Granulocytic sarcoma after allogeneic bone marrow transplantation: a retrospective European multicenter survey. Acute and Chronic Leukemia Working Parties of the European Group for Blood and Marrow Transplantation

In the newly established rat sarcoma cell line LSR-SF (SR) expression of pp60v-src was detected. Karyotype analyses revealed various chromosome aberrations during prolonged passaging of the tumor cells in vitro. Polyploidy was found to be a characteristic feature of the line studied. A large metacentric chromosome persistently present in the cells was accepted as a line marker.     

Risk assessment for patients with chronic myeloid leukaemia before allogeneic blood or marrow transplantation. Chronic Leukemia Working Party of the European Group for Blood and Marrow Transplantation

BACKGROUND: Transplantation of blood or bone-marrow stem cells is the treatment of choice for selected patients with chronic myeloid leukaemia (CML). Transplantation is used with increasing frequency and success, but remains associated with substantial risks of morbidity and mortality. Other treatments with satisfactory short-term outcome are available. For appropriate counselling of patients, a rapid and simple way to assess risk is needed. METHODS: Data from 3142 patients (1873 [60%] male, 1269 [40%] female; mean age 34 years, range <1-60 years) treated with allogeneic blood or marrow transplants for CML between 1989 and 1997, reported to the European Group for Blood and Marrow Transplantation (EBMT), were used to develop and test a simple risk score based on previously reported major pretransplant risk factors: histocompatibility, stage of disease at time of transplantation, age and sex of donor and recipient, and time from diagnosis to transplantation. We analysed probabilities of survival, leukaemia-free survival, transplant-related mortality, and relapse incidence with respect to these risk factors. FINDINGS: At the time of analysis, 1922 (61%) of the 3142 patients were alive-1567 (65%) of those with HLA-identical sibling donors and 417 (57%) of those with unrelated donors. 1682 (54%) were alive without relapse. 1220 (39%) patients had died, 1013 (83%) of transplant-related causes, 207 (17%) of relapse. 447 (14%) patients had relapsed. The final scoring system was highly predictive for leukaemia-free survival, survival and transplant-related mortality. Survival at 5 years was 72%, 70%, 62%, 48%, 40%, 18%, and 22% for patients with scores 0, 1, 2, 3, 4, 5, and 6, respectively. Risk of transplant-related mortality was 20%, 23%, 31%, 46%, 51%, 71%, and 73%. Data showed the same trends for HLA-identical sibling transplants and unrelated transplants for transplants done in 1989-93 and 1994-96. INTERPRETATION: Pretransplant risk factors are cumulative for individual patients with CML having blood or marrow transplantation. A simple system based on five main factors gives adequate risk assessment for counselling of patients and taking decisions.     

Incidence and outcome of hepatic veno-occlusive disease after blood or marrow transplantation: a prospective cohort study of the European Group for Blood and Marrow Transplantation. European Group for Blood and Marrow Transplantation Chronic Leukemia Working Party

To determine the incidence and outcome of hepatic veno-occlusive disease (VOD) after blood or marrow transplantation (BMT), we prospectively evaluated all consecutive patients receiving a BMT during a 6-month period in participating EBMT centers. All of them were evaluated for occurrence of VOD according to previously defined clinical criteria. The clinical course, outcome, value of prophylactic and therapeutic interventions, and the influence of previously described risk factors were analyzed. During the study period, 1,652 BMT were performed in 73 centers. VOD was diagnosed in 87 patients (5.3%; 95% confidence interval [CI], 4.2% to 6.4%). Fifty-six of 631 allogeneic BMT (8.9%) and 31 of 1,010 autologous BMT (3.1%) developed this complication (P <.0001). VOD was classified as mild in 7 (8%), moderate in 56 (64.4%), and severe in 24 (27.6%) cases. Sixteen patients died of VOD (corresponding to 1% of the whole series, 18.4% of VOD patients, and 66.7% of severe VOD). The use of unfractionated heparin did not significantly decrease the incidence of VOD. Independent variables associated with an increased risk of VOD were allogeneic BMT (relative risk [RR], 2.8; P <.001), pre-BMT elevation of serum aspartate aminotransferase (RR, 2.4; P =.001), high-dose cytoreductive therapy (RR, 2.3; P =.003), Karnofsky performance score less than 90% (RR, 2.7; P =.006), and prior abdominal radiation (RR, 2.9; P =.03). In conclusion, this prospective study shows that (1) the incidence of VOD is lower than that reported in smaller studies from single centers, (2) about one fourth of cases of VOD progress to severe disease, (3) main risk factors have a major impact on incidence of VOD, and (4) the use of prophylactic unfractionated heparin does not seem to reduce the incidence of VOD.     

