Efficacy of oral pancreatic enzyme therapy for the treatment of fat malabsorption in HIV-infected patients

What is the significance of a faecal elastase-1 level between 200 and 500μg/g?

Background

Pancreatic exocrine insufficiency is a cause of malabsorption. It is generally diagnosed if faecal elastase-1 (FE-1) levels are below 200 µg/g. Pancreatic function is assumed to be normal when faecal elastase levels are >500 µg/g. The significance of faecal elastase levels above 200 µg/g but less than 500 µg/g is unclear.

Methods

This retrospective study reports the response to treatment in patients who had an FE-1 level between 200 and 500 µg/g.

Results

Of these 82 patients, 28 were offered pancreatic enzyme replacement therapy (PERT). A clinical response, defined as an improvement in their initial symptoms after commencing PERT, was seen in 20 patients (71%), 7 with potentially predisposing conditions and 13 with functional diarrhoea. PERT particularly abolished or improved diarrhoea, steatorrhoea and flatulence.

Conclusion

Clinicians should, therefore, be aware that a trial of PERT given to patients with FE-1 levels between 200 and 500 µg/g may lead to improvement in gastrointestinal symptoms.

Enzyme Therapy: Current Challenges and Future Perspectives

In recent years, enzymes have risen as promising therapeutic tools for different pathologies, from metabolic deficiencies, such as fibrosis conditions, ocular pathologies or joint problems, to cancer or cardiovascular diseases. Treatments based on the catalytic activity of enzymes are able to convert a wide range of target molecules to restore the correct physiological metabolism. These treatments present several advantages compared to established therapeutic approaches thanks to their affinity and specificity properties. However, enzymes present some challenges, such as short in vivo half-life, lack of targeted action and, in particular, patient immune system reaction against the enzyme. For this reason, it is important to monitor serum immune response during treatment. This can be achieved by conventional techniques (ELISA) but also by new promising tools such as microarrays. These assays have gained popularity due to their high-throughput analysis capacity, their simplicity, and their potential to monitor the immune response of patients during enzyme therapies. In this growing field, research is still ongoing to solve current health problems such as COVID-19. Currently, promising therapeutic alternatives using the angiotensin-converting enzyme 2 (ACE2) are being studied to treat COVID-19.

Gastrointestinal Diseases in Children Living with HIV

Thanks to the advances in antiretroviral therapies (ART) and early diagnosis, pediatric HIV has turned into a chronic infection that requires the collaboration of all pediatric subspecialists for holistic patient management. Gastrointestinal complaints are a frequent reason for seeking access to medical care in all pediatric patients worldwide. Intestinal involvement is present in virtually all children with HIV infections. In high-prevalence settings, up to 25% of children accessing the hospital for diarrhea are diagnosed with HIV. More than half of patients with advanced disease present with gastrointestinal symptoms, from mild infectious diarrhea to severe gastrointestinal impairment, malabsorption and failure to thrive. Gastrointestinal disorders do not spare children on ART, particularly in the initial months of therapy. ART-associated pancreatitis and hepatitis are rare but potentially severe adverse events, whereas lower abdominal symptoms have been reported in more than a third of patients. The latter are usually mild and transient, but may limit ART adherence; a correct framing of the problem is necessary to minimize therapy switches while optimizing the quality of life of children on ART. This review aims to provide state-of-the-art guidance for the initial approach to gastrointestinal diseases in children living with HIV.

Effectivity of Pancreatic Enzyme Replacement Therapy in Malnourished Children

OBJECTIVE

Malnutrition is commonly seen in children with exocrine pancreatic insufficiency (EPI). Pancreatic enzyme replacement therapy (PERT) is the mainstay treatment of acute malnutrition in children detected with a disease closely associated with EPI (eg, cystic fibrosis). The effectiveness of PERT in children with malnutrition without any chronic disease, however, remains unclear. The aim of this study was to investigate the effectiveness of PERT on weight gain and EPI in children classified as moderately and severely malnourished according to the World Health Organization (WHO) classification.

