Alfonso Vasile

Iron deficiency in maintenance hemodialysis patients: assessment of diagnosis criteria and of three different iron treatments.

The study was carried out in order to evaluate in maintenance hemodialysis (MH) patients: (1) the reliability of serum ferritin (SF) measurement in iron deficiency diagnosis and therapy; (2) the possibility to improve iron stores assessment through laboratory indexes routinely used in clinical practice; (3) the most effective iron deficiency treatment. After a preliminary assessment of SF reference values in 250 healthy volunteers, we studied 72 MH patients divided into three groups according to their SF baseline values: high (group A), normal (group B), low (group C) (normal range 19-191 ng/ml). Each group was further divided into three subgroups receiving three different iron treatments for 6 months: (1) oral administration of 67.5 mg/day of Fe3+ as Fe-ferritin (subgroups A1, B1, C1); (2) oral administration of 60 mg/day of Fe3+ as Fe-chondroitin sulfate (subgroups A2, B2, C2); (3) i.v. administration at the end of each dialytic session of 31 mg of Fe3+ as Fe-gluconate-Na (subgroups A3, B3, C3). The response to the iron therapy was considered positive when the hemoglobin (Hb) and the hematocrit (Ht) increased to greater than or equal to 15% of the baseline values. The rate of positive responses in each subgroup was as follows: A1 0/5, A2 0/5, A3 0/7, B1 2/10, B2 1/6, B3 5/11, C1 1/7, C2 3/7, C3 10/16. We concluded that SF values above 191 ng/ml allow to exclude iron deficiency whereas SF values less than or equal to the normal range are inadequate. In an attempt to improve diagnostic sensitivity we divided patients of subgroup B3 and C3 into responders (R) and nonresponders (NR).(ABSTRACT TRUNCATED AT 250 WORDS)

Glucose-Induced Insulin Secretion in Uremia: Role of 1α,25(HO)2-Vitamin D3

To evaluate the role and mechanism of action of calcitriol on glucose-induced insulin secretion in uremia, 17 patients with severe chronic renal failure were studied. Glucose metabolism was investigated by the intravenous glucose tolerance test (IVGTT) before and after treatment for 21 days with 0.5 µg/day of calcitriol and 500 mg/day of calcium (C + Ca) (6 cases) or 0.5 µg/day of calcitriol alone (C) (11 cases). After these evaluations the patients on C + Ca were shifted to C and 6 patients on C were shifted to C + Ca, and IVGTT was repeated 21 days after the shift. For each test plasma glucose (G), immunoreactive insulin (IRI) and C-peptide (C-p) were measured at -30,0,2,5,15,30,45,60 min, and baseline plasma values of 1α,25(HO)2-vitamin D3, C-terminal parathyroid hormone (PTH-C), intact parathyroid hormone (PTH-I), calcitonin, and serum values of total and ionized calcium were dosed. Also, glucose constant decay (K-G), insulin response (IRI area), C-p production (C-p area), insulinogenic index (IGI) and insulin resistance index (RI) were calculated. A historical group of 21 healthy volunteers formed the normal controls. 1α,25(HO)2-vitamin D3 plasma levels in uremic patients before treatment were significantly lower than normal range. As compared to controls, uremic patients showed significantly lower K-G, IRI area and IGI values and significantly higher RI values. After treatment with C or C + Ca, the insulin response improved significantly at 2 and 5 min and G decrement was more marked at 30,45 and 60 min. K-G and 0-15 min IRI area, 0-15 min IGI and 0-15 min C-p area values increased significantly but did not reach the normal values. Serum calcium and plasma 1α,25(HO)2-vitamin D3 levels significantly increased after treatment but no correlations were found between changes in glucose metabolism parameters and changes in total or ionized serum calcium or changes in 1α,25(HO)2-vitamin D3 plasma levels. Serum calcium values significantly decreased after shift from C + Ca to C and significantly increased after shift from C to C + Ca, but glucose metabolism parameters showed no further changes. From these data we inferred that 1α,25(HO)2-vitamin D3 deficiency may contribute to the inhibition of glucose-induced insulin secretion in uremia. Calcitriol mainly influences the first phase of insulin release and its effect may be due to a direct action on the pancreatic β-cell.

