Pathogenesis of dialysis-related amyloidosis

Beta 2-microglobulin has been demonstrated to be a major constituent of amyloid fibrils in dialysis-related amyloidosis. However, the molecular pathogenesis of this complication remains unknown. Several lines of evidence suggest that beta 2-microglobulin is not an innocent bystander, but plays an active role in the development of dialysis-related amyloidosis. The evidence remains inconclusive, however, as to whether it is intact or modified beta 2-microglobulin which is amyloidogenic and contributes to bone and joint destruction. Recent biochemical and immunohistological studies have revealed a new modification of beta 2-microglobulin in amyloid fibrils, the advanced glycation end products formed nonenzymatically between aldoses and proteins. Further study has suggested that the interaction of advanced glycation end product-modified beta 2-microglobulin with monocytes/macrophages gives a plausible, albeit incomplete, explanation for the mechanism of bone and joint destruction in dialysis-related amyloidosis. This review focuses on new aspects of the pathogenesis of dialysis-related amyloidosis.     

N epsilon-(carboxymethyl)lysine in blood from maintenance hemodialysis patients may contribute to dialysis-related amyloidosis

BACKGROUND: Recent studies demonstrated not only that advanced glycation end product could be found in amyloid tissue from patient with dialysis related amyloidosis, but also that amyloid beta2-microglobulin was modified with N(epsilon)-(carboxymethyl)lysine (CML). We wanted to determine if CML could be a biomarker in these patients. METHODS: To raise polyclonal anti-carboxymethyllysine antibody, human serum albumin was carboxymethylated by glyoxylic acid and was immunized to rabbits as antigen. Carboxymethyllysine-hemoglobin (CML-Hb) levels were measured by the dot blotting method using this antibody. RESULTS: The levels of CML-Hb were 6.68 +/- 3.10 nmol CML/mg Hb in nondiabetic hemodialysis patients (N = 70), 6.39 +/- 3.43 nmol CML/mg Hb in diabetic hemodialysis patient (N = 21), and 3.13 +/- 0.88 nmol CML/mg Hb in 47 healthy volunteers. For clinical signs of dialysis-related amyloidosis, 70 nondiabetic hemodialysis patients were scored according Gejyo's criteria. The CML-Hb levels in patients with a high amyloid score as well as a low amyloid score were significantly higher than in patients with negative amyloid score (8.89 +/- 3.53 nmol CMLmg Hb, 7.28 +/- 2.32 nmol CML/mg Hb vs. 5.11 +/- 2.09 nmol CML/mg Hb, P < 0.001, P < 0.05). Furthermore, the CML-Hb levels correlated significantly with serum values of the methylguanidine over creatinine ratio and hyaluronate. CONCLUSIONS: We suggest that CML-Hb is increased in blood from patients on maintenance hemodialysis and is thus a potential biomarker of oxidative damage in these patients. Moreover, CML-modification of protein may play a pathogenic role in the development of dialysis related amyloidosis.     

Implication of the glycoxidation and lipoxidation reactions in the pathogenesis of dialysis-related amyloidosis (Review)

BACKGROUND: The term Marjolin ulcer is now synonymous with malignant transformation of chronic ulcers, sinus tracts, and burn scars. OBJECTIVE: To illustrate the importance of incisional or excisional biopsies in cases of suspected burn scar carcinoma. METHODS: Case report and review of the literature. RESULTS: Multiple punch biopsies were negative while a complete excision revealed the diagnosis of squamous cell carcinoma. CONCLUSION: Because of the focal nature of malignant change in burn scars, incisional or excisional biopsy should be performed.     

Identification of pentosidine as a native structure for advanced glycation end products in beta-2-microglobulin-containing amyloid fibrils in patients with dialysis-related amyloidosis

beta-2-Microglobulin (beta-2m) is a major constituent of amyloid fibrils in patients with dialysis-related amyloidosis (DRA). Recently, we found that the pigmented and fluorescent adducts formed nonenzymatically between sugar and protein, known as advanced glycation end products (AGEs), were present in beta-2m-containing amyloid fibrils, suggesting the possible involvement of AGE-modified beta-2m in bone and joint destruction in DRA. As an extension of our search for the native structure of AGEs in beta-2m of patients with DRA, the present study focused on pentosidine, a fluorescent cross-linked glycoxidation product. Determination by both HPLC assay and competitive ELISA demonstrated a significant amount of pentosidine in amyloid-fibril beta-2m from long-term hemodialysis patients with DRA, and the acidic isoform of beta-2m in the serum and urine of hemodialysis patients. A further immunohistochemical study revealed the positive immunostaining for pentosidine and immunoreactive AGEs and beta-2m in macrophage-infiltrated amyloid deposits of long-term hemodialysis patients with DRA. These findings implicate a potential link of glycoxidation products in long-lived beta-2m-containing amyloid fibrils to the pathogenesis of DRA.     