MATERIALS AND METHODS

The study included a total of 40 children aged 2-16 years who were classified as moderately and severely malnourished according to the WHO classification. The patients were randomly divided into 2 groups: PERT group (n = 20) received 2000 U lipase/kg/day (in 4 doses) in addition to hypercaloric enteral supplements and control group received hypercaloric enteral supplements only. In both groups, anthropometric measurements and the assessment of fecal elastase-1 (FE-1) levels were performed both at first admission and at the end of the 8-week treatment period.

RESULTS

On the basis of WHO classification, 10 (25%) children were classified as severely malnourished and 30 (75%) children as moderately malnourished. EPI was detected in all the patients, among whom 24 (60%) patients had severe EPI. At the end of the treatment, body weight, height, and body mass index (BMI) increased significantly in both groups compared to their pre-treatment values, whereas no significant difference was found with regard to waist circumference (WC) and FE-1 levels. Similarly, no significant difference was found between pre- and posttreatment measurements of PERT and control groups (P > 0.05) and between pre- and posttreatment measurements of patients with moderate and severe malnutrition (P > 0.05).

CONCLUSIONS

Malnutrition remains a serious public health problem, and thus, the development of novel treatment methods is highly essential. PERT is one of the most commonly considered alternatives, although there is little documentation of PERT in the literature. In the present study, although PERT resulted in higher weight gain, it established no significant difference between the 2 groups.

Enzymes for pharmaceutical and therapeutic applications

Enzymes are highly efficient and selective biocatalysts, present in the living beings. They exist in enormous varieties in terms of the types of reactions catalyzed by them for instance oxidation-reduction, group transfers within the molecules or between the molecules, hydrolysis, isomerization, ligation, bond cleavage, and bond formation. Besides, enzyme based catalyses are performed with much higher fidelity, under mild reaction conditions and are highly efficient in terms of number of steps, giving them an edge over their chemical counter parts. The unique characteristics of enzymes makes them highly applicable fora number of chemical transformation reactions in pharmaceutical industries, such as group protection and deprotection, selective acylation and deacylation, selective hydrolysis, deracemization, kinetic resolution of racemic mixtures, esterification, transesterification, and many others. In this review, an overview of the enzymes, their production and their applications in pharmaceutical syntheses and enzyme therapies are presented with diagrams, reaction schemes and table for easy understanding of the readers.

Nutritional Issues and Positive Living in Human Immunodeficiency Virus/AIDS

Nutritional counseling has been shown to improve dietary intake in individuals with human immunodeficiency virus (HIV)/AIDS. Registered dietitians/nutritionists can individualize diet interventions to optimize effectiveness in treating metabolic consequences of the HIV infection or highly active antiretroviral therapy. Nutrition management for individuals infected with HIV can be helpful in maintaining lean body weight, combating oxidative stress, reducing complications from hyperglycemia and hyperlipidemia, and managing gastrointestinal function. Consideration should be given to including the expertise of a registered dietitian/nutritionist.

Exocrine pancreatic insufficiency is common in people living with HIV on effective antiretroviral therapy

OBJECTIVES

The primary aim of this prospective study was to determine the prevalence of exocrine pancreatic insufficiency (EPI) in people living with HIV (PLHIV) on suppressive antiretroviral therapy (ART).

METHODS

PLHIV ≥18 years of age and on ART for >6 months and with HIV RNA <50 copies/mL plasma were included. Faecal elastase-1 measurement was performed on a single stool sample, serum markers of malnutrition were collected, and participants answered a short questionnaire about gastrointestinal symptoms. Participants with EPI and symptoms were offered pancreatic enzyme replacement therapy (PERT), and the result of this therapy was also evaluated.

RESULTS

Of 100 participants, 32% had EPI (faecal elastase-1 < 200 μg/g) and 20% severe EPI (faecal elastase-1 < 100 μg/g). We did not find any correlation between self-reported symptoms and degree of EPI. Twelve out of the 32 participants with EPI accepted to start PERT. Nine out of 12 (75%) reported improvement or became asymptomatic within 14 days.

