Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Reduced glomerular filtration rate and prior cardiovascular event entail similar risk for coronary atherosclerotic burden

OBJECTIVE

Prior cardiovascular event and kidney dysfunction are both strong risk factors for coronary artery disease. The aim of this study is to assess coronary atherosclerotic burden in a large population of patients undergoing coronary angiography, according to prior cardiovascular event or chronic kidney disease.

PATIENTS AND METHODS

We evaluated 700 consecutive patients who underwent coronary angiography (CA). Serum creatinine to estimate glomerular filtration rate (eGFR) was measured. Clinically significant coronary artery disease (CAD) was defined by the presence of a coronary lesion resulting in a luminal stenosis >50%. For the purpose of the study, the whole population was divided into 4 subgroups according to the presence/absence of eGFR <60 ml/min/1.73 m2 or prior cardiovascular event: eGFR≥60/no event (Group A), eGFR≥60/yes event (Group B), eGFR<60/no event (Group C), eGFR<60/yes event (Group D).

PATIENTS

As expected, patients in group D had the worst clinical and biochemical profile. These patients also presented the highest values of urinary albumin creatinine ratio (ACR, p<0.001) and the lowest values of eGFR (p<0.01). One-hundred-ninety-six patients had three-vessel disease. Patients who had undergone PCI procedure showed a lower eGFR as compared to patients who had not (p=0.009). Considering group A as reference, the risk of having three-vessel disease was increased in group B (OR= 2.09; 95% CI 1.37-3.19), in group C, (OR= 1.80; 95% CI 1.04-3.14), and finally in group D (OR= 3.35; 95% CI 2.01-5.58). The risk carried by group C was not significantly different from that carried by Group B: OR= 0.86; 95% CI 0.5-1.5.

CONCLUSIONS

In our study, low eGFR seems to have the same excess risk of prior CV event.

Reduction of Mononuclear Cytokine Production in Hemodialysis Patients Treated with Steam-Sterilized Low-Flux Polysulphone Membranes

An increased cytokine production, correlated with long term complications of uremic disease, has been described during hemodialysis. To identify possible differences in the cytokine release of differently sterilized membranes, we enrolled six uremic patients on chronic hemodialysis. The patients underwent dialysis with ETO-sterilized low-flux polysulphone membranes (F6, Fresenius AG) for at least three months (At), they were then switched to steam-sterilized polysulphone membranes (F6-HPS Fresenius AG) and further evaluations after one (B1) and two months (B2) were carried out. A final evaluation (A2) was made one month after switching back to F6 dialyzers. At each time period, samples were drawn to measure IL-1B released by cultured mononuclear cells (MN). Moreover, dialysate samples were collected to test endotoxin levels. C3a and C5a levels were assessed at 0, 5, 15 and 60 min from starting hemodialysis. Anti-ETO IgE levels were also assayed at A1, B1 and A2.

The LAL test revealed a good quality dialysate. The mean pre-dialysis IL-1B levels were 215 pg/million cells at A1; falling to 49 at B1, and 54 at B2 (p≤0.01); there was then a sharp rebound at A2:284, p≤0.01. Post-dialysis levels followed the same pattern. No correlation between the dialysate endotoxin level and cytokine release was found. Complement activation did not change and in all the phases of the study no anti-ETO IgE was detected in any of the subjects. Our data suggest that the steam sterilized polysulphone membrane induces a lower cytokine release than the ETO sterilized membrane, although the mechanism by which it does so remains to be clarified.

Hepatitis C Virus Infection and Diabetes Mellitus in End-Stage Renal Disease: Evidence of a Negative Association

Epidemiological studies have implicated hepatitis C virus (HCV) infection in the pathogenesis of diabetes mellitus (DM) both in the population as a whole and after solid organ transplantation. Whether this association exists in patients with end-stage renal disease (ESRD) undergoing dialysis is unclear. The aim of this study is to investigate the relationship between HCV and DM in a large group (n = 742) of patients with ESRD from Europe and North America. The presence of diabetes was ascertained by using American Diabetes Association guidelines based on fasting glucose measurement and medication history. Presence of HCV infection was assessed by serum testing for anti-HCV antibodies. The prevalence of anti-HCV antibody positive patients was 15% (112/742); the frequency of DM was higher among anti-HCV positive than -HCV negative patients but the difference did not approach statistical significance, 32% (36/112) vs 29.5% (186/630). The frequency of patients with diabetic nephropathy was not higher in anti-HCV positive than -negative patients; 21.4% (24/112) vs 23.3% (147/630), NS. Logistic regression model showed an independent and significant link between anti-HCV seropositive status and raised GPT (P = 0.032), male gender (P = 0.0462), positive history of prior renal transplant (P = 0.0006), and longer time on dialysis (P = 0.00001). In summary, no link between anti-HCV antibody and DM occurred in this ESRD population; there was no association between rate of anti-HCV antibody and diabetic nephropathy.

Intra-dialytic blood oxygen saturation (SO2): association with dialysis hypotension (the SOGLIA Study)

BACKGROUND

Intradialytic hypotension (IDH) has a dramatic impact on the main outcomes of dialysis patients. Early warning of hemodynamic worsening during dialysis would enable preventive measures to be taken. Blood oxygen saturation (SO₂) is used for hemodynamic monitoring in the critical care setting and may provide useful information about IDH onset.

AIM

To evaluate whether short- and medium-term variations in the SO₂ signal (ST-SO_2var, MT-SO_2var,) during dialysis are a predictor of IDH.

METHODS

In this 3-month observational cohort study, 51 hypotension-prone chronic hemodialysis (HD) patients, with vascular access by arteriovenous fistula (AVF) or central venous catheter (CVC), were enrolled. Continuous non-invasive blood SO₂ was monitored (fc = 0.2 Hz) by an optical sensor on the arterial line of the extracorporeal circulation; blood pressure (every 30 min), symptoms and their time of appearance were noted. Predictive power of IDH was expressed by the area under curve (AUC) sensitivity and specificity based on intradialytic variations in SO₂.

RESULTS

A total of 1290 HD sessions were analyzed. Overall, off-line ST-SO_2var analysis proved able to correctly predict IDH in 67 % of the sessions where IDH occurred. The best predictive performance was found in the presence of highly arterialized AVF (SO₂ > 95 %) (75 % sensitivity; AUC 0.825; p < 0.05). On the contrary, in sessions with CVC, IDH prediction proved more efficient by MT-SO_2var (AUC 0.575; p = 0.01).

CONCLUSIONS

Intradialytic SO₂ variability could be a valid parameter to detect in advance the hemodynamic worsening that precedes IDH. Appropriate timely intervention could help prevent IDH onset.

New horizon in dialysis depuration: Characterization of a polysulfone membrane able to break the ‘albumin wall’

The uremic syndrome is attributed to the progressive retention of a large number of toxins, which under normal conditions are excreted by the healthy kidneys. Standard dialytic membranes do not purify middle-high molecular weight toxins. Haemodiafiltration with endogenous reinfusion coupled with a highly permeable membrane could break the limit of the ‘albumin wall’ improving the dialytic depuration without loss of important nutrients.

The aim of this study was to evaluate the performance of a new polysulfone membrane, Synclear 0.2, to remove uremic molecules. Surface Enhanced Laser Desorption Ionization-Time of Flight was employed to evaluate the proteomic profile of ultrafiltrate and Electrospray Ionization-Quadruple-ToF coupled with on-chip elution was used for proteins identification.