Long-term results after allogeneic bone marrow transplantation for chronic myelogenous leukemia in chronic phase: a report from the Chronic Leukemia Working Party of the European Group for Blood and Marrow Transplantation

The purpose of this study was to determine the long-term results of allogeneic bone marrow transplantation for chronic myeloid leukemia. A retrospective analysis was carried out of the outcome of 373 consecutive transplants performed at 38 European institutions between 1980 and 1988 and reported to the registry of the European Group for Blood and Marrow Transplantation. All transplants were carried out for first chronic phase of chronic myelogenous leukemia using unmanipulated marow cells from HLA-identical sibling donors. The probability of survival and leukemia-free survival at 8 years were 54% (95% CI: 49-59) and 47% (95% CI: 41-52) respectively. The probabilities of developing acute GVHD (II-IV) at 100 days and chronic GVHD at 4 years after transplant were 47% (95% CI: 41-53) and 52% (95% CI: 46-58) respectively. The probabilities of transplant-related mortality and leukemic relapse 8 years after BMT were 41% (95% CI: 36-48) and 19% (95% CI: 14-25), respectively. Transplant within 12 months of diagnosis was associated with reduced transplant-related mortality (34 vs 45%, P = 0.013) and resulted in improved leukemia-free survival (52 vs 44%, P = 0.03). The probability of relapse was significantly reduced in patients who developed chronic GVHD (RR = 0.33, P = 0.004). The probability of relapse occurring more than 2 years after transplant was increased more than five-fold in patients transplanted from a male donor (RR = 5.5, P = 0.006). Sixty-seven patients in hematologic remission were studied for residual disease by two-step RT/PCR for BCR-ABL mRNA and 61 (91%) tested negative. We conclude that bone marrow transplantation can induce long-term survival in approximately one-half of CML patients; the majority of survivors have no evidence of residual leukemia cells when studied by molecular techniques. The probability of late relapse is increased with use of a male donor.     

Cataracts after total body irradiation and bone marrow transplantation in patients with acute leukemia in complete remission: a study of the European Group for Blood and Marrow Transplantation

PURPOSE: Advances in bone marrow transplantation (BMT) have consistently improved long-term survival. Therefore, evaluation of late complications such as cataracts is of paramount importance. METHODS AND MATERIALS: We analyzed data of 2149 patients from the EBMT registry. A cohort of 1063 patients were evaluable for survival and ophthalmologic status after transplant for acute leukemia (AL) in first or second complete remission. Conditioning therapy included either single-dose total body irradiation (STBI) or fractionated TBI (FTBI) grouped in different dose rates (low: LDR < or = 0.04 Gy/min; high: HDR > 0.04 Gy/min). RESULTS: The overall 10-year estimated cataract incidence (ECI) was 50%. It was 60% in the STBI group, 43% in the FTBI group < or = 6 fractions, and 7% in the FTBI group > 6 fractions (p < 10(-4)). It was significantly lower (30%) in the LDR than in the HDR groups (59%;p < 10(-4)). Patients receiving heparin for veno-occlusive disease prophylaxis had fewer cataracts than those who did not (10-year ECI: 33% vs. 53%, respectively;p = 0.04). The 10-year ECI was 65% in the allogeneic vs. 46% in the autologous BMT patients (p = 0.0018). Factors independently associated with an increased risk of cataract were an older age (> 23 years), higher dose rate (> 0.04 Gy/min), allogeneic BMT, and steroid administration (> 100 days). The use of FTBI was associated with a decreased risk of cataract. Heparin administration was a protective factor in patients receiving STBI. In terms of cataract surgery, the unfavorable factors for requiring surgery were: age > 23 yr, STBI, dose rate > 0.04 Gy/min, chronic graft-vs.-host disease (cGvHD), and absence of heparin administration. Among the patients who required cataract surgery (111 out of 257), secondary posterior capsular opacification was observed in 15.7%. CONCLUSION: High dose rate and STBI are the main risk factors for cataract development and the need for surgery, and the administration of heparin has a protective role in cataractogenesis.     

