Successful pregnancies after transplantation of ovarian tissue retrieved and cryopreserved at time of childhood acute lymphoblastic leukemia - A case report

Not available.

A Prospective Study on Fertility Preservation in Prepubertal and Adolescent Girls Undergoing Hematological Stem Cell Transplantation

Background

Hematological stem cell transplantation (HSCT) is an established method which has markedly increased the survival rate of hematologic malignancies since its introduction in the 1980’s. The conditioning for HSCT has known gonadotoxic effects and often leads to premature loss of fertility. In this study we have prospectively followed a cohort of girls undergoing HSCT and studied the outcomes of fertility preservation treatments performed before or after HSCT, as well as the long-term reproductive outcome.

Methods

In this one-center prospective study, 39 girls counselled for fertility preservation prior to or after conditioning for HSCT for malignant or benign diseases at childhood or adolescence between 1990 and 2017 were included. The patients were presented with the option to undergo cryopreservation of ovarian tissue or oocytes depending on their age and the time available. Follicle counts of the ovarian tissue and number of oocytes collected before or after HSCT were compared between patients treated for benign and malignant diseases. Hormone measurements post HSCT treatment, including FSH and AMH, reproductive outcomes and overall survival until January 2021 were investigated.

Results

In total, 34 girls and adolescents underwent fertility preservation before or after HSCT. Before HSCT, ovarian tissue was cryopreserved in 15 patients and two patients had oocytes preserved. Thirteen patients cryopreserved ovarian tissue after HSCT and seven patients returned to cryopreserve oocytes. Follicles were present in all tissue samples collected prior to HSCT, and in more than half of the samples collected post-HSCT. Half of the patients had spontaneous menarche or resumed menstruation post HSCT. Overall, 35 patients had survived at end of follow up and 7 patients had achieved parenthood.

Conclusions

Since fertility loss is common following HSCT, fertility preservation should be offered to all patients. Fertility preservation treatments can be performed both before and after HSCT.

Clinical Trial Registration

https://clinicaltrials.gov/show/NCT04602962, identifier NTC04602962

Hot Topics on Fertility Preservation for Women and Girls-Current Research, Knowledge Gaps, and Future Possibilities

Fertility preservation is a novel clinical discipline aiming to protect the fertility potential of young adults and children at risk of infertility. The field is evolving quickly, enriched by advances in assisted reproductive technologies and cryopreservation methods, in addition to surgical developments. The best-characterized target group for fertility preservation is the patient population diagnosed with cancer at a young age since the bulk of the data indicates that the gonadotoxicity inherent to most cancer treatments induces iatrogenic infertility. Since improvements in cancer therapy have resulted in increasing numbers of long-term survivors, survivorship issues and the negative impact of infertility on the quality of life have come to the front line. These facts are reflected in an increasing number of scientific publications referring to clinical medicine and research in the field of fertility preservation. Cryopreservation of gametes, embryos, and gonadal tissue has achieved quality standards for clinical use, with the retrieval of gonadal tissue for cryopreservation being currently the only method feasible in prepubertal children. Additionally, the indications for fertility preservation beyond cancer are also increasing since a number of benign diseases and chronic conditions either require gonadotoxic treatments or are associated with premature follicle depletion. There are many remaining challenges, and current research encompasses clinical health care and caring sciences, ethics, societal, epidemiological, experimental studies, etc.

Chondrodysplasia and growth failure in children after early hematopoietic stem cell transplantation for non-oncologic disorders

Bone dysplasias (osteochondrodysplasias) are a large group of conditions associated with short stature, skeletal disproportion, and radiographic abnormalities of skeletal elements. Nearly all are genetic in origin. We report a series of seven children with similar findings of chondrodysplasia and growth failure following early hematopoietic stem cell transplantation (HSCT) for pediatric non-oncologic disease: hemophagocytic lymphohistiocytosis or HLH (five children, three with biallelic HLH-associated variants [in PRF1 and UNC13D] and one with HLH secondary to visceral Leishmaniasis), one child with severe combined immunodeficiency and one with Omenn syndrome (both children had biallelic RAG1 pathogenic variants). All children had normal growth and no sign of chondrodysplasia at birth and prior to their primary disease. After HSCT, all children developed growth failure, with standard deviation scores for height at or below -3. Radiographically, all children had changes in the spine, metaphyses and epiphyses, compatible with a spondyloepimetaphyseal dysplasia. Genomic sequencing failed to detect pathogenic variants in genes associated with osteochondrodysplasias. We propose that such chondrodysplasia with growth failure is a novel, rare, but clinically important complication following early HSCT for non-oncologic pediatric diseases. The pathogenesis is unknown but could possibly involve loss or perturbation of the cartilage-bone stem cell population.

A prospective study on the long-term outcome of prepubertal and pubertal boys undergoing testicular biopsy for fertility preservation prior to hematologic stem cell transplantation

BACKGROUND

Few studies have reported the long-term outcomes of prepubertal and pubertal boys undergoing testicular biopsy for fertility preservation (FP).

PROCEDURE

This prospective longitudinal study examined 21 boys (aged 1.5-14.5 years) who underwent testicular biopsy for FP prior to allogeneic (n = 20) or autologous (n = 1) hematological stem cell transplantation (HSCT) between 2003 and 2010. During counseling, pubertal boys were encouraged to produce a sperm sample by masturbation , while prepubertal boys were presented with surgical testicular tissue retrieval as an option for experimental FP. Clinical outcomes included postoperative complications, pubertal development, and sex-hormone levels. Survivors approaching adulthood were encouraged to provide semen samples.

RESULTS

Twenty boys, including 14 in prepuberty and six in early puberty (Tanner stage 2-3), underwent open testicular biopsies. Two pubertal biopsies contained mature sperms, which were cryopreserved. Testicular tissue was vitrified in the remaining 18 cases. One pubertal boy (Tanner stage 4) underwent percutaneous testicular sperm aspiration and sperms obtained were cryopreserved. Postoperative complications (hematoma or infection) were rare. Overall, 14 boys survived >5 years (mean follow-up after HSCT, 7.2 years) and 11 showed advanced puberty. Semen samples were provided by five boys and obtained sperm were cryopreserved from two. Individuals at adulthood had normal testosterone levels but subnormal testicular size, high follicle stimulating hormone, and low inhibin B and anti-Müllerian hormone levels.

CONCLUSION

No long-term risks were detected during continuous clinical follow-up. Experimental testicular biopsies for FP were well accepted by the patients and families, despite the absence of methods to use prepubertal tissue for fertility treatment.

Fertility preservation for young adults, adolescents, and children with cancer

Options for fertility preservation (FP) through cryopreservation methods are currently available for young adults, adolescents, and children. Guidelines for FP have been provided by international clinical societies, and emergency procedures aimed at FP have been implemented into clinical practice worldwide. In this article, we review the current data on clinical standards of emergency FP in patients who are facing gonadotoxic effects of cancer treatment, and we also describe the methods that are still under development, usually denoted as experimental. In Sweden, programmes for FP have been established at large university hospitals, thus covering the whole country. The Swedish publicly financed health care covers both assisted reproduction for treatment of infertility and the cryopreservation of gametes or gonadal tissue when there is a medical indication, such as the risk to become infertile due to oncologic treatment; hence the access to FP is ensured for the whole population. At our centre at Karolinska University Hospital in Stockholm, methods for FP have been offered since 1988. In this article, we also review the oncologic indications for FP in our patient cohort of >3000 individuals during the period 1988-2018.

