[Current therapeutic strategies for HCV-associated cryoglobulinemia]. / Terapia attuale della sindrome crioglobulinemica HCV-correlata.

Cryoglobulinemia refers to the presence in serum of immunoglobulins, that reversibly precipitate at low temperatures. Cryoglobulins are classified according to their immunochemical properties as type I, composed of a single monoclonal immunoglobulin, and types II and III, referred as mixed cryoglobulinemia (MC), composed by a mixture of monoclonal (type II) and polyclonal (type III) IgM that have rheumatoid factor activity and bind to polyclonal IgGs. MC is a systemic vasculitis with cutaneous and multiple organ involvement including chronic hepatitis, membrano-proliferative glomerulonephritis, and peripheral neuropathy. In more than 90% of patients, MC is associated with chronic hepatitis C virus (HCV) infection, which is considered the triggering factor of the disease. Patients with HCV-related MC may be managed by means of etiological, pathogenetic or symptomatic therapeutic modalities. The choice of the more appropriate treatment is strictly related to the assessment of disease activity, and to the extent and severity of organ involvement. This paper reviews the currently available therapeutic strategies for MC syndrome, emphasizing the importance of HCV eradication, and the safety/efficacy of new biologic therapies for selective control of cryoglobulin-producing B-cells.

Interferon-alpha in combination with ribavirin as initial treatment for hepatitis C virus-associated cryoglobulinemic membranoproliferative glomerulonephritis.

Mixed cryoglobulinemia (MC) and glomerulonephritis are the most important extrahepatic manifestations of chronic hepatitis C virus (HCV) infection. In HCV-infected patients with MC, renal involvement worsens the overall prognosis because of a high incidence of infection or cardiovascular disease. The relationship between MC and HCV infection has prompted the use of antiviral therapy. Two patients with chronic HCV infection, type-II MC and membranoproliferative glomerulonephritis (MPGN), presenting as nephrotic syndrome were treated with interferon (IFN)-alpha (3 MU 3 times per week) and ribavirin (15 mg/kg daily) for 6 months. Laboratory tests included measurement of anti-HCV antibodies, HCV RNA, and HCV genotyping, and characterization of circulating cryoglobulins. A pretreatment renal biopsy was performed, and the histopathologic lesions were scored according to the index of disease activity. Viremia and cryoglobulinemia were suppressed in both patients. However, a complete remission of proteinuria was observed in 1 patient only. The evaluation of the renal biopsy specimens revealed a mild MPGN (activity score: 5/24) in the patient with remission of proteinuria and a severe MPGN (activity score: 15/24) in the patient who maintained a nephrotic-range proteinuria. Although a fully satisfactory treatment is not yet available, we feel that a reasonable therapeutic strategy for HCV-infected patients with MC nephritis could be as follows: (1) antiviral treatment alone for patients with a low-grade kidney involvement, and (2) a short-term course of steroids and cytotoxic drugs followed by antiviral therapy for acute exacerbations and/or rapidly progressive GN.

[Cryoglobulinemia and hepatitis C virus infection]. / Crioglobulinemie e infezione da virus dell'epatite C.

The demonstration of the high prevalence of HCV infection (HCV) in patients with MC has changed the clinico-biologic scenario of MC, supporting its subdivision into two groups: MC HCV- and MC HCV+. The former, which is predominantly a polyclonal cryoglobulinemia, should be regarded as an epiphenomenon of the immune system activation in the course of a variety of chronic infections or autoimmune disorders; the latter, which is a oligo- or monoclonal cryoglobulinemia, referred in the past as "essential mixed cryoglobulinemia", might be expression of an indolent B cell proliferation stimulated by HCV in an antigen-driven mechanism. The association of HCV infection with MC may have a pathogenetic an therapeutic significance. There are a number of reports demonstrating the beneficial effects of alpha-interferon (alpha-IFN) in about a half of patients with chronic HCV and MC. However, after the end of alpha-IFN therapy a recurrence of viremia and cryoglobulinemia is frequently observed and less than 25% of treated patients achieve long term remissions. To improve the sustained response rate, prolonged courses of alpha-IFN monotherapy or a combination of alpha-IFN and ribavirin should be considered. New agents with specific antiviral activity against HCV will probably further improve therapeutic options.