A high and specific permeability for middle-high molecular weight molecules was revealed by mass spectrometry for the investigated membrane. The identified proteins are mostly uremic toxins: their relative abundance, estimated in the ultrafiltrate by exponentially modified protein abundance index, showed a high purification efficiency of the new membrane when compared with conventional ones.

In conclusion, Synclear 0.2, used as convective membrane in hemodiafiltration with endogenous reinfusion treatment, permits to break the ‘albumin wall’, clearing middle-high molecular weight uremic toxins, improving the dialytic treatment purification efficiency.

[The acute renal and cerebral toxicity of lithium: a cerebro-renal syndrome? A case report]

This descriptive report describes the case of a 50 year-old woman with bipolar disorder, whose maintenance therapy comprised risperidone, sodium valproato and lithium carbonate without any past occurrence of toxicity. Her past medical history was significant for hypertension, cardiopathy and obesity. She presented with a 1-week history of fever, increasing confusion and slurred speech. At presentation, the patient was somnolent. Laboratory investigations revealed a serum creatinine of 3,6 mg/dl, BUN 45 mg/dl serum lithium 3,0 mEq/L with polyuria defined as more than 3 litres a day. EEG and ECG were abnormal. CT brain scanning and lumbar puncture were negative for brain haemorrage or infection. Lithium toxicity causes impairment of renal concentration and encephalopathy due to lithium recirculation, a mechanism responsible for the so-called cerebro-renal syndrome, where dialysis plays an important role in treatment.The patient was treated with continous veno-venous haemodiafiltration (CVVHDF) over 35 hours with gradual improvement of her general condition and efficacy of renal concentration. Our case highlights a few important points. Lithium nefrotoxicity and neurotoxicity can cause a cerebro-renal syndrome even when serum lithium levels are not particularly raised (2,5-3,5 mEq/L). Haemodialysis is the treatment of choice to reduce the molecular mechanisms of lithium-related changes in urinary concentration and reinstate dopaminergic activity in the brain.

Clock gene expression in mouse kidney and testis: analysis of periodical and dynamical patterns

Molecular clocks drive circadian rhythmicity of cellular functions in peripheral tissues and organs, kidney included, whereas in the testis this clockwork seems constitutively active. We have evaluated the periodicity and the dynamics of expression of the clock genes BMAL1, CLOCK, PER1, PER2, CRY1, CRY2 and REV ERBalpha over 24 h in the kidney and testis using a mouse model. The periodicity was explored by single cosinor, and dynamics were explored by calculation of fractional variations of gene expression related to time intervals. Kidney and testis were harvested at 4-h intervals over a 24-h period from eight-week-old C57BL/6 male mice housed individually on a 12 h light (L)-dark (D) cycle (lights on at 08:00 h; lights off at 20:00 h) and mRNA was extracted and analyzed by Quantitative Real-time Reverse Transcription PCR. A statistically significant difference was evidenced between kidney and testis for the original values of expression level of BMAL1, PER1, PER2 CRY1, CRY2 and REV ERB&#945;. A statistically significant difference was evidenced between kidney and testis for the fractional variation of BMAL1, PER2, CRY1, CRY2 and REV ERB&#945;. A significant 24-h rhythmic component was found for BMAL1, CLOCK, PER1, PER2, CRY1, CRY2 and REV ERB&#945; in the kidney, whereas no core clock gene showed circadian rhythmicity in the testis. Fractional variations provided significant circadian rhythms for BMAL1, PER2, CRY, CRY2 and REV ERB&#945; in the kidney, whereas in the testis the fractional variation calculations showed no circadian rhythmicity, but quantitative comparison showed statistically significant differences in only 16.7 percent of the time points studied. In conclusion, in the kidney the clock gene machinery shows circadian oscillation of mRNA levels and time-related variations in the rate of change of clock gene expression. In the testis the clock genes do not show circadian rhythmicity of expression and the dynamics of variation are not characterized by a periodical pattern, but are quantitatively similar to those observed in the kidney. These data suggest that in the testis the clock gene machinery shows a tissue-specific pattern of function and clock genes may play a different role in the testis with regard to other peripheral tissues, maybe in relation to the presence of developmental and differentiation phenomena.

[Color-Doppler ultrasound in renal artery stenosis and cardiovascular risk: case report]

Renal artery stenosis (RAS) is a common manifestation of generalized atherosclerosis, frequently involving other vascular districts, particularly the coronary tree. Duplex ultrasonography is the diagnostic procedure of choice for screening outpatients for RAS. We report a case of metabolic syndrome in a 63-year-old obese man with atherosclerosis and low-grade RAS that was an important sign of cardiovascular risk. In fact, cardioscintigraphy and coronary arteriography showed severe coronary artery disease. RAS is an independent predictor of adverse cardiovascular events such as myocardial infarction, stroke, and cardiovascular death. In this case, duplex ultrasonography demonstrated the importance of screening for RAS as the expression of coronary artery disease.

Proteinuria in the prognosis of IgA nephropathy

IgA Nephropathy (IgAN) is the most common lesion causing primary glomerulonephritis in the world. The main clinical predictors of progression are: elevated blood pressure, high histological score and proteinuria. Although elevated serum creatinine concentration at diagnosis, increased excretion of cytochines, age at onset, obesity and genetic factors may all influence clinical outcome, it is quite clear that proteinuria is the hallmark of renal damage in IgAN. Patients with IgAN and little or no proteinuria (<500 mg/day) have low risk of progression in the short term, while the rate of decline in renal function is 25-fold faster in those with sustained proteinuria >3 g/day. The product of duration (years) and urinary protein excretion (g/day) at the time of renal biopsy is more significantly correlated with progression. So, this so called proteinuria index may be a useful predictor for glomerular and interstitial histopathological changes and the fate of renal function in IgAN. The progression of IgAN may be slowed by antihypertensive and antiproteinuric therapy, such as angiotensin converting enzyme inhibitors and/or angiotensin II receptor blockers, that can minimize secondary glomerular injury. Proteinuria has been shown to be an adverse prognostic factor in IgAN, with a strong relationship between proteinuria and prognosis and established importance of remission. Consequently, targeting proteinuria may be a valid surrogate for individualized kidney protective therapy.

[Uremic pruritus: an unresolved challenge]

Pruritus is a common and unpleasant symptom in the dialysis setting, affecting about half of all hemodialysis and peritoneal dialysis patients. It has a great impact on patients' quality of life and is also associated with increased mortality. The pathogenesis of uremic pruritus (UP) is clearly multifactorial and still poorly understood. At least four main hypotheses have been put forward: dermatological abnormalities, an immune-system derangement that results in a proinflammatory state, an imbalance of the endogenous opioidergic system, and a neuropathic mechanism. The neurophysiology of itch has been shown to be quite similar to that of pain, supporting the hypothesis that the two phenomena may be closely related in dialysis patients, who often also experience uremic neuropathy. Moreover, an array of other triggering factors may include uremic toxins, systemic inflammation, cutaneous xerosis, and common comorbidities such as diabetes mellitus, endocrinopathies and viral hepatitis. The first step in the treatment of UP focuses on some general strategies that include the optimization of the dialysis schedule using biocompatible membranes such as polymethyl methacrylate, and the control of the divalent ion metabolism. The second step may be local therapy with skin emollients and capsaicin creams. More specific treatments that appear promising but have not been proven to be definitively efficacious include UVB light, gabapentin and the novel k-opioid-agonist nalfurafine. Nephrologists, who still tend to neglect this disabling symptom, need to be aware that UP is associated with poorer patient outcomes and that a stepwise therapeutic approach is now available.

