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To retrospectively evaluate the pharmacological profiles of antiepileptic drugs (AEDs) in epilepsy patients during haemodialysis using therapeutic drug monitoring data. The serum concentration of AEDs was collected before and after haemodialysis, and the clearance rate and concentration-to-dose ratio were calculated as pharmacological parameters. Thirty-six patients were enrolled in the study (25 males, 11 females; age: 65.3 ± 14.8 years). In 24 of the 36 patients, epilepsy was associated with cerebrovascular disorders, and diabetes was the most common reason for haemodialysis in 16 patients. With regards to seizure type, focal aware seizures were less frequent than focal impaired awareness seizures and focal-to-bilateral tonic-clonic seizures. Interictal EEG showed intermittent rhythmic slow waves and intermittent slow waves more often than spikes or sharp waves. Levetiracetam was the most commonly used AED and led to the highest percentage of responders (80%; 16/20 patients). However, the clearance rate of levetiracetam during dialysis was highest among the antiepileptic drugs used, requiring supplementary doses after haemodialysis in all 20 patients. Valproic acid was not effective for focal epilepsy for patients on haemodialysis, and non-responders to phenytoin had low serum concentration of phenytoin both before and after haemodialysis. The pre-haemodialysis concentration of levetiracetam tended to be higher than the reference range, suggesting a potential risk of overdosing before haemodialysis. The pre- and post-haemodialysis concentrations of valproic acid tended to be lower than the reference range, suggesting a potential risk of underdosing. The concentration-to-dose ratios for levetiracetam, valproic acid, phenytoin, and carbamazepine were significantly lower after than before haemodialysis. The majority of patients with epilepsy on haemodialysis had cerebrovascular diseases, and therapeutic drug monitoring for levetiracetam, valproic acid, and phenytoin, before and after haemodialysis, is needed to ensure proper dosing.

A 40-yr-old female received a living-related renal transplantation on January 29, 2008. She had type I diabetes mellitus and pyoderma gangrenosum (PG). Induction immunosuppressive therapy consisted of tacrolimus, mycophenolate mofetil, basiliximab, and prednisolone. Intravenous methylprednisolone pulse therapy was administered to prevent ulceration at the surgical site. The postoperative outcome was almost uneventful, and renal graft function was well preserved for 11 months. Her graft function deteriorated on December 24, 2008 and thus an episode biopsy was performed. The histopathological findings were consistent with plasma cell-rich acute rejection (PCAR). During hospitalization, it was noted that the patient was non-compliant. We then performed steroid pulse therapy, and her graft function and histological findings improved. This is the first report of PCAR in a patient with PG who received a renal allograft. It was thought that PCAR was triggered because of her non-compliance. Thus, we should recognize the importance of enhancing compliance in transplant recipients.

Graft survival rates of ABO-incompatible (ABO-I) living-related kidney transplantations have greatly improved with the progress of immunosuppressive protocols. However, there are several case reports in which hyperacute rejections (HAR) or delayed hyperacute rejections (DHAR) occurred with immunosuppression, and acute humoral rejection is a risk factor for early graft loss in ABO-I kidney transplantations. We report a case of early graft loss after ABO-I kidney transplantation. A 51-yr-old male received an ABO-I kidney transplant from his wife. Graft function deteriorated immediately after surgery and HAR developed. Although plasma exchange and steroid pulse were performed, graft function did not recover. A renal biopsy on postoperative day (POD) 4 indicated compatible findings with HAR. Renal function was deemed irreversible and the renal graft was removed on POD 7. A biopsy performed one h after transplantation revealed a clot in the glomerulus. As this was a case of ABO-I transplantation without human leukocyte antigen class I and II antibodies in the pre- and postoperative flow panel reactive antibody, HAR was most likely caused by the presence of anti-blood group antibodies. The preoperative anti-A antibody value of x64 was rather high in the present case. There is no clear standard for preoperative antibody values and it is difficult to predict prognosis preoperatively with the recent use of strong immunosuppressives. Although the mechanism of onset is unclear in this case, it is believed that the antibody titer should be reduced as much as possible prior to transplantation.