Renoprotective properties of ACE-inhibition in non-diabetic nephropathies with non-nephrotic proteinuria.

BACKGROUND: Stratum 2 of the Ramipril Efficacy in Nephropathy (REIN) study has already shown that in patients with chronic nephropathies and proteinuria of 3 g or more per 24 h, angiotensin-converting enzyme (ACE) inhibition reduced the rate of decline in glomerular filtration and halved the combined risk of doubling of serum creatinine or end-stage renal failure (ESRF) found in controls on placebo plus conventional antihypertensives. In REIN stratum 1, reported here, 24 h proteinuria was 1 g or more but less than 3 g per 24 h. METHODS: In stratum 1 of this double-blind trial 186 patients were randomised to a ramipril or a control (placebo plus conventional antihypertensive therapy) group targeted at achieving a diastolic blood pressure of less than 90 mm Hg. The primary endpoints were change in glomerular filtration rate (GFR) and time to ESRF or overt proteinuria (> or =53 g/24 h). Median follow-up was 31 months. FINDINGS: The decline in GFR per month was not significantly different (ramipril 0.26 [SE 0.05] mL per min per 1.73m2, control 0.29 [0.06]). Progression to ESRF was significantly less common in the ramipril group (9/99 vs 18/87) for a relative risk (RR) of 2.72 (95% CI 1.22-6.08); so was progression to overt proteinuria (15/99 vs 27/87, RR 2.40 [1.27-4.52]). Patients with a baseline GFR of 45 mL/min/1.73 m2 or less and proteinuria of 1.5 g/24 h or more had more rapid progression and gained the most from ramipril treatment. Proteinuria decreased by 13% in the ramipril group and increased by 15% in the controls. Cardiovascular events were similar. As expected, the rate of decline in GFR and the frequency of ESRF were much lower in stratum 1 than they had been in stratum 2. INTERPRETATION: In non-diabetic nephropathies, ACE inhibition confers renoprotection even to patients with non-nephrotic proteinuria.

[Hypo-osmolar hyponatremic syndromes: physiopathology and clinical aspects]. / Sindromi iposodiemiche ipoosmolari: fisiopatologia e clinica.

Hyponatremia in virtually all patients results from water retention due to an inability to excrete ingested water. In most cases, this defect represents the persistent secretion of ADH (such as in effective circulating volume depletion, and in the syndrome of inappropriate ADH secretion), although free water excretion can also be limited in disorders in which ADH levels may be appropriately suppressed (such as in advanced renal failure, and in primary polydipsia). The symptoms of hyponatremia primarily reflect neurologic dysfunction induced by cerebral edema and are related both to the severity and to the rapidity of reductions in the plasma sodium concentration. The degree of cerebral edema which occurs in acute hyponatremia is much less with chronic hyponatremia, because the brain cells lose solutes, leading to the osmotic movement of water out the cells and less brain swelling. In general, hyponatremia is corrected acutely by giving Na+ to patients who are volume-depleted and by restricting water intake in patients who are normovolemic or edematous. The optimal rate of correction should be defined to prevent the risk of central demyelinating lesions.

Hypertension as an etiopathological factor in the development of cerebral atrophy in hemodialyzed patients.

Twenty-five patients on long-term regular hemodialysis treatment (RDT) at our dialysis unit who underwent diagnostic cerebral computed tomography (CCT) participated in a study aimed at clarifying the pathogenesis of cerebral atrophy occasionally found at their original scan. The upper age limit was 55 years to exclude the physiological involutive brain changes occurring with age. Cerebral atrophy (CA), as defined morphologically (enlargement of cerebral sulci or an increased Evan's Index), was detected in all cases. Seventeen patients underwent magnetic resonance imaging (MRI) to define possible white matter changes more accurately. No significant correlation was found between the degree of atrophy and the following uremia-altered hematoseric parameters: creatinine, hematocrit, cholesterol, triglyceridemia, albumin, PTH, calcium, inorganic phosphate. There was no correlation between degree of atrophy and number of months the patients had been on RDT or time that passed between the finding of a creatinine clearance <30 ml/min and the start of RDT. Very high correlations were found between the degree of CA and predialytic blood pressure values, and between CA and the duration of hypertension (n = 13, r = 0.66, p < 0.013). Thus, hypertension seems to be an early cause of cerebral parenchymal damage in RDT patients, and should be promptly corrected.

