Lipoprotein glomerulopathy with a novel apolipoprotein E variant, APOE Kanto (Asp 151dup).

A 33-year-old Japanese man was admitted for possible kidney disease because of massive proteinuria. Laboratory findings were characterized by marked urinary protein of 4.7 g/day and high-serum triglyceride levels of 266 mg/dL. Renal biopsy revealed segmental proliferation in the mesangium and lipoprotein thrombi in the glomerular capillary. These results suggested that the diagnosis was lipoprotein glomerulopathy (LPG), although serum apolipoprotein E (apo E) levels were within normal ranges. The APOE phenotype was identified as E2/3 by isoelectric focusing polyacrylamide gel electrophoresis. Direct DNA sequencing analyses for apo E identified a duplication of amino acid 151, aspartic acid, and the gene mutation was named APOE Kanto. APOE gene mutations due to amino acid duplication are rare, and this is the first report showing that amino acid duplication among apo E gene mutations is involved in LPG. It is also noteworthy that the patient developed end-stage kidney disease after over than 10 years despite fibrate treatment.

Lipoprotein glomerulopathy with markedly increased arterial stiffness successfully treated with a combination of fenofibrate and losartan: a case report.

BACKGROUND: Lipoprotein glomerulopathy (LPG) is a apolipoprotein E (ApoE)-related glomerular disease and has been associated with type III hyperlipidemia. Without appropriate treatment, chronic kidney disease (CKD) caused by LPG progresses, and approximately half of the patients develop end-stage kidney disease within 1-27 years of disease onset. However, few studies have highlighted the clinical course of cardiovascular diseases (CVDs) in patients with LPG. Herein, we report the first case of LPG in which the CVD risk was assessed using arterial stiffness. CASE PRESENTATION: A 32-year-old Japanese man was referred to our hospital due to persistent proteinuria. Kidney biopsy showed markedly dilated capillary lumens containing pale-stained thrombi, which stained positively with Oil Red O. Electron microscopy revealed the presence of thrombi in the capillary lumen with low electron density and vacuoles of various sizes in part of the thrombi. Toluidine blue and Sudan IV stains were used to stain the thin sections of Epon-embedded tissue samples for electron microscopy. Sudan IV-positive droplets were observed in the capillary lumens, vascular walls, and cytoplasm of tubular cells. Increased serum ApoE concentration was observed. Liquid chromatography-tandem mass spectrometry of laser-microdissected glomeruli from paraffin sections revealed an increase in ApoE. Direct deoxyribonucleic acid sequencing of ApoE revealed a heterozygous ApoE Sendai mutation (Arg145Pro). The patient was finally diagnosed with LPG with heterozygosity for ApoE-Sendai mutation (Arg145Pro). Notably, at the time of diagnosis, he had markedly increased arterial stiffness for his age. Arterial stiffness was measured using brachial-ankle pulse wave velocity (baPWV), which was equivalent to that of a 56-year-old man. After three months of treatment with fenofibrate and losartan, a significant reduction in proteinuria was achieved along with an improvement in baPWV. Furthermore, these effects were maintained despite the lack of decrease in serum ApoE levels. CONCLUSION: Herein, we report the case of a patient with LPG with markedly increased arterial stiffness at the time of diagnosis, in whom combination therapy with fenofibrate and losartan successfully improved proteinuria and arterial stiffness. To the best of our knowledge, this is the first case report of LPG in which CVD risk was assessed using arterial stiffness.

Apolipoprotein E-associated Lipoprotein Glomerulo-tubulopathy.

A 32-year-old man was admitted for the evaluation of proteinuria (5.69 g/day). A light microscopic examination showed markedly dilated glomerular capillary loops with vacuolated areas in many glomeruli, and vacuolated areas were seen on peritubular capillaries in the tubulointerstitium. When electron microscopy specimens prepared by pre-fixation with glutaraldehyde and post-fixation with osmium tetroxide were used for oil red staining, the deposition was confirmed on the affected areas. A genetic analysis of apoE showed that the lipoprotein glomerulopathy was due to apoE-Sendai (Arg145Pro, p.R163P) heterozygosity, which was found in not only the patient but also his mother and twin brother.

Identification of antigens recognized by salivary IgA using microbial protein microarrays.

