Correlation Between Renal Cortical Stiffness and Histological Determinants by Point Shear-Wave Elastography in Patients With Kidney Transplantation.

INTRODUCTION: Renal allograft biopsy is the gold standard for the detection of histological lesions of chronic allograft dysfunction. The identification of a noninvasive routine test would be desirable. Elastosonography is used to assess tissue stiffness according to viscosity, and no data are available on the use of point quantification shear-wave elastography (ElastPQ) for the evaluation of renal chronic lesions. RESEARCH QUESTION: To evaluate the feasibility of ElastPQ to assess cortical allograft stiffness and to determine the correlation of clinical, biological, and pathological factors with the diagnostic accuracy of kidney stiffness values in patients with histological lesions. DESIGN: Forty-two patients underwent kidney transplant biopsy and 10 valid measurements of ElastPQ, blindly performed by 2 operators. The interobserver reproducibility was assessed according to intraclass correlation coefficient. The ElastPQ measurements and the clinical data were compared using the Spearman correlation analysis. RESULTS: 97.6% reliable measurements were obtained using ElastPQ, with an excellent interobserver agreement. The kidney stiffness was significantly higher in the patients with a time since transplantation >12 months and was correlated with chronic lesions (interstitial fibrosis, tubular atrophy transplant glomerulopathy, and mesangial matrix), with the interstitial fibrosis/tubular atrophy, score and with the sum of the scores of the chronic lesions. Mesangial matrix increase is the only independent determinant of kidney stiffness. DISCUSSION: ElastPQ is a noninvasive, reproducible, and sensitive diagnostic tool able to detect moderate/severe chronic lesions. Its routine use during follow-up can identify patients eligible for biopsy, which remains the gold standard exam for detecting chronic allograft dysfunction.

Investigation of an imported case of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) infection in Florence, Italy, May to June 2013.

On 31 May 2013, the first case of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) infection in Italy was laboratory confirmed in a previously healthy adult man, who developed pneumonia with moderate respiratory distress after returning from a holiday in Jordan. Two secondary cases were identified through contact tracing, among family members and colleagues who had not previously travelled abroad. Both secondary cases developed mild illness. All three patients recovered fully.

Presurgical setting of secondary hyperparathyroidism using high-resolution sonography and color Doppler.

PURPOSE: High-resolution sonography (US) with color Doppler imaging (CDI) is a simple, noninvasive, safe and repeatable technique able to highlight the presence of hyperplastic parathyroid glands and changes in their volume, structure, and vascularization during uremia. The primary aim of this study was to assess the diagnostic accuracy of US and the sensitivity for localizing parathyroid glands with a volume ≥ 500 mm(3). The secondary aim was to assess the parameters that define parathyroid glandular perfusion. MATERIALS AND METHODS: The diagnostic use of US was assessed in 40 consecutive uremic patients with severe secondary hyperparathyroidism (sHPT) who were receiving maintenance hemodialysis or conservative therapy with a hypoproteic-hypophosphoric diet and had undergone parathyroidectomy. Prior to surgery (99m)TC-sestamibi scintigraphy (SM) was performed in all patients. RESULTS: The sensitivity, specificity, positive predictive value and accuracy of US were 74 %, 75 %, 98 %, and 74 %, respectively. The sensitivity for localizing glands with a volume ≥ 500 mm(3) was 90 %. US and SM had a combined sensitivity of 83 %. The vascularization of parathyroid glands became more evident with increasing glandular volume. With CDI, the signs of hypervascularization (i. e. an enlarged feeding artery at the hilum, a peripheral arc of vascularity and/or ray-like endonodular vessels) were present in 77 % of glands with a volume ≥ 500 mm(3). CONCLUSION: The sensitivity of US is higher than that of SM, but it cannot be compared with that of parathyroidectomy (74 vs. 95 %). However, US/CDI is able to characterize glands with different volumes and vascular patterns. Since glandular volume and vascularization are indicative of the severity of sHPT, this study suggests that the main role of US/CDI in the setting of sHPT should be to complete the diagnosis and to evaluate the morphological changes of enlarged glands during uremia in order to define surgical timing, rather than to assess the presurgical location of glands.

