The localization of aluminium and other elements inbone tissue of a case of renal osteodystrophy with an associated dialysis encephalopathy syndrome

Bone tissue from a patient with chronic renal failure and a dialysis encephalopathy syndrome has been studied by histological and histochemical means, by flame emission spectroscopy and by electron probe X-ray microanalysis. There was significant renal osteodystrophy manifest as an osteomalacia. Emission spectroscopy showed the presence of iron (Fe), aluminium (Al), silicon (Si), zinc (Zn), strontium (Sr), lead (Pb) and copper (Cu) in the concentration range 100–1000 parts per million (ppm). Electron probe X-ray microanalysis showed focal concentrations of Fe and Si in the marrow tissue only, whereas Al was localized to the calcification front zones at the junction of osteoid and mineralized tissue of both trabecular and cortical bone. It is concluded that the presence of Al at these sites could interfere with the mineralization process and significantly contribute to the pathogenesis of haemodialysis-related osteomalacia and that it is unlikely that the other elements detected are significant in this regard.     

Histological and electron microprobe studies of mineralisation in aluminium-related osteomalacia.

AIMS: To determine a possible mechanism to explain the presence of aluminium lines within fully calcified bone in aluminium-related osteomalacia. METHODS: Fifty five bone cases shown by bone biopsy to be aluminium-related osteomalacia were studied. In 38 specimens aluminium lines were identified within calcified bone by means of the Aluminon stain and a characteristic form of patchy mineralisation was seen within thickened osteoid seams. Five representative examples were analysed quantitatively by histomorphometry and electronprobe X-ray microanalysis and compared with five cases of vitamin D deficiency-related osteomalacia which also had patchy mineralisation. RESULTS: The patchy calcification occupied 40 +/- 8% (mean +/- SEM) of the osteoid and consisted of small focal deposits (less than 40 microns diameter), often (52%) around osteoid osteocytes (probably an underestimate of the association), and larger areas that extended to the aluminium lines at the underlying mineralisation front. Small and large mineralisation nuclei were seen ultrastructurally in the patchy calcification. Quantitative electronprobe X-ray microanalysis showed that calcium concentrations and calcium:phosphorus ratios in the mineralisation nuclei and in the superficial layer of the fully calcified bone of the aluminium-related osteomalacia cases were significantly less than values measured at similar sites in the vitamin D deficiency-related osteomalacia cases. Furthermore, aluminium could not be detected by means of this technique at the mineralisation front or along cement lines in these specimens. CONCLUSIONS: Calcification can occur in thickened osteoid seams in osteomalacia. It can begin around osteoid osteocytes as small deposits that enlarge within the osteoid and extend to the underlying mineralisation front or cement line where aluminium lines may become trapped. Complete calcification of osteoid could account for the presence of aluminium lines within fully calcified bone. The Aluminon stain appears to be a more sensitive method for the detection of aluminium in bone than electronprobe X-ray microanalysis.     

Effect of parathyroidectomy on bone aluminum accumulation in chronic renal failure

In some patients with chronic renal failure, bone mineralization becomes defective after parathyroidectomy for secondary hyperparathyroidism. Because aluminum deposition in bone is associated with impaired bone formation and osteomalacia, we retrospectively studied bone-biopsy specimens from patients on hemodialysis who were not exposed to dialysate contaminated with aluminum, to determine whether aluminum accumulation on bone surfaces was enhanced by parathyroidectomy. Serial biopsy specimens taken before and after parathyroidectomy revealed an increase in the rate of aluminum deposition on the surface of mineralized bone after parathyroidectomy in each of the six patients studied. The accelerated rate of aluminum accumulation could not be explained by changes in the oral aluminum intake. The mean rate of bone formation (+/- S.E.M.) before parathyroidectomy was higher in the six patients than in six control patients who did not undergo parathyroid surgery (586 +/- 147 vs. 237 +/- 85 micron2 per square millimeter per day; P less than 0.05). After parathyroidectomy, the rate of bone formation fell to levels below normal (148 +/- 32 vs. 311 +/- 29 micron2 per square millimeter per day; P less than 0.05) but was not significantly different from the rate in the control group (319 +/- 126 micron2 per square millimeter per day). We conclude that parathyroidectomy in patients with chronic renal failure is associated with enhanced aluminum deposition on the bone surface, possibly as a result of low bone formation. Patients with secondary hyperparathyroidism who may be candidates for parathyroidectomy should be evaluated for aluminum excess before surgery, so that treatment with aluminum chelation may be considered.     