Autologous bone marrow transplantation in acute myeloid leukemia: the University of Minnesota experience

PURPOSE: To report the outcome of autologous bone marrow transplantation for patients with acute myeloid leukemia (AML) in first or greater complete remission (CR) treated by autologous bone marrow transplantation using two different preparatory regimens. METHODS AND MATERIALS: Between September 1986 and August 1993, 75 patients with AML ranging in age from 6 months to 58 years underwent autologous bone marrow transplantation using previously harvested and frozen unpurged (n = 6) or 4-hydroperoxycyclophosphamide purged marrows (n = 69). Patients were in first CR (n = 44) or beyond first CR (n = 31). The preparative regimen consisted of 120 mg/kg of cyclophosphamide (CY) and 1320 cGy total body irradiation (TBI) in eight fractions over 4 days (CY/TBI) in 29 patients; and 16 mg/kg of Busulfan (BU) and 200 mg/kg of CY (BU/CY) in 46 patients. Thirty-five of these 75 patients (18 CY/TBI and 17 BU/CY) were part of a randomized trial comparing the two preparative regimens. RESULTS: At 2 years, overall survival and disease-free survival (DFS) were 49% [95% confidence interval (C.I.) 37-61%] and 43% (95% C.I. 32-55%), respectively. Patients in first CR had a significantly better outcome than patients beyond first CR with an estimated 2-year DFS of 59% (95% C.I. 44-74%) vs. 21% (95% C.I. 5-36%, log-rank p = 0.0001), respectively. For patients conditioned with CY/TBI, the estimated 2-year DFS was 52% compared to 39% for BU/CY (log-rank p = 0.35). Estimated 2-year relapse rates were 44% vs. 56% (log-rank p = 0.40), respectively. For patients in first CR, no differences in DFS were observed between the two regimens (2-year estimates 69% vs. 55% log-rank p = 0.52). Patients beyond first CR had a significantly improved DFS with the CY/TBI regimen (2-year estimates of 38% vs. 7%, log-rank p = 0.04). No differences were found between the two regimens in terms of time to WBC engraftment, absolute neutrophil count of > 500, incidence of bacteremias, or median time to hospital discharge. Interstitial pneumonitis developed in two patients (one BU/CY, one CY/TBI) and venoocclusive disease developed in seven BU/CY patients (Fishers exact test p = 0.04). CONCLUSIONS: For patients beyond first CR, the CY/TBI regiment provided a better outcome, with a significantly better disease-free survival and less venoocclusive disease. For patients in first CR, no significant difference between the two regimens was found. The high relapse rate, especially for patients with advanced disease, emphasizes the need for early transplantation and for new strategies to improve outcome.     