[Why does a patient on hemodialysis have radiopaque material in his abdomen?]

Lanthanum is a third-generation, non-calcium and non-aluminium-based phosphate binder indicated for the treatment of hyperphosphatemia in stage 5 chronic kidney disease. The drug is well tolerated, with gastrointestinal complications as its main side effect. Recently, some case reports have described the typical X-ray features of this compound. We report another case of the radiopaque appearance of lanthanum carbonate, which underlines that clinicians need to be aware that its ingestion may cause opacifications in the colon.

Kinetics of hepatitis B virus load and haemodialysis: a prospective study

The control of the spread of hepatitis B virus (HBV) infection within dialysis units has been an important goal in the management of patients on regular dialysis but infected patients continue to enter the dialysis system. It is evident that HBV viraemia in hepatitis B surface antigen (HBsAg)-positive patients on dialysis is low but it remains unclear whether haemodialysis per se can contribute to viral load reduction in such patients. HBV DNA was determined in 40 HBsAg-positive patients on maintenance haemodialysis immediately before and at the end of a 4-h haemodialysis session. The same measurements were repeated 48 and 72 h later. Twenty (50%) of 40 HBsAg-positive patients had detectable HBV DNA in serum. Detectable HBV DNA in serum was not predicted by demographic, clinical or biochemical parameters. HBV load decreased in the majority of patients after haemodialysis, although the difference was not significant (29 390 +/- 48 820 vs 23 862.8 +/- 4 350 copies/mL, NS). There was a strong relationship between mean HBV DNA levels before dialysis and absolute reduction of HBV DNA during haemodialysis sessions (r = 0.75, P = 0.0001). No difference occurred in the magnitude of change in HBV DNA titre when comparing cellulosic to synthetic membranes. Haemodialysis per se leads to a reduction in HBV load in HBsAg-chronic carriers on maintenance dialysis. This phenomenon could explain the low viral loads in these patients. Prospective studies are in progress to identify the mechanisms responsible for reduction in HBV load during haemodialysis.

[Health-related quality of life in patients with chronic kidney disease]

Assessment of quality of life in patients with different degrees of chronic kidney disease is an important issue because of its impact on clinical decisions and financial resource management in the health-care system. The aim of this study was to assess whether a generic instrument like the SF-36 questionnaire is able to discriminate three different populations of patients with different degrees of renal disease (pre-ESRD, ESRD, TxR). Five hundred sixty-three patients from 12 Italian nephrology units completed the SF-36 scales by themselves. The results from these samples were compared with those from the general population. Univariate analysis and multivariate regression were used. The generic SF-36 questionnaire proved to be a powerful instrument to discriminate populations with different degrees of chronic renal failure. The quality of life of patients on dialysis is significantly worse than that of the normal population and other patients with less severe renal function impairment.

[Health technology assessment]

Health technology assessment (HTA) provides information about the effectiveness, costs and broader impact of health technologies to those who plan, administer or receive care in the national health system. ''Technology'' includes all interventions used to promote health, prevent and treat disease, and improve rehabilitation and long-term care. An HTA program addresses the questions to which patients and the national health systems need answers, by investigating four main factors: whether the technology (intervention) works, for whom and at what cost, and how it compares with alternatives. Health technology assessment is not simply another kind of research. It has a number of key features that are critical to its ongoing impact and distinguish it from research: it is policy oriented, it is interdisciplinary in its content and procedures, it summarizes information from databases/reviews and sometimes produces original data; moreover, those engaged in health technology assessment recognize the importance of disseminating and communicating the information acquired. Health technology assessment constitutes a bridge between the world of research and the world of decision-making, particularly policy-making, in health care.

Gamma glutamyltranspeptidase activity and viral hepatitis in dialysis population

BACKGROUND

Numerous investigations have reported that viral hepatitis is associated with significant hepatocellular damage, as expressed by raised aminotransferases in serum, in dialysis population. However, scarce information exists on the activity of gamma glutamyltranspeptidase (GGTP) in dialysis patients with infection by hepatotropic viruses.

OBJECTIVES

We measured serum GGTP values in a large cohort (n=757) of patients receiving long-term dialysis; healthy controls were also included. The relationship between GGTP values and a series of demographic, clinical, and biochemical parameters was analyzed.

METHODS

Serum GGTP levels were tested by spectrophotometry. A subset (n=333) of dialysis patients was tested by molecular technology (branched-chain DNA (bDNA) assay) to evaluate the relationship between serum GGTP and HCV viremia. A subgroup (n=78) of dialysis patients was analyzed by an ultrasound scan of gallbladder and biliary tract to assess the presence of gallstone disease. Multivariate analyses were made using regression models; serum GGTP values were included as a dependent variable. The usefulness of serum GGTP levels in detecting HBsAg and anti-HCV positivity was evaluated using receiver operating characteristics (ROC) curve analysis.

RESULTS

Univariate analysis showed that serum GGTP levels were significantly higher in HBsAg positive and/or anti-HCV positive patients than in HBsAg negative/anti-HCV negative patients on dialysis; 85.1+/-184.1 versus 25.86+/-23.9 IU/l (P=0.0001). The frequency of raised GGTP levels was 22.2% (41/184) among dialysis patients with chronic viral hepatitis. Multivariate analysis showed a significant and independent association between serum GGTP values and positive HBsAg (P=0.005) and anti-HCV antibody (P=0.0001) status. Mean GGTP values were significantly higher in study patients than controls, 32.32+/-60.02 versus 23.5+/-16.92 IU/L (P=0.01); however, no significant difference with regard to GGTP between study and healthy cohorts persisted after correction for age, gender, race, and viral markers. No relationship between gallstone disease and serum GGTP was found (NS). An independent and significant association (P=0.0291) between raised GGTP levels and detectable HCV RNA in serum was noted among patients tested by biology molecular techniques. ROC technology demonstrated that GGTP was equally useful for detecting HBV (P=0.0004) and HCV (P=0.0005) among dialysis patients.

CONCLUSIONS

We found an independent and significant association between serum GGTP values and HBsAg and/or anti-HCV antibody in dialysis population. Twenty-two percent of dialysis patients with chronic viral hepatitis had elevated GGTP. No difference in GGTP between HBsAg- negative/anti-HCV- negative dialysis patients and healthy individuals was found. Routine testing for serum GGTP levels to assess liver disease induced by hepatotropic viruses or other agents in dialysis population is suggested.

Quantitative ultrasound technique at the phalanges in discriminating between uremic and osteoporotic patients

This study was conducted to test the ability of quantitative ultrasound technique (QUS) at the phalanges to discriminate between uremic and osteoporotic patients. Three groups of subjects (38 dialytic women, 16 osteoporotic women with vertebral fractures, 19 non-dialytic and non-fractured women) were recruited at the Department of Radiology at "Casa Sollievo della Sofferenza" Hospital, San Giovanni Rotondo, Italy. The groups were matched for age and body mass index (BMI). On all subjects the following measurements were performed: spinal BMD by QCT and by DXA, Femoral BMD by DXA, phalangeal QUS. For QUS measurements, the DBM Sonic (IGEA, Carpi, Italy) was applied to the metaphysis of the proximal phalanges of the last four fingers of the hand. Osteoporotic women with vertebral fractures showed significantly lower values of spinal BMD by QCT and DXA and Ward's Triangle BMD with respect to hemodialytic patients (p<0.005). All QUS values, except for BTT and SoS, showed lower values in osteoporotic women with respect to hemodialytic patients (p<0.05). Control group showed higher values of AD-SoS, BTT and SoS than hemodialytic patients (p<0.005) while the two groups did not differ for BMD values measured with both QCT and DXA. UBPI and FWA data showed a similar behaviour to DXA and QCT results, whereas BTT and SoS showed a completely different behaviour. AD-SoS was the only parameter that could effectively discriminate among the three groups (ANOVA, p<0.0001). We conclude that phalangeal QUS can discriminate between hemodialysed patients and controls with similar bone mineral density, and can also discriminate between hemodialysed and osteoporotic subjects with vertebral fractures. Different characteristics of ultrasound signal can be ascribed to each bone tissue condition, enabling a clear differentiation of bone tissue changes occurring in menopause, osteoporosis and renal osteodystrophy.