Ultrasonographic bedside evaluation of maxillary sinus disease in mechanically ventilated patients

GABA modulates dopamine concentrations in the nucleus accumbens and corpus striatum. Using in vivo microdialysis techniques we examined this modulatory role and the extent to which three different GABAergic drugs can attenuate cocaine's ability to increase extracellular dopamine concentrations and gross locomotor activity. Ethanol, lorazepam (Ativan), and gamma-vinyl GABA (GVG) significantly and dose-dependently attenuated cocaine-induced dopamine release in the corpus striatum of freely moving animals. Unlike ethanol or lorazepam, however, GVG is not a sedative hypnotic in the doses used, and hence the strategy of selectively increasing GABAergic activity by suicide inhibition of the catabolic enzyme, GABA-transaminase, offers the unique advantage of attenuating cocaine-induced dopamine release without the apparent side effects typically associated with sedative hypnotics.     

Long-term clinical evaluation of an adsorbent column (BM-01) of direct hemoperfusion type for beta 2-microglobulin on the treatment of dialysis-related amyloidosis

The clinical efficacy and safety of a beta 2-microglobulin (beta 2M) adsorbent column, BM-01, on the treatment of dialysis-related amyloidosis were investigated in 7 hemodialysis patients for more than 6 months. The percent reduction of serum beta 2M was more than 60-70%, and the level at the end of each session was less than 10 mg/L in almost all patients. The amount of beta 2M removed was calculated as more than 200-300 mg/session. The results demonstrated that BM-01 performed very well for removing beta 2M, was capable of maintaining less than 25 mg/L of time average concentration (TAC) for beta 2M, and improved the clinical symptoms. Clinically severe side effects were not observed. We recommend that BM-01 should undergo further evaluation for its usefulness in the long-term treatment of dialysis-related amyloidosis, though treatment with the column may not be successful in preventing the onset of the disease.     

Amyloid beta 2-microglobulin is modified with imidazolone, a novel advanced glycation end product, in dialysis-related amyloidosis

We have recently demonstrated by immunohistochemistry that amyloid beta 2-microglobulin (beta 2m) is modified with advanced glycation end products (AGEs) in dialysis-related amyloidosis (DRA). To further investigate the role of the Maillard reaction in the pathogenesis of DRA, we produced a monoclonal antibody to imidazolone, a novel AGE, and a reaction product of arginine and 3-deoxyglucosone (3-DG) which was accumulated in uremic serum. Then we determined the localization of imidazolone in the amyloid tissues by immunohistochemistry using the antibody. The connective tissues in carpal tunnel and ligamentum flavum were obtained from six patients with carpal tunnel syndrome and two patients with destructive spondyloarthropathy. Imidazolone was localized to all the beta 2m-positive amyloid deposits in these patients. Western blotting using the antibody demonstrated that beta 2m extracted from the synovium amyloid of hemodialysis patients was modified with imidazolone. Further, beta 2m isolated from the blood ultrafiltrate of hemodialyzed patients was also modified with imidazolone. In vitro incubation of beta 2m with 3-DG produced imidazolone-modified beta 2m. In conclusion, amyloid tissue beta2m is modified with imidazolone in patients with DRA. 3-DG accumulating in uremic serum may be involved in the modification of beta 2m with imidazolone.     

Ultrasonographic evaluation of urinary tract in children with chronic functional constipation

Urinary tract anomalies were prospectively investigated with ultrasound in 31 children with chronic functional constipation. These children were compared with 29 healthy controls without constipation both before and after treatment. Bladder residue and upper renal tract dilatation after micturition were significantly more common in the group with constipation than in the improved after-treatment and control groups.     