Autologous bone marrow transplantation for acute myeloid leukemia using busulfan plus etoposide as a preparative regimen

We have studied the use of a new preparative regimen for the treatment of patients in remission of acute myeloid leukemia (AML) with autologous bone marrow transplantation. Chemotherapy consisted of busulfan 1 mg/kg every 6 hours for 4 days (total dose, 16 mg/kg) on days -7 through -4 followed by an intravenous infusion over 6 to 10 hours of etoposide 60 mg/kg on day -3. Autologous bone marrow, treated in vitro with 100 micrograms/mL of 4-hydroperoxycyclophosphamide, was infused on day 0. We have treated 58 patients up to the age of 60 years, 32 in first remission, 21 in second or third remission, and 5 with primary refractory AML unresponsive to high-dose Ara-C, but achieving remission with aggressive salvage regimens. Of the first remission patients, there has been 1 treatment related death and 5 relapses. With median follow-up of 22 months, the actuarial relapse rate is 22% +/- 9% and disease-free survival is 76% +/- 9% at 3 years. Patients with favorable French-American-British (FAB) subtypes (M3 or M4 EO) did especially well, with no relapses seen in 15 patients observed for a median of 30 months. Actuarial relapse rate at 3 years was 48% for first remission patients with less favorable FAB subtypes. Of patients in second or third remission, there were 5 treatment related deaths and 4 relapses. With median follow-up of 22 months, the actuarial relapse rate is 25% +/- 11% and disease-free survival is 56% +/- 11% at 3 years. Four of five primary refractory patients died during treatment and 1 remains in remission with short follow-up. These preliminary data are very encouraging and, if confirmed, support the use of autologous purged bone marrow transplantation using aggressive preparative regimens as one approach to improve the outcome of adults with AML.     

Allogeneic bone marrow transplantation for agnogenic myeloid metaplasia. French Society of Bone Marrow Transplantation

To explore the clinical heterogeneity associated with the Friedreich's ataxia (FRDA) expanded repeat and provide preliminary guidance for future gene testing in patients suspected of having FRDA, we tested patients with typical FRDA (group I), late-onset FRDA or FRDA with retained reflexes (group II), as well as those with early onset "non-Friedreich's" recessive or sporadic ataxia (group III). Eighty-seven percent of families in group I tested positive for the FRDA triplet repeat expansion. Thirty-six percent of families in group II demonstrated the FRDA expansion. Only one of 11 patients in group III had the FRDA expansion. Clinical criteria did not clearly distinguish between expansion-positive and expansion-negative individuals in groups I and II. Minimal criteria that were present in all the patients who tested positive were recessive or sporadic inheritance, progressive caudal-rostral gait and limb ataxia, and at least one of the following: dysarthria, Babinski sign, or cardiomyopathy. This study confirms recent findings that some patients in group II can carry the FRDA mutation. However, we did not observe the FRDA expansion in 64% of group II families or in 13% of families with typical FRDA (group I), suggesting other genetic or environmental causes for their ataxia.     

Immunotherapy with donor leukocyte infusions for patients with relapsed acute myeloid leukemia following partially mismatched related donor bone marrow transplantation

Donor leukocyte infusions (DLI) were used to treat 2 patients with AML who relapsed within 4 months of treatment with partially mismatched related donor (PMRD) BMT representing 1-2 HLA-mismatches. No other form of cytoreductive therapy was given to these patients. Both patients developed GVHD (grade II-III) following DLI requiring steroid therapy. One of these patients went into complete remission following development of GVHD and immunophenotypic analysis of peripheral blood showed increased numbers of CD3+/CD8+ T cells, CD56+/CD8+ lymphokine activated killer (LAK) cells and CD16+/CD56+ natural killer (NK) cells expressing intermediate affinity IL-2 receptor P75. Unfortunately, the response was of short duration and the patient relapsed 8 weeks later ultimately resulting in death. The second patient did not show any response to DLI and died of progressive leukemia in conjunction with active GVHD. We conclude that DLI from PMRD carries a high risk for the development of GVHD and may have an anti-leukemia effect for relapsed AML. The anti-leukemic effect from PMRD DLI may be mediated by cytotoxic T lymphocytes, LAK cells and NK cells.     

