Solubilized cystatin C amyloid is cytotoxic to cultured human cerebrovascular smooth muscle cells

Carotid artery color Doppler ultrasonography and plasma levels of lipoprotein-associated phospholipase A2 and cystatin C in arteriosclerotic cerebral infarction

Objective

This study was performed to evaluate the clinical application value of carotid artery color Doppler ultrasonography and the plasma levels of lipoprotein-associated phospholipase A2 (Lp-PLA2) and cystatin C (Cys C) in the diagnosis and treatment of arteriosclerotic cerebral infarction.

Methods

Sixty patients with arteriosclerotic cerebral infarction and 60 matched healthy participants were included. The patients were divided into mild, moderate, and severe groups according to their National Institutes of Health Stroke Scale (NIHSS) scores. Carotid artery intima plaque formation and the intima–media thickness (IMT) were observed using carotid artery color Doppler ultrasonography. The correlation between IMT and the Lp-PLA2 or Cys C level was statistically analyzed.

Results

Patients with arteriosclerotic cerebral infarction had a higher detection rate of carotid plaques, especially unstable plaques, than healthy participants. The plasma levels of Lp-PLA2 and Cys C were elevated in patients with arteriosclerotic cerebral infarction and increased with the NIHSS scores. The plasma levels of Lp-PLA2 and Cys C in patients with arteriosclerotic cerebral infarction were correlated with IMT.

Conclusion

The combination of carotid artery color Doppler ultrasonography with the Lp-PLA2 and Cys C plasma levels is of great clinical value in the diagnosis and treatment of arteriosclerotic cerebral infarction.

Preparation and Culturing of Human Primary Vascular Cells

Cerebral amyloid angiopathy (CAA) results from amyloid accumulation within arteries of the cerebral cortex and leptomeninges. This condition is age-related, especially prevalent in Alzheimer's disease (AD), and the main feature of certain hereditary disorders (i.e., HCHWA-I). The vascular smooth muscle cells (VSMCs) appear to play a vital role in the development of CAA, which makes them well suited as an experimental model to study the disease and screen for possible remedies. We describe two different methods for isolating and culturing human VSMCs: First, using the human umbilical cord as an easy source of robust cells, and secondly, using brain tissue that provides the proper cerebral VSMCs, but is more problematic to work with. The umbilical cord also provides human umbilical vascular endothelial cells (HUVEC), useful primary cells for vascular research. Finally, the maintenance, preservation, and characterization of the isolated vascular cells are described.

Pathological changes in basement membranes and dermal connective tissue of skin from patients with hereditary cystatin C amyloid angiopathy

Hereditary cystatin C amyloid angiopathy (HCCAA) is a genetic disease caused by a mutation in the cystatin C gene. Cystatin C is abundant in cerebrospinal fluid and the most prominent pathology in HCCAA is cerebral amyloid angiopathy due to mutant cystatin C amyloid deposition with associated cerebral hemorrhages, typically in young adult carriers. Analyses of post-mortem brain samples shows that pathological changes are limited to arteries and regions adjacent to arteries. The severity of pathological changes at post-mortem has precluded the elucidation of the evolution of histological changes. Mutant cystatin C deposition in carriers is systemic and has, for example, been described in the skin, suggesting similar pathological mechanisms both in the brain and outside of the central nervous system. The aim of this study was to use skin biopsies from asymptomatic and symptomatic carriers to study intermediate events in HCCAA pathogenesis. We found that cystatin C deposition in minimally affected samples was limited to the basement membrane (BM) between the dermis and epidermis. When the deposits were more advanced, they extended to other BM regions in the skin. Our results showed that the immunoreactivity of the BM protein COLIV was increased to a similar extent in all carrier biopsies and cystatin C deposits were in close association with COLIV. The density of fibroblasts in the upper dermis of carrier skin was increased, whereas the distribution of other cell types examined did not differ compared with control biopsies. COLIV and cystatin C immunoreactivity in carrier biopsies was closely associated with the fibroblasts. The results of this study, in conjunction with our previous results regarding pathological BM changes in leptomeningeal arteries of patients, suggest that BM changes are early and important events in HCCAA pathogenesis that could facilitate cystatin C deposition and aggregation.

Deposition of collagen IV and aggrecan in leptomeningeal arteries of hereditary brain haemorrhage with amyloidosis

Hereditary Cystatin C Amyloid Angiopathy (HCCAA) is a rare genetic disease in Icelandic families caused by a mutation in the cystatin C gene, CST3. HCCAA is classified as a cerebral amyloid angiopathy and mutant cystatin C forms amyloid deposits in cerebral arteries resulting in fatal haemorrhagic strokes in young adults. The aetiology of HCCAA pathology is not clear and there is, at present, no animal model of the disease. The aim of this study was to increase understanding of the cerebral vascular pathology of HCCAA patients with an emphasis on structural changes within the arterial wall of affected leptomeningeal arteries. Examination of post-mortem samples revealed extensive changes in the walls of affected arteries characterised by deposition of extracellular matrix constituents, notably collagen IV and the proteoglycan aggrecan. Other structural abnormalities were thickening of the laminin distribution, intimal thickening concomitant with a frayed elastic layer, and variable reduction in the integrity of endothelia. Our results show that excess deposition of extracellular matrix proteins in cerebral arteries of HCCAA is a prominent feature of the disease and may play an important role in its pathogenesis.

Preparation of cultured human vascular cells

Cerebral amyloid angiopathy (CAA) results from amyloid accumulation within arteries of the cerebral cortex and leptomeninges. This condition is age-related, especially prevalent in Alzheimer's disease (AD), and the main feature of certain hereditary disorders (i.e., HCHWA-I). The vascular smooth muscle cells (VSMCs) appear to play a vital role in the development of CAA, which makes them well suited as an experimental model to study the disease and screen for possible remedies. We describe two different methods for isolating and culturing human VSMCs. First, using the human umbilical cord as an easy source of robust cells, and secondly, using brain tissue that provides the proper cerebral VSMCs, but is more problematic to work with. The umbilical cord also provides human umbilical vascular endothelial cells (HUVECs), useful primary cells for vascular research. Finally, the maintenance, preservation, and characterization of the isolated vascular cells are described.

Isolation of amyloid by solubilization in water

Amyloid fibrils are highly insoluble in neutral aqueous media of regular ionic strengths making solubilization a difficult task that normally calls for extremely harsh treatment. This is among the reasons for the routine employment of synthetic proteins in amyloid research, where the amylogenic components are needed. Here we describe a process for solubilizing amyloid in pure water that we adopted from a method developed by Mordechai Pras and associates. We have used it for solubilizing cystatin C amyloid and extracting it out of leptomeningeal tissue and skin from Hereditary Cerebral Hemorrhage with Amyloidosis-Icelandic type (HCHWA-I) patients. HCHWA-I is a rare and very aggressive heritable form of cerebral amyloid angiopathy (CAA)-specific Icelandic type. Similar approach has been employed for solubilization of different forms of amyloid from other organs suggesting broad range of applicability.