CONCLUSION

EPI is common in PLHIV on effective ART. We could, however, not find a correlation between gastrointestinal symptoms and the presence of EPI. Assessment of pancreatic exocrine function could be considered in PLHIV particularly in those with gastrointestinal discomfort, since there is a possible gain in treating them with relief of symptoms and improved quality of life. The effects of PERT in PLHIV on effective ART need further study.

Improving the stability and activity of oral therapeutic enzymes-recent advances and perspectives

Exogenous, orally-administered enzymes are currently in clinical use or under development for the treatment of pathologies, such as celiac disease and phenylketonuria. However, the administration of therapeutic enzymes via the oral route remains challenging due to potential inactivation of these fragile macromolecular entities in the harsh environment of the gastrointestinal tract. Enzymes are particularly sensitive because both proteolysis and unfolding can lead to their inactivation. Current efforts to overcome these shortcomings involve the application of gastro-resistant delivery systems and the modification of enzyme structures by polymer conjugation or protein engineering. This perspective manuscript reviews and critically discusses recent progress in the oral delivery of therapeutic enzymes, whose substrate is localized in the gastrointestinal tract.

Pancreatic insufficiency in HIV: is it possible?

Pancreatic involvement in AIDS is very important and common, but there are few studies in the literature concerning the pancreas in AIDS. Therefore, our research involves an important issue in the pancreatic field. The objective of the study was to evaluate the profile of HIV-infected patients with probable exocrine pancreatic insufficiency and its relation to the degree of human immunodeficiency virus (HIV) infection. This is a cross-sectional study carried out at Faculdade de Medicina do ABC in partnership with the basic health care unit Vila Guiomar in Santo André. We selected 118 individuals divided into four groups (a control group and three other groups composed of AIDS patients, separated according to CD4 levels); participants had an interview, completed a questionnaire, and had laboratory and imaging tests. The only clinical variables with significant differences among the studied groups were the use of highly active antiretroviral therapy (HAART), the incidence of opportunistic infections, the administration of chemoprophylaxis, and weight loss. There were no differences in the amylase, lipase, and steatocrit dosages among the groups. Levels of fecal elastase 1 were lower in the HIV patient groups (2, 3, and 4) when compared with the control group, although all of them showed average levels that were much higher than the cutoff point (200 μg/g). Only nonalcoholic individuals showed a relationship between diarrhea and alterations in elastase levels. A relationship between the use of HAART and exocrine pancreatic insufficiency in different phases of HIV infection could not be verified.

Pancreatic insufficiency in patients with HIV infection: role of didanosine questioned

OBJECTIVES

The aim of the study was to identify possible causes of pancreatic insufficiency in patients with HIV infection.

METHODS

A retrospective analysis of 233 HIV-positive patients for whom faecal elastase measurement was available was performed to investigate potential associations with core demographic data, HIV infection characteristics, degree of immunosuppresion, exposure to antiretroviral therapy (ART), alcohol misuse, diabetes, hepatitis C virus (HCV) infection, triglyceride and cholesterol levels and symptomatology. The response to pancreatic enzyme replacement for patients with evidence of insufficiency was also evaluated.

RESULTS

Of 233 patients, 104 (45%) had evidence of pancreatic exocrine insufficiency (faecal elastase < 200 mcg/g). A positive association with exocrine pancreatic insufficiency was found for HCV infection (P = 0.007), previous or current HCV treatment (P = 0.003), alcohol misuse history (P = 0.006) and the presence of steatorrhoea (P = 0.03). There was no demonstrated association between exocrine pancreatic insufficiency and didanosine (ddI) exposure (P = 0.43) or stavudine (d4T) exposure (P = 0.62). Seventy-seven per cent of patients who were treated with pancreatic enzymatic supplementation reported a subjective improvement in symptoms.