Combined hemofiltration and desferrioxamine treatment for aluminum induced osteomalacia

A 61-year-old male hemodialysis patient developed the syndrome of aluminum intoxication including bone pain, fractures, proximal myopathy, progressive anemia and expressive aphasia. Serum aluminum was 130 micrograms/l and rose to 445 micrograms/l after the administration of 2 grams of desferrioxamine. Bone biopsy of the iliac crest revealed severe osteomalacia, heavy staining for aluminum and a bone aluminum content of 229 mg/kg dry bone. Treatment with combined hemofiltration and desferrioxamine administration led to a marked clinical improvement and a repeat bone biopsy striking healing of the osteomalacia with a bone aluminum content of 11 mg/kg dry bone.     

Azotaemic renal osteodystrophy: a quantitative study on iliac bone

The histopathology of bone is described in 60 patients with chronic renal failure due to a variety of renal diseases. Changes of azotaemic renal osteodystrophy included osteitis fibrosa, osteomalacia, and osteosclerosis. Quantitative histology using a point-counting technique revealed a significant increase in total bone, mineralized bone, and osteoid in comparison with a control group of 68 individuals. Osteitis fibrosa due to secondary hyperparathyroidism occurred in 93%, osteomalacia in 40%, and osteosclerosis in 30% of patients. Woven bone formation was a characteristic feature and was related to the severity of osteitis fibrosa. There were significant correlations between the weights of parathyroid glands and the number of osteoclasts, amounts of woven bone, and marrow fibrosis in the ilium. Hyperparathyroidism caused degradation of mineralized bone but the loss was balanced or exceeded by the aggradation of woven mineralized bone. Woven bone formation together with excess osteoid gave rise to osteosclerosis. The histological findings indicate that hyperparathyroidism and osteitis fibrosa usually occur early in chronic renal failure and that osteomalacia develops subsequently.     

Histomorphometric profile of bone fluorosis induced by prolonged ingestion of Vichy Saint-Yorre water. Comparison with bone fluorine levels

Nine transiliac bone biopsies from 7 patients with skeletal fluorosis due to prolonged ingestion of often high quantities of Vichy Saint-Yorre water were analyzed. Four of these patients also suffered from a chronic renal failure. A histomorphometric study was possible in 8 out of the 9 biopsies. The measurement of bone fluoride content, and a microradiographic examination, were performed on all bone samples. The radiologically evident osteosclerosis observed in each patient was confirmed by the significant increase of trabecular bone volume. Furthermore, the osteoid surfaces were very extended but the thickness of osteoid seams was normal in 6 out of 8 cases. Two biopsies demonstrated a morphological evidence of osteomalacia with abnormally thick osteoid seams. Calcification rate, measured in one of these 2 cases after tetracycline double labeling, was extremely low (less than 0.20 micron/d). The bone fluoride content was significantly high in each specimen (greater than 0.40 bone ash%) and correlated with relative osteoid volume (r' = 0.91) and thickness index of osteoid seams (r' = 0.83). Histologically, bone tissue showed modifications classically reported in the various types of skeletal fluorosis (formation defects, mottled bone with mottled periosteocytic lacunae). In conclusion, the prolonged administration of Vichy Saint-Yorre water containing 8.5 mg of fluoride ion per liter, provokes a skeletal fluorosis. This intoxication appeared very quickly if the patient suffered from an even mild renal failure. Once again, it is shown that a disturbed renal function predisposes to an excessive retention of fluoride.     

Die Toxizität des Aluminiums

Summary In view of the increasing pollution of our environment and forest decline, growing interest has been focused on aluminum toxicity. Aluminum is one of the most abundant metals and commonly present in tap water, beverages, food, cosmetics, and pharmaceutical preparations. Thus everybody is exposed to aluminum to a greater or lesser extent. It is now beyond any doubt that aluminum intoxication may cause encephalopathy, fracturing vitamin D resistant osteomalacia, and microcytic anemia in patients with chronic renal insufficiency as well as in experimental animals. The risk of aluminum intoxication has also to be considered in several other groups. These include elderly individuals with physiologically impaired excretory renal function who are treated with aluminum — containing antacids, patients with chronic liver disease, infants who are fed highly aluminum-contaminated formula at a time when their excretory renal function has not jet fully developed, patients on total parenteral nutrition, and, possibly, patients with Alzheimer's disease.