The cellular distribution of malondialdehyde (MDA) was assessed immunohistochemically in brain specimens from young and normal elderly subjects as well as patients with Alzheimer's disease (AD). MDA was increased in the cytoplasm of neurons and astrocytes in both normal aging and AD, but was rarely detected in normal young subjects. By electron microscopic immunohistochemistry, neuronal MDA formed cap-like linear deposits associated with lipofuscin, while glial MDA deposits surrounded the vacuoles in a linear distribution. In the hippocampus, neuronal and glial MDA deposition was marked in the CA4 region but mild in CA1. By examination of serial sections stained with anti-MDA and antibodies against an advanced glycation end product, N(epsilon)-(carboxymethyl)lysine (CML), neuronal and glial MDA deposition was colocalized with CML in AD, but only neuronal MDA was colocalized with CML in normal aged brains. Glial MDA, although abundant in the aged brain, typically was not colocalized with CML. In AD cases, MDA was colocalized with tau protein in CA2 hippocampal neurons; such colocalization was rare in CA1. MDA also was stained in cores of senile plaques. Thus, while both MDA and CML accumulate under oxidative stress, CML accumulation is largely limited to neurons, in normal aging, while MDA also accumulates in glia. In AD, both MDA and CML are deposited in both astrocytes and neurons.

Advanced glycation and lipidoxidation of the peritoneal membrane: Respective roles of serum and peritoneal fluid reactive carbonyl compounds.BackgroundAdvanced glycation of proteins has been incriminated in the progressive alteration of the peritoneal membrane during chronic peritoneal dialysis (PD). Advanced glycation end products (AGEs) result from a modification of proteins by reactive carbonyl compounds (RCOs). RCOs resulting from glucose breakdown are present in commercial PD fluid. They also accumulate in uremic plasma. The present study was undertaken to evaluate the respective contribution of these two sources of RCOs in the genesis of peritoneal AGEs.MethodsThree major RCOs formed during heat sterilization of PD fluid, that is, glyoxal, methylglyoxal, and 3-deoxyglucosone, and total RCOs were measured in commercial PD fluid and in PD effluent. The generation of pentosidine, used as a surrogate marker for AGEs, during one-week incubations of PD fluid and effluent samples fortified with bovine serum albumin (BSA) was measured by high-performance liquid chromatography. Peritoneal samples were stained with antibodies specific for two AGEs derived from carbohydrate-dependent RCOs, Nε-(carboxymethyl)lysine (CML) and pentosidine, or for two advanced lipoxidation end products (ALEs) derived from lipid-dependent RCOs, malondialdehyde (MDA)-lysine and 4-hydroxynonenal (HNE)-protein adduct.ResultsGlyoxal, methylglyoxal, and 3-deoxyglucosone were identified in commercial PD fluid. Their levels in PD effluents decreased with dwell time probably by diffusion into blood circulation. In contrast, the levels of total RCOs were initially low in commercial PD fluid, increased in PD effluent with dwell time probably by diffusion from circulation into the peritoneal cavity, and after 12 hours, reached values observed in uremic serum. The relevance of the rise in total RCOs for AGE formation is demonstrated by a parallel increase in the generation of pentosidine during incubations of PD effluents. In contrast with RCOs present in glucose-rich PD fluid, RCOs diffusing from uremic circulation originate from both carbohydrates and lipids. Their role in the modification of peritoneal proteins is demonstrated by the immunohistochemical study of peritoneal tissue. Two AGEs and two ALEs increase in parallel in the mesothelial layers and in vascular wall of small arteries in the peritoneum.ConclusionsProtein modification of the peritoneum is determined not only by RCOs originating in PD fluid, but also by RCOs originating from the uremic circulation. The present data might be relevant to current attempts to improve PD fluid toxicity by lowering its glucose content.