Allogeneic matched T-cell-depleted bone marrow transplantation for acute leukemia patients

It has been shown that high doses of human recombinant erythropoietin (r epo) increase haemoglobin levels by augmentation of F-cells, and Hb-F production in animal models and in human trials. In this study, r epo was used in patients with beta thalassemia intermedia. Our purpose was to improve haemoglobin levels by at least 2 g and maintain an average level between 10 and 12 g/dl. Ten patients aged 6-29 years (mean 14 +/- 7.6 years) with thalassemia intermedia were treated with r epo. It was given subcutaneously in rising doses from 500 to 1000 U/kg three times weekly for 3 months. During r epo therapy eight cases (80 per cent) showed an increase in haemoglobin, haematocrit, and reticulocyte levels, and an increase of at least 2 g of haemoglobin was obtained. Blood transfusion was not needed during the study except in one case. Five cases (50 per cent) improved life quality with therapy. Hb levels of all patients returned to baseline values over 1 or 2 months after r epo was discontinued. There was no significant change in absolute Hb-F, F-cells, and ferritin levels during treatment. Generally, the drug was well tolerated. No patient had hypertension. Recombinant erythropoietin seems to be an effective treatment for anaemia of beta-thalassemia intermedia, but longer term randomized trials are needed especially in patients with beta thalassemia major.     

Chronic myelogenous leukemia and acute promyelocytic leukemia: new bone marrow transplantation options

PURPOSE/OBJECTIVES: To describe new bone marrow transplantation (BMT) options for chronic myelogenous leukemia (CML) and acute promyelocytic leukemia (APL), as well as their applications and prognoses, and to describe the role of the oncology nurse in caring for the BMT recipient and options for future nursing research. DATA SOURCES: Published articles, book chapters, and personal experience. DATA SYNTHESIS: Various pretransplant agents and methods are under investigation to improve the outcome and reduce the costs of allogeneic and autologous BMT and peripheral blood progenitor cell (PBPC) transplants. Preliminary results of current studies indicate that autologous BMTs and PBPC transplants have merit as a treatment option in patients with AML and require further research. For patients with APL, BMT usually is reserved for those who fail to achieve or relapse after achieving remission with chemotherapy. Preliminary data show that patients with CML and APL who receive a PBPC transplant engraft more rapidly with decreased morbidity and mortality. CONCLUSIONS: BMT options for patients with CML and APL continue to evolve as advances in pretransplant methods and symptom management become capable of improving the outcome, decreasing costs, and shifting patient care to the outpatient and homecare settings. IMPLICATIONS FOR NURSING PRACTICE: Understanding the marrow transplant options available to patients with CML and APL is essential for nurses. They must stay informed about ongoing improvements in pretransplant processes and symptom-management procedures that reduce BMT morbidity and mortality. Inpatient and outpatient nurses need to collaborate and participate in nursing research to find better ways of providing the best care possible for patients.     

Bone marrow transplantation for children less than 2 years of age with acute myelogenous leukemia or myelodysplastic syndrome

We analyzed results of 40 infants less than 2 years of age who received bone marrow transplants (BMT) between May 1974 and January 1995 for treatment of acute myelogenous leukemia (AML; N = 34) or myelodysplastic syndrome (MDS; N = 6) to determine outcome and survival performance. Among the AML patients, 13 were in first remission, 9 were in untreated first relapse or second remission, and 12 were in refractory relapse. Patients were conditioned with cyclophosphamide in combination with either total body irradiation (TBI; N = 29) or busulfan (N = 11). Source of stem cells included 6 autologous donors, 15 HLA genotypically identical siblings, 14 haploidentical family members, and 5 unrelated donors. Graft-versus-host disease (GVHD) prophylaxis was methotrexate (MTX) for 17, MTX plus cyclosporine (CSP) for 14, or CSP plus prednisone for 3. Incidence of severe (grade 3-4) regimen-related toxicity was 10% and transplant-related mortality was 10%. Acute GVHD (grades II-III) occurred in 39% of allogeneic patients, and chronic GVHD developed in 40%. Relapse, the most significant problem for patients in this study, occurred in 1 MDS patient and 23 AML patients and was the cause of death for 19 patients. The 2-year probabilities of relapse are 46%, 67%, and 92%, respectively, for patients transplanted in first remission, untreated first relapse or second remission, and relapse. One MDS and 8 AML patients received second marrow transplants for treatment of relapse, and 5 of these survive disease-free for more than 1.5 years. All 6 MDS patients and 11 of 34 AML patients survive more than 1.5 years later. The 5-year probabilities of survival and disease-free survival are 54% and 38% for patients transplanted in first remission and 33% and 22% for untreated first relapse or second remission. None of the patients transplanted with refractory relapse survive disease-free. Outcome was significantly associated with phase of disease at transplantation and pretransplant diagnosis of extramedullary disease. Long-term sequelae included growth failure and hormonal deficiencies. Survival performance was a median of 100% (80% to 100%) and neurologic development for all survivors was appropriate for age. This study indicates that infants with AML have similar outcome after BMT compared with older children and that BMT should be performed in first remission whenever possible. In addition, allogeneic BMT provides effective therapy for the majority of infants with MDS.     