Food intake and nutritional status in stable hemodialysis patients.

This is a cross-sectional, multicenter, controlled study aiming to evaluate changes of actual dietary nutrient intake in 94 stable hemodialysis patients in respect to 52 normal subjects and guideline recommendations, and to assess the prevalence of signs of malnutrition. Energy and nutrients intake assessment was obtained by a three-day period food recall. Anthropometric and biochemical parameters of nutrition, bioelectric impedance vector analysis, and subjective global assessment (SGA) have been performed to assess nutritional status. SGA-B was scored in 5% of the patients. Body mass index < 20 Kg/m(2), serum albumin <35 g/L, nPNA < 1.0 g/Kg, and phase angle <4.0 degrees were detected in 16.3%, 16%, 23%, and 8.0 % of patients, respectively. HD patients showed a lower energy and protein intake in respect to controls, but no difference occurred when normalized per ideal body weight (29.3 +/- 8.4 vs. 29.5 +/- 8.4 Kcal/Kg i.b.w./d and 1.08 +/- 0.35 vs. 1.12 +/- 0.32 Kcal/Kg i.b.w. /d, respectively). Age was the only parameter that inversely correlates with energy (r = -0.35, p < 0.001) and protein intake (r = -0.34, p < 0.001). This study shows that in stable dialysis patients, abnormalities of nutritional parameters are less prevalent than expected by analysis of dietary food intake. Age is the best predictor of energy and protein intake in the dialysis patients who ate less than normal people, but no difference emerged when energy and protein intakes were normalized for body weight. These results recall the attention for individual dietetic counseling in HD patients, and also for a critical re-evaluation of their dietary protein and energy requirements.

Insulin resistance and low urinary citrate excretion in calcium stone formers.

Epidemiological data suggest an association between kidney stones and some features of metabolic syndrome such as an overweight condition, arterial hypertension or glucose intolerance. However, mechanisms remain to be elucidated. This study aimed to evaluate insulin resistance, as assessed by homeostasis model assessment (HOMA-IR), and urine composition analysis in patients affected by calcium nephrolithiasis. A cohort of 61 (38 male, 29-57 years of age) non-diabetic calcium stone formers was studied. Data about body mass index, arterial blood pressure, serum biochemistry including parathyroid hormone and calcitriol were recorded in all the patients; fasting glucose and insulin were determined to calculate HOMA-IR value and accordingly the patients were grouped into tertiles. Urine pH and urinary excretion of calcium, citrate, phosphate, oxalate, uric acid, urea and creatinine were measured on 24h urine samples. Patients of the highest HOMA-IR tertile showed lower urine citrate levels than patients of the lowest HOMA-IR tertile (475+/-243 vs. 630+/-187 mg/24h, p<0.05), whereas no difference was detected as far as urinary oxalate, calcium, uric acid, phosphate, and urine pH and urine volume output were concerned. HOMA-IR values were positively related to uric acid serum levels (r=0.31, p<0.05) and negatively to urinary citrate excretion (r=-0.26, p<0.05). Hypocitraturic patients showed higher levels of HOMA-IR than normocitraturic ones (3.03+/-0.92 vs. 2.25+/-1.19, p<0.05). This study shows that a higher level of insulin resistance is associated with lower urinary citrate excretion, and that hypocitraturic patients show a greater insulin resistance than normocitraturic calcium stone formers. This may be related to changes in citrate, Na(+)-K(+) and H(+) renal tubule transports, which have been described in insulin resistance. In conclusion, insulin resistance may contribute to an increased risk of calcium stone formation by lowering urinary citrate excretion. This finding suggests the need for a careful metabolic assessment in patients known to form calcium stones in order to ensure stone recurrence prevention and cardiovascular protection.