CONCLUSIONS

Faecal elastase sampling should form part of the routine work-up for HIV-positive patients with chronic diarrhoea even in the absence of 'traditional' risk factors such as ddI exposure. In particular, if the patient has steatorrhoea, a history of alcohol exposure or their HCV serology is positive, they should be considered for investigation. Treatment with pancreatic enzyme supplementation appears to be effective in the treatment of chronic diarrhoea caused by pancreatic insufficiency in the majority of patients.

Review: Management of postprandial diarrhea syndrome

Unexpected, urgent, sometimes painful bowel movements after eating are common complaints among adults. Without a clear etiology, if pain is present and resolves with the movements, this is usually labeled "irritable bowel syndrome-diarrhea" based solely on symptoms. If this symptom-based approach is applied exclusively, it may lead physicians not to consider treatable conditions: celiac disease, or maldigestion due to bile acid malabsorption, pancreatic exocrine insufficiency, or an a-glucosidase (sucrase, glucoamylase, maltase, or isomaltase) deficiency. These conditions can be misdiagnosed as irritable bowel syndrome-diarrhea (or functional diarrhea, if pain is not present). Limited testing is currently available to confirm these conditions (antibody screens for celiac disease; fecal fat as a surrogate marker for pancreatic function). Therefore, empirical treatment with alpha amylase, pancreatic enzymes, or a bile acid-binding agent may simultaneously treat these patients and serve as a surrogate diagnostic test. This review will summarize the current evidence for bile acid malabsorption, and deficiencies of pancreatic enzymes or a-glucosidases as potential causes for postprandial diarrhea, and provide an algorithm for treatment options.

The role of fecal elastase-1 in detecting exocrine pancreatic disease

Exocrine pancreatic disease is thought to be uncommon in clinical practice and usually secondary to excess alcohol intake. Although excess alcohol intake does account for many cases of exocrine pancreatic disease, other conditions are associated with exocrine pancreatic insufficiency and such dysfunction perhaps occurs more frequently than conventionally expected. A reliable, patient-friendly, cheap and easy to use test for exocrine pancreatic disease is yet to be established; however, in many countries the main (and often only available) method of assessment of exocrine pancreatic function is the fecal-elastase-1 test. This Review examines the role of fecal-elastase-1 testing in detecting exocrine pancreatic insufficiency in a number of gastrointestinal and nongastrointestinal conditions and determines the value of pancreatic enzyme supplementation in these settings.

Pilot study: a randomised, double blind, placebo controlled trial of pancrealipase for the treatment of postprandial irritable bowel syndrome-diarrhoea

OBJECTIVE: To evaluate the efficacy of pancrealipase (PEZ) compared with placebo in the reduction of postprandial irritable bowel syndrome-diarrhoea (IBS-D). DESIGN: An intention to treat, double blind, randomised, crossover trial comparing PEZ to placebo for reduction of postprandial IBS-D. Patients had to recognise at least two different triggering foods, be willing to consume six baseline 'trigger meals' and again blinded with PEZ and placebo. Patients then chose which drug they preferred for another 25 meals. SETTING: Outpatient internal medicine practice clinic. PATIENTS: 255 patients were screened; 83 met the criteria, including 5 years of symptoms, recognised 'food triggers', no other identifiable cause for the symptoms, either a normal colonoscopy or barium enema while symptomatic and able to discontinue all anticholinergic medications. 69 patients were enrolled, 20 withdrew before randomisation, leaving 49 patients: 14 men, 35 women, mean age 52 years (SD 15.3). Over 60% had experienced symptoms for 11-30 years and 16% for more than 40 years. INTERVENTIONS: After completing six baseline meals, patients were randomised in blocks of four to receive either identical PEZ or a placebo for another six meals, and after a washout period of time received the alternative drug. MAIN OUTCOME MEASURES: The primary analysis was number of patients who chose PEZ over placebo for the extended use. RESULTS: Overall, 30/49 (61%) would have chosen PEZ (p=0.078), with first drug preference for PEZ at 0.002. Among the PEZ subgroup, PEZ use compared with placebo, demonstrated improvement in all symptoms (p≤0.001) for cramping, bloating, borborygami, urge to defecate, global pain and decrease stooling with increase in stool firmness. CONCLUSIONS: PEZ was found in a small group of patients to reduce postprandial IBS-D symptoms and deserves further evaluation.