[Physiopathology, clinical aspects and prevention of renal insufficiency caused by contrast media]. / Fisiopatologia, clinica e prevenzione dell'insufficienza renale da mezzi di contrasto.

Contrast-media associated nephropathy (CMAN) consists in a sudden impairment of glomerular filtration rate following exposure to radiographic contrast materials. Damage may be limited to an asymptomatic mild increase of blood creatinine, or reach the highest levels of nitrogen retention compatible with acute renal failure. Some preexisting clinical conditions or pathologies may lead to CMAN: not only renal insufficiency, diabetes mellitus, multiple myeloma, congestive heart failure and severe hypertension, but also simple dehydration and a growing series of immunologic diseases are recognized as predisposing condition. The exact mechanism responsible for renal injury is still doubtful but recently animal models have shown substantial ischemic changes that may be added to the traditional presumed pathogenesis of direct tubular toxicity and intra-tubular obstruction. As renal ischemia stimulates both endogenous vasoconstrictor and vasodilator substances, it is now supposed that CMAN acts similarly to non-steroidal anti-inflammatory agents, selectively inhibiting the vasodilatory prostaglandin phase and therefore causing a derangement of the physiologic vasoconstriction/vasodilatation balance of renal circulation. The role of oxygen free radicals to contribute to renal dysfunction is considered. Low osmolality non ionic contrast media when compared to conventional high osmolality ionic contrast media have reduced but not eliminated CMAN. Simple but effective lines of prevention include the previous selection of patients predisposed to CMAN for concomitant pathology, suspension of FANS or any other recognized nephrotoxic substance, the least amount of contrast media compatible with radiologic visualization of the patient's problem, careful hydration of the patient before contrast injection and sustained diuresis afterwards. The usefulness of pre-treatment with Ca-channel blockers or atrial natriuretic factors remains sub judice.

[The L-arginine-nitric oxide system: physiology, physiopathology and clinical relevance]. / II sistema L-arginina-ossido nitrico. Fisiologia, fisiopatologia e rilevanza clinica.

In this review we describe what is known about nitric oxide (NO), focusing on its clinical significance. It is now well appreciated that NO is a pivotal endogenous messenger molecule in a variety of physiological and pathophysiological processes. In the cardiovascular system NO participates in the paracrine regulation of vascular tone, body fluid homeostasis and platelet aggregation and adhesion. In the nervous system NO is a neurotransmitter that underpins several functions, including the formation of memory. In addition, NO is produced in large quantities during host defense and immunologic reactions. Perturbation in NO bioactivity has been shown to represent an important pathophysiologic mechanism underlying a number of disease states, such as atherosclerosis, hypertension, diabetes mellitus, and septic shock.

Renal effects of captopril, indomethacin and nifedipine in nephrotic patients after an oral protein load.