Endothelial function and common carotid artery wall thickening in patients with essential hypertension.

Intimal-medial thickening of the carotid wall is considered an early marker of atherosclerosis. Endothelial function is impaired in the presence of various cardiovascular risk factors that are implicated in the pathogenesis of atherosclerosis. To evaluate the relationship between vascular reactivity and carotid intimal-medial thickening, in 44 (mean+/-SD age, 45.7+/-8.8 years; range, 28 to 60 years; 31 men and 13 women) patients with essential hypertension who had never been treated and whose history of increased blood pressure was no longer than 12 months, we evaluated several parameters: intimal-medial thickening of the common carotid arteries (by B-mode ultrasound); forearm vascular response (by strain-gauge plethysmography) to intrabrachial infusion of acetylcholine (0.15, 0.45, 1.5, 4.5, and 15 microg/100 mL forearm tissue per minute), an endothelium-dependent vasodilator, or sodium nitroprusside (1, 2, and 4 microg/100 mL forearm tissue per minute), an endothelium-independent vasodilator; calculated minimal forearm vascular resistances (the ratio between mean arterial pressure and maximal forearm vasodilation induced by 13 minutes of ischemia and 1 minute of exercise); and left ventricular mass index (on echocardiography profile). Carotid wall intimal-medial thickening showed a significant (P<0.001) inverse correlation with vasodilation to acetylcholine (r=-0.58) and age (r=-0.40), whereas no correlation was observed with the response to sodium nitroprusside or with minimal forearm vascular resistances, left ventricular mass index, systolic and diastolic blood pressures, and plasma cholesterol and glucose levels. Moreover, vasodilation to acetylcholine showed no correlation with minimal forearm vascular resistances or left ventricular mass index. Although comparison of different vascular "districts," such as the forearm microcirculation and carotid artery, does not allow for a conclusive interpretation, the present data indicate that in patients with essential hypertension, carotid wall thickening is associated with reduced endothelium-dependent vasodilation and suggest that endothelial dysfunction might be involved in early arterial structural alterations.

Color-Doppler in the imaging work-up of primary hyperparathyroidism.

Primary hyperparathyroidism (PHP) is a rare disease that must be suspected in all the cases of recurrent calcium nephrolithiasis, and that may be totally corrected by surgery. The imaging techniques permit to locate the hyperplastic gland or adenoma before intervention, but their usefulness in patients without a history of previous neck surgery is still debated. Several imaging techniques have been proposed with the aim of locating parathyroid hyperfunctioning glands, including high resolution sonography (US) with color-Doppler (CD), scintigraphy, computed tomography (CT) and magnetic resonance imaging (MRI). We report here a case of recurrent calcium oxalate nephrolithiasis sustained by PHP, which demonstrates how US coupled with CD and echocontrast enhancement is useful in the preoperative location of parathyroid glands. US is the first choice technique in the evaluation of PHP because it is less expensive and useful in detailing lesions of the neck when carried out by a skilled operator. CD should be regarded as a useful complement of US enhancing its sensitivity (80 vs 90%) especially in the cases of associated thyroid gland diseases. Tc-99m SESTAMIBI scintigraphy coupled with MRI is mandatory in high risk surgical patients, namely in those undergoing repeated neck surgery. In conclusion, considering that surgeon must explore all the four parathyroid glands (because of the possibility of multiple adenomas or hyperplasia) a well definite location of the adenomatous lesion may reduce the risks and the time of intervention, and allow the use of alternative procedures, such as videoscopic surgery. On this view and in terms of economy, only US and CD coupled with Tc-99 SESTAMIBI scintigraphy should be considered before surgery.

Bilateral perinephric fluid accumulation: an unusual manifestation of pulmonary hypertension--a case report.