Management of pancreatic exocrine insufficiency: Australasian Pancreatic Club recommendations

Pancreatic exocrine insufficiency (PEI) occurs when the amounts of enzymes secreted into the duodenum in response to a meal are insufficient to maintain normal digestive processes. The main clinical consequence of PEI is fat maldigestion and malabsorption, resulting in steatorrhoea. Pancreatic exocrine function is commonly assessed by conducting a 3-day faecal fat test and by measuring levels of faecal elastase-1 and serum trypsinogen. Pancreatic enzyme replacement therapy is the mainstay of treatment for PEI. In adults, the initial recommended dose of pancreatic enzymes is 25,000 units of lipase per meal, titrating up to a maximum of 80,000 units of lipase per meal. In infants and children, the initial recommended dose of pancreatic enzymes is 500 units of lipase per gram of dietary fat; the maximum daily dose should not exceed 10,000 units of lipase per kilogram of bodyweight. Oral pancreatic enzymes should be taken with meals to ensure adequate mixing with the chyme. Adjunct therapy with acid-suppressing agents may be useful in patients who continue to experience symptoms of PEI despite high-dose enzyme therapy. A dietitian experienced in treating PEI should be involved in patient management. Dietary fat restriction is not recommended for patients with PEI. Patients with PEI should be encouraged to consume small, frequent meals and to abstain from alcohol. Medium-chain triglycerides do not provide any clear nutritional advantage over long-chain triglycerides, but can be trialled in patients who fail to gain or to maintain adequate bodyweight in order to increase energy intake.

Pancreatic insufficiency in adult celiac disease: do patients require long-term enzyme supplementation?

BACKGROUND

Celiac disease is associated with exocrine pancreatic insufficiency. We previously reported that in 30% (20/66) of adult celiac patients with current or persistent diarrhea the underlying cause was exocrine pancreatic insufficiency. Of these 20 patients, 19 initially improved on pancreatic supplementation. To date, there are no published longitudinal studies.

METHODS

The 20 patients who had initially received therapy for exocrine pancreatic insufficiency were prospectively followed-up for 4 years. Gastrointestinal symptoms, dietary adherence, celiac antibody status, and dose of enzyme supplementation were recorded. Fecal elastase-1 (Fel-1) was repeated to reassess exocrine pancreatic function.

RESULTS

In the study, 19/20 patients were reviewed, as one had died (mean age 59.7 years, 7 males). The mean duration of celiac disease was 13.2 years. Eleven out of nineteen were still taking enzyme supplementation at a mean dose of 45,000 units of lipase per day. Only 1/11 reported no symptomatic benefit and 8/19 patients had discontinued supplementation because their diarrhea had improved. In the whole group there was a significant increase in Fel-1 levels over time, with median values of 90 μg/g at 0 months, 212 μg/g at 6 months, and 365 μg/g at follow-up (45-66 months)(p < 0.0001).

CONCLUSIONS

Fecal elastase-1 is useful in identifying exocrine pancreatic insufficiency in adult celiac patients with diarrhea. Our longitudinal data suggests that pancreatic enzyme supplementation could be discontinued in a substantial proportion of patients as symptoms improve.

Some patients with irritable bowel syndrome may have exocrine pancreatic insufficiency

BACKGROUND & AIMS

Patients with irritable bowel syndrome (IBS) might have other underlying pathologies. Pancreatic disease can be elusive-especially in the early stages, and some symptoms overlap with those of IBS. We evaluated the prevalence of exocrine pancreatic insufficiency in diarrhea-predominant IBS (D-IBS) and assessed the effects of pancreatic enzyme supplementation.