Posttransplant recurrence of proteinuria in a case of focal segmental glomerulosclerosis associated with WT1 mutation

Posttransplant recurrence of inherited focal segmental glomerulosclerosis (FSGS) is still an enigma owing to the evident paradox of the molecular origin of proteinuria. A young girl with FSGS for WT1 mutation (IVS9+4C>T) and Frasier syndrome received a renal transplant at the age of 11 years. After an initial good outcome with recovery of renal function, proteinuria re-appeared after 7 days and steadily increased up to a nephrotic range. Determination of plasma permeability activity showed concomitant high Palb (0.7). At this point, plasmapheresis was started and after nine cycles with 1500 mL exchange and albumin re-infusion, proteinuria decreased to normal range and is still normal after 3 years. This is the first description of posttransplant recurrence of proteinuria in Frasier syndrome that should be included in potential outcome of renal transplant in this category of patients. This observation confirms the concept that recurrence of proteinuria may occur in inherited forms of FSGS so far reported only for patients carrying NPHS2 mutations and reinforces the idea on multifactorial origin of the disease.

Occult hepatitis B virus infection in dialysis patients: a multicentre survey

BACKGROUND

The epidemiology and clinical significance of occult hepatitis B virus infection (serum hepatitis B surface antigen-negative patients with detectable hepatitis B virus viraemia in serum) remains controversial with only limited information about its prevalence in patients on long-term dialysis.

AIM

To address the epidemiology of occult HBV infection in a large cohort of dialysis patients.

METHODS

We screened a large cohort (n = 585) of Italian chronic dialysis patients; from this population, a group of hepatitis B virus surface antigen seronegative patients (n = 213) was tested by Amplicor hepatitis B virus Monitor Test to detect hepatitis B virus viraemia (hepatitis B virus-DNA) in serum.

RESULTS

Occult hepatitis B virus infection was absent (zero of 213 = 0%). Persistent hepatitis B virus surface antigen carriage was less frequent than anti-hepatitis B virus core antibody (anti-hepatitis B core antigen) seropositive status in this study group [1.88% (11 of 585) vs. 36% (216 of 585), P = 0.0001]. No dialysis patients seropositive for anti-hepatitis B core antibody in serum (zero of 123 = 0%) had detectable hepatitis B virus-DNA by polymerase chain reaction technology. No significant association between abnormal biochemical liver tests and serum anti-hepatitis B core antibody was noted in our population. Nominal logistic regression analysis demonstrated an independent and significant relationship between anti-HCV antibody and anti-hepatitis B virus core antibody in serum (Wald chi-square 16.06, P = 0.0001). The rate of seropositive patients for anti-hepatitis B virus core antibody was higher among study patients than controls with normal renal function [36.9% (216 of 585) vs. 21.4% (59 of 275), P = 0.0001]; this difference partially persisted after correction for demographic parameters, and viral markers.

CONCLUSION

In conclusion, occult hepatitis B virus was absent in our study group. Anti-hepatitis B core antibody was significantly related to presence of anti-HCV antibody supporting shared modes of transmission. Clinical studies based on molecular biology techniques provided with higher sensitivity are planned.

Occult hepatitis B virus infection in dialysis patients: a multicentre survey

BACKGROUND

The epidemiology and clinical significance of occult hepatitis B virus infection (serum hepatitis B surface antigen-negative patients with detectable hepatitis B virus viraemia in serum) remains controversial with only limited information about its prevalence in patients on long-term dialysis.

AIM

To address the epidemiology of occult HBV infection in a large cohort of dialysis patients.

METHODS

We screened a large cohort (n = 585) of Italian chronic dialysis patients; from this population, a group of hepatitis B virus surface antigen seronegative patients (n = 213) was tested by Amplicor hepatitis B virus Monitor Test to detect hepatitis B virus viraemia (hepatitis B virus-DNA) in serum.

RESULTS

Occult hepatitis B virus infection was absent (zero of 213 = 0%). Persistent hepatitis B virus surface antigen carriage was less frequent than anti-hepatitis B virus core antibody (anti-hepatitis B core antigen) seropositive status in this study group [1.88% (11 of 585) vs. 36% (216 of 585), P = 0.0001]. No dialysis patients seropositive for anti-hepatitis B core antibody in serum (zero of 123 = 0%) had detectable hepatitis B virus-DNA by polymerase chain reaction technology. No significant association between abnormal biochemical liver tests and serum anti-hepatitis B core antibody was noted in our population. Nominal logistic regression analysis demonstrated an independent and significant relationship between anti-HCV antibody and anti-hepatitis B virus core antibody in serum (Wald chi-square 16.06, P = 0.0001). The rate of seropositive patients for anti-hepatitis B virus core antibody was higher among study patients than controls with normal renal function [36.9% (216 of 585) vs. 21.4% (59 of 275), P = 0.0001]; this difference partially persisted after correction for demographic parameters, and viral markers.

CONCLUSION

In conclusion, occult hepatitis B virus was absent in our study group. Anti-hepatitis B core antibody was significantly related to presence of anti-HCV antibody supporting shared modes of transmission. Clinical studies based on molecular biology techniques provided with higher sensitivity are planned.

Review article: hepatitis C virus infection and type-2 diabetes mellitus in renal diseases and transplantation

A link between hepatitis C virus infection and development of diabetes mellitus has been suggested by many investigators; however, this remains controversial. The mechanisms underlying the association between hepatitis C virus and diabetes mellitus are unclear but a great majority of clinical surveys have found a significant and independent relationship between hepatitis C virus and diabetes mellitus after renal transplantation and orthotopic liver transplantation. We have systematically reviewed the scientific literature to explore the association between hepatitis C virus and diabetes mellitus in end-stage renal disease; in addition, data on patients undergoing orthotopic liver transplantation were also analysed. The unadjusted odds ratio for developing post-transplant diabetes mellitus in hepatitis C virus-infected renal transplant recipients ranged between 1.58 and 16.5 across the published studies. The rate of anti-hepatitis C virus antibody in serum was higher among dialysis patients having diabetes mellitus (odds ratio 9.9; 95% confidence interval 2.663-32.924). Patients with type-2 diabetes-related glomerulonephritis had the highest anti-hepatitis C virus prevalence [19.5% (24/123) vs. 3.2% (73/2247); P < 0.001] in a large cohort of Japanese patients who underwent renal biopsy. The link between hepatitis C virus and diabetes mellitus may explain, in part, the detrimental role of hepatitis C virus on patient and graft survival after orthotopic liver transplantation and/or renal transplantation. Preliminary evidence suggests that anti-viral therapies prior to renal transplantation and novel immunosuppressive regimens may lower the occurrence of diabetes mellitus in hepatitis C virus-infected patients after renal transplantation. Clinical trials are under way to assess if the hepatitis C virus-linked predisposition to new onset diabetes mellitus after renal transplantation may be reduced by newer immunosuppressive medications.