A prospective study of women and girls undergoing fertility preservation due to oncologic and non-oncologic indications in Sweden-Trends in patients' choices and benefit of the chosen methods after long-term follow up

INTRODUCTION

In Scandinavian countries, programs for fertility preservation are offered free of charge at tertiary-care university hospitals to all patients facing treatments with risk of subsequent sterility. In this prospective study we aimed to investigate trends in female patients' choices after counseling and fertility preservation outcomes during follow up in relation to benign vs malignant indications.

MATERIAL AND METHODS

Data on 1254 females including 1076 adults and 178 girls who received fertility preservation counseling for either oncologic (n = 852) or benign indications (n = 402) at Karolinska University Hospital, Stockholm, between 1 October 1998 and 1 December 2018 were analyzed. As appropriate, t tests and chi-square tests were used to compare groups. Logistic regression was used to compare outcomes among groups depending on indications.

RESULTS

Adult women generally elected to undergo oocyte retrieval after controlled ovarian stimulation for cryopreservation of embryos or oocytes (n = 538, 73%), whereas a minor proportion opted for cryopreservation of ovarian tissue retrieved through laparoscopy (n = 221, 27%). More than half of the women with a partner chose either not to fertilize their oocytes aiming at cryopreservation of oocytes or to share obtained oocytes attempting both cryopreservation of oocytes and cryopreservation of embryos. All pre-pubertal (n = 48) and 73% of post-pubertal girls (n = 66) elected cryopreservation of ovarian tissue. In recent years, an increasing number of teenagers have opted for controlled ovarian stimulation aiming at cryopreservation of oocytes, either before (n = 24, 17%) or after completion of cancer treatment (n = 15, 10%). During follow up, 27% of the women returned for a new reproductive counseling, additional fertility preservation or to attempt pregnancy. Utilization rates among individuals who were alive and of childbearing age by December 2018 indicated 29%, 8% and 5% for embryos, oocytes and ovarian tissue with live birth rates of 54%, 46% and 7%, respectively. Women with benign indications were significantly younger than women with previous malignant indications at the time of attempting pregnancy. Although the pregnancy rates were similar among both groups, the live birth rate was significantly higher in women with benign vs previous malignant indications (47% vs 21%, P = .002).

CONCLUSIONS

Trends in fertility preservation choices have changed over time. Women with previous malignancy had lower live birth rates than women with benign fertility preservation indications.

Cancer Risks in Patients Treated With Growth Hormone in Childhood: The SAGhE European Cohort Study

CONTEXT

Growth hormone (GH) is prescribed for an increasing range of indications, but there has been concern that it might raise cancer risk. Published data are limited.

OBJECTIVE

To examine cancer risks in relation to GH treatment.

DESIGN

Cohort study.

SETTING

Population-based.

PATIENTS

Cohort of 23,984 patients treated with recombinant human GH (r-hGH) in eight European countries since this treatment was first used in 1984. Cancer expectations from country-specific national population statistics.

MAIN OUTCOME MEASURES

Cancer incidence and cancer mortality.

RESULTS

Incidence and mortality risks in the cohort were raised for several cancer sites, largely consequent on second primary malignancies in patients given r-hGH after cancer treatment. There was no clear raised risk in patients with growth failure without other major disease. Only for bone and bladder cancers was incidence significantly raised in GH-treated patients without previous cancer. Cancer risk was unrelated to duration or cumulative dose of r-hGH treatment, but for patients treated after previous cancer, cancer mortality risk increased significantly with increasing daily r-hGH dose (P trend < 0.001). Hodgkin lymphoma (HL) incidence increased significantly with longer follow-up (P trend = 0.001 for patients overall and 0.002 for patients without previous cancer).

CONCLUSIONS

Our results do not generally support a carcinogenic effect of r-hGH, but the unexplained trend in cancer mortality risk in relation to GH dose in patients with previous cancer, and the indication of possible effects on bone cancer, bladder cancer, and HL risks, need further investigation.

Adult testicular volume predicts spermatogenetic recovery after allogeneic HSCT in childhood and adolescence

BACKGROUND

Testicular dysfunction and infertility are of major concern in long-term survivors after allogeneic hematopoietic stem cell transplantation (HSCT). This study assesses predictive factors for very long-term testicular recovery after allogeneic HSCT in childhood and adolescence.

PROCEDURE

Testicular volume, sperm production and long-term need of testosterone substitution were evaluated among 106 male survivors transplanted at Huddinge and Helsinki University Hospitals from 1978 through 2000, at a mean age of 8 ± 4.6 years (range 1-17). A mean ± SD of 13 ± 4.8 years (range 4-28) had elapsed since their HSCT and the mean age of the participants was 22 ± 6.0 years (range 12-42). An adult testicular volume was recorded in 74 patients at a mean age of 19 ± 3.3 years (range 14-36).

RESULTS

Recipients conditioned with busulfan-based regimens or regimens containing only cyclophosphamide had significantly larger adult testicular volumes (mean volume 18 ml and 16 ml vs. 9 ml, P < 0.00001, respectively) and lower serum levels of FSH (mean 9 IU and 5 IU vs. 19 IU, P < 0.01 and 0.001, respectively) compared to those conditioned with total body irradiation (TBI). Multivariate analysis demonstrated that a non-leukemia diagnosis (P < 0.01) and adult testicular volume ≥ 15 ml (P < 0.03) positively impacted spermatogenetic recovery.

CONCLUSIONS

A larger adult testicular volume, normal serum levels of FSH and spermatozoa detected in a majority of seminal fluids after busulfan-based or cyclophosphamide conditionings suggest very long-term recovery of spermatogenesis after chemotherapy-based regimens. A simple measurement of adult testicular volume may help predict spermatogenetic potential among pediatric HSCT survivors.

Ovarian function after allogeneic hematopoietic stem cell transplantation in childhood and adolescence

OBJECTIVE

The aim of the study was to evaluate long-term ovarian function after allogeneic hematopoietic stem cell transplantation (HSCT) in childhood and adolescence.

SUBJECTS AND METHODS

Predictive factors for ovarian function were evaluated among 92 adult or pubertal female survivors transplanted at Huddinge and Helsinki University Hospital during 1978-2000, at a mean age of 9±4.3 years (range 1-19). At the time of the study a mean±s.d. of 13±5.5 years (range 6-27) had elapsed since the HSCT and the mean age of the participants was 22±6.3 years (range 9-41).