This is the case report of a forty-seven-year-old man with an ostium secundum atrial septal defect and a very high grade of pulmonary hypertension, associated with a large bilateral perinephric fluid accumulation. The fluid accumulation was remarkably reduced after eleven phlebotomies over a twelve-month period. A pathogenetic relation with the Eisenmenger's syndrome is discussed. No previous report of this association has been found in a survey of the literature.

A scanning electron microscope study of the effect of etching time and mechanical pre-treatment on the pattern of acid etching on the enamel of primary teeth.

Eighty-five deciduous teeth, divided into five groups, were examined using a scanning electron microscope. The first two groups were etched for 60 and 120 sec respectively; the third and fourth groups were lightly milled and then etched for 60 and 120 sec respectively. In the first two groups, etching produced very few histological modifications. In the milled groups removal of the prismless enamel exposed the prisms to dissolution by the phosphoric acid. It was found that pretreatment and an etching time of 120 sec produced a constant and regularly distributed loss of inter- and intraprismatic substances.

[Aging of the aorta: a morphological study]. / L'invecchiamento dell'aorta: studio morfologico.

Aim of this study was to evaluate the aging of aorta with respect to atherosclerotic modifications: abdominal aorta echotomography is the preferred approach for this study. In 354 elderly patients, 65 and over, we have evaluated the diameter and the course of the aorta, the presence of atherosclerotic plaques in the aorta and iliac vessels, and the presence of aneurysms. Two kinds of findings could be identified by echotomography: age-related physiologic modifications, represented essentially by an increase of the aortic diameter; pathologic changes, characteristic for atherosclerosis, of which aneurysms are the most dangerous complications.

Color Doppler sonography in the study of chronic ischemic nephropathy.

In western countries, the risk of cardiovascular disease has increased considerably in recent decades. This trend has been paralleled by an increase in cases of atherosclerotic renal disease, which is related to the improved prognosis of cardiovascular diseases, aging, and the increasing mean age of the general population. It is reasonable to expect that in the near future, there will be a sharp increase in the number of elderly patients with atherosclerotic vascular disease in chronic dialysis programs. The result will be a dramatic rise in the social and economic costs of dialysis that could constitute a true clinical emergency. In this epidemiologic scenario, one of the most important targets of 21st century nephrology will be the early diagnosis of chronic ischemic nephropathy and the development of new and more effective strategies for its treatment.Color Doppler (CD) ultrasonography has displayed high sensitivity, specificity, and positive and negative predictive values in the diagnosis of this disease in selected population, making it an ideal tool for use in screening programs. Eligibility for screening should be based on clinical criteria. For the most part, it will be aimed at adults (especially those who are elderly) with atherosclerotic vascular disease involving multiple districts and chronic kidney disease (CKD), stage 2-3, in the absence of a documented history of renal disease. In these patients, hypertension may be a secondary manifestation or a symptom of the ischemic nephropathy itself. The objectives of sonographic screening should be (1) to identify subjects in the population at risk who are affected by stenosis of the main renal artery (RAS); (2) to identify and characterize patients without RAS who have chronic ischemic nephropathy caused by nephroangiosclerosis and/or atheroembolic disease. The former group will require second-level diagnostic studies or angioplasty with stenting; the latter can be managed conservatively. The most important CD parameters in the workup of suspected RAS are those that are direct signs, i.e., increases in peak systolic velocity (PSV) and diastolic velocity (DV), spectral broadening, and an altered renal:aortic ratio (RAR). Their assessment requires full-length sampling of the renal artery and is associated with greater practical/technical difficulties. Measurement in triplicate of the PSV in the ostial, medial, and hilar segments of both arteries and bilateral measurement of parenchymal resistance indices are usually sufficient to detect the presence of stenosis and refer the patient for second-level studies. Important parameters for estimating the severity of a stenosis include the renal:aortic ratio (>3.5), disappearance of the early systolic peak in segmental vessels, lateralization of the resistance index (ΔRI > 0.05), and the evaluation of the acceleration index (AI) and acceleration time (AT). Second-level imaging studies (CT angiography, MR angiography) are still indispensable for precise definition of the location and extension of the stenosis and the therapeutic approach during digital subtraction angiography (DSA). In the absence of direct or indirect signs of RAS, increases in the intraparenchymal resistance indices (RI > 0.75-0.80; PI > 1.50) associated with systemic atherosclerotic disease are indicative of microcirculatory damage related to nephroangiosclerosis or atheroembolic disease.