Secretory IgA plays an important role in the mucosal immune system for protection against pathogens. However, the antigens recognized by these antibodies have only been partially studied. We comprehensively investigated the antigens bound by salivary IgA in healthy adults using microbial protein microarrays. This confirmed that saliva contained IgA antibodies that bind to a variety of pathogenic microorganisms, including spike proteins of severe acute respiratory syndrome coronavirus 2, severe acute respiratory syndrome coronavirus, Middle East respiratory syndrome coronavirus, and other human coronavirus species. Also, many subtypes and strains of influenza virus were bound, regardless of the seasonal or vaccine strains. Salivary IgA also bound many serogroups and serovars of Escherichia coli and Salmonella. Taken together, these findings suggest that salivary IgA, which exhibits broad reactivity, is likely an essential element of the mucosal immune system at the forefront of defense against infection.

Membranous Nephropathy-Like Apolipoprotein E Deposition Disease with Apolipoprotein E Toyonaka and Homozygous Apolipoprotein E2/2 without Dyslipidemia, with Characteristic Electron-Dense Deposits.

Recently, several cases of novel apolipoprotein E (apoE)-related glomerular disease known as membranous nephropathy (MN)-like apoE deposition disease with apoE Toyonaka (Ser197Cys) and homozygous apoE2/2 have been reported. However, the clinical and pathological characteristics are uncertain due to the small number of reports. Here, we report an additional case with various clinical and pathological characteristics. A 28-year-old Japanese man with mild proteinuria and hematuria underwent a kidney biopsy. Examination under a light microscope revealed mesangial proliferation, mesangial matrix expansion, and segmental spike lesion. An immunofluorescence study showed no immunoglobulin or complement depositions. In the electron microscopic (EM) examination, massive deposits with various electron densities in the subepithelial, subendothelial, and paramesangial areas were more prominent than those reported in previous cases, which resembled microbubbles or microcysts on higher magnification. The glomerular basement membrane (GBM) structure was partly degenerated by these deposits. Serum triglyceride and cholesterol levels were within the normal range. However, the serum apoE concentration was significantly high, and glomerular apoE accumulation was detected in immunohistochemistry. The DNA sequence revealed apoE Toyonaka and homozygous apoE2/2 similar to that of the previous cases with MN-like apoE deposition disease. MN-like apoE deposition disease can manifest as only mild hematuria and proteinuria without dyslipidemia. Various characteristic deposits associated with GBM degeneration can be observed in the EM study.

Favorable therapeutic efficacy of low-density lipoprotein apheresis for nephrotic syndrome with impaired renal function.

Many reports have shown the therapeutic efficacy of LDL apheresis (LDL-A) in drug-resistant nephrotic syndrome (NS) for improvement of heavy proteinuria and severely impaired renal function. To obtain comprehensive results in a large number of cases, a post hoc analysis of the Prospective Observational survey on the Long-Term Effects of the LDL-Apheresis on the Drug Resistant Nephrotic Syndrome (POLARIS) study was performed by stratifying enrolled cases according to the pretreatment estimated glomerular filtration rate (eGFR) levels indicating normal (N) (≥60 ml/min/1.73 m2 ), moderately impaired (M) (≥30 to <60 ml/min/1.73 m2 ), and severely impaired (S) (<30 ml/min/1.73 m2 ) renal function. Significant improvements of proteinuria and renal function were found in Group N and, most interestingly, in Group M. A tendency for improvement in proteinuria was found in Group S. Most cases in all groups had not entered end-stage renal disease at 2 years after LDL-A treatment. These results suggest that LDL-A has therapeutic efficacy even in cases in which renal function has declined to 30 ml/min/1.73 m2 .

Validation of the diagnostic criteria for IgG4-related kidney disease (IgG4-RKD) 2011, and proposal of a new 2020 version.

