologic therapies taking into account individual anatomy and physiology, but these are rarely sufficient to avoid PN. New hormonal therapies targeting intestinal adaptation hold promise. Surgical options for SBS including intestinal transplant are available, but have significant limitations. Home PN (HPN) is therefore the mainstay of treatment for severe SBS. HPN involves chronic administration of macronutrients, micronutrients, fluid, and electrolytes via central venous access in the patient's home. HPN requires careful clinical and biochemical monitoring. Main complications of HPN are related to venous access (infection, thrombosis) and metabolic complications including intestinal failure associated liver disease (IFALD). Although HPN significantly impacts quality of life, outcomes are generally good and survival is mostly determined by the underlying disease. As chronic intestinal failure is a rare disease, registries are a promising strategy for studying HPN patients to improve outcomes.

Definitions of intestinal failure and the short bowel syndrome

The European Society for Clinical Nutrition and Metabolism defined intestinal failure (IF) as "the reduction of gut function below the minimum necessary for the absorption of macronutrients and/or water and electrolytes, such that intravenous supplementation is required to maintain health and/or growth". IF is classified as type 1-acute, type 2-prolonged acute and type 3-chronic IF. A short bowel syndrome (SBS) due to the intestinal malabsorption associated with a functional small intestine length of less than 200 cm is the most frequent mechanism of IF. SBS is a difficult and multifaced disease. Complications due to SBS itself and to treatments, such as long term home parenteral nutrition, can adversely affect the patient outcome. The care of SBS requires complex technologies and multidisciplinary and multiprofessional activity and expertise. Patient outcome is strongly dependent on care and support from an expert specialist team. This paper focuses on the aspects of the pathophysiology and on the complications of SBS, which are most relevant in the clinical practice, such as intestinal failure associated liver disease, renal failure, biliary and renal stones, dehydration and electrolyte depletion, magnesium deficiency and D-lactic acidosis.

ESPEN guidelines on chronic intestinal failure in adults

BACKGROUND & AIMS

Chronic Intestinal Failure (CIF) is the long-lasting reduction of gut function, below the minimum necessary for the absorption of macronutrients and/or water and electrolytes, such that intravenous supplementation is required to maintain health and/or growth. CIF is the rarest organ failure. Home parenteral nutrition (HPN) is the primary treatment for CIF. No guidelines (GLs) have been developed that address the global management of CIF. These GLs have been devised to generate comprehensive recommendations for safe and effective management of adult patients with CIF.

METHODS

The GLs were developed by the Home Artificial Nutrition & Chronic Intestinal Failure Special Interest Group of ESPEN. The GRADE system was used for assigning strength of evidence. Recommendations were discussed, submitted to Delphi rounds, and accepted in an online survey of ESPEN members.

RESULTS

The following topics were addressed: management of HPN; parenteral nutrition formulation; intestinal rehabilitation, medical therapies, and non-transplant surgery, for short bowel syndrome, chronic intestinal pseudo-obstruction, and radiation enteritis; intestinal transplantation; prevention/treatment of CVC-related infection, CVC-related occlusion/thrombosis; intestinal failure-associated liver disease, gallbladder sludge and stones, renal failure and metabolic bone disease. Literature search provided 623 full papers. Only 12% were controlled studies or meta-analyses. A total of 112 recommendations are given: grade of evidence, very low for 51%, low for 39%, moderate for 8%, and high for 2%; strength of recommendation: strong for 63%, weak for 37%.

CONCLUSIONS

CIF management requires complex technologies, multidisciplinary and multiprofessional activity, and expertise to care for both the underlying gastrointestinal disease and to provide HPN support. The rarity of the condition impairs the development of RCTs. As a consequence, most of the recommendations have a low or very low grade of evidence. However, two-thirds of the recommendations are considered strong. Specialized management and organization underpin these recommendations.

Cholecystectomy and Liver Disease in Short Bowel Syndrome

BACKGROUND

Recently, an association has been proposed between cholecystectomy and various liver diseases. Our aim was to determine whether cholecystectomy in short bowel patients influences the risk of liver disease.