Allogeneic bone marrow transplantation vs filgrastim-mobilised peripheral blood progenitor cell transplantation in patients with early leukaemia: first results of a randomised multicentre trial of the European Group for Blood and Marrow Transplantation

In a multicentre trial involving 20 transplant centres from 10 countries haematopoietic stem cells were obtained either from the bone marrow of 33 sibling donors or from the peripheral blood of 33 such donors after administration of filgrastim (10 microg/kg/day). The haematopoietic stem cells were infused into their HLA-identical recipients suffering from acute leukaemias in remission or chronic myeloid leukaemia in chronic phase. PBPC donors tolerated filgrastim administration and leukapheresis well with the most frequent side-effects being musculoskeletal pain, headache, and mild increases of LDH, AP, Gamma-GT or SGPT. Pain and haematoma at the harvest site and mild anaemia were the most frequent complaints of BM donors. Severe or life-threatening complications were not seen with any type of harvest procedure. Time to platelet recovery greater than 20 x 10(9)/l was 15 days (95% confidence interval (CI) 13-16 days) in the PBPCT group and 19 days (CI 16-25) in the BMT group. Time to neutrophil recovery greater than 0.5 x 10(9)/l was 14 days (CI 12-15 days) in the PBPCT group as compared to 15 days (CI 15-16 days) in the BMT group. The numbers of platelet transfusions administered to PBPCT and BMT patients were 12 (range: 1-28) and 10 (range: 3-39), respectively. Sixteen patients (48%) transplanted with bone marrow and 18 patients (54%) transplanted with PBPC developed acute GVHD of grades II-IV; acute GVHD of grades III or IV developed in six (18%) and seven (21%) patients, respectively. Kaplan-Meier plots for transplant-related mortality until day 100 and leukaemia-free survival at a median of 400 days after BMT or PBPCT showed no significant differences. Administration of filgrastim and leukapheresis in normal donors were feasible and well tolerated. The number of days with restricted activity and of nights spent in hospital was lower in donors of PBPC. Transplantation of PBPC to HLA-identical siblings with early leukaemia resulted in earlier platelet engraftment. The incidence of moderate to severe acute GVHD, transplant-related mortality, and leukaemia-free survival did not show striking differences. Further investigation of allogeneic PBPCT as a substitute for allogeneic BMT is warranted.     

Cytosine arabinoside and mitoxantrone induction chemotherapy followed by bone marrow transplantation or chemotherapy for relapsed or refractory pediatric acute myeloid leukemia

The purpose of this study was to determine the induction rate, duration of response and toxicity of cytosine arabinoside (1.0 gm/m2 i.v. over 2 h q 12 h x 8 doses days 1 through 4) and mitoxantrone (12 mg/m2 over 1 h daily x 4 doses days 3 through 6) in pediatric patients with acute myeloid leukemia (AML). Patients achieving a complete remission received either bone marrow transplantation or further chemotherapy. Twenty-seven of 37 evaluable patients (73% (95% confidence interval 59-87%)) achieved a complete remission. For all responding patients, the projected median time to relapse is 12 months. The projected 1 and 2 year disease-free survival is 47% (28-66) and 41% (21-61) with a range of follow-up of 0 to 48+ months. The major toxicity was bone marrow suppression and infection. This therapy is very active in pediatric AML and has acceptable toxicity. Some patients treated achieve prolonged survival.     