RESULTS

Spontaneous puberty based on breast development occurred in 40 and menarche in 30 of the 70 girls who were prepubertal at transplantation. Six out of 20 girls who received HSCT after initiation of pubertal development recovered their ovarian function. Younger age at HSCT, conditioning without total body irradiation (TBI), and a non-leukemia diagnosis predicted the spontaneous menarche. The incidence of menarche was higher after fractioned vs single fraction TBI (P<0.05), cyclophosphamide (Cy) vs busulfan (Bu)-based conditioning (P<0.05), and among leukemia patients transplanted at first remission vs later remissions (P<0.01) and with no cranial irradiation (cranial radiotherapy, CRT) vs given CRT (14-24 Gy) (P<0.01). The majority of recipients conditioned with only Cy vs TBI (P<0.001) or vs Bu-based regimens (P<0.01) showed preserved ovarian function and required no estrogen replacement at their latest follow-up visit at a mean age of 23±6.3 years (range 15-41). Ten women became pregnant.

CONCLUSIONS

Patients conditioned with TBI or Bu-based regimes are at high risk of ovarian failure. Intensive anti-leukemia therapy before HSCT including CRT especially among relapsed patients may further decrease the possibility of spontaneous menarche.

Long-term mortality and causes of death in isolated GHD, ISS, and SGA patients treated with recombinant growth hormone during childhood in Belgium, The Netherlands, and Sweden: preliminary report of 3 countries participating in the EU SAGhE study

CONTEXT

The long-term mortality in adults treated with recombinant GH during childhood has been poorly investigated. Recently released data from the French part of the European Union Safety and Appropriateness of GH treatments in Europe (EU SAGhE) study have raised concerns on the long-term safety of GH treatment.

OBJECTIVE

To report preliminary data on long-term vital status and causes of death in patients with isolated GH deficiency or idiopathic short stature or born small for gestational age treated with GH during childhood, in Belgium, The Netherlands, and Sweden.

DESIGN

Data were retrieved from national registries of GH-treated patients and vital status from National Population Registries. Causes of death were retrieved from a National Cause of Death Register (Sweden), Federal and Regional Death Registries (Belgium), or individual patient records (The Netherlands).

PATIENTS

All patients diagnosed with isolated GH deficiency or idiopathic short stature or born small for gestational age started on recombinant GH during childhood from 1985-1997 and who had attained 18 yr of age by the end of 2010 were included. Vital status was available for approximately 98% of these 2,543 patients, corresponding to 46,556 person-years of observation.

MAIN OUTCOME MEASURE

Vital status, causes of death, age at death, year of death, duration of GH treatment, and mean GH dose during treatment were assessed.

RESULTS

Among 21 deaths identified, 12 were due to accidents, four were suicides, and one patient each died from pneumonia, endocrine dysfunction, primary cardiomyopathy, deficiency of humoral immunity, and coagulation defect.

CONCLUSIONS

In these cohorts, the majority of deaths (76%) were caused by accidents or suicides. Importantly, none of the patients died from cancer or from a cardiovascular disease.

Fertility preservation in girls with turner syndrome: prognostic signs of the presence of ovarian follicles

CONTEXT

Many girls with Turner syndrome have follicles in their ovaries at adolescence.

OBJECTIVE

Our objective was to study which girls might benefit from ovarian tissue freezing for fertility preservation.

DESIGN

Clinical and laboratory parameters and ovarian follicle counts were analyzed among girls referred by 25 pediatric endocrinologists.

SUBJECTS AND SETTING

Fifty-seven girls with Turner syndrome, aged 8-19.8 yr, were studied at a university hospital.

INTERVENTIONS

Ovarian tissue was biopsied laparoscopically, studied for the presence of follicles, and cryopreserved. Blood samples were drawn for hormone measurements.

MAIN OUTCOME MEASURES

Presence of follicles in the biopsied tissue related to age, signs of spontaneous puberty, karyotype, and serum concentrations of gonadotropins and anti-Müllerian hormone were assessed.

RESULTS

Ovarian biopsy was feasible in 47 of the 57 girls. In 15 of the 57 girls (26%), there were follicles in the tissue piece analyzed histologically. Six of seven girls (86%) with mosaicism, six of 22 (27%) with structural chromosomal abnormalities, and three of 28 with karyotype 45X (10.7%) had follicles. Eight of the 13 girls (62%) with spontaneous menarche had follicles, and 11 of the 19 girls (58%) who had signs of spontaneous puberty had follicles. The age group 12-16 yr had the highest proportion of girls with follicles. Normal FSH and anti-Müllerian hormone concentrations for age and pubertal stage were more frequent in girls with follicles.

CONCLUSIONS

Signs of spontaneous puberty, mosaicism, and normal hormone concentrations were positive and statistically significant but not exclusive prognostic factors as regards finding follicles.

Outcome in six children with mucopolysaccharidosis type IH, Hurler syndrome, after haematopoietic stem cell transplantation (HSCT)

AIM

To follow-up six children with severe mucopolysaccharidosis type IH, Hurler syndrome, who were treated before 24 months of age with haematopoietic stem cell transplantation.

METHODS

In Sweden, during the last 10-year period, six consecutive children born with severe mucopolysaccharidoses type IH have been successfully transplanted using matched unrelated donors between the ages of 11 and 24 months (mean age 18 months). Three children received intravenous enzyme replacement therapy once a week, from diagnosis until engraftment of their bone marrow.

RESULT

Two children developed chimerism and a progressive increase in recipient cells and later received a successful re-transplantation. One to two years after transplantation the children demonstrated some developmental delays in cognitive function. Latterly this was followed by normalization. Orthopaedic operations on the spine and hips and carpal tunnel syndrome were still required following transplantation. Cardiac valve involvement remained progressive in the children.

CONCLUSION

The outcome of six children in this study confirms that early haematopoietic stem cell transplantation in mucopolysaccharidosis type I, Hurler syndrome, preserves an affected child's mental ability. Consequently, it is essential that clinical recognition and early diagnosis take place, providing an additional challenge to paediatricians treating this condition.

Intramuscular autotransplantation of pancreatic islets in a 7-year-old child: a 2-year follow-up

A 7-year-old girl with severe hereditary pancreatitis underwent total pancreatectomy. A total of 160,000 islet equivalents (6400 islet/kg) were transplanted to the brachioradialis muscle of the right forearm. Her plasma C-peptide level was undetectable after pancreatectomy but increased to 1.37 ng/mL after 17 days; at this time point, her insulin requirement was 0.75 units of insulin/kg/day. At 5- and 27-months, her hemoglobin A1c (HbA1c) and insulin requirements were 4.5 and 5.3% and 0.3 and 0.18 units/kg/day, respectively. Basal and stimulated C-peptide levels were 0.67 +/- 0.07 and 3.36 +/- 1.37 ng/mL, respectively. Stimulated insulin levels were 30% higher in the islet-bearing arm compared to the contralateral arm after glucagon stimulation. After surgery and islet transplantation, the quality of life improved dramatically and she gained 8 kg of weight. In summary, a normal HbA1c, a low insulin requirement and the absence of recurrent hypoglycemia and the gradient of insulin between the arms indicate that the intramuscularly transplanted islets contribute to a long-term clinically significant metabolic control.

Methods of cryopreservation of testicular tissue with viable spermatogonia in pre-pubertal boys undergoing gonadotoxic cancer treatment

BACKGROUND

Banking of testicular tissue from pre-pubertal boys before gonadotoxic treatment is a crucial step in fertility preservation. We wanted to find optimal methods for cryopreservation of testicular tissue from pre-pubertal boys, modifying techniques developed for fetal and adult human testicular tissue cryopreservation.