Early and Late Effects of Erythropoietin on Glucose Metabolism in Maintenance Hemodialysis Patients

The effects of recombinant human erythropoietin (rHuEPO) on the glucose metabolism were evaluated by intravenous glucose tolerance test in 20 maintenance hemodialysis patients. In 8 cases the glucose tolerance tests were performed before and after a single intravenous injection of 50 IU/kg of rHuEPO and in 12 cases before and after 3 months of rHuEPO therapy at doses of 50 IU/kg three times/week and 2 weeks after rHuEPO withdrawal. For each test glucose, immunoreactive insulin (IRI) and C peptide (C-p) plasma values were measured, and glucose constant decay, whole IRI (area IRI) and C-p area C-p) production, insulinogenic index, and insulin resistance index were calculated. After 3 months of rHuEPO therapy, the glucose constant decay increased significantly, area IRI, area C-p, and insulin resistance index decreased significantly, and the insulinogenic index did not change. No correlations were found between changes in hemoglobin values and changes in glucose metabolism parameters. Acute rHuEPO administration and rHuEPO withdrawal had no effect on glucose metabolism, despite significant changes in plasma erythropoietin levels. Long-term rHuEPO therapy improves glucose metabolism in maintenance hemodialysis patients significantly, mainly by reduction of insulin resistance. Neither anemia correction nor a direct effect of rHuEPO on some metabolic steps seem to be responsible of these effects.

Immune Response after Vaccination with Recombinant Hepatitis Surface Antigen in Maintenance Hemodialysis Patients and Healthy Controls

We evaluated anti-HBs titers 2 months after vaccination with recombinant hepatitis surface antigen (rDNA-HBsAg) in 43 maintenance hemodialysis patients (MHP). Of these, 34 had not undergone hepatitis B virus vaccination previously (NV-MHP) and 9 had shown negative response to vaccination with plasma-derived HBsAg (HEVAC Pasteur; V-MHP). 120 healthy workers from the same hospital undergoing rDNA-HBsAg immunization were used as controls. All low responders (LR) (anti-HBs less than 100 mIU/ml) and nonresponders (NR; anti-HBs less than 10 mIU/ml) were given a booster dose 3 months after the last dose of vaccine. Seroconversion rates were lower in NV-MHP (52.9%) than in controls (98.4%). V-MHP showed higher seroconversion rates (88.9%) than NV-MHP. In each group, the number of responders (R; anti-HBs greater than or equal to 100 mIU/ml), LR and NR was as follows: controls 101, 17, 2; NV-MHP 6, 12, 16; V-MHP 8, 0, 1. After booster dose, 17/17 controls LR and no NV-MHP LR showed a rise in anti-HBs titers over 100 mIU/ml. Six months after the last dose of vaccine or the booster dose, anti-HBs titer fell under 10 mIU/ml in 4/12 MHP LR and under 100 mIU/ml in 6/14 MHP R. To achieve high seroconversion rates and to avoid the decline of anti-HBs to nonprotective titers in MHP, a booster injection should be made at different dates after the first vaccination.

Prospective and retrospective assessment of clinical and laboratory parameters in maintenance hemodialysis patients with and without HCV antibodies

In order to clear some aspects of HCV infection, we evaluated quarterly HCV markers by a RIBA 1 test (antigens c100-3 and 5.1.1) and monthly transaminases (ALT and AST) for 14 months in 89 HBsAg-free maintenance hemodialysis patients (MHP), and we retrospectively examined clinical records until the start of hemodialysis treatment. At the start of the study, 16 patients showed HCV antibodies (HCV+) and 73 were antibody-free (HCV-). 39 subjects of the staff were also examined. No HCV+ patient showed seroconversion, 10 showed irregular or persistent elevation of AST and ALT. In the retrospective evaluation 14 patients suffered from acute hepatitis (AH). Only 3 cases showed temporal relation with blood transfusions. In 1 case a 36-month temporary normalization of transaminases was noticed. 3 HCV-patients showed seroconversion (1 during AH), 13 showed severe or moderate elevations of transaminases. In the retrospective evaluation, 6 patients suffered from AH. All subjects of the staff were HCV- and showed no seroconversion or changes of transaminases. At the end of the study, we performed a RIBA 2 test containing the HCV antigens c100-3, 5.1.1, c22-3 and c33c. The 6 patients who suffered from AH showed at least 1 positivity for new proteins. Most of AH in MHP are likely due to HCV infection; besides transfusions, cross-infection during the dialytic procedure may be responsible for many cases of HCV infection; long-term normalization of transaminases may not secure against infectivity.