Online Convective Therapies: Results from a Hemofiltration Trial

With the introduction of the on-line preparation of dialysis fluids, the hemofiltration technique, which has never had a widespread diffusion in its old version with the infusion bags, has gained a new interest. We planned a prospective, randomized, 3-year-long study comparing survival and morbidity in ultrapure bicarbonate dialysis (BD) with on-line predilution hemofiltration (HF). Since comorbidity is one of the main factors limiting survival, the study was addressed to patients with a severe degree of comorbidity. The paper presents the preliminary results of the trial. Sixty-four patients were enrolled and randomized to either BD (N = 32) or HF (N = 32). Mean age and dialysis vintage were comparable. Twenty patients died during the study, 12 in BD and 8 in HF. The relative risk of death was 11% higher in patients treated with BD compared to those in the HF group (p < 0.005). The number of hospitalisation events per single patient was lower, even though not significantly, in HF compared to BD (1.94 + 1.26 in HF vs 2.48 + 1.98 in BD, p = NS). As concerns biochemistry, apart from beta-2-microglobulin, any other substantial difference was not found during the study, though the small solute concentration was generally a little more elevated in HF than in BD. Dialysis hypotension showed a trend to decrease in both the dialysis modalities up to near half of the trial, then, during the last year, it remained quite stable in HF, while, on the contrary, it increased in the BD group. By the end of the protocol, patients in HF showed a 2.5% incidence of acute dialysis hypotension, while patients in BD had 23%.

[Acute biocompatibility of hemodiafiltration with endogenous reinfusion (HFR)]

PURPOSE

In order to reduce the hemodialysis (HD)-induced pro-inflammatory activity we need to use a biocompatible dialysis membrane, avoid backfiltration and possibly use adsorbents. Hemodiafiltration reinfusion (HFR) is a new on-line hemodiafiltration (HDF) technique combining these aspects. This study aimed to evaluate the biocompatibility of the single dialysis session comparing standard HD and HFR.

METHODS

Eighteen patients on chronic HD were enrolled in five Centers. Patients underwent one standard and two HFR study sessions; in each session we evaluated leukocyte activation at 0, 5, 15, 60 and 240 min; and interleukin-6 (IL-6), C-reactive protein (CRP) and IL-1 receptor antagonist (IL-1Ra) levels at 0, 60 and 240 min.

RESULTS

Leukocyte activation was similar in HD and HFR, while the post-dialysis IL-6 increase was lower with HFR; CRP levels were stable during HFR, but increased after HD, and IL-1Ra did not demonstrate any difference.

CONCLUSIONS

These preliminary data show that HFR still has a better biocompatibility in the single dialysis session.

[The hemodiafiltration with endogenous reinfusion reduces the erythroid progenitor inhibition by uremic serum]

PURPOSE

Anemia in end-stage renal disease (ESRD) patients shows a lower proliferation of erythroid progenitor cells such as burst forming unit-erythroid (BFU-E) than in normal subjects. As on-line hemodiafiltration with endogenous reinfusion(HFR) is thought to have a better biocompatibility and a wide range of uremic toxin removal, we compared the effect of serum obtained pre- and post-standard hemodialysis (HD) and HFR dialysis performed in four ESRD patients with proliferation in normal subject) (controls) bone marrow BFU-E.

METHODS

Mononuclear fraction was obtained by Ficoll-Hypaque density centrifugation and studies were performed in three different conditions: standard culture, adding serum from controls, adding serum from ESRD patients pre- and post HD and HFR dialysis. BFU-E were counted after 14 days with an inverted microscope and expressed as average scores from two dishes. Standardization between experiments was checked with a control culture for each experimental culture.

RESULTS

The BFU-E proliferation rate was clearly reduced by adding serum from ESRD patients either pre-HD or pre-HFR. However, while this inhibition was exacerbated by post-HD serum, it showed a significant reduction with post-HFR serum.

CONCLUSIONS

This effect could be due to the removal of uremic toxins or to a lower dialysis-induced cytokine release, both mechanisms involved in erythropoiesis inhibition in ESRD.

Epidemiology and clinical significance of hepatotropic infections in dialysis patients. Recent evidence

Hepatitis C virus (HCV) infection is frequent among patients receiving long-term dialysis in developed and developing countries. It is difficult to assess the natural history of HCV in the dialysis population; however, recent studies have demonstrated that positive anti-HCV status is a significant and independent risk factor for mortality among dialysis patients. Recent meta-analyses have shown that interferon (IFN) initial monotherapy is effective in the treatment of chronic hepatitis C among dialysis patients, but tolerance to IFN mono-therapy was rather poor. Large, multicenter and prospective trials based on pegylated IFN for the treatment of chronic hepatitis C are planned. The frequency of HBV infection in patients undergoing maintenance dialysis in the industrialized world is low but not negligible; persistent HBsAg seropositivity is much higher in less-developed countries. Recent surveys have shown that detectable HBsAg/ HBV DNA status in serum is an independent and significant predictive factor for hepatocellular dysfunction in dialysis patients. No significant difference in morbidity and mortality between dialysis patients according to hepatitis B surface antigen status has been consistently shown. Preliminary reports suggest that lamivudine appears to be safe and effective in patients receiving long-term dialysis.

[Quantitative bone ultrasonography: state of the art and perspectives]

Quantitative Ultrasound (QUS) is a relatively new method of bone assessment that measures the velocity of sound and the broadband ultrasound attenuation at different skeletal sites: heel and phalanges. This is a mobile, inexpensive, easy to perform and radiation-free technique, capable of assessing not only bone density, commonly measured by means of Single Energy X-ray Absorptiometry, SXA, Dual Energy X-ray Absorptiometry, DXA and Quantitative Computed Tomography, QCT, but also its elasticity and structure. QUS has been validated for diagnosis of osteoporosis and prevention of hip fractures. Very recently, QUS was also been applied to the study of uremic osteodistrophy, of female premenopausal osteoporosis, male osteoporosis and in paediatric population. Moreover, many studies in the dialysis population has also shown the effectiveness of QUS at the phalanges site in evaluating bone turn-over and bone osteopenia. QUS may be an useful tool for the nephrologist in the day by day monitoring of uremic osteodistrophy and secondary hyperparathyroidism.

[A genetic viewpoint of focal glomerular sclerosis: fom genes to glomerular pathophysiology [corrected]]

Recent studies of Mendelian disease have begun to clarify the clinical spectrum of the group of disorders that make up familial, focal segmental glomerulosclerosis (FSGS) and nephrotic syndromes. In familial forms of focal segmental glomerulosclerosis (FSGS), both autosomal recessive and dominant inheritance patterns have been reported. At least three genes have been identified which, when defective, cause familial FSGS or nephrosis: the NPHS1 gene, encoding nephrin; the NPHS2 gene, encoding podocin; and the ACTN4 gene, encoding a-actinin-4. Because the majority of FSGS cases occur as sporadic disease, the recently described mutations in the NPHS2 gene "in approximately 25 percent of cases of apparently sporadic, steroid-resistant FSGS in children" have claimed great interest. The applicability of these observations to adults, including the possible importance of the nephrin and alpha-actinin-4 genes in the sporadic disease, remain to be determined. Finally, the mechanisms of podocyte damage and the molecular basis of glomerulosclerosis are reviewed.

Is steam sterilization really making any difference in dialysis-induced cytokine release?