METHODS

Testicular tissue was collected from five pre-pubertal boys undergoing gonadotoxic treatment in a clinical programme. Two freezing protocols, originally developed for fetal and adult human testicular tissue, were applied for pre-pubertal testicular tissue cryopreservation. In both methods, 5% dimethyl sulphoxide (DMSO) was used as a cryoprotectant. The integrity of the tissue was investigated in non-frozen tissue cultured for 24 h and in cryopreserved-thawed tissue, using two different programmes. We also analysed frozen-thawed samples cultured for 24 h in comparison with untreated fresh fixed control tissue. Immunohistochemical analysis using anti-MAGE-A4, vimentin and CD34 monoclonal antibodies was performed in order to visualize and characterize the cryodamage of the different testicular cells and compartments. The structure of the tissue was evaluated using light microscopy. Qualitative control analysis was performed using transmission electron microscopy.

RESULTS

No clear structural changes were observed in the fresh, fresh cultured and cryopreserved testicular tissue after using the protocol developed for adult testicular tissue. The programme earlier successfully used for human fetal testicular tissue cryopreservation caused more tissue damage.

CONCLUSIONS

Pre-pubertal testicular tissue from boys facing gonadotoxic treatment survives cryopreservation, can be cryobanked and hopefully used for fertility preservation. Slow programmed freezing with DMSO as a cryoprotectant is efficient in maintaining the spermatogonia, Sertoli cells and stromal compartment during freezing, thawing and tissue culture.

[Somatic complications of anorexia nervosa in children and adolescents. Prognosis is good if the patient achieves normal weight within a couple of years]

This article presents an overview of somatic complications in anorexia nervosa in children and adolescents. Cardiovascular-, gastrointestinal-, and endocrine- complications are often observed as a consequence of starvation in anorexia nervosa, Prolongation of QT interval can cause fatal arrhythmias. Checking levels of serum electrolytes, phosphate and magnesium daily during initial phase of refeeding is necessary to avoid the Refeeding syndrome. The activity of the thyroid gland and the gonads is depressed. The patients will remain or return to a prepubertal status with poor growth and low levels of sex hormones. This, in addition to low IGF-I, low adrenal androgens and lack of energy, may result in subnormal development of bone density. If anorexia nervosa starts early in life and continues for many years there will not be a full recovery, resulting in osteoporosis and a decrease of final height. The other complications however have a good prognosis when food intake is normalised.

Growth Hormone Induces Low-Density Lipoprotein Clearance but not Bile Acid Synthesis in Humans

OBJECTIVE

Growth hormone (GH) induces hepatic low-density lipoprotein (LDL) receptors and lowers plasma cholesterol. We characterized the influence of GH treatment on plasma LDL clearance in normal humans and investigated the relative role of LDL receptor (LDLR) activity and stimulation of bile acid synthesis in subjects with different LDLR expression.

METHODS AND RESULTS

Plasma clearance of autologous 125I-LDL was measured before and during 3 weeks of treatment with GH (0.1 IU/kg per day) in 9 healthy young males. Plasma LDL cholesterol was reduced by 13% and the fractional catabolic rate of LDL increased by 27%. More marked changes were seen in a patient with hypopituitarism substituted with GH (0.07 IU/kg per day) for 3 months. In a second study, GH dose-dependently reduced LDL cholesterol and increased Lp(a) levels in 3 groups of males: younger and elderly healthy subjects and heterozygous familial hypercholesterolemia (FH). No effect on bile acid synthesis measured by the plasma marker 7alpha-hydroxy-4-cholesten-3-one was observed. In an LDLR-deficient FH homozygote, LDL cholesterol was not affected by GH.

CONCLUSIONS

GH treatment reduces plasma LDL cholesterol by inducing LDL clearance. In humans, LDLR expression is a prerequisite for this effect, whereas it is not related to stimulation of bile acid synthesis.

Follicles are found in the ovaries of adolescent girls with Turner's syndrome

Infertility caused by ovarian failure is a characteristic feature in Turner's syndrome. Spontaneous pregnancies are seen in 2-5% of these women, and up to 30% have at least some pubertal development, indicating the presence of follicles in their ovaries in adolescence. It has not been clear at which age the follicles disappear. We analyzed the numbers and densities of follicles in ovarian cortical tissue from nine adolescent girls with Turner's syndrome who came to our clinics after having been informed about the study, with an aim to preserve ovarian tissue for possible infertility treatment later in life. A quarter to one whole ovary was laparoscopically removed for the procedure. Follicles were seen in the biopsy tissue in eight of nine subjects from whom ovarian tissue was laparoscopically obtained, the highest numbers being seen in the youngest girls and in those with mosaicism. In one 17-yr-old girl, no ovarian tissue was found. Follicle density was correlated with serum levels of FSH; individuals with the lowest FSH levels had the highest follicle density. One to 190 follicles were counted in the approximately 0.1-2.0 mm(3) of tissue analyzed, giving a density of 1.5-499 follicles/mm(3) of ovarian cortical tissue. Girls up to the age of 17 had primordial follicles in their ovaries. Three girls, two aged 15 yr and one aged 19, had only secondary follicles, with many being atretic. Our finding that adolescent girls with Turner's syndrome still have follicles in their ovarian cortical tissue raises the possibility of future fertility through cryopreservation of ovarian tissue. However, before such procedures can be recommended for clinical management, it is essential that future studies be performed to determine whether the oocytes retrieved from girls with Turner's syndrome have a normal chromosomal complement.

Cataract in children after bone marrow transplantation: relation to conditioning regimen

PURPOSE

To compare the frequency of cataract development in bone marrow transplanted children who have been given either total body irradiation (TBI) or busulphan as conditioning treatment before bone marrow transplantation (BMT).

MATERIAL AND METHODS

Forty-five children who underwent BMT between 1987 and 1994 were included in the study. Twenty-one children were conditioned with TBI and 24 with busulphan before BMT. All children underwent an ophthalmic examination before BMT in order to exclude lens opacities. Yearly examinations for 2-10 years were performed after BMT.

RESULTS

Cataracts developed in 20 of the 21 (95%) children conditioned with TBI and in five of the 24 (21%) children conditioned with busulphan. There was no relationship between cataract development and age at BMT, or between cataract development and prednisolone given before or after BMT.

CONCLUSION

The present study confirms earlier reports of the high risk of cataract development after TBI and suggests that busulphan is related to cataract development, although less frequently than TBI. The report discusses the possible additive effect of the disease itself, of any corticosteroid treatment and of other cytostatic drugs. It then stresses the importance of early diagnosis of cataracts in children in order to prevent the development of amblyopia.