A clinical study of dialysis-related osteoarthropathy in long-term hemodialysis patients

Amyloid osteoarthropathy has been seen frequently in long-term hemodialysis (HD) patients, in which the bone X-ray examination reveals characteristic cystic radiolucency (CRL) of the carpal bone, shoulder joint, hip joint and knee joint, and destructive spondylarthropathy (DSA) of cervical vertebrae. To clarify the clinico-pathological significance of CRL and DSA in HD-related amyloidosis, we investigated the grade and frequency of CRL or DSA and these relationship with age, HD duration, primary diseases, osteoarticular symptoms and blood analysis in 817 HD patients (492 male and 325 female, age: 52.6 + 15.5 years, dialysis duration: 6.8 + 5.4 years). The number of cases with osteoarticular symptoms increased with the prolongation of HD duration. CRL and DSA were observed even in patients without osteoarticular symptoms: 26.7% for carpal bone, 26.2% for shoulder joint, 17.3% for hip joint and 22.2% for DSA. The grade and frequency of CRL and DSA also increased in accordance with age and HD duration. In patients with CRL of the carpal bone, shoulder CRL was noticed in 39.7%, hip CRL in 25.8%, and DSA in 14.3% of cases, respectively, and these frequencies increased with the prolongation of HD duration. In the carpal CRL negative group, shoulder CRL was noticed in 14.6%, hip CRL in 7.5%, and DSA in 6.0%, respectively. Although there was no relationship between CRL or DSA and serum beta 2-MG level in any of the cases, the serum beta 2-MG level was lower in patients with HD showing shoulder CRL (+2) and DSA (+) for more than 16 years. No significant relationship was noticed between CRL or DSA and serum C-PTH and aluminum level. These results suggested that aging was related to CRL or DSA formation in dialysis-related amyloidosis. The findings also suggested that systemic bone X-ray examination should be considered in patients with carpal bone CRL, high-age patients and long-term HD patients even without osteoarticular symptoms.     

Ultrasonographic diagnosis of the parotid gland tumors--experience with 310 patients

The diagnostic value of ultrasonography of parotid gland tumors is to determine if the tumor is benign or malignant. In the period from 1984 to 1995, ultrasound examinations were performed on 310 patients with a space-occupying lesion of the parotid gland, using real time 3.75 MHz, 5 MHz and 7.5 MHz transducers. From a histological standpoint, there were 246 benign tumors, namely 144 pleomorphic adenomas, 35 adenolymphomas, 23 other adenomas, 14 cysts, 9 neurinomas, 3 lymphomas, 9 hemangiomas, 3 lymphangiomas and 6 lymph nodes. Another 64 were malignant tumors, namely, 7 mucoepidermoid carcinomas, 7 acinic cell carcinomas, 7 adenoid cystic carcinomas, 15 adenocarcinomas, 7 squamous cell carcinomas, 4 undifferentiated carcinomas, 10 carcinomas in pleomorphic adenoma, 3 malignant lymphomas, 2 metastatic carcinomas and 2 other carcinomas. According to our criteria for ultrasonographic diagnosis of the parotid gland tumors, the benign or malignant pattern was determined by the following findings; shape, boundary echo, internal echo and posterior echo. But in some cases we could not differentiate the two echogram patterns, and we call them the intermediate pattern. The total accuracy rate of the diagnosis of the 310 patients was 79.0%. (The intermediated pattern was found in 39 patients and these cases were considered to be misinterpreted.) In 268 primary parotid gland tumors (210 benign and 58 malignant tumors) excluding recurrent cases, lymph nodes, hemangiomas and so on, the sensitivity was 62.1%, the specificity was 91.4% and the total accuracy rate was 85.1%. The accuracy of sonography in determining whether a tumor was benign or malignant was affected by the tumor size; tumors smaller than 2 cm in diameter showed a tendency to be diagnosed as benign and tumors larger than 6 cm in diameter as malignant. In the 268 cases, the importance of the pattern of the boundary echo and the internal echo in differentiating benign and malignant tumors was examined retrospectively. In the 210 primary benign tumors, the benignity of the tumors was assessed correctly in 84.3% by the boundary echo and 85.7% by the internal echo. In the 58 primary malignant tumors, the malignancy was assessed correctly in 58.6% by the boundary echo and 43.1% by the internal echo. Strong echos, which are the signs of a malignant pattern, were seen in 14.8% of the benign tumors, and in 51.7% of the malignant tumors. It can be concluded that ultrasonography is very reliable for the examination of parotid gland tumors.     