[Color-Doppler of renovascular diseases]. / Il color-Doppler nelle malattie vascolari del rene.

The color-flow mapping (CD-PD) is a safe, repeatable and non invasive imaging technique that shows the vessels trip and simplifies the spectral wave detection wich is fundamental to perform a quantitative analysis of Doppler signal. In the last years, digital ultrasound technology has increased the sensitivity and accuracy of Doppler procedures and has also reduced technical pitfalls. The role of CD-PD in the diagnosis and follow-up of a great number of renal vascular diseases is very important. Particularly, it is a screening test of chronic ischemic nephropathy caused by stenosis of the main renal artery or by atherosclerotic remodelling of the intrarenal vascular tree. The Systolic and Diastolic velocity peak (SVP and DVP), as were as spectral broadening and reno-aortic ratio (RAR), are the most significant criteria for the diagnosis of renal artery stenosis. The bilateral evaluation of the resistance indices and of the early systolic peak, in order to highlight parvus-tardus sign, leads the clinical choice between stenting and conservative therapy. MRI and TC complete the diagnostic flow-chart and allow the clinician to define the treatment. Values of IR > 0.80 and IP > 1.50, without a clinical history of chronic nephropathy and main renal artery stenosis, must be considered as indicators of nephroangiosclerosis and/or atheroembolic disease. In other words, the increased impedance suggests a remodelling of the microcirculation with a reduction of the cross sectional area of vessels and an increase of the total peripheral resistance of the kidney.

Morphology of the aprismatic enamel: a SEM study of different etching.

Using the SEM, 55 longitudinally sectioned deciduous teeth were examined. The specimens were treated with a 37% solution of phosphoric acid and subsequently subdivided into groups in order that they could undergo etching for 1 min., 2 mins., 1 min. + 1 min. A minimal change was obtained with an etching time of 1 min., while an etching time of 2 mins. produced large porosity and deep, evenly distributed fossae. No important differences were seen following intermediated washing.

Free-hand ultrasound-guided renal biopsy: report of 650 consecutive cases.

In the past 4 years we have carried out 650 percutaneous renal biopsies (PRB), 54 on transplanted and 596 on native kidneys. PRB was performed with a 14-gauge one-piece disposable needle that was introduced free-handedly into the lumbar wall without any form of fixed guidance or support. Ultrasound was used to locate the kidney pole and to follow the progression of the needle tip in the renal parenchyma. The time needed for the whole procedure was about 5 min. The tissue specimen was adequate for histological evaluation in 98.8% of the cases. The prevalence of post-biopsy complications (haematuria, pain, anaemia) was 2.5%. Haematuria was not a common complication (1.6%) in our series, whereas clinically silent perirenal haematoma was common. Mild perirenal bleeding (volume < 5 ml) was found in 40 of a series of 150 patients (26.6%) who underwent ultrasound scan 24 h after the PRB. Haematoma exceeding 100 ml was revealed with US in only 0.6% of the patients. We conclude that free-hand ultrasound-guided PRB makes this technique easier, highly successful, time-saving and almost free of severe side effects.

Low urine citrate excretion as main risk factor for recurrent calcium oxalate nephrolithiasis in males.