Ethylene oxide (ETO) is presently the most commonly used sterilization method for medical devices. Although alternative sterilization modes such as steam sterilization have been suggested, the effect of steam on dialysis-induced cytokine release is unknown. We enrolled 9 patients on chronic hemodialysis and evaluated at different intervals IL-1beta production while treated with ETO (NC 1785-Bellco) and steam sterilized NC 1785S-Bellco) Synthetically Modified Cellulose (SMC). A basal test during treatment with NC 1785 was performed (A); the same test was set up 4 weeks after treatment with NC 1785S (B) and, lastly, 4 weeks after returning to NC 1785 (C). Peripheral blood mononuclear cells (PBMC) were purified before and after the dialysis session, were isolated on a Ficoll/Hypaque gradient and incubated for 24 h. Spontaneous IL-1beta release was evaluated in the supernatant and in the lysate. In A, IL-1beta levels were (in pg/ml/10(6) cells, in supematant and lysate, respectively): 5.8 +/- 4.8 and 7.6+/-5.2 in pre-HD and 4.68 +/- 3.6 and 9.7 +/- 6.65 in post-HD. These levels showed a clear reduction in B: 2.5 +/- 2.2 and 4.4 +/- 3.1 in pre-HD, and 4.35+/- 6.6 and 7.52 +/- 7.22 in post-HD. In the C test, 4 weeks after the return to the ETO membrane, IL-1beta levels remained unchanged: 2.9 +/- 1.8 and 4.5 +/- 3.1 in pre-HD; and 2.6 +/- 3 and 5.7 +/- 6.6 in post-HD. Statistical analysis showed significant changes in the pre-HD levels both in supematant (p < 0.04) and in lysate (p < 0.04). Steam sterilization of SMC induced a lower spontaneous IL-1beta release, but this effect was not statistically significant due to the large inter-individual variation. Hence, contrary to claims of better biocompatibility, steam sterilization does not result in a reduced production of pro-inflammatory IL-1beta.

[Thalassaemia minor: national survey of uraemic patients under substitutive treatment]

BACKGROUND

The incidence of thalassaemia minor in end-stage renal disease patients is similar to that of the general population. Both these conditions are characterized by anaemia, but the underlying pathophysiology is quite different. Current literature lacks an adequate clinical survey of haemodialysis patients with thalassaemia minor.

METHODS

The prevalence of thalassaemia minor (thal-m) in haemodialysis patients was assessed by a national survey collecting general information as well as clinical and haematological parameters. Data were also collected on the use of recombinant erythropoietin in these subjects. A dedicated questionnaire was sent to all Italian dialysis units.

RESULTS

Only 116/705 dialysis units returned the questionnaire (16.4%): 33 units did not have any patients affected by thalassaemia minor. No response was obtained from six Italian regions whereas ten regions returned only partial answers. The response from four regions was satisfactory (20%) while the completed questionnaire was returned by all units in only two small regions. A total of 7731 ESRD patients were collected, 240 (3.1%) were also affected by thal-m, 142 males and 98 females. In the four regions with the highest response rates, Calabria 45%, Puglia 65%, Basilicata and Molise 100%, the prevalence of thal-m were 3.68%, 4.56%, 3.3% and 1%, respectively. A total of 3623 uraemic patients (47% of all enrolled subjects) were collected from these four regions. Here is the patient geographic distribution: northern Italy 2.16% (response rate of 9.44%); central Italy 1.69% (response rate of 7.64%), southern Italy 3.77% (response rate of 29.46%). The age range of thal-m patients was 17 to 90 years, the time spent on dialysis was between 3 and 384 months, the body weight was between 35 and 93 kg, the Hb value was between 6.2 and 13.6 g/dl, and the Htc value was between 19 and 44%. A total of 230 thal-m patients were on haemodialysis while 10 patients were on peritoneal dialysis (4.2%). The mean haemoglobin level for the thal-m group was 9.8+/-1.4 g/dl and for the control group the value was 11.4+/-1.4 g/dl (p < 0.0001). The use of rhEPO was on the average 7659+/-6256 u/wk for the thal-m and 4378+/-4435 u/wk for the control group (p < 0.0001). The bodyweight was 129+/-105 u/kg/wk (range 0-370). Finally, 17.9% of the thal-m patient did not use rhEPO, their Hb value was 10.66+/-1.67 g/dl (range 8.2-13). No patient went over 30 thousand units and only 4 had such dosage in therapy. The 12.1% thal-m patients with Hb < 10 g/dl did not use rhEPO. The need for rhEPO per gram of Hb was 796+/-722 u/wk in thal-m patients and 416+/-449 U/wk in control patients (p < 0.0001). Uraemic anaemia was corrected with 4.8 million red blood cells in the control group and with about 7.7 million red blood cells in the thal-m group.

CONCLUSIONS

Data from this national survey, although incomplete, show that rHuEpo is less effective in these patients and its use does not seems to be correct. It is important to emphasise that recent Guidelines do not recommend neither a specific treatment for these patients nor the use of r-HuEpo. However, it should also be underscored that most thal-m patients do not reach the target Hb level suggested by the National Guidelines for the general population in chronic dialysis.

[Increased in vitro and ex vivo proliferation of erythroid precursors induced by calcitriol in chronic renal failure. Synergistic effect with rHuEPO]

BACKGROUND

Calcitriol (C) improves anemia in chronic renal failure. This improvement may be related to the suppression of iPTH release, but also to a direct effect on erythropoiesis.

MATERIALS AND METHODS

In order to verify this hypothesis, 33 patients with chronic renal failure were enrolled: 24 were undergoing hemodialysis, 9 managed conservatively. All patients were free from other chronic or hematological disease, had a negative DFO test and aluminum levels below 20 mcg/l. iPTH range was 250-480 pg/l. None had yet been treated with C. In vitro study- Samples were drawn for a basal erythroid precursors (Burst Forming Unit-Erythroid BFU-E) study. After mononuclear cells were isolated by centrifugation with Ficoll-Hypaque, they were incubated for 15 days with rHuEPO 3U/ml (A), rHuEPO 3U/l + C 30 pg (B), rHuEPO 3U/ml + C 300 pg (C), rHuEPO 30 U/ml + C 300 pg (D) was performed. Ex vivo study- After the basal evaluation, 10 pts on dialysis were treated with C (Calcijex-Abbott) 1 g three times a week. BFU-E studies were performed after 1,2 and 4 months.

RESULTS

In vitro, culture B showed an increased BFU-E proliferation vs A (41+/- 23 vs 27+/-15, p less than 0.02); in C and D cultures proliferation was 61+/-31 and 78+/- 42 respectively, p less than 0.01 vs A. There was no difference among pts with renal failure and pts treated conservatively. During the in vivo study all cultures showed a progressive proliferation increase, without a plateau level (basal, after 1, 2, 4 months respectively): in A: 17+/-8, 22+/-13, 30.9+/-14.9, 41.4+/-20; in B: 27.3+/-15, 35.6+/-20, 45.5+/-21, 57+/-26; in C: 48.2+/-20.6, 63.7+/-32, 75.7+/-37, 83+/-40; in D: 72+/-24, 91+/-42, 106+/-42, 110+/-42.3 (always p less than 0.001). The hematocrit and hemoglobin increase was constant but not significant. The iPTH decrease was not related to BFU-E proliferation.

CONCLUSIONS

In chronic uremia C has a direct effect on erythroid precursor proliferation, both in vitro and ex vivo, with a sinergystic effect with rHuEPO. This effect is not related to iPTH suppression. C may be a useful adjuvant therapy for rHuEPO treatment.