Advanced glycation end products (AGE) include a variety of protein adducts whose accumulation has been implicated in tissue damage associated with diabetic nephropathy (DN). It was recently demonstrated that among AGE, glycoxidation products, whose formation is closely linked to oxidation, such as carboxymethyllysine (CML) and pentosidine, accumulate in expanded mesangial matrix and nodular lesions in DN, in colocalization with malondialdehyde-lysine (MDA-lysine), a lipoxidation product, whereas pyrraline, another AGE structure whose deposition is rather independent from oxidative stress, was not found within diabetic glomeruli. Because CML, pentosidine, and MDA-lysine are all formed under oxidative stress by carbonyl amine chemistry between protein amino group and carbonyl compounds, their colocalization suggests a local oxidative stress and increased protein carbonyl modification in diabetic glomerular lesions. To address this hypothesis, human renal tissues from patients with DN or IgA nephropathy were examined with specific antibodies to characterize most, if not all, carbonyl modifications of proteins by autoxidation products of carbohydrates, lipids, and amino acids: CML (derived from carbohydrates, lipids, and amino acid), pentosidine (derived from carbohydrates), MDA-lysine (derived from lipids), 4-hydroxynonenal-protein adduct (derived from lipids), and acrolein-protein adduct (derived from lipids and amino acid). All of the protein adducts were identified in expanded mesangial matrix and nodular lesions in DN. In IgA nephropathy, another primary glomerular disease leading to end-stage renal failure, despite positive staining for MDA-lysine and 4-hydroxynonenal-protein adduct in the expanded mesangial area, CML, pentosidine, and acrolein-protein adduct immunoreactivities were only faint in glomeruli. These data suggest a broad derangement in nonenzymatic biochemistry in diabetic glomerular lesions, and implicate an increased local oxidative stress and carbonyl modification of proteins in diabetic glomerular tissue damage (“carbonyl stress”).

In the previous study [Takeda et al. (1996) Neurosci Lett 221: 17-21], we reported that the advanced glycation end products (AGEs) in the external space of neuronal perikarya (extraneuroperikaryal AGE deposits) were significantly abundant in the Alzheimer's brain. In this study, we investigated the spatial relationship of the extraneuroperikaryal AGE (carboxymethyllysine and pentosidine) deposits in astrocytes and microglial cells in the Alzheimer's disease brain using double immunolabelling for AGEs and astrocyte or microglial cell markers. Most of the extraneuroperikaryal AGE deposits were co-localized with glial fibrillary acidic protein-positive astrocytes. AGE deposit-bearing astrocytes also contained Gomori-positive granules. Furthermore, some of the extraneuroperikaryal AGE deposits were co-localized with microglial cells. These extraneuroperikaryal AGEs may activate astrocyte and microglia, and play a role in pathogenesis of Alzheimer's disease.

Lipofuscins are intracellular fluorescent pigments accumulating in the central nervous system (CNS) with aging and degenerative processes such as Alzheimer's disease (AD). Although they are thought to be lipid peroxidation products derived from malondialdehyde, their biogenesis remains controversial. We further characterize the chemical nature of lipofuscins in brain tissues from AD patients and normal aged subjects. Advanced glycation end products (AGEs), pentosidine and carboxymethyllysine (CML), were identified by appropriate specific antibodies. They have physicochemical properties similar to those of lipofuscin and also increase with aging. Pentosidine and CML were identified in the neuronal perikarya and the extraneuroperikaryal deposits of both the AD and aged brain. Pentosidine, but not CML, was present in the fiber-like structure within the neuropil and the core of classical senile plaque. In the brain of young subjects without CNS disease, pentosidine and CML staining was faint. Pentosidine and CML co-localized with lipofuscin pigments in the neuronal perikarya of both the AD and aged brain. We demonstrate for the first time that lipofuscin is constituted not only of lipid peroxidation products but also from glycation products which may be the origin of fluorescent pigments. Lipofuscins should thus be considered as fluorescent pigments generated by lipid- and sugar-derived Schiff base-protein polymers.