BACKGROUND: In this study we investigated whether the increase in proteinuria induced by an oral protein load may be prevented by the angiotensin-converting enzyme inhibitor (ACEI) captopril in patients with nephrotic syndrome, and whether the effects of captopril on renal haemodynamics and/or glomerular selectivity are comparable to those obtained with the nonsteroidal anti-inflammatory drug (NSAID) indomethacin and the calcium-channel blocker (CaCB) nifedipine. METHODS: Twelve subjects underwent the following treatments: (1) low-protein meal (0.2 g protein/kg body wt), (2) high-protein meal (1.3 g protein/kg body wt), (3) high-protein meal plus oral captopril (50 mg), (4) high-protein meal plus oral nifedipine (10 mg), (5) high-protein meal plus oral indomethacin (50 mg). Urine and blood samples were obtained after meals and tested for total protein, immunoglobulin G and albumin. GFR and renal plasma flow (RPF) were calculated from iothalamate and p-aminohippuric acid clearances respectively. RESULTS: Mean arterial pressure decreased significantly after both captopril (-4%, P = 0.001) and nifedipine (-5%, P = 0.0019). Compared with the low-protein meal, mean values of GFR and RPF increased significantly after the high-protein meal alone (+21%, P = 0.0002; +10%, P = 0.0491 respectively), and after captopril (+18%, P = 0.0025; +24%, P = 0.0034 respectively) or nifedipine administration (+30%, P = 0.0001; +21%, P = 0.0036 respectively), whereas they remained unchanged after the high-protein meal plus indomethacin administration. FF did not change significantly under the five experimental conditions. The increase in urinary protein excretion induced by the meat load (total protein +18%, P = 0.0102; albumin +26%, P = 0.0316; IgG +28%, P = 0.0203) was entirely blocked by both captopril and indomethacin, whereas it was further increased by nifedipine administration. CONCLUSIONS: Both captopril and indomethacin, but not nifedipine, are able to prevent the increase in urinary protein excretion rate following a meat meal. The antiproteinuric effect of captopril is comparable to that of indomethacin, but the renal haemodynamic changes induced by these drugs differ considerably, because the filtration capacity and the renal functional reserve were preserved by captopril and decreased by indomethacin. The reduction in systemic blood pressure following administration of both captopril and nifedipine does not account for changes in proteinuria, since, with a similar degree of blood pressure lowering, urinary protein excretion is reduced by captopril and increased by nifedipine.

Effectiveness of dietary protein augmentation associated with angiotensin-converting enzyme inhibition in the management of the nephrotic syndrome.

To determine whether the increase in proteinuria resulting from high dietary protein intake could be prevented by angiotensin-converting enzyme inhibition (ACEI), we performed paired studies on 8 nephrotic patients with normal GFR. They were fed sequential diets with a protein content of 0.8 (LPD) and 1.6 g/kg BW (HPD) each for 8 weeks. Patients on HPD received enalapril (ENAL) 10 mg/day. Despite the significant difference in protein intake, urinary protein excretion, at the end of the two dietary periods, was not statistically different. However, total serum protein and serum albumin increased significantly with HPD + ENAL treatment. The capability of ACEI to prevent the increase in proteinuria induced by HPD may be due to changes in glomerular hemodynamics, possibly mediated by changes in the activity of angiotensin II. Our study indicates that protein metabolism in nephrotic patients is better maintained with HPD + ENAL than with LPD alone.

Apparent preferential loss of heterozygosity at TSC2 over TSC1 chromosomal region in tuberous sclerosis hamartomas.

To investigate the molecular mechanisms of tuberous sclerosis (TSC) histopathologic lesions, we have tested for loss of heterozygosity the two TSC loci (TSC1 and TSC2) and seven tumor suppressor gene-containing regions (TP53, NF1, NF2, BRCA1, APC, VHL, and MLM) in 20 hamartomas from 18 TSC patients. Overall, eight angiomyolipomas, eight giant cell astrocytomas, one cortical tuber, and three rhabdomyomas were analyzed. Loss of heterozygosity at either TSC locus was found in a large fraction of the informative patients, both sporadic (7/14) and familial (1/4). Interestingly, a statistically significant preponderance of loss of heterozygosity at TSC2 was observed in the sporadic group (P < 0.01). Among the possible explanations considered, the bias in the selection for TSC patients with the most severe organ impairment seems particularly appealing. According to this view, a TSC2 defect might confer a greater risk for early kidney failure or, possibly, a more rapid growth of a giant cell astrocytoma. None of the seven antioncogenes tested showed loss of heterozygosity, indicating that the loss of either TSC gene product may be sufficient to promote hamartomatous cell growth. Finally, the observation of loss of heterozygosity at different markers in an astrocytoma and in an angiomyolipoma from the same patient might suggest the multifocal origin of the second-hit mutation.

[Thoracic actinomycosis with lung, mediastinal and pericardial involvement. A case report]. / Actinomicosi toracica con interessamento polmonare, mediastinico e pericardico. Descrizione di un caso.

A case of actinomycosis is reported in a 17-years-old woman with pleural and pericardial effusions and anterior mediastinal mass. Histopathological diagnosis of actinomycosis was performed by mediastinal mass biopsy. There was no evidence of immunodeficit or neoplasia. Probably a dental manipulation favoured the Actinomyces infection. Treatment with antibiotics resulted in a reduction of mediastinal mass and in a complete resolution of pleural and pericardial effusions.