BACKGROUND: In 2011, the IgG4-related kidney disease (IgG4-RKD) working group of the Japanese Society of Nephrology proposed diagnostic criteria for IgG4-RKD. The aim of the present study was to validate those criteria and develop a revised version. METHODS: Between April 2012 and May 2019, we retrospectively collected Japanese patients with kidney disease, for whom data on serum IgG4 values and/or immunohistological staining for IgG4 in renal biopsy samples were available. These patients were classified as IgG4-RKD or non-IgG4-RKD based on the diagnostic criteria for IgG4-RKD 2011, and the results were evaluated by expert opinion. Accordingly, we developed some revised versions of the criteria, and the version showing the best performance in the present cohort was proposed as the IgG4-RKD criteria for 2020. RESULTS: Of 105 included patients, the expert panel diagnosed 55 as having true IgG4-RKD and 50 as mimickers. The diagnostic criteria for IgG4-RKD 2011 had a sensitivity of 72.7% and a specificity of 90.0% in this cohort. Of the 15 patients with true IgG4-RKD who were classified as non-IgG4-RKD, all lacked biopsy-proven extra-renal lesions, although many had clinical findings highly suggestive of IgG4-RD. The revised version to which "bilateral lacrimal, submandibular or parotid swelling, imaging findings compatible with type 1 autoimmune pancreatitis or retroperitoneal fibrosis" was added as an item pertaining to extra-renal organ(s) improved the sensitivity to 90.9% while the specificity remained at 90.0%. CONCLUSION: The revised version has considerably improved test performance after addition of the new extra-renal organ item (imaging and clinical findings).

Salivary Immunoglobulin A Secretion Rate During Peak Period Conditioning Regimens in Triathletes.

ABSTRACT: Matsumoto M, Satoh, K, Kushi, H, Hamuro, K, Sakurai, M, Saito, H, Tanaka, R, Saito, T, Kohda, N, and Hamada, K. Salivary immunoglobulin A secretion rate during peak period conditioning regimens in triathletes. J Strength Cond Res 35(5): 1389-1396, 2021-Triathletes often feel unwell during the conditioning period (peak period) leading up to a race. The aim of this study was to evaluate the factors relevant to the condition of athletes and their impact on mucosal immune responses and the salivary immunoglobulin A (IgA) secretion rate. This study recruited college student triathletes (33 men and 7 women) who participated in an Olympic distance race. For each subject, the salivary IgA rate was measured continuously for 1 month before the race (peak period). Data on physical activity during the peak period were calculated in metabolic equivalents, and the relationships between these factors and the salivary IgA secretion rate were evaluated. The average amount of physical activity was highest during the 2- to 3-week period before the race, at 744.7 ± 51.5 kcal expended per day. In subjects who, on average, expended more than 1,000 kcal·d-1 in physical activity between 12 and 14 days before the race, the salivary IgA secretion rate was significantly reduced compared with the value at 1 week before the race (p < 0.05). On the day before the race, a further reduction was observed (p < 0.1). The salivary IgA secretion rate was decreased by high-intensity exercise during the peak period in advance of a race; this was associated with a loss of optimal condition just before the race.

Apolipoprotein E-related glomerular disorders.

Of the glomerular disorders that occur due to apolipoprotein E (apoE) mutations, apoE2 homozygote glomerulopathy and lipoprotein glomerulopathy (LPG) have been characterized. ApoE2 homozygote glomerulopathy has been found in individuals expressing homozygous apoE2/2. This was characterized histologically by glomerulosclerosis with marked infiltration of foam cells derived from macrophages, and occasionally with non-lamellated lipoprotein thrombi. Recently, several cases of apoE Toyonaka (Ser197Cys) combined with homozygous apoE2/2 have been reported, in which non-immune membranous nephropathy-like features were observed in glomeruli. Interestingly, in these cases, apoE accumulation was identified by tandem mass spectrometry. Therefore, it is speculated that these findings may arise from apoE molecules without lipids, which result from hinge damage by apoE Toyonaka and may cross the glomerular basement membrane as small molecules. LPG is primarily associated with heterozygous apoE mutations surrounding the low-density lipoprotein-receptor binding site, and it is histologically characterized by lamellated lipoprotein thrombi that lack foam cells. Recent studies have suggested that LPG can be induced by thermodynamic destabilization, hydrophobic surface exposure, and the aggregation of apoE resulting from the incompatibility of apoE mutated residues within helical regions. Additionally, apoE5 may play a supporting role in the development of LPG and in lipid-induced kidney diseases via hyperlipoproteinemia. Thus, it is interesting that many apoE mutations contribute to characteristic glomerular disorders through various mechanisms. In particular, macrophages may uptake lipoproteins into the cytoplasm and contribute to the development of apoE2 homozygote glomerulopathy as foam cells, and their dysfunction may contribute to the accumulation of lipoproteins in the glomerulus, causing lipoprotein thrombi in LPG.

Total Synthesis of 3-epi-Juruenolide C.