Clinical and histologic findings in patients with renal amyloidosis

Renal amyloidosis is a rare disease when compared to other kidney diseases. During the period of last fifteen years, at the Institute of Nephrology and Immunology in Sarajevo renal amyloidosis was diagnosed with 15 patients. The disease occurred more often with men than with women. Only during 1988, renal amyloidosis was revealed and followed up with five patients. The most common clinical manifestations of renal amyloidosis are nephrotic syndrome and chronic renal failure, with respective laboratory findings. Using immunofluorescent analysis of the kidney biopsy material, we discovered deposits of immunoglobulins of different intensity and deposits of lambda and kappa light chains of immunoglobulins. The intensity of lambda light chains is greater than that of kappa chains. The analysis of light microscopy showed nodular mesangial deposits and deposits along GBM without proliferation. The diagnosis of amyloidosis was confirmed by staining of amyloid. Application of therapy for amyloidosis was without any effect. Although renal amyloidosis is a rare disease, we want to point out disease as being an etiologic factor in nephrotic syndrome.     

Signal-averaged electrocardiography in patients with AL (primary) amyloidosis

One hundred thirty-three patients with biopsy-proven AL amyloidosis were studied with echocardiography, Holter recording, 12-lead electrocardiography, and signal-averaged electrocardiograms. Features from these tests were analyzed in relation to their effect on mortality. Late potentials were more frequent in patients with echocardiographic evidence of cardiac amyloidosis (31%) compared with patients with normal echocardiograms (9%, p < 0.003). One hundred six of the 133 patients died during follow-up, of which 34 were nonsudden cardiac deaths and 33 were sudden deaths. Abnormal echocardiograms and signal-averaged electrocardiograms were each predictive of all-cause cardiac death (p < 0.0001 ) and sudden cardiac death (p < 0.0001). Abnormal signal-averaged electrocardiograms were also independently predictive of sudden death in the subgroup of patients with an abnormal echocardiogram (p < 0.05). Thus late potentials are predictive of sudden death in patients with AL amyloidosis and provide independent prognostic information in patients with echocardiographic evidence of amyloid involvement.     

Prevalence of histological beta2-microglobulin amyloidosis in CAPD patients compared with hemodialysis patients

BACKGROUND: The prevalence of beta2-microglobulin amyloidosis (Abeta2m) in patients on continuous ambulatory peritoneal dialysis (CAPD) is unknown. METHODS: We prospectively obtained a median of 2 (range 1 to 4) joint samples from 26 CAPD patients aged 44 to 93 (median 73) years at post-mortem evaluation after 4.5 to 126 (median 27) months solely on CAPD (N = 19) or primarily on CAPD (that is, < or = 10% and < or = 1 year of renal replacement therapy time on other modalities; N = 7). The diagnosis of Abeta2m rested on Congo red staining (typical birefringence) and positive immunostaining of amyloid deposits by a monoclonal anti-beta2m antibody. RESULTS: Abeta2m was diagnosed in 8 of 26 patients (31%). Prevalence ranged from 20% (2 of 10 patients) within < or = 24 months CAPD to 30% (3 of 10 patients) after 24 to 48 months and 50% (3 of 6 patients) after 49 to 126 months (P = 0.11). The prevalence of Abeta2m was similar in patients without or with one or more peritonitis episodes. No significant difference in prevalence (P = 0.118) was found between CAPD patients (8+/26; 31%) and hemodialysis patients (13+/26; 50%) carefully matched for time on dialysis and age at the onset of dialysis. CONCLUSIONS: The prevalence of histological Abeta2m reaches 31% after a median duration of 27 months of CAPD. This prevalence is not significantly different from that observed in a group of HD patients matched for age and dialysis duration.     

Long-term survival (10 years or more) in 30 patients with primary amyloidosis

The median survival in primary systemic (AL) amyloidosis is less than 18 months. No published series of patients with AL amyloidosis have reported survival of more than 10 years. The records of all Mayo Clinic patients with a diagnosis of AL amyloidosis between January 1, 1966 and March 1, 1987 were reviewed. Patients with secondary amyloidosis, familial amyloidosis, senile systemic amyloidosis, and localized amyloidosis were excluded. During the 21 years of the study, 841 patients with AL amyloidosis were seen. Of these, 29 were excluded because the diagnosis was made at autopsy, and 2 others were excluded because no follow-up data were available. Actuarial survival for the 810 patients was 51% at 1 year, 16% at 5 years, and 4.7% at 10 years. Thirty patients survived for 10 years or more after the histologic diagnosis of AL amyloidosis; all received alkylating-agent therapy. In 14 patients, the monoclonal protein disappeared from the serum or urine. Of 10 patients with nephrotic syndrome, 4 had an objective response. Congestive heart failure, older age, creatinine value of 2 mg/dL or more, bone marrow plasma cell value of 20% or more, platelet count of 500 x 10(9)/L or less, and the presence of peripheral neuropathy were underrepresented in the 10-year survivors and are unfavorable prognostic features. Five percent of patients with AL amyloidosis survived for 10 years or more.     