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Abkürzungen Al Aluminium - Cu Kupfer - Mg Magnesium - PTH Parathormon - sHPT sekundärer Hyperparathyreoidismus - PTX Parathyreoidektomie - EEG Elektroenzephalogramm - DOPA 3,4-Dihydroxyphenylalanin - TPN Total Parenteral Nutrition     

Intravenous 1α, 25[OH]2 vitamin D3 (calcitriol) pulse therapy for bone lesions in a murine model of chronic cadmium toxicosis

The aim of the present study was to clarify the therapeutic effects of 1alpha, 25[OH]2 vitamin D3 (calcitriol) pulse injection on bone lesions induced in a rat model of chronic cadmium toxicosis. Ovariectomized (OVX) and control-operated (sham-OVX) rats were given repeated intravenous injections of 0.5 mg/kg/day CdCl2 for 70 weeks. The rats were then treated intravenously with 0.02 microg/kg/day calcitriol 3 days per week for 8 weeks. CdCl2 treatment induced increases in osteoid volumes of the femur cortex and trabecula. This change was accompanied by an increase in the volume of iron deposition at the mineralization front of the trabeculae and a reduction in mineral density. Abnormalities of bone metabolic parameters, which were increases in the blood calcium, inorganic phosphorous, bone-specific alkaline phosphatase, parathyroid hormone (PTH) and osteocalcin levels, and in the urine deoxypyridinoline (D-PYR) level, were also induced. Calcitriol treatment increased the blood calcium and inorganic phosphorous levels, and reduced the blood PTH level. Decreases in blood tartrate-resistant acid phosphatase and urine d-PYR levels were also induced indicating that bone resorption was suppressed. The findings indicated that the increased osteoid volume of the cortex and Fe-deposition volume of the trabecula were improved. These effects or improvements were observed in the sham-OVX rats but not in the OVX rats.     

Aluminum-related bone disease. Correlation between symptoms, osteoid volume, and aluminum staining

In order to correlate symptoms, osteoid volume, and aluminum deposition in bone, 46 methacrylate-embedded biopsy specimens from 26 hemodialysis patients were examined. Osteoid volume was measured using computer-assisted morphometric analysis, and aluminum was detected using the Aluminon stain. Positive staining for aluminum was present in biopsies from 21 patients. Osteoid volume did not correlate with duration of dialysis therapy or ingestion of aluminum hydroxide but displayed a logarithmic relationship with dialysate aluminum exposure. Patients with bone pain at the time of biopsy had a greater degree of hyperosteoidosis than asymptomatic subjects. Osteoid volume in patients with fractures and positive aluminum staining decreased on withdrawal from aluminum-rich dialysate. The Aluminon staining technic is a convenient method of confirming aluminum overload.     

The prevalence of bone aluminum deposition in renal osteodystrophy and its relation to the response to calcitriol therapy

A histochemical stain for bone aluminum allowed us to determine the prevalence and staining characteristics of aluminum in renal osteodystrophy. The staining method correlated well with the results of atomic-absorption studies in 96 samples (r = 0.81; P less than 0.001). We examined 315 bone-biopsy samples. No aluminum was seen in controls or patients with nonrenal bone disease. In renal osteodystrophy, the mean level of stainable aluminum was significantly higher in osteomalacic lesions (1.12 +/- 0.09 mm per square millimeter of tissue area) than in mild, mixed, of fibrotic lesions (0.43 +/- 0.06, 0.34 +/- 0.11, and 0.10 +/- 0.03 mm per square millimeter, respectively; P less than 0.001). Seventy per cent of osteomalacic samples had heavy aluminum staining. The bone-apposition rate, measured by double tetracycline labels, was low in 89 per cent of the samples with high levels of aluminum. The mean level of stainable bone aluminum in patients who had a clinical response to calcitriol was significantly lower than in those who did not respond (0.13 +/- 0.4 vs. 1.06 +/- 0.9 mm per square millimeter; P less than 0.01). We conclude that aluminum deposition is associated with impaired bone formation or mineralization and with a poor response to calcitriol therapy.     