Glucose-Induced Insulin Secretion in Uremia: Relation with Acid-Base Balance and Effects of Bicarbonate Administration

In order to evaluate effects of metabolic acidosis on glucose metabolism in uremia, we studied, by an intravenous glucose tolerance test (IVGTT), 46 patients with severe chronic renal failure divided into three groups according to their blood bicarbonate (BB) values: group A formed by 15 patients without or with light metabolic acidosis (BB > or = 20 mEq/1); group B formed by 18 patients with moderate metabolic acidosis (16 < or = BB < 20 mEq/1); group C formed by 13 patients with severe metabolic acidosis (BB < 16 mEq/1). In 8 patients of group B (subgroup B1) and in 8 of group C (subgroup C1), IVGTT was also repeated after adjustment of acid-base balance by intravenous or oral bicarbonate administration. Twenty-nine healthy volunteers formed the normal controls. For each test, glucose constant decay (K), immunoreactive insulin (IRI) area and C-peptide (C-p) area response, insulinogenic index (IGI) and insulin resistance index (RI) were calculated. Compared to controls, all uremic groups showed significantly lower values of K and IGI and significantly higher values of C-p area and RI. In group C, RI was significantly higher than in groups A and B. No differences were found in the other glucose metabolism parameters among the uremic groups. After bicarbonate administration, subgroup C1 showed a significant decrease in RI and a rise in K values, while subgroup B1 showed no changes in glucose metabolism parameters. From these data, we infer that abnormalities of acid-base balance do not affect insulin response but severe metabolic acidosis may play an additional role in the insulin resistance of uremic patients.

Glucose-induced insulin secretion in uremia: role of anemia.

Dr. Vincenzo Allegra, Servizio Emodialisi, Ospedale Civile, I-33057 Palmanova (Italy) Dear Sir, Impaired glucose metabolism in uremic patients has long been recognized [1]. However, until recently, little has been known about the pathogenetic mechanisms responsible for the disturbance in glucose metabolism [1]. Recently Kokot et al. [2] have found that erythro-poietin treatment improves insulin response and glucose tolerance after a test meal in maintenance hemodialysis (MH) patients, and concluded that anemia plays a major role in the derangement of glucose metabolism in uremia. Vasile et al. [3], using the intravenous glucose tolerance test (IVGTT), have not confirmed this report. Also studies in animals [4] have demonstrated that red blood cells actively participate in glucose homeostasis by regulating glucose transport to peripheric tissues. To clear the role of anemia in the pathogenesis of insulin response and glucose tolerance abnormalities in uremia, we studied glucose metabolism, by IVGTT, in nondialyzed and dialyzed uremic patients with different hemoglobin (Hb) levels. 54 patients with endstage chronic renal failure (ESRF) and 119 patients on MH were studied. Their body weights varied between 90 and 110% of ideal body weight; none showed severe hyperkale-mia. Abnormalities of acid-base balance in ESRF patients, if present, were corrected by oral bicarbonate therapy before the test. For MH patients dialysis schedule was as follows: 3.5-4.5 h × 3/week, plate or hollow fiber dia-lyzer with cuprophan membrane of 1-1.5 m2 surface and 8 μm thickness, blood flow 250-350 ml/min, dialysate flow 500 ml/min. IVGTT was performed 2-6 months after start of MH in the morning after the second weekly hemodialysis treatment, 39 patients were examined both in the phase of ESRF and after start of MH. Both ESRF and MH patients were divided into groups according to their Hb levels (A Hb≤6 g/dl, B6 < Hb≤8 g/dl, C8 < Hb≤10 g/dl, D Hb > lO g/dl). Four MH patients of group A were examined even after blood transfusions. For each test we measured plasma levels of glucose (G), immunoreactive insulin (IRI) and C-peptide (C-p) at -30,0,2, 5,15,30,45,60 min and we calculated glucose constant decay (K), IRI and C-p areas of response (IRI area, C-p area), insulinogenic index (IGI) and insulin resistance index (RI). The technique was described in detail in a previous investigation [5]. Results are summarized in table 1. No differences were found in the various glucose metabolism parameters among the groups both in ESRF and MH patients. The 39 patients examined before

Metabolic and hormonal assessment of patients on maintenance hemodialysis for 10 years or more and their importance in long-term survival.