[Urinary infections in adults: clinical approach and therapeutic indications]. / Infezioni urinarie dell'adulto: approccio clinico e indicazioni terapeutiche.

Urinary tract infections (UTI) are the most common of all the bacterial infections affecting humans during their life span. In adult patients, UTI may be categorized into the following groups: acute uncomplicated cystitis, acute uncomplicated pyelonephritis, recurrent bacterial UTI infections, asymptomatic bacteriuria, complicated UTI, acute and chronic bacterial prostatitis. In patients with uncomplicated cystitis, short-course (3 days) empirical therapy is more effective than single dose therapy. Recurrent cystitis can be effectively managed by continuous antimicrobial prophylaxis. Acute pyelonephritis in patients with anatomically normal urinary tracts should be treated with antimicrobial therapy for 10 to 14 days. Complicated infections require a full 10- to 14-day course of antimicrobial therapy. Urologic evaluation in patients with acute pyelonephritis or recurrent infections should not be routinely performed. Screening for asymptomatic bacteriuria is unnecessary in adults, except in particular circumstances. There is little evidence that UTI in adult patients lead to progressive chronic renal injury, unless complicating factors are concurrently present.

[The treatment of arterial hypertension in diabetes mellitus. Choices and problems]. / Trattamento dell'ipertensione arteriosa in corso di diabete mellito. Scelte e problemi.

Recent studies indicate that arterial hypertension in diabetes mellitus is a paramount pathogenetic step in the evolution and acceleration of diabetic macro- and microangiopathy and in particular in the development of nephropathy and uremia. This paper deals with the clinical problems of antihypertensive treatment in diabetic patients and discusses the antihypertensive repertory with the aim at determining the best drug choice in the individual case. In the light of our present pathophysiologic knowledges of the intrarenal effects of the various classes of antihypertensive drugs the possibility of preventing diabetic nephropathy is discussed.

[Adherence to dietetic treatment, the nutritional metabolic status and the progression of chronic kidney failure]. / Aderenza al trattamento dietetico, stato metabolico nutrizionale e progressione dell'insufficienza renale cronica.

Effects of two protein restricted diets on dietary compliance, nutritional and metabolic state, and progression of chronic renal failure (CRF) were investigated. Twenty-one patients with CRF were randomly assigned to either a conventional low protein diet (0.6 g of protein/kg b.w./day) or to a very low protein diet, providing 0.4 g of protein/kg b.w./day, supplemented with a mixture of essential amino acids which contained HIS, TYR and a high proportion of branched chain amino acids. Nutrition, assessed by body weight, anthropometry, serum protein levels and nitrogen balance studies, was maintained in all patients. Some metabolic abnormalities of CRF (i.e., secondary hyperparathyroidism, glucose intolerance) improved in both groups. The supplemented diet provided better adherence to protein prescription, corrected the depletion of VAL and LEU in muscle and was more effective than conventional diet in slowing the rate of progression of CFR.

[Current approach in the prevention and treatment of diabetic nephropathy]. / Attuali orientamenti di prevenzione e trattamento della nefropatia diabetica.

Diabetic renal microangiopathy accounts for enormous morbidity and mortality, particularly in patients who develop diabetes in childhood or early youth; in the last few years its pathogenesis has been therefore extensively studied, aiming to prevent renal complications or at least of slowing down its progression toward uremia. Though not always in accordance with theoretical expectations, the results of clinical trials have nevertheless widened our therapeutic possibilities; in fact, besides the attainment of an optimal metabolic control, other possible interventions include a careful correction of albeit minimal elevations in arterial pressure; the interference with intrarenal hemodynamic parameters; the correction of insulin-independent metabolic pathways, abnormally activated in the diabetic, such as non enzymatic glycation and polyol pathway; the treatment of endothelial and platelet alterations; the improvement of the rheologic properties of blood.

[Etiopathogenesis of membranous nephropathy: is there a correlation between experimental and human pathology?]. / Eziopatogenesi della nefropatia membranosa: quale correlazione tra la patologia sperimentale ed umana?

