Agostino Mallamace

Parathyroidectomy in Chronic Renal Failure: Short- and Long-Term Results on Parathyroid Function, Blood Pressure and Anemia

To evaluate the long-term results of parathyroidectomy (PTX) on parathyroid function, blood pressure and anemia, data of 45 patients with secondary Hyperparathyroidism in dialysis who had undergone PTX were collected retrospectively from 8 different dialysis units. The patients, 25 M and 20 F, mean age 56 ± 11 years, who were followed up for an average period of 3.3 ± 2.3 years, were divided into four groups according to the surgical procedure: 19 patients had had a subtotal PTX; 10 patients had undergone total PTX with autotransplantation (AT); 10 patients had had total PTX without AT, and 6 patients had undergone partial PTX. Taking a reduction in intact PTH >50% as sign of successful PTX, only 5 patients did not attain this result. Considering values of PTH between 20 and 200 pg/ml at the mid-term observation (1–2 years) as the optimal result, values under 20 pg/ml as an expression of permanent hypoparathyroidism, and those above 200 pg/ml as indicating persistent/recurrent hyperparathyroidism, 65.5% of patients operated with subtotal PTX and total PTX + AT had a therapeutic success, versus 31.2% of patients in the other two groups, due to excess permanent hypoparathyroidism and persistent/recurrent hyperparathyroidism; 20 of 45 patients with preoperative hypertension experienced a statistically and clinically significant decrease in blood pressure levels. An increase in serum hemoglobin was also observed, despite a reduction of administered erythropoietin. In conclusion, the results of PTX obtained from this multicenter study are comparable to those reported by single leading centers. Recommended surgical procedures are subtotal PTX and total PTX with AT. The fall in blood pressure in hypertensive patients is clinically significant, and improvement in anemia is also observed with a reduction in erythropoietin dosage.

Involvement of Interleukin-18 in Patients on Maintenance Haemodialysis

Maintenance dialysis induces a clinical state of immunodeficiency. The pathway of circulating T cells from haemodialyzed patients is changed and characterized by an increase of Th1 cells. The unbalanced T helper differentiation derives from an altered regulation of interleukin-12 (IL-12), which represents an important inducer of Th1. IL-18 is a pro-inflammatory cytokine expressed by a variety of cell types that is structurally related to the Th1 family and shares biological properties with IL-12 as the promotion of Th1 responses. To explain the involvement of IL-18 in the typical disorders of dialysis, we analyzed IL-18 serum levels in a group of haemodialyzed patients. We enrolled 16 patients on chronic haemodialysis (HD) treatment for end-stage renal failure and 16 healthy volunteers as the control group. IL-18 levels were assessed by immunoenzymatic methods (detection limit was <12.5 pg/ml). HD patients strongly showed higher IL-18 serum levels compared to healthy donors (508.47 ± 314.39 vs. 193.44 ± 56.33 pg/ml, p < 0.005). Moreover, IL-18 levels in HD directly correlated to dialytic age (Rho = 0.544, p = 0.0419) and indirectly to Kt/V (Rho = 0.703, p = 0.0086). Our data represent the first evidence of the relation between IL-18 serum levels and HD. In the light of our results, we think that the unbalanced T helper differentiation may depend, at least in part, on an abnormality in the IL-18 production.

Phosphate Salivary Secretion in Hemodialysis Patients: Implications for the Treatment of Hyperphosphatemia

Background/Aims: Hyperphosphatemia is recognized as contributing to the increased risk of cardiac death in end-stage renal disease (ESRD) and hemodialysis (HD) patients. Currently available pharmacologic treatment for hyperphosphatemia is based on phosphate binders but, despite treatment, only half of the patients fall within the range for serum phosphorus of the K/DOQI guidelines. Therefore, there is a need to identify other therapeutic approaches in order to reduce serum phosphate. Salivary fluid contains phosphate which, if related to the daily salivary secretion (1,000–1,880 ml), may raise interest in order to identify further additive approaches to phosphorus removal in uremic patients, while data about salivary phosphate secretion in ESRD patients are controversial. Methods: This study evaluates salivary phosphate secretion in 68 HD patients compared with 30 healthy subjects. Saxon’s test confirmed normal salivary function in patients and controls. Salivary calcium and serum phosphate, calcium and PTH were also measured. Results: HD patients had significantly higher salivary phosphorus levels compared with healthy controls: 30.35 (26.5–34.6) vs. 12.1 (10.58–14.73) mg/dl (p < 0.0001), and this significantly correlated (p < 0.0001) with serum phosphorus. Multiple regression analysis confirmed serum phosphorus as the only predictor (p < 0.0001) of salivary phosphorus. Conclusions: Given the functional secretive similarity between salivary glands and the kidneys, this increased salivary phosphate secretion might be interpreted as being compensatory in the presence of renal failure. Absorption of the increased salivary phosphate secretion, however, may worsen hyperphosphatemia; therefore, the binding of salivary phosphate might be considered as a further therapeutic approach to hyperphosphatemia in ESRD.