METHODS

We reviewed 422 adults: 182 underwent cholecystectomy prior to short bowel, 102 after developing short bowel, and 138 patients still had the gallbladder in place.

RESULTS

Compared to pre and post short bowel, gallbladder patients were significantly less likely to have obesity (18 % and 21 % vs 9 %), central line infections (59 % and 69 % vs 46 %), intestine <60 cm (30 % and 39 % vs 26 %), and require parenteral nutrition >1 year (72 % and 77 % vs 64 %). The incidence of fatty liver was similar (31, 26, and 25 %). Fibrosis/cirrhosis was less common in the gallbladder group (26 % and 36 % vs 16 %). Frequency of end-stage liver disease was similar (15, 22, and 11 %). On multivariate analysis, cholecystectomy, parenteral nutrition >1 year, line infection, and intestine <60 cm were predictors of fibrosis/cirrhosis. Parenteral nutrition >1 year, line infection, and intestine <60 cm were predictors of end-stage liver disease.

CONCLUSIONS

Cholecystectomy does not appear to increase the incidence of liver disease in short bowel patients overall. Fibrosis/cirrhosis occurs significantly less frequently in patients with an intact gallbladder.

Gallstones

Gallstone disease is a worldwide medical problem, but the incidence rates show substantial geographical variation, with the lowest rates reported in African populations. Publications in English language on gallstones which were obtained from reprint requests and PubMed database formed the basis for this paper. Data extracted from these sources included authors, country, year of publication, age and sex of patients, pathogenesis, risk factors for development of gallstones, racial distribution, presenting symptoms, complications and treatment. Gallstones occur worldwide, however it is commonest among North American Indians and Hispanics but low in Asian and African populations. High biliary protein and lipid concentrations are risk factors for the formation of gallstones, while gallbladder sludge is thought to be the usual precursor of gallstones. Biliary calcium concentration plays a part in bilirubin precipitation and gallstone calcification. Treatment of gallstones should be reserved for those with symptomatic disease, while prophylactic cholecystectomy is recommended for specific groups like children, those with sickle cell disease and those undergoing weight-loss surgical treatments. Treatment should be undertaken for a little percentage of patients with gallstones, as majority of those who harbor them never develop symptoms. The group that should undergo cholecystectomy include those with symptomatic gallstones, sickle cell disease patients with gall stones, and patients with morbid obesity who are undergoing laparotomy for other reasons.

Liver disease secondary to intestinal failure

IFALD is a common and potentially life-threatening condition for patients with SBS requiring long-term PN. There exists the potential for decreasing its incidence by optimizing the composition and the rate of infusion of parenteral solutions, by advocating a multidisciplinary approach, and by early referral for intestinal-liver transplantation to ensure long-term survival of patients with SBS.

Home parenteral nutrition therapy in seven patients with anorexia nervosa: the role and indications

Home parenteral nutrition (HPN) is a well-established intervention to sustain life in malnourished patients at home. Because it is difficult for patients with anorexia nervosa (AN) to gain weight or stop purging, such patients require repeated hospitalizations. Although HPN has not been commonly used for AN patients in Japan, we utilized this approach to treat seven AN patients. We herein present the clinical course and outcome of these seven patients, the application criteria for HPN in our institution, and the potential problems associated with HPN. Despite its complications, HPN may be a useful measure to help patients with persistent AN avoid multiple hospitalizations.

Prophylactic cholecystectomy during abdominal surgery

The presence of asymptomatic gallstones is no longer an indication for elective prophylactic cholecystectomy (PC) according to the recommendations of the 1991 French Consensus Conference on cholelithiasis. However, there may be potential benefits of performing prophylactic cholecystectomy during certain abdominal procedures for non-biliary disease; this remains a subject of debate. This debate has become livelier with the recent increase in bariatric surgery. Gastrectomy for cancer, small bowel resection, colonic resection, and splenectomy for hereditary spherocytosis as well as all bariatric surgical interventions can all alter the physiology of gallstone disease raising the question of the value of PC, but the specific morbidity of cholecystectomy must be kept in mind. The purpose of this study was to report epidemiological and pathophysiological data and the results from literature reports in order to assess the value of concomitant prophylactic cholecystectomy during various common surgical situations.