Ultrasonography methods in the diagnosis of renal osteodystrophy

Bone disease, i.e. renal osteodystrophy, is commonly seen in patients with chronic renal failure. It encompasses all the disorders of mineral and bone metabolism associated with chronic renal insufficiency, i.e. secondary hyperparathyroidism, retention and accumulation of beta 2 microglobulin and aluminum. The most frequent cause of renal osteodystrophy is secondary hyperthyroidism, with a consequence of high turnover bone disease. Secondary hyperparathyroidism, i.e. increased parathyroid hormone (PTH) secretion and parathyroid gland hyperplasia, develops early in the course of chronic renal insufficiency. Hypocalcemia, phosphate retention and deficiency of calcitriol stimulate PTH synthesis and secretion and parathyroid cell proliferation, i.e. hyperplasia. Parathyroid cell proliferation is initially polyclonal (diffuse hyperplasia), and later it is monoclonal or multiclonal (nodular hyperplasia). Calcitriol receptors as well as calcium-sensing receptors are significantly reduced in parathyroid glands in nodular hyperplasia. Patients with such parathyroid gland hyperplasia are often resistant to vitamin D therapy. A specific form of bone disease is beta 2 amyloidosis. Destructive arthropathy, cystic changes and carpal tunnel syndrome are clinical manifestations of dialysis-related amyloidosis, which is one of the major complications in patients on longterm hemodialysis. Aluminum intoxication leads to the low turnover bone disease and consequential osteomalacia or aplastic bone lesions, the cause of which has not yet been fully clarified. Ultrasound can be a useful, economical and noninvasive method in the evaluation of renal osteodystrophy. Ultrasound waves are very important for noninvasive imaging of soft tissue, especially parathyroid glands, pathologic changes of the joints, and for detection of metastatic calcifications. They are also useful in the evaluation of skeletal status in dialysis patients. Ultrasound waves of a frequency above the limit of human hearing are used in the morphological diagnosis of parathyroid gland. Today, because of its simplicity and non-invasiveness, it is a generally accepted method for the detection of enlarged parathyroid gland in patients with secondary hyperparathyroidism, for the monitoring of pathologic changes, and for making decisions on the method of treatment based on the size and number of parathyroid glands. Ultrasound can distinguish nodal from diffuse parathyroid hyperplasia. Under ultrasound guidance it is possible to perform fine needle aspiration biopsy, to confirm ultrasound findings, and percutaneous inactivation of parathyroid gland (PEI) with alcohol. Ultrasound is useful in the diagnosis of pathologic changes of the musculoskeletal system in patients with beta 2 amyloidosis, to assess the process of its spread, especially in the shoulder joint where the changes are most pronounced (rotator cuff thickness, amyloid deposits as hyperechogenic pads, and detection of fluid in the joint), but it can also be used to examine other joints as well as soft tissue in which metastatic calcifications may occur. Standard ultrasound equipment (pulse-echo) and linear probe of 5-13 MHz are used, also serving for ultrasound examination of the neck, joints and soft tissue. Quantitative bone ultrasonometry is based on different physical characteristics of the ultrasound including: transmission, Speed Of Sound (SOS) in meters/sec and Broad Band Attenuation (BUA) in dB/MHz, and different concepts of the apparatus. These parameters depend on the strength and architecture of the bones and describe better the changes in bone structure in dialysis patients by calculation of the Stiffness Index (QUI), better than the standard bone densitometry by dual-energy x-ray absorptiometry, which only measures bone density. Combined ultrasound measurement of the bone in several locations may be successful in monitoring dialysis patients.     

Dialysis osteomalacia: a possible role for zirconium as well as aluminium

Six patients with dialysis osteomalacia were studied before and after treatment with desferrioxamine. Before treatment, all six had severe osteomalacia with histochemical evidence of metals at the mineralization front, confirmed by energy dispersive X-ray microanalysis to include Al, Zr and Fe. Zr was not detected by histological staining in patients without dialysis osteomalacia. After treatment a decrease of Al and Zr was associated with improvement in clinical, biochemical, radiological and histological parameters. These observations suggest the possibility of a role for metals other than Al in the pathogenesis of dialysis osteomalacia.     