[Calcitriol increases burst forming unit-erythroid (BFU-E) in vitro proliferation in chronic uremia. Synergic effect with DNA recombinant erythropoietin (rHu-Epo)]

BACKGROUND

It has been suggested that calcitriol (C) could improve anemia in chronic renal failure. However it remains debatable whether vitamin D has a specific effect on erythropoiesis, or it acts via suppression of hyperparathyroidism.

METHODS

We enrolled 29 patients with chronic renal failure, free from malignancies, iron deficiency or other chronic or hematological diseases. Aluminium accumulation was also excluded by DFO test. 22 were on hemodialysis and 7 on conservative management, creatinine clearance ranging 22-48 ml/min. Their mean age was 62+/-28 years and duration of renal disease was 98+/-51 months. No patient under-went rHu-Epo or Vitamin D treatment. 4 subjects were enrolled as controls. Samples of peripheral blood were drawn for the Burst Forming Unit-Erythroid (BFU-E) assay. After isolation of mononuclear cells by density gradient centrifugation with Fycoll-Hypaque, a 15-day incubation was set up with four different conditions: a) adding standard dose, 3 U/ml, of r-HuEpo (Dompè Biotec), standard colture; b) combined doses of r-HuEpo, 3 U/ml, and C (Abbott), 30 pg; c) standard dose, 3 U/ml, of r-HuEpo and high dose, 300 pg, of C; and lastly d) combined high doses of r-HuEpo, 30 U/ml, and C, 300 pg.

RESULTS

In the b colture (combined low doses) a higher BFU-E proliferation was found vs standard (a) colture (33.2+/-15.5 vs 17.1+/-9.2, p<0.02); interestingly, either in the c and d studies BFU-E showed an even higher proliferation (52.3+/-24 and 86.3+/-37.8 respectively, p<0.01 vs a). No difference was found when evaluating separately preterminal and hemodialysis patients. In control subjects only colture d showed an increased BFU-E proliferation.

CONCLUSIONS

C has a direct effect on erythroid precursors proliferation in vitro, acting in a sinergystic manner with rHuEpo. C may be useful as adjuvant therapy for renal anemia.

Systematic monitor disinfection is effective in limiting HCV spread in hemodialysis

BACKGROUND

Patients on chronic hemodialysis are at high risk of HCV infection due to nosocomial transmission. The strict adhesion to universal precautions is the first step in prevention, but other simple tools such as systematic monitor disinfection and the use of separate machines for anti-HCV-positive patients need to be evaluated.

METHODS

A 5-year prospective study was carried out in 4 dialysis centers enrolling 135 patients. General precautions were adopted, but anti-HCV-positive patients were not isolated. In period A, lasting 24 months, monitor disinfection was performed after each dialysis session with sodium hypochlorite; peracetic acid was also used 3 times a week. In period B, lasting 36 months, 3 dialysis units (77 patients) prolonged the same preventive protocol of period A, while another unit (58 patients) also adopted the use of separate machines for anti-HCV-positive subjects. A third-generation ELISA anti-HCV test was performed every 2 months throughout the study.

RESULTS

Anti-HCV antibodies were initially detected in 43 patients (31.8%), prevalence rate ranging from 25 to 39.4%. One seroconversion occurred in period A, with an overall seroconversion rate of 0.54%/year. Also in period B one seroconversion occurred (unit 2), seroconversion rate of 0.36%/year. Therefore the mean seroconversion rate throughout the 5 years was 0.43%/year.

CONCLUSION

Systematic monitor disinfection may be a simple and quite effective tool to avoid nosocomial transmission of HCV infection in the hemodialysis setting. In our opinion its use is mandatory. The use of separate machines for anti-HCV-positive patients seems unnecessary.

Polymorphism of the angiotensin-converting enzyme gene in end-stage renal failure patients

The plasma levels of angiotensin-converting enzyme (ACE) are modulated by the insertion (I)/deletion (D) polymorphism within the ACE gene locus. An association between progressive renal disease, raised cardiovascular risk, and ACE plasma levels has been shown. To evaluate the genotype frequencies of the I/D polymorphism in terminal renal failure, we have enrolled 341 dialysis patients (321 on hemodialysis and 20 on peritoneal dialysis) in a district of southern Italy (Foggia). As controls, 1,307 subjects from the same area have been enrolled. Genomic DNA was obtained from leukocytes, and the ACE I/D polymorphism was determined by polymerase chain reaction. Among uremics, 151 subjects (44.3%) carried the DD genotype, 149 (43.7%) the ID, and 41 (12.0%) the II genotype. In controls, 560 subjects (42.8%) had the DD genotype, 577 (44.1%) the ID, and 170 (13.1%) the II genotype (p = n.s.). Among patients, the frequency of DD subjects was higher in men (48.3%) than in women (39. 7%, p < 0.01). A slight different frequency of the DD genotype was found according to the duration of dialysis treatment: 47.5% in patients on dialysis up to 60 months and 41.7 and 40.6% in those with a dialytic age of 60-120 and >120 months, respectively (p for trend: 0.53). Patients with or without cardiovascular diseases, such as hypertension, left ventricular hypertrophy, coronary artery disease, and chronic cardiac failure, did not exhibit any difference in ACE I/D allele and genotype frequencies (p always >0.05). In conclusion, frequencies of the ACE DD genotype were similar in uremics and in controls and did not differ between patients with and without cardiovascular diseases. A nonsignificant inverse relationship with the time spent on dialysis was observed, suggesting that ACE I/D polymorphism may influence the cardiovascular death rate.

Synergistic effect of desferrioxamine and recombinant erythropoietin on erythroid precursor proliferation in chronic renal failure

BACKGROUND

Desferrioxamine (DFO) has been suggested to improve erythropoiesis in end-stage renal failure independently of its aluminium (Al)-chelating effect. A possible synergistic effect of DFO and recombinant human erythropoietin (r-HuEpo) could be very useful in treating anaemia of chronic renal failure.

METHODS

In order to verify whether a synergistic action of DFO and r-HuEpo exists, we enrolled 11 patients undergoing chronic haemodialysis and r-HuEpo treatment. All had a negative DFO test, very low serum Al levels (< 20 microg/l), ferritin > 100 ng% and iPTH < 200 pg/l. Samples were drawn for a basal erythroid precursor (burst-forming unit-Erythroid, BFU-E) evaluation. After isolation by Ficoll Hypaque, a 14 day incubation was carried out with: (i) r-HuEpo 3 U/ml; (ii) r-HuEpo 30 U/ml; and (iii) r-HuEpo 30 U/ml + DFO 167 microg/ml. Patients then received 5 mg/kg DFO infused during the last hour of each dialysis session for 12 weeks. New BFU-E evaluations were performed after 2, 6 and 12 weeks of treatment. BFU-E colonies were counted in duplicate with an inverted microscope after 14 days. Haemoglobin (Hb), ferritin, transferrin, reticulocytes, hypochromic erythrocytes, soluble transferrin receptor and serum erythropoietin were also evaluated at the same time.