In this study, the total synthesis of 3-epi-juruenolide C is achieved in 10 steps (longest linear sequence) starting from ethyl (2E,4S,5S)-4,5-dihydroxy-2-hexenoate. The synthetic highlights of our approach include one-pot regioselective bromination, intramolecular carbonylation using bis(triphenylphosphine)dicarbonylnickel, and face-selective hydrogenation using a homogeneous Wilkinson's catalyst.

A case of apolipoprotein E Toyonaka and homozygous apolipoprotein E2/2 showing non-immune membranous nephropathy-like glomerular lesions with foamy changes.

A 47-year-old Japanese man with mild proteinuria was treated with an ACE inhibitor and antiplatelet agent for 7 years. However, urinary protein levels increased and renal biopsy was performed. Eight out of 20 glomeruli showed global or segmental sclerosis with foamy changes or bubbles, but with a different appearance to typical foam cells or lipoprotein thrombi. "Spike" formation, as observed in membranous nephropathy (MN), was segmentally detected in methenamine silver-stained sections. In an immunofluorescence study, weak linear patterns for IgG and scanty deposits for C3 were observed in glomeruli, but were not specific for immunogenetic MN. An electron microscopy study showed highly dense deposits in the subepithelial, subendothelial, and mesangial areas, in which microbubbles appeared under a higher magnification. Since this case exhibited hypertriglyceridemia and cholesterolemia with high serum apolipoprotein E (apoE) clinically and homozygous apoE2/2 by apoE phenotype and genotype analyses, apoE2 homozygote glomerulopathy was diagnosed and various lipid-lowering agents, e.g., probucol, fenofibrate, and ezetimibe, were administered. However, renal dysfunction gradually developed and peritoneal dialysis was initiated 11 years after the diagnosis. ApoE Toyonaka (Ser197Cys) and homozygous E2/2 were recently identified by direct DNA sequencing. Therefore, non-immune MN-like lesions may develop with the combination of these apoE mutations.

Effect of exercise intensity on renal blood flow in patients with chronic kidney disease stage 2.

BACKGROUND: Acute exercise reduces renal blood flow (RBF). However, the effect of exercise intensity on RBF in patients with chronic kidney disease (CKD) stage 2 is not known. We investigated the association between RBF and exercise intensity in patients with CKD stage 2 using pulsed Doppler ultrasonography. METHODS: Eight men with CKD stage 2 (cystatin C-based estimate of glomerular filtration rate: 60-89 ml/min/1.73 m2) participated in this study. Using a bicycle ergometer, participants undertook a maximal graded exercise test (MGET) (experiment 1) and a multi-stage exercise test (experiment 2) to determine their lactate threshold (LT). Participants undertook a multi-stage exercise test for 4-min each. Workloads of 60%, 80%, 100%, 120%, and 140% of LT were used in experiment 3. RBF was measured by pulsed Doppler ultrasonography at rest, immediately after exercise, and 1 h after exercise in experiment 1, and at rest and immediately after each exercise bout in experiment 3. RESULTS: Renal blood flow after the MGET was 52% lower than at rest, and did not recover as well as after the exercise test. Cross-sectional area (CSA) was significantly lower after graded exercise. RBF tended to be lower at 100% of LT and was significantly lower at 120% of LT. CSA was significantly lower at 100% of LT. CONCLUSIONS: Renal blood flow does not change during exercise until the LT is reached. These findings may assist in making appropriate exercise recommendations to patients with CKD stage 2.

Histopathological classification of anti-neutrophil cytoplasmic antibody-associated glomerulonephritis in a nationwide Japanese prospective 2-year follow-up cohort study.

BACKGROUND: The prognostic value of the EUVAS-proposed histopathological classification of anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis has been evaluated throughout the world. Here, we performed a Japanese nationwide biopsy survey to assess the association between this histopathological classification and renal prognosis after 2-year follow-up in ANCA-associated glomerulonephritis. METHODS: We collected 67 renal biopsy materials of the 321 entries in the RemIT-JAV-RPGN cohort study, and assessed their histologies. Based on the EUVAS-proposed histopathological classification and some histological parameters, we statistically evaluated renal survival and the comparison of renal function for 2 years. RESULTS: Based on the histopathological classification, the largest number of biopsy samples belonged to the Focal class, followed by the Mixed, Crescentic, and Sclerotic classes (n = 30, 19, 10, 8, respectively). Although the number of events might be too low (four patients with renal death) to make this conclusion, the Focal and Mixed classes had higher renal-survival rates compared to the others in the renal-survival curve. Comparing renal function among all classes, the estimated glomerular filtration rate (eGFR) throughout 2-year follow-up period was significantly higher in the Focal class compared to the other 3 classes. The eGFR-values in the Crescentic, Mixed, and Sclerotic classes increased with time. Based on both combined results, the Focal class could be the best prognosis. CONCLUSION: This histopathological classification was valuable for both the stratification of renal function and the estimation of partial renal survival during 2-year follow-up in ANCA-associated glomerulonephritis.