Implication of an increased oxidative stress in the formation of advanced glycation end products in patients with end-stage renal failure. Recent studies have demonstrated a marked increase in the level of advanced glycation end products (AGEs) in the plasma, skin and amyloid fibrils of hemodialysis (HD) patients. The presence of AGEs in (β2m) forming amyloid fibrils has been established in a previous immunochemical study relying on a monoclonal anti-AGE antibody. In the present study, Western blot analysis and immunohistochemistry reveal that the epitope recognized by this antibody is Nε-(carboxymethyl)lysine (CML) and that CML is one of the AGE structures present in amyloid fibrils. Thus, two AGE structures, CML and pentosidine, are now recognized in dialysis-related amyloidosis. AGE accumulation in uremia is not accounted for by elevated glucose levels. Since CML and pentosidine formation are closely linked to oxidative processes, we tested the hypothesis that a high oxidative stress enhanced AGE formation in HD patients. We focused on ascorbic acid (AA) because AA is easily oxidized under oxidative stress and its oxidized form (oxiAA) is a source of CML and pentosidine. In vitro incubation of β2m with AA under atmospheric oxygen resulted in: (1) the rapid appearance of characteristic physicochemical properties of AGEs (brown color, fluorescence, polymerization tendency); (2) the transformation of β2m into AGE-modified β2m recognized by a specific monoclonal antibody; and (3) the accelerated formation of CML in β2m and β2m-peptide, recognized by mass spectrometry. A similar in vitro incubation of human serum albumin disclosed a parallel production of pentosidine measured by high-performance liquid chromatographic assay. In HD patients, the degree of AA oxidation, assessed as the ratio of oxiAA to total ascorbate, was more than twice as high as that of normal subjects (0.87 ± 0.16 vs. 0.35 ± 0.11, P < 0.0001), suggesting the presence of an increased oxidative stress. Interestingly, plasma level of oxiAA was correlated with the plasma levels of protein linked (P < 0.01,r2 = 0.25) and free (P < 0.05, r2 = 0.22) pentosidine. Altogether these results demonstrate that AGE, that is, CML and pentosidine, production is accelerated under oxidative stress, even in the absence of glucose. They suggest that, in uremia, CML and pentosidine production is determined both by an increased oxidative stress and the availability of precursors such as oxiAA. Finally, both CML and pentosidine contribute to the AGEs present in dialysis-related amyloid fibrils.

Advanced glycation end products (AGEs) in the brain were immunohistochemically examined in Alzheimer's disease (AD) and aging using anti-AGE antibody recognizing mainly carboxymethyllysine. AGE positive staining diffusely located in the neuronal perikarya of hippocampus and parahippocampus in AD and aged brains without dementia, but not in young brains less than 17 years of age. Extra-neuroperikaryal AGE deposits were also detected in the neuropil of AD and aged brains. The extra-neuroperikaryal AGE deposits markedly increased in AD brains as compared to aged brains. These AGE-positive deposits in the neuropil were not related to the senile plaque identified by anti-beta amyloid protein antibody. These findings suggest a potential link of AGE accumulation in the central nervous system to the aging process of neurons and the degenerating process of AD neurons.

A 40-yr-old female received a living-related renal transplantation on January 29, 2008. She had type I diabetes mellitus and pyoderma gangrenosum (PG). Induction immunosuppressive therapy consisted of tacrolimus, mycophenolate mofetil, basiliximab, and prednisolone. Intravenous methylprednisolone pulse therapy was administered to prevent ulceration at the surgical site. The postoperative outcome was almost uneventful, and renal graft function was well preserved for 11 months. Her graft function deteriorated on December 24, 2008 and thus an episode biopsy was performed. The histopathological findings were consistent with plasma cell-rich acute rejection (PCAR). During hospitalization, it was noted that the patient was non-compliant. We then performed steroid pulse therapy, and her graft function and histological findings improved. This is the first report of PCAR in a patient with PG who received a renal allograft. It was thought that PCAR was triggered because of her non-compliance. Thus, we should recognize the importance of enhancing compliance in transplant recipients.