Ultrasonographic evaluation of the anterior recess in the normal hip: a prospective study on 166 asymptomatic children

Bypass graft patency with ultrafast computed tomography (= Electron Beam Tomography, EBT) was examined in 72 bypass grafts (47 saphenous veins, 25 internal mammary arteries) in 30 patients and compared with coronary angiography. Angiography was performed a mean of 4.4 +/- 3.5 months (range 1-13) from the EBT examination. Contrast material (120 ml) was continuously administered via a peripheral vein and 40 axial slices (3 mm slice thickness, 110 ms scan time) without overlap sequences were obtained, ECG triggered with the single slice scanner mode. Imaging of internal mammary artery grafts began at the thoracic inlet, for saphenous vein grafts, at the undersurface of the aorta. Sixty of 63 angiographically patent bypass grafts were determined patent by EBT (sensitivity 95%), 8 bypass grafts could not be detected by EBT, and 9 were angiographically occluded (specificity 89%). Twenty-four of 25 internal mammary artery grafts were patent at EBT and coronary angiography, one was occluded. In 27 of the 30 patients (90%), all of the angiographically patent grafts could be confirmed as open with EBT. Obstructions of 10 grafts could not be visualized with EBT. Graft insertion into native coronary vessels could be visualized in axial slices, although morphologic quantification of graft insertion stenosis (75-90%) in two cases was not possible. Three dimensional reconstruction of the 40 axial slices allowed graft anatomy to be delineated. Visualization of bypass insertion into the native coronary vessel was less successful because of opacification of the left and right ventricle. Electron beam computed tomography is a minimally invasive procedure capable of evaluating the patency of saphenous vein and internal mammary artery grafts. The morphologic quantification of graft obstruction and visualization of the insertion of the bypasses into the native coronary vessels is less successful with present technology and imaging modalities.     

Dose-intensive melphalan with blood stem cell support for the treatment of AL amyloidosis: one-year follow-up in five patients

The morbidity and lethality of AL amyloidosis is caused by the deposition of lg light chains as fibrillar amyloid protein in vital organs, disrupting their function, and not by the generally low burden of clonal plasma cells that produce the paraproteins. Survival of patients with AL amyloidosis is no more than 1 to 2 years from the time of diagnosis with current management approaches. Clearly, more effective therapies are needed for this rapidly lethal disease. Five patients were treated with dose-intensive melphalan and blood stem cell support and followed for a period of 1 year. Patients were diagnosed with AL amyloidosis by tissue biopsy and categorized by performance status and organ involvement. Their plasma cell dyscrasias were evaluated with immunofixation electrophoresis of serum and urine specimens, quantitative serum lgs, and immunohistochemical staining of bone marrow biopsy specimens. After treatment with dose-intensive intravenous melphalan followed by infusion of autologous growth-factor-mobilized blood stem cells, clinical evaluations and plasma cell studies were repeated at 3 and 12 months. Three men and 2 women aged 38 to 53 years were treated. Median performance status (SWOG) was 2 (1 to 3), and clinical presentations included nephrotic syndrome (n = 1), symptomatic cardiomyopathy (n = 1), gastrointestinal involvement with polyneuropathy (n = 2), and hepatomegaly (n = 1). With a median follow-up of 13 months (12 to 17 months), all five patients are well and have shown stable or improved performance status and clinical remission of organ-related dysfunction, including a 50% reduction in daily proteinuria with no change in creatinine, reversal of symptoms of cardiomyopathy and reductions of posterior wall and septal thickening, reversal of polyneuropathy and gastric atony, and resolution of hepatomegaly by computed tomographic scan. In 3 of the 5 patients (60%) at 12 months after treatment, plasma cell dyscrasias could not be detected. Dose-intensive chemotherapy with intravenous melphalan and growth-factor-mobilized blood stem cell support is feasible therapy for patients with AL amyloidosis, even when there is clinical evidence of cardiac involvement. At least some patients with AL amyloidosis achieve complete remission of their plasma cell dyscrasia, improvement in performance status, and clinical remission of organ-specific disease after this form of treatment.