Quantitative bone histology in 38 patients with advanced renal failure.

The clinical, biochemical, radiological and histological appearances of the bones of 38 patients with advanced renal failure are presented. Thirty-three patients had histological evidence of hyperparathyroidism and 17 also showed osteomalacia. Of five showing evidence of neither hyperparathyroidism nor osteomalacia, two had borderline osteopenia. There was an inverse correlation between the plasma calcium concentration and trabecular surface covered by osteoid with a tendency for those with the lowest concentrations of plasma calcium to show histological osteomalacia. There was an inverse correlation between extent of calcification front and both volume and surface extent of osteoid. No relation was found between plasma phosphorus concentration and any of the histological measurements made. Patients with radiological hyperparathyroidism had a lower calcium and higher plasma phosphorus than those without. Phalangeal sub-periosteal erosions were as common in those with histological osteomalacia as in those with histological hyperparathyroidism alone. There was no association between plasma alkaline phosphatase activity and type of bone disease. There was no correlation between the radiological second metacarpal index and the histological volume of cancellous iliac bone.     

Short-lasting accumulation in osteoid bone seams of radioactive iron injected as citrate into mice.

The possible role in vivo of osseous structures in binding radioactive iron injected as a low-molecular-weight complex was studied in mice, using combined autoradiography and histomorphometry on sections of undecalcified, plastic-embedded femur epiphyses/metaphyses. A single intraperitoneal injection of 10 microCi 59Fe (1.2 micrograms Fe) per animal as citrate within 3 hours led to a preferential accumulation of this metal in the osteoid mineralized tissue interphase (osteoid seams) of bone. Within the next 2 days the labeling intensity in this localization diminished markedly to approximate levels of the bone marrow and calcified bone. The bulk of the injected radioiron was utilized according to known erythrokinetics. Findings suggest a direct entry of "free," ie, not transferrin-bound, iron into osteoid seams and its consecutive rapid removal from this site.     

Fibrillary glomerulopathy secondary to light chain deposition disease in a patient with monoclonal gammopathy

The pathologic manifestations of renal diseases related to monoclonal plasma cell dyscrasia include light chain deposition disease, the AL type of amyloidosis, and myeloma cast nephropathy. Light chain deposit disease (LCDD) is an uncommon condition in which monoclonal light chains are deposited in the glomeruli, tubules, and vessels causing varying degree of damage. We report a case of LCDD coincident with fibrillary glomerulonephropathy (FGN) in a 73-yr-old man with a diagnosis of monoclonal gammopathy of undetermined significance who presented with progressive renal insufficiency and mild proteinuria. The serum kappa light chain level was markedly raised. Immunofluorescent stains showed IgG along with C3 and kappa staining in glomeruli, but lambda staining was negative. Electron microscopic studies revealed diffuse punctuate-type deposits along the subendothelial areas. There were also scattered randomly oriented fibrils with a mean fibril thickness of 15-25 nm seen mainly in the glomerular mesangium, consistent with FGN. The congo red stain was negative on the histologic section. The present case illustrates that LCDD can progress to develop FGN in a patient with monoclonal gammopathy.     

Sensitivity of bone histomorphometry in the diagnosis of metabolic bone diseases

Diagnostic sensitivity of bone histomorphometry was assessed in different metabolic bone diseases, after fixing the specificity at 75%, 90% and 95% reference levels. Sensitivity was particularly high in cases with greatly increased osteoid and/or resorption features, as in renal osteodystrophy (ROD). All the remodeling indicators were highly sensitive toward advanced or severe forms of mixed ROD (mROD). Osteoid indicators were the most sensitive parameters in ROD with predominant osteomalacia (oROD). Osteoclastic and several osteoid indicators were very sensitive in all grades of ROD with predominant hyperparathyroidism (hROD). Sensitivity was generally low in uremic patients without bone changes (wROD) and also in patients with idiopathic osteoporosis (OP). It is our recommendation, however, that for each individual patient the definite diagnosis should be based on both morphological, clinical and metabolic parameters.     

Bone aluminium in haemodialysed patients and in rats injected with aluminium chloride: relationship to impaired bone mineralisation.