A case of nephrotic syndrome showing contemporary presence of apolipoprotein E2 homozygote glomerulopathy and membranous nephropathy-like findings modified by apolipoprotein E Toyonaka.

A 79-year-old man was admitted to our hospital for proteinuria due to nephrotic syndrome. Renal biopsy revealed focal sclerosis and foam cell infiltration in the glomerulus. In addition, electron microscopic findings (EM) revealed peculiar electron-dense deposits (EDDs) in both sides of the glomerular basement membrane. Although subepithelial deposits had spike formation highly resembling those seen in membranous nephropathy (MN), immunoglobulins and complements were not identified by immunofluorescence study, and microbubbles appeared in high magnification of EM different from the immune disease. The analysis of apolipoprotein (Apo) E showed an elevated concentration of plasma ApoE. The phenotype, genotype, and DNA sequence studies revealed homozygous ApoE2/2 and a novel missense mutation called ApoE Toyonaka (Ser197Cys). This case may confirm the independent responsibility of ApoE2/2 and ApoE Toyonaka for ApoE2 homozygote glomerulopathy and MN-like EDD findings, respectively.

Total Syntheses of 3- epi-Litsenolide D2 and Lincomolide A.

The first total syntheses of 3- epi-litsenolide D2 and its enantiomer lincomolide A were achieved. The synthetic highlights of our approach include olefin cross metathesis and bromine addition to the generated double bond, followed by the regioselective HBr-elimination and intramolecular carbonylation using bis(triphenylphosphine)dicarbonylnickel. This investigation also revealed that the previously reported specific optical rotation of 3- epi-litsenolide D2 should be revised.

Focal segmental glomerulosclerosis with heterozygous apolipoprotein E5 (Glu3Lys).

Apolipoprotein (apo) E5 is a rare apoE isoform. The apoE5 (Glu3Lys) variant, which is caused by the substitution of lysine with glutamic acid at codon 3, has a relative frequency of 0.1% in Japan. Previous studies have reported that apoE5 (Glu3Lys) is associated with hyperlipidemia and cardiovascular diseases, but this isoform has higher LDL receptor-binding activity than that of normal apoE3. Nephropathy associated with apoE5 (Glu3Lys) alone has not yet been reported. We present a case of a 51-year-old man with nephrotic syndrome. On renal biopsy, three glomeruli showed segmental sclerosis with hypertrophy of podocytes and intracapillary marked infiltration of intraglomerular foam cells. These findings were compatible with focal segmental glomerulosclerosis (FSGS). The patient had mild diabetes mellitus and monoclonal gammopathy of undetermined significance, but there were no specific findings of nephrolopathy related to these diseases. Various factors are involved in the pathogenesis of FSGS, including dyslipidemia and apoE activity. Our findings suggest that abnormal lipid metabolism by ApoE5 (Glu3Lys) is involved in the onset of FSGS.

Membranous Nephropathy-Like Apolipoprotein E Deposition Disease with Apolipoprotein E Toyonaka (Ser197Cys) and a Homozygous Apolipoprotein E2/2.

A 20-year-old female student underwent renal biopsy because of chance proteinuria and hematuria. Histological study revealed a membranous nephropathy-like appearance by light microscopy. But immunoglobulins and complements were negative in the glomerulus by immunofluorescence study. On the other hand, plasma apolipoprotein E (ApoE) concentration was elevated to more than 2 times the normal range, and the phenotype, genotype, and DNA sequence studies of her ApoE showed homozygous ApoE2/2 and a heterozygous novel missense mutation called ApoE Toyonaka (Ser197Cys). Detailed immunohistochemical studies found that the dense deposits in subepithelial, subendothelial, and mesangial areas contained ApoE. Tandem mass spectrometry also proved a large amount of ApoE in the glomerulus. These findings suggest that ApoE Toyonaka with a homozygous ApoE2/2 may cause a new form of ApoE-related glomerular disease resembling membranous nephropathy.