Engraftment and chimerism, particularly of T- and B-cells, in children undergoing allogeneic bone marrow transplantation

The spectrum of pediatric bone marrow transplantation has changed in recent years. Mismatched and unrelated donor transplants are common, demanding an increased vigilance to detect incipient graft failure, secondary lymphoma as well as relapse and other problems, which now are potentially treatable. To diagnose these complications it may be important to know whether blood and marrow cells are of recipient or donor origin. To evaluate the role of mixed donor-recipient chimerism in relation to clinical problems we adapted a polymerase chain-reaction technique, using fluorescent primers analyzing DNA fragment length polymorphisms, to follow prospectively 17 bone marrow grafted children. To increase the precision of chimerism analysis, immunomagnetically isolated leukocyte populations were assayed in selected cases. Five patients encountered clinical problems related to chimerism. One infant with adenosine deaminase deficiency failed to engraft stem cells, yet succumbed to graft-versus-host disease, mediated by mature donor T-cells. Three children developed significant mixed chimerism. One of these three patients died in relapse of leukemia, while the two other patients who had received T-cell depleted grafts had persistent recipient T-cells, in spite of engraftment. After 5 months, these were displaced by donor T-cells in one of the patients. In the fifth patient, also after T-cell depleted BMT, a fatal donor cell lymphoma occurred. Twelve children had stable full chimerism or in one case a low grade mixed chimerism and remain disease-free throughout follow up (median 9 months). In conclusion, the analysis of chimerism, particularly of separated leukocyte populations, offers an almost indispensable insight and a basis for therapeutic decisions in complicated situations such as grafting involving unrelated or mismatched donors, graft manipulation, adoptive immunotherapy and in immunodeficiency patients.

Bone marrow transplantation in children using unrelated donors at Huddinge Hospital

Twenty-eight out of 31 children that underwent bone marrow transplantation (BMT) from unrelated donors between 1984 and 1995 received HLA-A, HLA-B and HLA-DR matched unrelated donor (MUD) marrows as defined by serologic HLA class I and genomic HLA class II typing. Compared with 28 case-matched controls transplanted with HLA identical sibling donors, MUD patients received a more intensive conditioning. Twenty-six patients (93%) engrafted while two died of septicaemia during the aplastic phase. Two patients rejected their grafts and four developed Evans syndrome. All controls engrafted without incidents of rejection or Evans syndrome. The probability of acute graft-versus-host disease (GVHD) of grade II or above was 27% after MUD-BMT and 7% in the controls. The 5-year probability of survival was 60% in MUD patients and 89% after sibling BMT (p = 0.03). Leukaemia-free survival was 60% with one relapse in the MUD patients, and 59% with five relapses in the sibling group. Three children who received a mismatched donor marrow died, two of severe GVHD and one after graft rejection. In conclusion, today, a matched unrelated donor BMT is an acceptable alternative for many children who need a BMT but lack a suitable related donor.

Longitudinal study of adrenocortical function following allogeneic bone marrow transplantation in children

Basal serum concentrations of cortisol, dehydroepiandrosterone (DHA) and its sulfate (DHAS), 4-androstene-3,17-dione (A4) and 17 alpha-hydroxyprogesterone (17OHP) were measured yearly in children treated with bone marrow transplantation (BMT) with or without preceding total body irradiation (TBI). Age-matched controls were used for comparison. ACTH stimulation tests were performed in the patients before and after treatment. However, in the samples taken before BMT only cortisol was measured. Basal posttreatment cortisol levels were subnormal in TBI-treated boys (n = 14, aged 5-17 years at BMT) during the adrenarcheal period (7-14 years) but became normal afterwards. All other groups had normal cortisol values. Treatment neither affected basal levels nor the ACTH-induced increment (delta-value) of cortisol. In the boys treated with TBI, normal basal levels of 17OHP and adrenal androgens were found with the exception of decreased DHA levels in the postadrenarcheal boys. However, the delta-17OHP values and had an abnormal age relation and were significantly higher than in the patients not treated with TBI. In the patients not treated with TBI (6 boys aged 2-17 years) normal responses were found for 5 years or more after treatment. In female patients treated with TBI (n = 12, aged 1-16 years) circulating levels of DHA, DHAS and A4 were significantly decreased up to 5 years or more following treatment. It is concluded that after TBI, the cortisol homeostasis is maintained at the cost of reduced adrenal androgen secretion.

Changes in craniofacial development induced by growth hormone therapy in children treated with bone marrow transplantation

The effect of growth hormone (GH) treatment on craniofacial development was studied in nine children exhibiting low growth velocity after bone marrow transplantation (BMT). Comparisons were made with seven BMT children who had not received GH. Two groups of age- and sex-matched healthy children served as controls for the respective patient groups. After an average observation period of 3.5 years, the BMT children not treated with GH exhibited significantly reduced mandibular length and alveolar height (p < 0.01). The increase in mandibular length was only 30% of that found in healthy controls. Maxillary growth was less affected by BMT treatment. In the GH treated group, no significant differences were found in craniofacial growth increments compared with controls. Although exogenous GH therapy in this group of children did not induce a catch-up growth, it appears to have prevented further loss in growth potential.

Craniomandibular dysfunction in children treated with total-body irradiation and bone marrow transplantation

The prevalence of pain and dysfunction in the stomatognathic system was studied in a group of 19 long-term survivors after pediatric bone marrow transplantation (BMT), conditioned with total-body irradiation (TBI). Compared with the control group, the children and adolescents in the BMT group had a significantly reduced mouth opening capacity. A reduced translation movement of the condyles was diagnosed in 53% of children treated with TBI, compared with 5% in the control group. Signs of craniomandibular dysfunction were found in 84% of children in the BMT group, compared with 58% in the control group. Both irradiation and chemotherapy induce long-term alterations in connective and muscle tissues resulting in inflammation and eventually fibrosis. These changes in tissue homeostasis and concomitant growth retardation may lead to the observed malocclusion and reduced mobility of the temporomandibular joint, with subsequent muscle pain and headaches, which were found in this study.

Thyroid function in children after allogeneic bone marrow transplantation

Thyroid function was investigated in 35 children after allogeneic BMT. The study was longitudinal and all patients were followed for at least 5 years. Once a year TSH, T4, T3 and the TRH test were performed. Patients with severe aplastic anemia (n = 6) were transplanted without total body irradiation (TBI) and they had no detectable alterations in thyroid function. Patients with leukemia (n = 27) were conditioned with 10 Gy TBI in one fraction. The accumulated frequencies of thyroid dysfunction were 3 of 27 (11%) with high TSH and low T3 or T4 levels, and 10 of 27 (37%) with high basal TSH and normal T3 and T4 levels. An additional 11 of 27 (41%) had an exaggerated TSH response in the TRH test and normal basal TSH and T3/T4 levels. Only 3 of 27 (11%) continued to have normal values. Treatment with levo-thyroxine (L-T4) was given to the patients with a high basal TSH level. As 24 of 27 (89%) children had signs of disturbance in the thyroid axis, prophylactic L-T4 treatment for a few years after BMT with TBI may be of value. The main cause of a change in thyroid function after BMT seems to be conditioning with TBI.