RESULTS

High dose r-HuEpo achieved greater proliferation than low dose r-HuEpo cultures during all phases of the study. At baseline, r-HuEpo and DFO culture had a greater number of colony units than high dose r-HuEpo culture ( 103.7 +/- 50.2 vs 95.1 +/- 50.5, NS). This increase became significant after 2 weeks (145 +/- 59.3 vs 122.9 +/- 59.6, P < 0.02), and remained so at 6 (167.4 +/- 60.3 vs 149 +/- 55.6, P < 0.01) and 12 weeks (191 +/- 64.5 vs 155.1 +/- 56.3, P < 0.01). An increased proliferation was observed after DFO therapy in all culture studies: low dose r-HuEpo culture increased from 69.4 +/- 38.2 to 86.6 +/- 48.5, 115 +/- 39 and 123 +/- 46; high dose r-HuEpo culture increased from 95.1 +/- 50.5 to 122.9 +/- 59, 149 +/- 55.6 and 155.1 +/- 56.3 and r-HuEpo plus DFO culture from 103.7 +/- 50.2 to 145 +/- 59.3, 167 +/- 60.3 and 191 +/- 64.5 at 2, 6 and 12 weeks, respectively (all P < 0.01 by ANOVA). Haemoglobin, reticulocytes and soluble transferrin receptor were slightly increased, while ferritin decreased. Hypochromic erytrocytes were variable.

CONCLUSIONS

DFO increases erythroid precursor proliferation and has a synergistic in vivo effect with r-HuEpo in patients with chronic renal failure. Further investigations are needed to evaluate whether such an effect may have clinical application.

Desferrioxamine improves burst-forming unit-erythroid (BFU-E) proliferation in haemodialysis patients

BACKGROUND

In chronic renal failure, desferrioxamine (DFO) may improve erythropoiesis independent from its aluminium (Al) chelating effect. The mechanism of this action is still unknown.

METHODS

To verify whether DFO influences proliferation of erythropoietic precursors, we studied 10 patients on chronic haemodialysis, free from malignancies or other haematological diseases, iron deficiency, bone marrow fibrosis, and Al toxicity. Al accumulation was excluded by the DFO test. Peripheral blood samples were drawn for basal burst-forming unit erythroid (BFU E) assay. Mononuclear cells were isolated by density gradient centrifugation with Ficoll Hypaque, and incubated for 15 days with three different experimental conditions: (a) low-dose recombinant human erythropoietin (rHuEpo) (3 U/ml); (b) high dose rHuEpo, (30 U/ml); (c) both DFO (167 microg/ml) and rHuEpo (3 U/ml). We determined TIBC, transferrin, ferritin, reticulocytes, hypochromic erythrocytes, soluble transferrin receptor (sTR), haemoglobin (Hb), and haematocrit (Hct) at baseline and then every 14 days. Patients received 5 mg/kg DFO infused during the last hour of each dialysis session for 6 weeks; six patients remained in the study for an additional 6 more weeks. BFU E assays were set up after 6 and 12 weeks of DFO therapy.

RESULTS

At baseline DFO had small effect on BFU E proliferation (33.9+/-25 vs 30.4+/-25.9) and high-dose rHuEpo had a significant effect (45.15+/-27 vs 30.4+/-25.9, P<0.01). After 6 weeks of DFO therapy a significant increase in BFU E proliferation was observed in all culture conditions (78.25+/-32 vs 30.45+/-25.9 standard culture, P<0.01; 110.9+/-30 vs 45.15+/-27 high dose rHuEpo, P<0.01; 98.75+/-32 vs 45.15+/-27 DFO culture, P<0.01). Moreover, the increase in BFU E proliferation was significant greater with DFO culture than standard culture (P<0.01). The same trend was found at the third BFU E assay, performed in only six patients, when all culture conditions showed a further increase of erythroid precursor proliferation. However, the DFO culture was not significantly greater than the standard culture, while the high-dose rHuEpo was significantly greater than the DFO culture. Patients in group I (n=10), had a significant increase in reticulocytes (1.5+/-0.6 vs 1.72+/-0.3, P<0.01) and of hypochromic erythrocytes (HE) (5.6+/-5.1 vs 14.4+/-12.7, P<0.01), while sTR, Epo, Hb, and Hct were only minimally increased. Ferritin decreased significantly (448+/-224 vs 196+/-215, P<0.01) and TIBC and transferrin were unchanged.

CONCLUSIONS

Thus DFO increases erythroid activity by BFU E proliferation and increases reticulocytes in haemodialysis patients. Such an effect may be related to increased iron utilization. DFO may be a useful tool for anaemic patients with good iron stores and without Al overload.

Reduction of mononuclear cytokine production in hemodialysis patients treated with steam-sterilized low-flux polysulphone membranes

An increased cytokine production, correlated with long term complications of uremic disease, has been described during hemodialysis. To identify possible differences in the cytokine release of differently sterilized membranes, we enrolled six uremic patients on chronic hemodialysis. The patients underwent dialysis with ETO-sterilized low-flux polysulphone membranes (F6, Fresenius AG) for at least three months (A1), they were then switched to steam-sterilized polysulphone membranes (F6-HPS Fresenius AG) and further evaluations after one (B1) and two months (B2) were carried out. A final evaluation (A2) was made one month after switching back to F6 dialyzers. At each time period, samples were drawn to measure IL-1beta released by cultured mononuclear cells (MN). Moreover, dialysate samples were collected to test endotoxin levels. C3a and C5a levels were assessed at 0, 5, 15 and 60 min from starting hemodialysis. Anti-ETO IgE levels were also assayed at A1, B1 and A2. The LAL test revealed a good quality dialysate. The mean pre-dialysis IL-1beta levels were 215 pg/million cells at A1; falling to 49 at B1, and 54 at B2 (p<0.01); there was then a sharp rebound at A2: 284, p<0.01. Post-dialysis levels followed the same pattern. No correlation between the dialysate endotoxin level and cytokine release was found. Complement activation did not change and in all the phases of the study no anti-ETO IgE was detected in any of the subjects. Our data suggest that the steam sterilized polysulphone membrane induces a lower cytokine release than the ETO sterilized membrane, although the mechanism by which it does so remains to be clarified.

Ethylene-oxide and steam-sterilised polysulfone membrane in dialysis patients with eosinophilia

Eosinophilia and some acute dialysis side-effects, such as itching, flushing and bronchospasm, are often associated with the presence of ethylene oxide (ETO) as dialyzer sterilizing agent. This study evaluated the effects of two different polysulfone (PS) hollow-fiber dialysers sterilized with ETO and steam in 31 chronic dialysis patients with eosinophilia. Clinical symptoms, metabolic and biochemical parameters, complement (C3a and C5a) activation and production were evaluated in each patient dialysed for two months at a time with Cuprophan dialyser, ETO-PS dialyser and steam-PS dialyser. The steam-sterilizer agent does not alter the purifying capacity of the PS membrane which maintains its superiority over Cuprophan in terms of biocompatibility. Using steam-PS, intradialytic eosinophil kinetics seems to improve. In some patients with high serum levels of ETO-specific IgE these levels tend to diminish. Generic intradialytic symptoms do not differ between the two sterilization methods, although some hypersensitivity symptoms during the first dialysis hour are considerably lower in some patients when steam-sterilized PS is used.

[Epidemiology of hepatitis C virus infection in hemodialysis. A study of the Gargano area]

In order to evaluate epidemiological features of hepatitis C virus infection in patients with chronic renal failure, we enrolled 80 haemodialyzed subjects in four centers of Gargano area (Southern Italy). In a 28 months follow-up we checked antiHCV antibodies by EIA II and viraemia by polymerase chain reaction. Seroprevalence of HCV infection was 35%, while incidence was 2.4%/year; viraemia was detected in 62.5% of antiHCV+ and in only one of antiHCV-. In our opinion there is a definitive need of special precautions (or isolation of antiHCV+) in haemodialysis units to avoid community-acquired HCV infection.