To better define the relative role of metabolic factors in the recurrence of stone formation, we studied the 24-hour urinary excretion of calcium (uCa), citrate (uCit), oxalic acid (uOx) and uric acid (uUa) in 73 male patients with primary calcium oxalate urolithiasis. According to the episodes of stone formation per year, we identified 51 recurrent stone formers (RSF) and 22 single stone formers (SSF). 20 normal adult males constituted the control group (C). uCa and uOx were higher in RSF than in C, but quite similar in SSF and RSF. The only difference between RSF and SSF was uCit, significantly lower (2.06 +/- 1.04 mmol/24 h) in RSF than in SSF (3.22 +/- 1.18 mmol/24 h, p less than 0.001) and in C (3.42 +/- 1.33 mmol/24 h, p less than 0.001). Hypocitraturia (uCit less than 1.5 mmol/24 h) was found in 16 of 51 RSF (31.4%) and in 1 of 22 SSF (4.5%). These data confirm that high levels of uCa and uOx represent a risk factor for lithogenesis, but also strongly indicate the low uCit excretion as the most important urinary abnormality accounting for the recurrence of calcium oxalate stones.

Ultrasound diagnosis of suspected urinary tract obstruction using a stimulated diuresis test.

The aim of this study was to evaluate whether a stimulated diuresis test associated with ultrasound is able to differentiate pelvic dilation due to atonicity from pelviureteric junction obstruction (PUO). 42 patients (25 f, 17 m) with minimal or moderate renal pelvis dilation revealed by sonography were selected for the test. Three different measurements of the anteroposterior diameter (APD) of the renal pelvis were done at the renal hilus level, by using a transversal ultrasound scan: the first under spontaneous diuresis conditions, the second after hydration with 1.5 liters of water, and the third with a full bladder 15 min after intravenous injection of 20 mg frusemide. All the patients underwent pyelography. Baseline APD (bAPD) linearly correlated with the PAD both after hydration and frusemide (r = 0.89 and r = 0.84, respectively). A descriptive evaluation of the frequency distribution of the bAPD suggested the possibility that the data samples could belong to three populations with different underlying pathophysiological conditions. Correspondence analysis between bAPD distribution and PUO suggested that the best grouping of data was: group 1 (11 patients) bAPD < 13 mm, group 2 (14 patients) 13 > or = bAPD < or = 20 mm, group 3 (17 patients) bAPD > 20 mm (likelihood ratio chi 2 46.36; d.f. = 2). Standard intravenous pyelography showed an increase in pelvis size compatible with PUO in 2 patients from group 2 and in all patients from group 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypertension in kidney stone patients.

The prevalence of arterial hypertension (HT) was investigated in 258 patients (171 m, 87 f, 22-68 years) with a history of primary stone disease. HT was detected in 64 patients (24.8%), with no difference between males (25.7%) and females (23.0%). The prevalence of HT by age was very similar to that of a general population, especially in the calcium stone group. The discriminant analysis demonstrated that the composition of stones, other than the age and body weight of the patients, were the main factors associated with HT. As far as the different kind of stone is concerned, the prevalence of HT was higher in patients with uric acid (17/37, 45.9%) and struvite stones (11/27, 40.7%) than in calcium stone formers (35/188, 18.6%) (chi 2 16.31, p < 0.001). The prevalence of hypercalciuria was higher in the calcium stone group than in uric acid or struvite stone patients (36.4 vs. 9.7 vs. 13.7%; chi 2 10.35, p < 0.01). Furthermore, the hypercalciuria showed a trend to be more prevalent in the untreated (47.0%) than in the treated (31.2%) hypertensives, or normotensives (35.1%). Uric acid stone formers were older, heavier and with higher triglycerides and uric acid plasma levels than calcium or struvite patients. Also the struvite stone formers were older than the calcium stone ones. Our data suggest that the prevalence of HT in kidney stone patients and particularly in calcium stone formers is similar to that of a general population. The role of hypercalciuria as the link for HT-urolithiasis association seems quite uncertain. Struvite and uric acid stone formers have higher risk for HT than calcium stone formers, probably due to the old age or to the associated metabolic abnormalities.