Salivary phosphorus and phosphate content of beverages: implications for the treatment of uremic hyperphosphatemia.

BACKGROUND Hyperphosphatemia provides relevant and dangerous evidence of end-stage renal disease (ESRD) in patients undergoing periodic hemodialysis. The relationship between hyperphosphatemia and cardiovascular calcification, with the consequences of high morbidity and mortality after cardiovascular events, is well-defined. Hyperphosphatemia is treated by dietary limitation of phosphorus ingestion and by phosphate binders, but only half of ESRD patients fall within the range of K/DOQI guidelines. OBJECTIVE AND METHODS We summarize the results of our studies on salivary phosphate secretion in hemodialysis (HD) and chronic kidney disease (CKD) patients, and on the habit of HD patients to drink beverages with a high or low phosphate content. We also examine the correlation between hyperphosphoremia and the phosphate content of common beverages consumed by HD patients. RESULTS AND CONCLUSIONS Higher levels of salivary phosphate secretion were found in HD and in CKD patients, along with a relationship between serum phosphorus levels and a high phosphate content of beverages in HD patients.

HLA haplotype in a patient with systemic lupus erythematosus triggered by hepatitis B vaccine.

AIM Find an association between hepatitis B vaccine-related systemic lupus erythematosus and HLA. MATERIAL A 27-year-old woman who developed a lupus nephritis after the administration of hepatitis B vaccine. METHODS We studied HLA antigen expression on lymphocytes and genomic haplotype. Class I-II HLA antigen typing was performed by the microlymphocytotoxicity test with the standard NIH method, and Class I-II HLA allele typing by polymerase chain reaction, using single-strand oligonucleotide dot-blot kits. RESULTS The serological haplotype was HLA A24/25, B18 (Bw6)/-, C-/-, DQ7/-, DR11(5)/52. The genomic haplotype was A*2403/2504, B*1825/1825, C*1207/ 1207, DRB1*1102/1132, DRB3*0202/0202, DQA1*0505/0505, DQB1*0301/0301. Then we sought for analogies with haplotypes known to be related to other systemic AID. Since we have found HLA alleles typical both of systemic lupus erythematosus and Sjogrens syndrome, the persistence of ENA-SSA positivity was highly suspicious for a possible overlap syndrome. CONCLUSIONS Hepatitis B vaccine can potentially trigger both the onset or the exacerbations of several autoimmune disorders, including systemic lupus erythematosus, by reduced immune complex clearance or molecular mimicry. This study represents the first report on the association between hepatitis B vaccine related systemic lupus erythematosus and HLA. Probably autoimmune reactions triggered by vaccines occur only in predisposed subjects, in which antigen presentation influenced by HLA haplotypes leads to the autoimmune cascade. More studies are needed to corroborate our hypothesis. They could disclose new pathways in the field of prevention.

Sevelamer carbonate in the treatment of hyperphosphatemia in patients with chronic kidney disease on hemodialysis

Sevelamer carbonate is an anion exchange pharmaceutical, developed to improve on the performance of the non-absorbable, non-calcium, and metal-free phosphate binder sevelamer hydrochloride. Sevelamer carbonate is expected not to worsen metabolic acidosis, as previously reported during long-term treatment with sevelamer hydrochloride in hemodialysis (HD) patients. Carbonate is the alternate counterion to chloride on the sevelamer polymeric backbone, but the active poly(allylamine) responsible for phosphate (PO4) binding remains unaltered. Therefore, sevelamer carbonate is expected to reduce elevated serum phosphorus level, similarly to sevelamer hydrochloride. Sevelamers are prescribed in uremic HD patients to control hyperphosphatemia, but the carbonate has also been proposed for the treatment of chronic kidney disease (CKD) non-dialysis patients. Although hyperphosphatemia is regarded as a main contributor to increased mortality in the HD population because of cardiovascular calcification, metabolic acidosis has also been advocated as a major player in the increased mortality in this population, by engendering malnutrition, negative nitrogen balance, and inflammation. This paper reviews the evidence showing that sevelamer carbonate is as good as sevelamer hydrochloride in terms of hyperphosphatemia control in CKD, but with a better outcome in serum bicarbonate balance.

Time-dependent effect of sevelamerHCl on the cardiovascular system.