MHC class 1-related chain A (MICA) has been reported to be recognized by specific antibodies in the sera of transplanted patients, and it may be a target molecule in allograft rejection. MICA was originally pointed out to be an HLA-related polymorphic gene, the product of which may be recognized by a subpopulation of intestinal gamma delta T-cells and may play a role in the activation of a subpopulation of natural killer cells. Although their association with chronic rejection has been demonstrated before, there are few reports of any relation with acute rejection. We encountered a possible case of MICA-related acute early rejection. The recipient was a 25-year-old female; the original disease was IgA nephropathy, and the hemodialysis period was 12 months. She underwent ABO-compatible living-related renal transplantation from her mother. The HLA type was A24, A31, B7, B52, DR1, and DR15 in the donor and A31, A33, B7, B44, DR1, and DR12 in the recipient. A pre-operative direct cross-match was negative by a conventional cytotoxic test, and HLA class 1 and 2 antibodies were negative by LABScreen single antigen testing. Induction immunosuppressive therapy was started with TAC, MMF, MP, and BXM. The graft functioned at once, and SCr was 2.4 mg/dl on post-transplant day 1. SCr increased from post-transplant day 2, and oliguria progressed. Hemodialysis was restarted on post-transplant day 6. A biopsy revealed Banff 2b vascular rejection. The graft was finally rescued by steroid pulse and plasma exchange therapy. SCr went down to 1.07 mg/dl, and a re-biopsy showed improvement on post-transplant day 42. HLA class 1 and 2 antibodies were negative during this period, and MICA019 antibody was higher before transplantation retrospectively. Additionally, this antibody titer was decreased at the time of discharge. These data show that MICA may induce rejection in the early phase of renal transplantation. Further study is needed to evaluate this phenomenon.

We have pursued the hypothesis that the carbonyl modification of proteins by glycoxidation and lipoxidation reactions plays a role in atherogenesis. Human atherosclerotic tissues with fatty streaks and uremic arteriosclerotic tissues were examined, with specific antibodies, to detect protein adducts formed with carbonyl compounds by glycoxidation or lipoxidation reactions, i.e. advanced glycation end products (AGEs) or glycoxidation products, such as carboxymethyllysine (CML) and pentosidine, and lipoxidation products, such as malondialdehyde (MDA)-lysine and 4-hydroxy-nonenal (HNE)-protein adduct. All the four adducts were identified in the proliferative intima and in macrophage-rich fatty streaks. If the carbonyl modification is not a mere result but is a contributor to atherogenesis, inhibition of glycoxidation and lipoxidation reactions might prevent vascular tissue damage. We tested this hypothesis in rats following balloon injury of their carotid arteries, a model exhibiting a remarkable intimal thickening, which are stained positive for all the four adducts. Oral administration of 2-isopropylidenehydrazono-4-oxo-thiazolidin-5-ylacetanilide (OPB-9195), an inhibitor of both glycoxidation and lipoxidation reactions, in rats following balloon injury effectively prevented the intimal thickening. These data suggest a role for the carbonyl modification of proteins by glycoxidation and lipoxidation reactions in most, if not all, types of vascular tissue damage (`carbonyl stress'), and the usefulness of inhibitors of carbonyl reactions for the treatment of vascular tissue damage.