Iliac bone aluminium was determined by neutron activation analysis in 34 patients with chronic renal failure and in eight control subjects. In 17 patients treated by haemodialysis there was a significant increase in the amount of aluminium (mean +/- SE = 152 +/- 30 ppm bone ash). In eight patients treated by haemodialysis and subsequent renal transplantation, bone aluminium was still significantly increased (92 +/- 4.5 ppm bone ash) but was less than in the haemodialysed patients. In some patients aluminium persisted in bone for many years after successful renal transplantation. There was no relationship between hyperparathyroidism and bone aluminium. Although no statistically significant relationship was found between the mineralisation status of bone and bone aluminium, patients dialysed for the longest periods tended to be those with the highest levels of aluminium, osteomalacia, and dialysis encephalopathy. In 20 rats given daily intraperitoneal injections of aluminium chloride for periods of up to three months, there was accumulation of aluminium in bone (163 +/- 9 ppm ash) to levels comparable to those obtained in the dialysis patients, and after about eight weeks osteomalacia developed. The increased bone aluminium and osteomalacia persisted after injections had been stopped for up to 49 days, although endochondral ossification was restored to normal. As a working hypothesis it is suggested that aluminium retained in the bone of the dialysis patients and the experimental animals interferes with normal mineralisation.     

Effects of fluoride on bone in chronic renal failure.

Fluoride is concentrated in the bones of patients with chronic renal failure when fluoridated water is used during hemodialysis. Excessive osteoid is produced that is not normally mineralized and severe osteomalacia occurs. Electron microscopical examination of iliac crest bone biopsy specimens from four patients suggests that fluoride induces the synthesis of disarrayed collagen by the activated osteoblasts. Collagen fibers were found to be normal in size and in axial periodicity.     

Bone histoquantitative findings and histochemical staining reactions for aluminium in chronic renal failure patients treated with haemodialysis fluids containing high and low concentrations of aluminium.

A total of 112 undecalcified bone biopsies from 67 patients under treatment for chronic renal failure by maintenance haemodialysis was available for retrospective study. The patients were divided into three groups. Group I (15 cases) had been dialysed for the majority of the time in their own homes with a fluid containing a low concentration of aluminium. Group II (28 cases) had been dialysed exclusively in hospital (prior to 1978) with a fluid containing a high concentration of aluminium and group III (24 cases) had been treated exclusively in hospital (from 1978 onwards) with a fluid of low aluminium concentration. The tissues from these groups were subjected to histoquantitative assessment and stained by a histochemical technique to demonstrate aluminium salt. In group II, 71.4% of cases showed positive aluminium staining reactions (at the osteoid/mineralised tissue interface) compared to 26.6% in group I and 37.5% in group III. Staining reactions were also more extensive in group II cases. The osteoid volume was significantly increased and the calcification front extents significantly decreased in group II compared to both groups I and III. A comparison of histochemically positive with negative cases in each group showed a significantly increased osteoid volume and significantly decreased calcification fronts in the positive cases. It was, therefore, concluded that haemodialysis against a fluid containing a high concentration of aluminium leads to intraosseous aluminium accumulation of greater degree in a larger number of patients than a fluid with low aluminium content and that there is an accompanying osteomalacia manifest by an increase in osteoid volume together with diminution in the extent of the calcification fronts.     

Effects of anodic oxidation parameters on a modified titanium surface

Bioactive ceramics used as coating materials combine the conductive properties of a bioceramic with the mechanical stability of the metal implant. We studied a calcium zirconium phosphate-containing coating material, FA-CZP [Ca(5)(PO(4))(3)F, CaZr(4)(PO(4))(6)], that is relatively insoluble in the biological milieu. The reaction of bone to this material was investigated histologically and histomorphometrically in an animal trial. Cylindrical Ti6Al4V specimens that had been coated with FA-CZP by plasma spraying were implanted in the femoral condyles of rabbits. The implants were left in place for 2, 4, 6, 12, and 14 weeks. FA-CZP led to impaired mineralization of the newly formed bone at the interface. Noncalcified osteoid was found throughout the whole study period. The layer seemed to become thicker with time. The mineralization disorder is evidently caused by zirconium ions. The presence of zirconium in the osteoid in contact with the implant was demonstrated by means of two different staining methods.