METHODS

The study included patients who met the Rome II criteria for D-IBS, patients with chronic diarrhea, and subjects without diarrhea (controls). Subjects' baseline weight, stool frequency, stool consistency (using the Bristol score), and fecal elastase-1 (Fel-1) levels were determined. Patients were assessed using British Society of Gastroenterology IBS guidelines. Patients with Fel-1 levels less than 100 microg/g stool (indicating pancreatic exocrine insufficiency; group 1) were compared with age- and sex-matched patients with D-IBS and normal levels of Fel-1 (group 2), given pancreatic enzyme therapy, and reassessed at 12 weeks.

RESULTS

Fel-1 levels were less than 100 microg/g in stool from 19 of 314 patients with D-IBS (6.1%; 95% confidence interval [CI], 3.7%-9.3%), none of the 105 patients with chronic diarrhea (95% CI, 0.0%-3.5%), and none of 95 controls (95% CI, 0.0-3.8%) (P < .001). After enzyme supplementation, improvements in stool frequency (P < .001), stool consistency (P < .001), and abdominal pain (P = .003) were observed in patients in group 1, but not in group 2.

CONCLUSIONS

Pancreatic exocrine insufficiency was detected in 6.1% of patients who fulfilled the Rome II criteria for D-IBS. In these patients, pancreatic enzyme therapy might reduce diarrhea and abdominal pain. Pancreatic exocrine insufficiency should be considered in patients with D-IBS.

Validation of fecal elastase-1 determination using immunoenzymatic assay in HIV-infected patients

Pancreatic elastase-1 is a proteolytic enzyme exclusively produced in the pancreas, is stable when passing through the bowel, and its determination is associated with chronic pancreatitis. The clinical diagnosis of pancreatitis is based on anamnesis, physical examination, radiological, sonographic, endoscopic, and laboratory findings. Nowadays, there is a test for the determination of fecal elastase-1, by enzymatic reaction (enzyme-linked immunosorbent assay, ELISA), which specifically determines human elastase-1, promoting the pancreatic function evaluation. Parameters such as linearity, calibration curve, sensitivity, specificity, precision, accuracy, recovery, and receiver operator characteristic (ROC) curve are used to evaluate the test. The aim of this study was the validation of the immunoenzymatic assay (ELISA) and the use of its results in patients with HIV, alcoholics, and under antiretroviral therapy. The study involved 157 patients, 95 of them were HIV-infected, and 62 were completely healthy. The elastase-1 ELISA kit from Bioserv was used, and we noted that the obtained results were linear, sensitive, precise, and accurate. Moreover, our results suggest that this test can be a laboratory evaluation to determine the relationship of pancreatitis with alcohol use, but not its association with antiretroviral use in HIV patients (P=0.424). This test is useful to diagnose pathologies related to pancreatic insufficiency.

Is exocrine pancreatic insufficiency in adult coeliac disease a cause of persisting symptoms?

BACKGROUND

Patients with coeliac disease may have diarrhoea despite being on a gluten-free diet.

AIM

To assess whether exocrine pancreatic insufficiency causes persisting symptoms compared with controls, we determined whether pancreatic enzyme supplementation provided symptomatic benefit in coeliac patients with chronic diarrhoea.

METHODS

Patients (n = 259) were subdivided into four groups: (a) new coeliac disease (n = 57), (b) coeliac disease patients on a gluten-free diet without gastrointestinal symptoms (n = 86), (c) coeliac disease patients on a gluten-free diet with chronic diarrhoea (n = 66) and (d) patients with chronic diarrhoea without coeliac disease (n = 50). Stool frequency and weight, before and after treatment with pancreatic enzyme supplementation were recorded.