Histologic changes in dental morphology induced by high dose chemotherapy and total body irradiation

Disturbances in dental development were studied with the use of radiography and histology in a patient with acute lymphoblastic leukemia who was treated with induction chemotherapy at 2.3 years of age and bone marrow transplantation at 4.3 years of age. The follow-up 9.5 years after bone marrow transplantation showed evidence of short tapered roots, enamel hypoplasia, microdontia, and aplasia. A histologic examination of two extracted permanent teeth showed that the crown of the maxillary lateral incisor exhibited numerous incremental lines that corresponded closely to the treatment periods with cytotoxic drugs. The maxillary second premolar exhibited regularly spaced incremental lines in the enamel and dentine. A gross hypoplasia was seen in the cervical part of the crown corresponding to the time of administration of 10 Gy total body irradiation. The results indicate that chemotherapy mainly induces qualitative disturbances in dentine and enamel, whereas total body irradiation induces both qualitative and quantitative changes.

Phosphatidylcholine as substrate for human pancreatic phospholipase A2. Importance of the physical state of the substrate

The long-chain phosphatidylcholine/sodium cholate aqueous system as substrate for human pancreatic phospholipase A2 (PLA2) was investigated. At a constant phosphatidylcholine (PC) concentration of 8 mM, the enzyme activity increased with a decrease in cholate (C) concentration up to a PC/C ratio of approximately 0.8 and then rather abruptly decreased to lower values at a ratio above 1.5. At ratios between 0.8 and 1.5, an increasing lag phase in the PLA2 activity was seen, indicating a progressive decrease in substrate availability to the enzyme. Reaction mixtures with a PC/C ratio of up to 0.67 were optically clear solutions composed of mixed bile salt/PC micelles of increasing mixed micellar aggregate size. Ratios between 0.67 and 1.5 were characterized by an increase in turbidity (at 330 and 450 nm) due to increasing formation of vesicles or liposomes. Above a PC/C ratio of 1.5, a sharp increase in turbidity was seen due to increasing formation of bilayer structures other than vesicles. Pure vesicles obtained by dialysis of mixed micellar solutions were not hydrolyzed by the enzyme. Addition of bile salts reversed the inhibition which was accompanied by a decrease in turbidity. Phosphatidylcholine was preferred as substrate for human PLA2 when present in large mixed disc-like bile salt micelles. Vesicular or other types of lamellar liquid-crystalline phases of long-chain phosphatidylcholine did not serve as substrate for PLA2.

Human pancreatic proenzymes are activated at different rates in vitro

The rates of activation of procolipase, prophospholipase (proPLA2), chymotrypsinogen, and trypsinogen were studied after incubation of human pancreatic juice with porcine enterokinase in vitro. Under the conditions chosen procolipase was fully activated within 10 min of incubation. Full activation of phospholipase (PLA2) was seen within 15 min, whereas complete activation of chymotrypsin and trypsin was not seen until after 30 to 60 min, respectively. The different proenzymes probably differ in their suitability as substrates for trypsin. A physiologic consequence of a differentiated activation of the pancreatic proenzymes in vivo could be a delayed proteolytic degradation of the lipolytic enzymes in the intestine.

Is there a specific lysophospholipase in human pancreatic juice?

The existence of a specific lysophospholipase in human pancreatic juice was evaluated. The proteins were separated by a series of chromatographic steps including Sephacryl S-200, cholate-Sepharose 4B, Sephadex G-100 and CM-Sephadex G-50. The enzyme activities against 1-palmitoyl lysolecithin (LL) as well as tributyrin (TB) and p-nitrophenyl butyrate (PNPB) were determined in all the fractions of these purification procedures. Enzyme activity against LL was always eluted in parallel with activities against TB and PNPB, and no unique activity against LL could be found. The specific activity against LL was 40-times lower than that against PNPB and 200-times lower than that against TB. It is concluded that there is no unique lysophospholipase in human pancreatic juice and that the hydrolysis of lysolecithin is most likely performed by carboxyl ester lipase.

Bacterial deconjugation and enterohepatic circulation of norursocholic acid conjugates in rats

Experiments were performed to define the metabolism of norusocholic acid (nUC) conjugates and to quantify to what extent the bile acid pool can be enriched in these bile acids. In vitro incubations of norusocholylglycine (nUCG) and -taurine (nUCT) with small intestinal or cecal content showed deconjugation with only cecal content. Cholylglycine (CG) was deconjugated by small intestinal and cecal content. Infusion of nUCG and CG showed that only a small proportion of nUCG was deconjugated after 24 h of enterohepatic circulation, whereas all CG was deconjugated. When nUCT was administered orally, deconjugation was shown to take place mainly in the cecum. Chronic feeding of nUCT enriched the bile acid pool with only 20% nUCT. We conclude that nUC conjugates are deconjugated primarily by bacteria in the cecum and colon, in contrast to CG, which, in addition to cecum and colon, is deconjugated in the distal small intestine. nUCT and its metabolites do not enrich in the circulating bile acid pool mainly for the following reasons: 1) nUC conjugates have a low affinity for the ileal transport system; 2) nUC, even if formed by deconjugation, is not passively absorbed at a sufficient rate; 3) the small amount of norursodeoxycholic acid formed from nUC is glucuronidated in the liver and glucuronide conjugates do not undergo enterohepatic circulation; and 4) nUC conjugates do not suppress bile acid biosynthesis.

Hepatic and ileal transport and effect on biliary secretion of norursocholic acid and its conjugates in rats

The enterohepatic circulation of norursocholic acid (nUC) and its glycine (nUCG) and taurine (nUCT) conjugates was investigated in the rat; cholic acid (C) was studied as control. The biliary recovery of intravenously infused 14C-labeled bile acids was high: nUC, 88%; nUCG, 80%; nUCT, 99%, and C, 90%. Biliary recovery after the same bile acids were infused intraduodenally was similar: nUC, 90%; nUCG, 66%; nUCT, 97%; and C, 99%. The two conjugated bile acids, nUCG and nUCT, were not biotransformed during intestinal or hepatic transport; nUC was also secreted largely unchanged, but approximately 10% was secreted as an unknown conjugate or sulfate; C was completely conjugated with taurine or glycine. To compare the rates of active ileal transport, biliary recovery was measured after an in situ ileal perfusion technique. The rate of absorption of nUC, nUCG, and nUCT was one-fourth to one-half that of cholyltaurine, which served as control. Competition experiments indicated that the same transport system was involved. When infused intravenously, nUC, nUCG, and nUCT induced far less biliary lipid secretion than an identical dose of C; the secretion of both phospholipid and cholesterol was decreased, cholesterol to a greater extent than phospholipid. It is concluded that nUC and its conjugates are well transported by the ileum, are efficiently secreted into bile without undergoing appreciable hepatic biotransformation, and induce bile flow as other hydrophilic bile acids, but in contrast to C induce little phospholipid and cholesterol secretion into bile.

Pancreatic lipolytic enzymes in human duodenal contents. Radioimmunoassay compared with enzyme activity

The total pancreatic lipolytic capacity was determined in duodenal contents in healthy humans 10-120 min after a liquid test meal, by estimating the amount of pancreatic lipase, colipase, carboxyl ester lipase, and phospholipase A2 by means of radioimmunoassays and enzymatic assays. The molar concentrations of the different proteins were of the same order of magnitude. The relative specific activity (enzyme activity/milligram immunoreactive protein expressed as a percentage of the specific activity of the respective pure protein) amounted to 75-120% for lipase, 45-80% for colipase, 30-70% for carboxyl ester lipase, and 45-120% for phospholipase A2. These varied, and sometimes low values can be explained by the fact that the enzymes are inhibited or partly inactivated in the duodenal contents by surface denaturation, in which cases the products are still immunoreactive. Also, the proforms of colipase and phospholipase A2 may not always be completely activated. Furthermore, the specific activities of the pure enzymes (and thus the relative specific activities) are related to the methods used, which are not specific enough to distinguish completely the three enzymes and the cofactor in duodenal contents.