We studied metabolic and hormonal patterns in 11 patients on hemodialysis for over 10 years (group A) to determine whether some metabolic abnormalities worsen with long-term dialysis or whether a particular endocrine-metabolic pattern discriminates long-term hemodialysis survivors. Data were compared to those of 14 subjects of similar age and sex on dialysis for 1-3 years (group B) and to those measured in the same patients during the 1st year of dialytic treatment. As to glucose metabolism, group A showed elevation of fasting plasma glucose and a decrease of glucose constant decay (K) and insulin production (IIG) values as compared to the 1st year of dialysis. No difference was found between group A now and group B. However in the 1st year of dialysis group A showed significantly higher K values than group B. As regards lipid metabolism, group A presented higher alpha-lipoprotein values and high-density lipoprotein-cholesterol/cholesterol, high-density lipoprotein-cholesterol/apoprotein A, and apoprotein A/apoprotein B ratios, while low-density lipoprotein-cholesterol and apoprotein B values and beta/alpha-lipoprotein ratio were lower. These data demonstrate less vascular risk in group A. We explain these results as depending on natural selection. Multivariate analysis of survival confirmed that survival in hemodialysis patients is influenced negatively by glucose and lipid metabolism abnormalities. As to Ca-P metabolism, group A showed higher carboxy-terminal parathyroid hormone and alkaline phosphatase values than group B. However, these data may be superimposed to those determined in the same patients in 1981, when we began the regular use of 1 alpha,25-(OH)2-vitamin D3.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-Term Monitoring of Iron Stores in Renal Transplant Recipients

Dr. Vincenzo Allegra, Servizio Emodialisi, Ospedale Civile, I-33057 Palmanova (Italy) Dear Sir, In a recent article [1] the authors found that serum ferritin (SF) levels in renal transplant recipients (RTR) 3 years after transplantation were similar in all patients and concluded that iron deficiency anemia is not clinically relevant because dietary iron is sufficient to normalize iron stores. In some situations, however, SF alone may not be indicative of the iron store status [2–4]. Recently we have developed a more sensitive criterion [4] than SF assay alone for iron store assessment in maintenance hemodialysis patients. In order to make clear whether this method is effective even in iron store assessment in RTR, we re-evaluated retrospectively iron stores in our RTR by SF levels and by this criterion. We studied 22 RTR (17 males and 5 females) with good graft function (serum creatinine < 2 mg/dl). The follow-up period after transplantation was between 13 and 97 months (mean ± SE: 50 ± 6 months). The patients were divided into three groups (A, B and C) according to their SF basal levels before transplantation: high (6 cases), normal (11 cases) and low level (5 cases), respectively. The normal reference range (19–191 μg/l) was calculated in 250 healthy volunteers [4]. In each patient we considered the following parameters monthly during the first 6 months and every 3 months thereafter: SF, hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), red cell distribution width (RDW), serum iron (Fe), total iron binding capacity (TIBC), saturation index of transferrin (SI). On these parameters we calculated the score according to our criterion [4] (score = 2.4 SF +11.4 Fe -0.8 TIBC +2.3 SI +1.8 MCV +30.5 MCH ± 55.1 RDW; optimal discriminant value =451). Changes in Hb and SF levels after transplantation are summarized in figure 1. Hb value rise was quicker in group A. At 6 months, however, Hb values were similar in all groups. Four patients of group A showed a very slow decrease of SF values (3 reverted to the normal range after 18, 42 and 51 months, respectively, and 1 had SF GROUP A GROUP B GROUP C 0 2 4 6 9 12 18 24 30 36 48 Months Fig. 1. Changes in the Hb and SF values after renal transplantation. Data are presented as mean ± SE; statistical analysis was performed by ANOVA table and Tukey’s test after conversion of