RESULTS

The prevalence of a low faecal elastase-1 within the groups was: group (A) six of 57 (11%), group (B) five of 86 (6%), group (C) 20 of 66 (30%) and group (D) two of 50 (4%). Low faecal elastase-1 was more frequent in coeliac disease patients with chronic diarrhoea vs. other subgroups of coeliac disease (P < or = 0.0001) and controls (P < or = 0.0003). In 18 of 20 stool frequency reduced following pancreatic enzyme supplementation from four per day to one (P < or = 0.001). No weight increase (P = 0.3) was observed.

CONCLUSIONS

Low faecal elastase is common in patients with coeliac disease and chronic diarrhoea, suggesting exocrine pancreatic insufficiency. In this group of patients, pancreatic enzyme supplementation may provide symptomatic benefit.

Counteracting muscle wasting in HIV-infected individuals

HIV-infected persons often experience a loss of lean tissue mass, which includes decreases in skeletal muscle mass. This HIV-associated wasting is significant because it has been associated with accelerated disease progression and increased morbidity. Signalling related to several circulating molecules, including tumour necrosis factor (TNF)-alpha, growth hormone, insulin-like growth factor (IGF)-1 and testosterone, has been associated with the aetiology of muscle wasting. Additionally, nutritional status related to malnutrition and specific dietary deficiencies may be involved. In an attempt to counter muscle wasting in HIV-infected persons, treatments have been suggested that target these mechanisms. Nutritional supplementation, cytokine reduction, hormone therapy and resistance exercise training are potential treatments for this condition. Resistance exercise training, which is more easily accessible to this population than other treatments, holds promise in counteracting the process of HIV wasting, as it has been successfully used to increase lean tissue mass in healthy and clinical populations. This review will explore the HIV/AIDS muscle-wasting syndrome, its aetiology, and the treatments used to counteract wasting.

Management of gastrointestinal disorders in children with HIV infection

A double scenario characterizes the epidemiology of HIV infection in children. In countries where highly active antiretroviral therapy (HAART) is available, the pattern of HIV infection is evolving into that of a chronic disease, for which control strictly depends on patients' adherence to treatment. In developing countries with no or limited access to HAART, AIDS is rapidly expanding and is loaded with a high fatality ratio, due to the combined effects of malnutrition and opportunistic infections. The digestive tract is a target of the disease in both settings. Opportunistic infections play a major role in children with severe immune impairment, with Cryptosporidium parvum being the leading agent of severe diarrhea. Several therapeutic approaches are effective in reducing fecal output, but the eradication of the parasite is rarely obtained. Other opportunistic infections may induce severe and protracted diarrhea, including atypical mycobacteria and cytomegalovirus. Diagnosis of diarrhea should be individually tailored based on presenting symptoms and risk factors. A stepwise approach is effective in limiting patient discomfort and minimizing the costs of investigations, starting with microbiologic investigation and proceeding with endoscopy and histology. Aggressive treatment of infectious diarrhea is required in severely immunocompromised children. However, antiretroviral therapy prevents the development of severe cryptosporidiosis. The liver and pancreas are also target organs in HIV infection, although functional failure is rare. The digestive-absorptive functions are impaired, with steatorrhea, nutrient malabsorption, and increased permeability occurring in 20-70% of children. Intestinal dysfunction contributes to growth failure and further immune derangement, leading to wasting, the terminal stage of AIDS. Nutritional management is crucial in HIV-infected children and is based on aggressive nutritional rehabilitation through enteral or parenteral routes and micronutrient supplementation.HIV may play a direct enteropathogenic role and is implicated in both diarrhea and intestinal dysfunction. This explains the efficacy of antiretroviral therapy in inducing remission of diarrhea and restoring intestinal function. Gastrointestinal side effects of antiretroviral drugs are increasingly observed; they are often mild and transient. Severe reactions are rare but require the withdrawal of drugs. In conclusion, severe enteric infections and intestinal dysfunction characterize the intestinal involvement of HIV infection. This is more common in, but not limited to, children who do not receive effective antiretroviral therapy. Diagnostic approaches include microbiologic and morphologic examinations and assessment of digestive processes, but immunologic and virologic data should be also carefully considered. Treatment is based upon specific anti-infectious drugs, antiretroviral therapy, and nutritional rehabilitation.