Review article: the management of long-term parenteral nutrition

BACKGROUND

Home parenteral nutrition (HPN) is currently the management of choice for patients with chronic intestinal failure.

AIM

To summarise the major issues in delivering long-term parenteral nutrition (>3 months) and assess outcome as per complications, mortality and quality of life. To assess the evidence for the therapeutic use of trophic factors such as teduglutide and to review evolving therapeutic options in the treatment of chronic intestinal failure.

METHODS

A literature search using PubMed and MEDLINE databases was performed.

RESULTS

Safe delivery of HPN relies upon individualised formulations of parenteral nutrition administered via carefully maintained central venous catheters by trained patients or carers, supported by a skilled multidisciplinary team. Early diagnosis and treatment of complications including catheter-associated blood stream infection (reported incidence 0.14-0.83 episodes/patient-year on HPN) and central venous thrombosis (reported incidence 0.03 episodes/patient-year) is important to minimise mortality and morbidity. There is a significant variation in the reported incidence of both hepatobiliary complications (19-75%) and advanced liver disease (0-50%). Five-year survival rates in large centres are reported between 60% and 78% with survival primarily related to underlying diagnosis. Long-term survival remains higher on HPN than with intestinal transplantation. The role of intestinal lengthening procedures is yet to be validated in adults.

CONCLUSIONS

Home parenteral nutrition delivered by skilled nutrition teams has low incidences of catheter-related complications. Most deaths relate to the underlying disease. Therapies such as teduglutide and small bowel transplantation appear promising, but home parenteral nutrition appears likely to remain the bedrock of management in the near term.

ESPEN Guidelines on Parenteral Nutrition: home parenteral nutrition (HPN) in adult patients

Home parenteral nutrition (HPN) was introduced as a treatment modality in the early 1970s primarily for the treatment of chronic intestinal failure in patients with benign disease. The relatively low morbidity and mortality associated with HPN has encouraged its widespread use in western countries. Thus there is huge clinical experience, but there are still few controlled clinical studies of treatment effects and management of complications. The purpose of these guidelines is to highlight areas of good practice and promote the use of standardized treatment protocols between centers. The guidelines may serve as a framework for development of policies and procedures.

Interstitial Cajal-like cells in human gallbladder

We describe here an interstitial Cajal-like cell type (ICLC) in human gallbladder, resembling the archetypal enteric interstitial cells of Cajal. Gallbladder ICLC were demonstrated in fresh preparations (tissue cryosections) using methylene-blue, and fixed specimens in Epon semi-thin sections stained with toluidine blue or transmission electron microscopy (TEM). The positive diagnosis of gallbladder ICLC was further verified by immunohistochemistry: CD117/c-kit, CD34, and another 16 antigens: vimentin, desmin, nestin, alpha-smooth muscle actin, NK-1, S-100, PGP-9.5, tau protein, chromogranin A, NSE, GFAP, CD1a, CD62-P, CD68, estrogen and progesterone receptors. Double immunostaining was performed for CD117, CD34 and CD117 and nestin, respectively. In fresh specimens, the spatial density of gallbladder ICLC was 100-110 cells/mm(2). ICLC mainly appeared beneath the epithelium and in muscularis (about 7%, and approximately 5%, respectively). In toto, ICLC represent in gallbladder approximately 5.5% of subepithelial cells. TEM showed that diagnostic criteria were fulfilled by ICLC. Moreover, TEM indicated that the main ultrastructural distinctive feature for ICLC, the cell processes, develop into the characteristic shape at a relatively early stage of development. It remains to be established if, in humans, ICLC are involved in gallbladder (dis)functions (e.g. pace-making, secretion (auto-, juxta- and/or paracrine), intercellular signaling, or stone formation).