The Authors discuss the etiologic, pathogenetic and immunopathologic aspects of Heymann nephritis, in order to compare the numerous acquisitions concerning this nephropathy with the scanty knowledge of human membranous nephropathy, of which it represents the experimental counterpart. This rat disease can be obtained by inoculation of tubular brush border preparations (active form) or of the relevant antibodies (passive form); after an initial hypothesis of glomerular deposition of circulating immune complexes, studies on its pathogenetic mechanisms, instead demonstrated that in situ immunoaggregates, caused by an interaction between circulating antibodies and fixed glomerular antigens, are formed. Recent investigations have led to the identification of a major nephritogenic antigen (gp330), which is a tubular brush border glycoprotein expressed by coated pits located at the glomerular epithelial cell surface. Studies on antigen-antibody interactions at this level have demonstrated that there is a quick redistribution and accumulation of the so-formed immune complexes, and when polyclonal antibodies were utilized, growth of subepithelial electron dense deposits was observed. Although other tubulo-glomerular antigens, which can also be expressed by endothelial cells, play an uncertain role, they seem to favour transmembrane passing of anti-gp330 antibodies. Immune complex formation gives rise to the onset of proteinuria through complement system activation, without leukocyte involvement: in particular a MAC and C9 fraction lytic effect was demonstrated on cultured epithelial cells. In conclusion, studies on Heymann nephritis contribute to our understanding of the etiopathogenetic mechanisms regarding human membranous nephropathy, and emphasize a possible role played by tubular antigens and in situ formed immune complexes.

[Mechanisms of progression of glomerular sclerosis in chronic renal diseases in man]. / Meccanismi di progressione delle sclerosi glomerulari nelle nefropatie croniche dell'uomo.

The available data indicate that in chronic renal failure (CRF) loss of renal function usually progresses at a constant rate toward end-stage renal disease. Although immunological events might be responsible for initiating most glomerular diseases, certain clinical and experimental observations suggest that the rate of progression of these diseases is influenced by several non immunological factors. These factors include systemic hypertension, proteinuria, hyperlipidemia, high protein intake, and probably conditions leading to glomerular hypertrophy. Interventions designed to minimize the potential contribution of these factors to the progression of renal insufficiency may halt or slow the loss of function at early and late stages of CRF.

[The physiopathologic bases of the neurotoxicity of phosphorus chelating agents containing soluble aluminum salts in patients with renal insufficiency]. / Le basi fisiopatologiche della neurotossicità dei chelanti del fosforo contenenti sali solubili di alluminio nel paziente con insufficienza renale.

To what extent can damage to the central and peripheral nervous systems be ascribed to chronic aluminum (Al) intoxication taken as a chelating agent for phosphorus, to limit hyperphosphatemia in uremic patients? Since Al is normally eliminated by the renal route, its accumulation in uremia has to be ascribed to a reduced or abolished renal clearance of the metal, which results in preferential toxicity for certain tissues, especially nervous tissue, which shows difficulty in eliminating Al, even after intake has been stopped. This review discusses, on the basis of toxicologic, experimental and clinical data, the possible pathogenic steps of Al neurotoxicity in uremia, considering: the damage to axonal transport in which Al intoxication tends to affect the components of the cytoskeleton, the polymerization phase of the alpha and beta tubulin constituents of neurotubules, and the normal translocation of neurofilaments from the perikaryon to more distal positions of the axon; the abnormalities in the brain pool of adrenergic, cholinergic and GABA neurotransmitters; the increase in permeability and changes in perm-selectivity of the blood-brain-barrier, with further loss of neurotransmitters and with acquisition, from the systemic circulation, of neurotransmitter-like substances such as hormones, monoamines and peptides, which may adversely modulate synaptic and membrane functions; the cerebral energy metabolism and particularly the hexokinase reaction, by Al replacement of the Mg-ion in the Mg-ATP complex, so that phosphorylation of glucose to G6P is blocked; the interaction of Al with calmodulin by displacement of the Ca-ion and subsequent formation of a stable Al-calmodulin complex with a cytotoxic effect due to the increase in the intracellular calcium concentration.(ABSTRACT TRUNCATED AT 250 WORDS)