Pancreatic exocrine insufficiency in HIV-positive patients

OBJECTIVES

We describe the management of a cohort of eight HIV-positive patients on antiretroviral medication with evidence of pancreatic insufficiency consisting of chronic diarrhoea and a low faecal elastase measurement.

PATIENTS AND METHODS

Twenty-two patients with chronic diarrhoea for whom a faecal elastase measurement was available were identified retrospectively. We compared baseline demographic characteristics, antiretroviral treatment and symptoms of steatorrhea between patients with evidence of pancreatic insufficiency, i.e. a low faecal elastase measurement of <200 microg/g (cases), and patients with evidence of normal pancreatic function, i.e. a normal faecal elastase measurement of >200 microg/g (controls). We describe the management of the patients with evidence of pancreatic insufficiency.

RESULTS

Of the 22 patients, eight had evidence of pancreatic insufficiency, i.e. a low faecal elastase measurement. Comparing cases with controls, cases were more likely to have symptoms of steatorrhea (P=0.03) or to have lost weight (P=0.02). Cases were also significantly more likely to have taken didanosine (ddI) as part of their antiretroviral treatment when their symptoms started. Seven cases were treated with oral pancreatic supplements and all had symptomatic improvement of their diarrhoea. One patient stopped treatment with oral pancreatic supplements because of side effects without a relapse of symptoms; he had also stopped zalcitabine (ddC).

CONCLUSIONS

We believe that measurement of faecal elastase to detect pancreatic insufficiency should be part of the standard investigation of HIV-positive patients with chronic diarrhoea alongside assessment for other causes of diarrhoea. Faecal elastase measurements should be requested, in particular, in all patients with diarrhoea and weight loss, or symptoms of steatorrhea, and in those on treatment with an antiretroviral regime containing ddI. If the faecal elastase level is low, a switch of antiretroviral medication to a nonddI/ddC-containing regime should be considered and treatment with oral pancreatic enzyme therapy should be instituted.

The enzyme as drug: application of enzymes as pharmaceuticals

Enzymes as drugs have two important features that distinguish them from all other types of drugs. First, enzymes often bind and act on their targets with great affinity and specificity. Second, enzymes are catalytic and convert multiple target molecules to the desired products. These two features make enzymes specific and potent drugs that can accomplish therapeutic biochemistry in the body that small molecules cannot. These characteristics have resulted in the development of many enzyme drugs for a wide range of disorders.

Ultrastructural study of the pancreas in AIDS

INTRODUCTION

Frequent histologic changes (90%) in the pancreas suggesting protein-energy malnutrition were found in a previous necropsy study of pancreas morphology in patients with AIDS. However, additional studies were required to clarify subcellular changes.

AIM

To ultrastructurally analyze pancreas changes in AIDS patients through transmission electron microscopy.

METHODOLOGY AND RESULTS

Pancreas specimens for necropsy were obtained from nine consecutive AIDS patients and four normal controls. A semiquantitative histologic and ultrastructural analysis of exocrine pancreas was carried out with the following findings: preserved pancreas structure with little autolysis, marked decrease in zymogen granules (100%), increased lipofuscin pigment (80%), augmented and dilated rough endoplasmic reticulum (100%), and increased number and size of mitochondria. The Golgi complex could be identified only in two cases. In all cases, acinar nuclei were decreased in size, with peripherally condensed chromatin and undulated membrane suggesting early apoptosis. In addition, immunohistochemical evaluation of the pancreas was carried out to detect opportunistic agents.

CONCLUSION

Decreased zymogen granules, acinar atrophy, increased lipofuscin pigment, and rarefying Golgi complex represent the morphologic substrate of protein-energy malnutrition in AIDS patients. The combination of rough endoplasmic reticulum and mitochondria changes could be due to the need for supplying vital plasma proteins rather than exportation protein synthesis associated, or not, with the deleterious effects of inflammatory cytokines and/or therapy for disease.