Novel styrylbenzene derivatives for detecting amyloid deposits

Amyloid Proteins and Their Role in Multiple Sclerosis. Considerations in the Use of Amyloid-PET Imaging

Thioflavin T derivatives are used in positron-emission tomography (PET) studies to detect amyloid protein deposits in patients with Alzheimer disease. These tracers bind extensively to white matter, which suggests that they may be useful in studies of multiple sclerosis (MS), and that proteins resulting from proteolytic processing of the amyloid precursor protein (APP) may contribute to MS. This article reviews data from both clinical and preclinical studies addressing the role of these proteins, whether they are detected in CSF studies or using PET imaging. APP is widely expressed in demyelinated axons and may have a protective effect in MS and in experimental allergic encephalomyelitis in animals. Several mechanisms associated with this increased expression may affect the degree of remyelination in MS. Amyloid-PET imaging may help determine the degree of demyelination and provide information on the molecular changes linked to APP proteolytic processing experienced by patients with MS.

Life-threatening hematuria in a hemodialysis patient with systemic light-chain amyloidosis

BACKGROUND

Direct amyloid invasion of prostate tissue resulting in massive bleeding may be fatal, and rapid diagnosis is difficult.

CASE REPORT

A 71-y-old male undergoing regular hemodialysis with primary light-chain (AL) amyloidosis was admitted due to gross hematuria for 2 days. Cystoscopy revealed oozing from the prostatic urethra. Therefore, electrocauterization was performed, and his symptoms resolved. Unfortunately, he experienced recurrent massive hematuria 3 months later. Tests for serum D-dimer and fibrin degradation products were both positive. Followed serum factor X level was low at 5.4%. Gross hematuria persisted despite of blood transfusions, desmopressin, and vitamin K therapy. Emergent cystoscopy revealed oozing from the prostatic urethra, as was found previously. Therefore, electrocauterization and transurethral resection of the prostate were performed. Analysis of a biopsy specimen of prostate demonstrated strong amyloid deposition in the vascular and perivascular regions. Electron microscopy showed relatively straight fibrils with diameters of 7-10nm in the perivascular region. Gross hematuria subsided then, and no recurrence was noted at a 6-month follow-up.

CONCLUSIONS

Systemic AL amyloidosis can cause potentially life-threatening hemorrhage. Hemostatic defects and direct invasion with amyloid angiopathy are main pathogenic factors. Timely surgical intervention may be imperative.