Autologous bone marrow transplantation with monoclonal antibody purged marrow for children with acute lymphoblastic leukemia in second remission. Spanish Working Party for BMT in Children

The purpose of this study was to evaluate the outcome of children with acute lymphoid leukemia (ALL) in second remission who have undergone high-dose chemotherapy and radiotherapy and autologous bone marrow transplantation (ABMT) with monoclonal antibody purged marrow, and to determine the main prognostic factors. From 1987 to 1992, 55 children with ALL in second remission underwent ABMT. The conditioning regimen consisted of total body irradiation (TBI) plus cyclophosphamide in 21 patients and TBI plus cyclophosphamide plus cytarabine or VP-16 in 28 patients; the remaining six patients were treated with chemotherapy alone (cyclophosphamide and busulfan, and/or VP-16). The marrow was purged using monoclonal antibodies and complement or magnetic microspheres in all cases. All patients engrafted. Three patients (5%) died early post transplant from infections. Twenty-six patients (47%) relapsed (median 150 days); 26 patients (47%) are alive and in complete remission (CR) at a median of 36 months. The Kaplan-Meier estimation showed a probability of event-free survival (EFS) of 46 +/- 0.007%. In the univariate analysis, first CR length and conditioning with TBI plus two or more cytotoxic drugs were found to be the most significant predictors of EFS. ABMT with purged marrow is a treatment modality which offers a chance of cure in children with ALL after relapse, including children who relapse early.     

Allogeneic bone marrow transplantation for chronic myelomonocytic leukemia in childhood: a report from the European Working Group on Myelodysplastic Syndrome in Childhood

The purpose of this study was to investigate the mechanisms of action of pituitary adenylate cyclase-activating polypeptide (PACAP) in stimulating aldosterone production in two different models: bovine adrenal zona glomerulosa (ZG) cells in primary culture and the human adrenocortical carcinoma cell line H295R. PACAP binds to two major groups of receptors: type I, which prefers PACAP38 and PACAP27 over vasoactive intestinal peptide (VIP); and type II, which has approximately equal affinity for PACAP38, PACAP27, and VIP. The type I subclass comprises multiple splice variants that can be distinguished by their specificity to PACAP38 and PACAP27 in their activation of adenylate cyclase and phospholipase C. Type II PACAP/ VIP receptors couple only to AC. In bovine ZG cells, PACAP38 and PACAP27 stimulated aldosterone production in a dose-dependent manner, whereas VIP was ineffective. In H295R cells, PACAP38, PACAP27, and VIP dose-dependently stimulated aldosterone production with roughly the same ED50. In bovine ZG cells, PACAP38 and PACAP27 stimulated cAMP production with similar efficacy, whereas VIP had no effect. In H295R cells, all three peptides stimulated cAMP accumulation. PACAP38 and PACAP27 also activated PLC in bovine ZG cells as they induced an increase in Ins(1,4,5)Ps production. In H295R cells, neither of these peptides was able to stimulate IP turnover. These results indicate that PACAP stimulation of aldosterone production is mediated by the PVR1s or the PVR1hop splice variants of the type I PACAP-specific receptor subtype in bovine ZG cells, whereas only type II PACAP/VIP receptors seemed to occur in the human H295R cell line. In addition, PACAP-stimulated aldosterone production was inhibited by atrial natriuretic peptide in bovine and human adrenocortical cells, however not by the same mechanism. This further supports species-specific and/or cell type-specific signaling pathways for PACAP in the regulation of aldosterone production.