Effect of pancreatic phospholipase A2 and gastric lipase on the action of pancreatic carboxyl ester lipase against lipid substrates in vitro

Preincubation of a triolein/phospholipid/cholesteryl oleate-emulsion in vitro with either pancreatic phospholipase A2 (PLA2) or gastric lipase (GL) resulted in hydrolysis (measured by pH-stat-titration) of cholesteryl [3H]oleate only after human pancreatic carboxyl ester lipase (CEL) was added to the system. No appreciable hydrolysis was observed when CEL was added alone. Consequently, a concerted action either of PLA2 and CEL or of GL and CEL made the substrate cholesteryl oleate available for hydrolysis by CEL. This was the case when cholesteryl oleate was solubilised in a phospholipid-stabilised triglyceride emulsion, which is the physico-chemical form in which the major part of dietary cholesteryl esters are presented to the gastro-intestinal tract of man.

Craniofacial growth in bone marrow transplant recipients treated with growth hormone after total body irradiation

The effect of growth hormone (GH) treatment on craniofacial development was studied in five children exhibiting growth retardation following bone marrow transplantation. Linear and angular measurements were made on lateral radiographic cephalograms taken prior to the start of GH treatment and after an average treatment time of 1.2 yr. The results showed that the mean growth increments of mandibular length in the GH treated children, exceeded the corresponding values of the control group by 150% during the period of investigation. It is suggested that this dimensional increase in the patients was due to GH stimulation on the chondral growth process in the mandibular condyles.

cDNA cloning of carboxyl ester lipase from human pancreas reveals a unique proline-rich repeat unit

We report the isolation and nucleotide sequence of the cDNA for carboxyl ester lipase (CEL) from human pancreas. CEL was purified from human pancreas and microsequence analysis was performed on the amino-terminal and internal peptides. Peptide sequence was used to design oligonucleotide probes for screening a human pancreas cDNA library. Partial length cDNAs for CEL were isolated from the library, and the 5' portion of the cDNA was obtained using the anchored polymerase chain reaction. The deduced amino acid sequence indicates that mature CEL contains 722 amino acids and is synthesized with a 20 amino acid leader peptide. The amino acid sequence is rich in proline (12.2%), with 68% of the proline residues occurring within the final 25% of protein length. This is due to the occurrence of a series of proline-rich tandem repeat units near the carboxyl terminus, and accounts for the previously observed species variation in CEL size and amino acid composition. The primary sequence of CEL shows strong similarity to members of the serine esterase family, including the identical G-E-S-A-G motif at the putative active site. A striking homology also occurs between CEL and acetylcholinesterase and cholinesterase, essential enzymes of the nervous system. Proteins with cholesteryl esterase activity have been detected in extra-pancreatic tissues including liver, intestine, kidney, aorta, macrophage, and in the milk of some species (human, gorilla, cat, dog), but not others (rat, cow). To clarify the structural relationships between these various esterases and CEL, we used the CEL cDNA to study expression in pancreas and liver. CEL mRNA was abundant in pancreas of human and rat, with the human CEL mRNA approximately 300 nucleotides larger than that from rat. CEL mRNA was not detected in human adult or fetal liver, nor in rat liver. These results indicate that CEL is not synthesized in significant amounts in liver, and suggest that the cholesterol esterase activity that has been described in liver may be due to a distinct enzyme, or may be derived from pancreas, as has been proposed for the cholesterol esterase activity in intestine.

Intestinal absorption of retinol and retinyl palmitate in the rat. Effects of tetrahydrolipstatin

The aim of the present study was to characterize the intestinal absorption of retinol and retinyl palmitate in thoracic duct and bile duct fistulated rats and to investigate the effect of a simultaneously administered lipase inhibitor, tetrahydrolipstatin (THL). Absorption was determined as lymphatic recovery over a 24-hr period, including an initial 12-hr continuous intraduodenal infusion of either [11,12-3H]retinol or [11,12-3H]retinyl palmitate given in emulsified glyceryl trioleate or in mixed micellar solution of monoolein and oleic acid. From micellar dispersion, labeled retinol and retinyl palmitate were recovered in the lymph to 50-60% and both to the same extent. Administered in emulsified form, labeled retinol from fed retinyl palmitate was recovered to 47%, but retinol from fed retinol to only 18%. THL (10(-4) M) in the infusate had no significant effect on the recovery of 14C-labeled oleic acid. The recovery of label from emulsified glyceryl tri[1-14C]oleate was significantly decreased at this concentration of THL (76.5% vs 19.6% recovery). When administered in emulsified form, retinol absorption was not significantly affected by THL at 10(-4) M, while retinyl palmitate absorption was very significantly decreased (5.0% compared to 47.8%). In the presence of THL, retinol absorption from retinyl palmitate in micellar solution was decreased (from 58% to 17%). Most of the retinol in the lymph extracts (72.2 to 91.3) was present as retinyl ester, regardless of the chemical and physical form of administration. Furthermore, THL did not induce any change in this pattern.

Facial growth and morphology in long-term survivors after bone marrow transplantation

A roentgen cephalometric investigation was used to study facial growth and morphology in 17 children who had undergone bone marrow transplantation (BMT) because of acute leukaemia and aplastic anaemia. The ages at BMT varied from 1.0 to 12.9 years. Preoperative treatment included high doses of cyclophosphamide and in children with acute leukaemia also 10 Gy total body irradiation (TBI). The median observation period following BMT was 3.9 years. The control group comprised 85 age and sex matched healthy children. In comparison to the controls, all linear measurements studied were found to be significantly diminished in children conditioned with TBI. For variables describing vertical dimensions, the degree of reduction appeared to be associated with the patients' ages at the time of irradiation. It was concluded that the disturbance in dental development, which is also a consequence of TBI, could be partly responsible for this association. Children who were not conditioned with TBI exhibited no significant differences when compared to controls in respect of the variables studied.