Advanced glycation end products (AGE) are formed in long-lived matrix proteins by a nonenzymatic reaction with sugar. The presence of AGE in beta 2-microglobulin-amyloid fibrils of dialysis-related amyloidosis, one of the characteristic features of which is an accelerated bone resorption around amyloid deposits, was recently demonstrated. This suggested a potential link of AGE in bone resorption and initiated this investigation of whether AGE enhance bone resorption. When mouse unfractionated bone cells containing osteoclasts were cultured on dentin slices, both AGE-modified beta 2-microglobulin and BSA increased the number of resorption pits formed by osteoclasts, whereas their normal counterparts of those modified with the early glycation products did not. AGE proteins, however, did not increase the number of newly formed osteoclasts, even in the coculture of mouse bone marrow cells with osteoblastic cells isolated from mouse calvaria. Enhanced bone resorption was also observed when unfractionated bone cells were cultured on AGE-modified dentin slices. AGE-enhanced bone resorption was effectively inhibited by calcitonin and ipriflavone, both of which are inhibitors of bone resorption. AGE-enhanced bone resorption was further supported by in vivo evidence that rat bone particles-upon incubation with glucose for 60 days (AGE-bone particles)-when implanted subcutaneously in rats, were resorbed to a much greater extent than control bone particles upon parallel incubation without glucose. These findings suggest that AGE enhance osteoclast-induced bone resorption. Although the mechanism remains unknown, AGE are unlikely to promote differentiation of osteoclast progenitors into osteoclasts, suggesting that AGE activate osteoclasts or alter microenvironments favorable for bone resorption by osteoclasts. The modification of bone matrices with AGE might play a role in the remodeling of senescent bone matrix tissues, further implicating a pathological significance of AGE in dialysis-related amyloidosis or osteoporosis associated with diabetes and aging.

Accumulation of carbonyl derivatives of proteins (protein carbonyl) is taken as a biomarker of oxidative protein damage in aging and in various diseases. We detected protein carbonyls in situ in human diabetic arteriosclerotic tissues and characterized the formation of protein carbonyls. Protein carbonyls were identified in the thickened intima of arterial walls and co-localized with protein adducts formed by carbonyl amine chemistry between protein and carbonyl compounds derived from autoxidation of carbohydrates, lipids, and ascorbate, i.e. advanced glycation end products or glycoxidation products, such as carboxymethyllysine (CML) and pentosidine, and lipoxidation products, such as malondialdehyde (MDA) and 4-hydroxy-nonenal (HNE). In vitro incubation of proteins with ascorbic acid accelerated the production of protein carbonyls as well as CML and pentosidine, and incubation with arachidonate accelerated the production of protein carbonyls as well as CML, MDA, and HNE. By contrast, incubation of proteins with glucose resulted in the production of CML and pentosidine, but not protein carbonyls. Schiff base inhibitors, (±)-2-isopropylidenehydrazono-4-oxo-thiazolidin-5-ylacetanilide and aminoguanidine, inhibited the production of protein carbonyls after incubation with ascorbate and arachidonate. The present study suggests that ascorbate and polyunsaturated fatty acids, but not glucose, represent potential sources of protein carbonyls, and that both the glycoxidation and lipoxidation reactions contribute to protein carbonyl formation in aging and various diseases.

Renal catabolism of advanced glycation end products: The fate of pentosidine. Advanced glycation end products (AGEs) generated through the Maillard reaction significantly alter protein characteristics. Their accumulation has been incriminated in tissue injury associated with aging, diabetes, and renal failure. However, little is known about their clearance from the body. The present study delineates the catabolic pathway of a well-defined AGE product, pentosidine. Synthesized pentosidine given intravenously in rats with normal renal function was rapidly eliminated from the circulation through glomerular filtration, but was undetectable in the urine by chemical analysis. Immunohistochemistry with anti-pentosidine antibody disclosed that pentosidine accumulated transiently in the proximal renal tubule one hour after its administration, but had disappeared from the kidney at 24 hours. After an intravenous load of radiolabeled pentosidine, radioactivity peaked in the kidney at one hour and subsequently decreased, whereas it rose progressively in the urine. Over 80% of the radioactivity was recovered in the 72-hour collected urine. However, only 20% of urine radioactivity was associated with intact pentosidine chemically or immunochemically. In gentamicin-treated rats with tubular dysfunction, up to 30% of the pentosidine load was recovered as intact pentosidine in the urine. The present study suggests that free pentosidine (and possibly other AGEs) is filtered by renal glomeruli, reabsorbed in the proximal tubule where it is degraded or modified, and eventually excreted in the urine. Kidney thus plays a key role in pentosidine disposal.