These potential benefits of newer agents, including sevelamer, and other anion-exchange resins, as discussed by Drs Wrong and Harland [5], are supported, only in part, by very large-scale observational studies, where lower levels of serum calcium, phosphorus, and less so parathyroid hormone, are associated with improved survival for people with chronic kidney disease [1,6]. As we have previously discussed extensively, this is not enough [7–9]. What remains important is that the direct relationship between modification of calcium, phosphorus or PTH with improved survival and cardiovascular outcomes in randomized, controlled trials is still far from proven. This is despite the largest trial in this area, the Dialysis Clinical Outcomes Revisited (DCOR) trial enrolling over 2100 patients to either sevelamer or calcium salts, which showed no difference for mortality between treatment arms [10] and the meta-analyses of phosphate binders [11], calcimimetics [9] and vitamin D compounds [8]. The ongoing search for efficacious and cost-effective agents, such as anion exchange resins, is laudable. Therefore, the suggestion of Wrong and Harland that colestipol, or other cheaper alternatives, could be promoted in preference to the more expensive sevelamer, is appealing. However, while these and other measures may be temporarily supported, the real priority for resources in this area should be directed at understanding the effects of the treatment for altered mineral metabolism on patient centred outcomes, including bone pain, cardiovascular events and mortality in chronic kidney disease. Do any of these drugs, which can control phosphorus levels, really have any effect on reducing the excess mortality which is attributable to high serum phosphorus levels in chronic kidney disease? Certainly there are numerous resins that can be used to absorb intestinal phosphorus, but just as well there are now numerous data to support that adequately powered, randomized trials investigating either pharmaceutical agents or the serum targets of calcium, phosphorus and parathyroid hormone levels should be developed.

Defense mechanisms in hemodialysis-dependent patients.

Defense mechanisms are automatic psychological processes that protect the individual against anxiety and from the awareness of internal or external dangers or stressors. The influence of defense mechanisms in patients on chronic hemodialysis treatment was studied. There were 53 uremic subjects (37 males and 16 females), aged between 22 and 88 years (mean age 60.11, SD 15.03), on chronic dialysis and 50 healthy subjects as controls have been enrolled in the study. According to the duration of dialysis, uremic patients were divided in two subgroups: 21 patients with less than 5 years and 19 patients with more than 10 years of dialytic treatment. Assessment was conducted using the Defense Mechanisms Inventory DMI. The inventory identifies five defensive styles: turning against the object (TAO), projection (PRO), principalization (PRN), turning against the self (TAS) and reversal (REV). Results showed DMI scores within the normal range both for uremics and controls with significant differences in TAO (t = -3.053, p = 0.003) and REV (t = 5.067, p < 0.0001) between groups. No significant differences in the use of defensive styles related to the duration of dialytic treatment were observed. Besides other psychological features, the assessment of defense mechanisms in patients with chronic and invalidating diseases may contribute to ameliorate the knowledge of the adjustment processes and of the psychological well-being of the patients.

The discovery of nephrouroameba: was it real or not?

In 1938 Procaccini showed scientific interest in a new kind of ameba, and called it ‘nephrouroameba’ from which the disease ‘nephrouroamebiasis’ is derived. He wrote a paper titled ‘La Nefrouroamoebiasi’ thus describing its history, the biopathogenetic evolutionary cycle of the protozoon, its therapeutic, epidemiological, anatomo-biological, diagnostic, cultural, biological and morphological features. Between 1934 and 1939, Procaccini had the opportunity to follow many patients belonging to a group of Italian soldiers serving in the Eastern Italian Army in Ethiopia. At that time he was responsible for the biopathological laboratory. After a short preclinical stage of fatigue, patients suffering from nephrouroamebiasis showed a nephrotic syndrome with gross hematuria. The symptoms ceased within a few days but residual microhematuria, albuminuria and urine casts persisted for many months. After microscopic observation, he reproduced some protozoons and classified them as a kind of ameba. Critical analysis of his report leads to the morphological identification of Trichomonas, thus excluding his classification as nephrouroamebas.

Intradialytic Behaviour of β-2-Microglobulin During Acetate Dialysis (HDac), Biofiltration (BF) and Paired Filtration Dialysis (PFD)

Literature data report the presence of a like-amyloid substance in the tendons, synovias and in the bones of the patients undergoing long term dialytic treatment (1,2,3,4). The β-2-microglobulin, produced by lynphoid cells and by the mastocytes when the blood comes into contact with the dialytic membranes, was identified as the most important component of the like-amyloid substance. Many autors (1,2,3,4) refer that the above substance plays a negative role on the bones allegation progression of the dialyzed patients and it may be considered as an index of the adequate dialysis. The above considerations and the introduction of the PFD among the new dialytic strategies, suggested us to carry a study on the intradialytic behaviour of β-2-microglobulin during standard haemodialytic treatment using cuprophan membranes during BF and during PFD using respectively AN 69 S and Cuprophan associated to Polisulphone membranes.