A low-nitrogen low-phosphorus Vegan diet for patients with chronic renal failure.

The nutritional treatment of chronic renal failure with a low-protein low-phosphorus diet (conventional low-protein diet, CLPD) is effective in reducing uremic intoxication, slowing the progression of renal failure and preventing secondary hyperparathyroidism. Unfortunately, in some patients, the poor palatability and the high cost of the protein-free substitutes, together with difficulties in following the diet away from home, can make good compliance difficult, possibly causing low energy intake and malnutrition. Here the results are reported of an attempt we made to overcome these drawbacks, using a diet supplying only natural foods of plant origin in definite proportions to give an essential amino acid supply satisfying the recommended dietary allowance. This is possible thanks to an appropriate cereal-legume mixture, supplying proteins complementary for essential amino acids. Additional positive features of this special vegan diet (SVD) are the high ratio of unsaturated to saturated fatty acids, the absence of cholesterol, and the lower net acid production in comparison with a mixed diet. This study indicates that the results obtained with the SVD are similar to those obtained with the CLPD. Therefore the SVD can be a substitute for the CLPD in the management of patients with mild chronic renal failure. The SVD is the diet of choice when products made of starch are not available or poorly tolerated.

Serum oxalic acid in uremia: effect of a low-protein diet supplemented with essential amino acids and ketoanalogues.

Serum oxalic acid (sOx) was determined with a new, specific enzymatic method in 73 uremic patients and the values were plotted against serum creatinine. 41 patients received a free mixed diet, and 32 similar patients were given a low-nitrogen diet supplemented with essential amino acids, ketoanalogues, and calcium carbonate (AD). A significant correlation was found between serum creatinine and sOx levels in patients following a free mixed diet, while no correlation appeared in patients on AD: The sOx concentrations were significantly lower and even normal in this group, and a significant reduction of sOx occurred in 10 patients with chronic renal failure, who changed from a free mixed diet to the AD. The lowering of sOx concentration in patients following AD is attributed both to low intake of its metabolic precursors and to the oral calcium carbonate supplementation.

Secondary hyperparathyroidism in severe chronic renal failure is corrected by very-low dietary phosphate intake and calcium carbonate supplementation.

The main purpose of our study was to verify the effect of a very-low-protein, low-phosphorus diet, supplemented with essential amino acids and keto analogues and with calcium carbonate, on circulating levels of intact parathyroid hormone (i-PTH) in severe chronic renal failure patients with secondary hyperparathyroidism, not treated with any vitamin D preparation. To this aim, we shifted 21 chronic uremics (12 males, 9 females; age 56 +/- 13 years) with serum creatinine >6.5 mg/dl and i-PTH >150 pg/ml, from a standard low-protein diet (0.6 g/kg/day approximately) to a very-low-protein (0.3 g/kg/day), very-low-phosphorus (5 mg/kg/day) diet supplemented with a mixture of essential amino acids and calcium keto analogues (Ketodiet), calcium carbonate (2-4 g/day), iron, and vitamin B12 preparations. The energy supply of both diets was 30-35 kcal/kg/day. Exclusion criteria were a poor compliance with dietary or supplement prescriptions or signs of autonomic hyperparathyroidism. After 4 +/- 2 months of Ketodiet, the i-PTH serum levels decreased by 49% as a mean (from 441 +/- 233 to 225 +/- 161 pg/ml, p < 0.001); serum phosphorus and alkaline phosphatase decreased, whereas serum calcium increased. The great reduction of serum and urinary urea demonstrated a good compliance with Ketodiet, and no sign of protein malnutrition was observed. These findings confirm that even in severe chronic uremic patients dietary phosphorus restriction and calcium carbonate supplementation lower i-PTH serum levels. This is one of the goals of the dietary treatment that can be safely achieved, provided good compliance both with the dietary prescriptions and with adequate energy and supplement intakes.