Effects of tetrahydrolipstatin, a lipase inhibitor, on absorption of fat from the intestine of the rat

Tetrahydrolipstatin (THL) derived by hydrogenation from lipstatin, a lipase inhibitor produced by Streptomyces toxytricini, has been shown to inhibit in vitro the activity of all three lipases secreted to the gastro-intestinal tract; gastric lipase, pancreatic lipase and carboxylester lipase (cholesterol ester hydrolase). The effects of THL on intestinal absorption of fat (transport to the thoracic duct chyle) has now been investigated after intraduodenal infusion in a rat model. Absorption of label from oleic acid when administered with monoolein in micellar bile salt solution was not affected by THL in concentrations up to 10(-4) M calculated on the volume of the aqueous phase. Absorption of free cholesterol in micellar bile salt solution of the lipolytic products of triolein; oleic acid and monoolein, is not significantly affected at a concentration of THL of 10(-4) M. Absorption of cholesterol from cholesteryl oleate under the same conditions is almost completely inhibited. The results indicate that absorption of free cholesterol is not dependent on the activity of pancreatic cholesterol ester hydrolase. The absorption of emulsified triolein was not significantly affected by 10(-5) M THL but decreased to around 30% of the controls by a concentration 10-times higher. There was no significant decrease of cholesterol absorption when administered in emulsified triolein while absorption of cholesteryl oleate was reduced at both concentrations of THL and almost completely at 10(-4) M. Radioactivity from [2-14C]THL when administered emulsified in triolein was recovered in urine, bile and thoracic duct lymph to 10-14, 8-13 and 1-3%, respectively, largely independent on dose administered. Label from [1"-14C] THL was recovered in the same amounts in lymph but much less in bile and urine indicating that the amino acid moiety has been split off early in the absorption process.

Mode of action of tetrahydrolipstatin: a derivative of the naturally occurring lipase inhibitor lipstatin

Tetrahydrolipstatin is a specific lipase inhibitor derived from lipstatin, a lipid produced by Streptomyces toxytricini. In addition to pancreatic lipase, it is shown in the present study that tetrahydrolipstatin also inhibits human gastric lipase, carboxyl ester lipase (cholesterol esterase) of pancreatic origin and the closely related bile-salt-stimulated lipase of human milk. It does not inhibit the exocellular lipase from Rhizopus arrhizus or a lipase recently isolated from Staphylococcus aureus. In the presence of a water-insoluble substrate, such as tributyrin, the inhibition has the characteristics of an irreversible inactivation of the uncompetitive type, thus indicating that an enzyme.substrate.inhibitor complex is formed, which cannot undergo further reaction to yield the normal product. This reaction probably takes place at the aqueous/oil interface of the substrate. In aqueous solution, in the absence of substrate, the inhibition of carboxyl ester lipase by tetrahydrolipstatin has the characteristics of being reversible, and finally becomes of a temporary nature analogues to the trypsin-trypsin inhibitor system. It is suggested that an enzyme-inhibitor complex of an acyl-enzyme type is formed that is slowly hydrolysed, with water as the final acceptor, leaving an intact enzyme and an inactive form of the inhibitor. The enzyme thus consumes the inhibitor, which undergoes a chemical conversion, as indicated by a change in mobility in an appropriate thin-layer chromatographic system, indicating an increase in hydrophilicity. Evidence is presented that the reaction product is an acid and that the functional group of tetrahydrolipstatin is the beta-lactone reacting with the active site of the enzyme.

Concerted action of human carboxyl ester lipase and pancreatic lipase during lipid digestion in vitro: importance of the physicochemical state of the substrate

The pancreatic enzyme carboxyl ester lipase (CEL) has been shown to hydrolyse a large number of different esters, including triacylglycerols, cholesteryl esters and retinyl esters with an absolute requirement for bile salts. Some of the lipids that are substrates for CEL can also be hydrolysed by pancreatic lipase. In order to investigate the relative roles of human CEL and pancreatic lipase, the two enzymes were incubated on a pH-stat with isotope-labelled lipid substrate mixtures in physicochemical forms resembling the state of the dietary lipids in human intestinal contents. In the first set of experiments, cholesteryl oleate (CO) and retinyl palmitate (RP) were solubilised in an emulsion of triolein (TO) stabilised by egg phosphatidylcholine and bile salts. Lipase (always added together with its cofactor, colipase) hydrolysed TO, with monoolein and oleic acid as end-products, whereas CEL alone could not hydrolyse TO in the presence of phosphatidylcholine (PC). Lipase alone did not hydrolyse CO or RP, but CEL did hydrolyse these esters if lipase was present. Release of [3H]glycerol from labelled TO increased only slightly if CEL was added compared to lipase alone, suggesting that monoolein hydrolysis was slow under these conditions. In the second set of experiments, CO and RP were dissolved in bile salt/monoolein/oleic acid dispersions with varying bile salt concentrations. CEL hydrolysed CO and RP more rapidly in a system with a high bile salt concentration containing mixed micelles than in a system with a low bile salt concentration, where the lipids were dispersed in the form of mixed micellar and non-micellar aggregates; both types of aggregate have been reported to exist in human intestinal contents. In conclusion, these data suggest that the main function of CEL under physiological conditions is to hydrolyse cholesteryl and retinyl esters, provided that the triacylglycerol oil phase is hydrolysed by pancreatic lipase, which probably causes a transfer of the substrate lipids of CEL from the oil emulsion phase to an aqueous bile salt/lipolytic product phase. Depending on the bile salt/lipolytic product ratio, the substrate will reside in either micellar or non-micellar lipid aggregates, of which the micellar state is preferred by CEL.

Growth and growth hormone in children after bone marrow transplantation

Growth and growth hormone (GH) were investigated every year in 24 children after allogeneic bone marrow transplantation (BMT) for severe aplastic anemia (SAA) or leukemia. Conditioning included total body irradiation (TBI) in all cases of leukemia. The young leukemic children grew poorly. At 4 years after BMT, the mean standard deviation score for attained height had decreased from 0 to -1.73. GH deficiency was diagnosed with provocation tests. Three years after BMT, 10/18 children had a subnormal response. Ten children were further investigated with 24-hour GH profiles. Children with SAA had normal growth and GH levels. TBI seemed to be the major factor responsible for impaired growth.

Factors regulating the formation of chylomicrons and very-low-density lipoproteins by the rat small intestine

The aim of this study was to investigate how the relationship between chylomicron and very-low-density lipoprotein (VLDL) transport of fatty acid into lymph was affected by the total amount of lipid transported via the intestinal lymphatics in the rat. Two different experimental conditions were employed. First, intestinal lymph fistula rats were infused with four different levels of [3H]oleic acid (15, 30, 60 and 120 mumol per h) at a constant rate for 8 h. Lymphatic transport of [3H]oleic acid via chylomicrons and VLDLs was measured in lymph collected during the seventh h. Within the dose range studied chylomicron increased exponentially, while the output in VLDL reached a plateau at a total lymph [3H]oleic acid output of approx. 60 mumol/h. A linear regression analysis of the ln(chylomicron/VLDL) versus the total output in lymph yielded a coefficient of correlation of 0.95. Second, we utilized the fact that intraduodenal infusion of the nonionic detergent Pluronic L-81 (L-81) inhibits chylomicron transport and that this inhibition is reversed by the cessation of L-81 infusion (unblocking). A linear regression analysis of the ln(chylomicron/VLDL) versus total lymph [3H]oleic acid output during the first 4 h of unblocking gave a coefficient of correlation of 0.79. Statistical analysis of the regression equations from the two experiments showed that for the same lymphatic [3H]oleic acid output, the chylomicron/VLDL ratio was significantly lower in the L-81 experiment, indicating that the relative rates of formation of chylomicron to VLDL were different under these two experimental conditions. However, the principal pattern was the same, i.e., chylomicron production increased, while VLDL production became saturated when the amount of oleic acid transported to the lymph was increased.