Prevention of Late-Onset Cytomegalovirus Infection and Disease in Donor-Positive/Recipient-Negative Kidney Transplant Recipients Using Low-Dose Valganciclovir

BACKGROUND

The main challenge with cytomegalovirus (CMV) prophylaxis in IgG donor-positive/recipient-negative (D+/R-) kidney transplant recipients is late-onset CMV disease. We evaluated a novel protocol for the prevention of late-onset CMV infection and disease in D+/R- organ recipients.

METHODS

Our prospective, observational, cohort study included 100 adult kidney transplant recipients. Prophylaxis with low-dose valganciclovir (450 mg/d, 3 times a week for 6 months) was administered to D+/R- recipients. Risk factors for CMV infection and disease were identified. Renal function and the outcomes of CMV infection and disease were compared between D+/R- (n = 15) and recipient-positive (R+; n = 81) organ recipients.

RESULTS

D+/R- recipients showed significant independent risk factors with high hazard ratios for CMV infection (2.04) and disease (10.3). The proportion of CMV infection in D+/R- and R+ recipients was 80% and 46% (P = .023), and that of CMV disease was 33% and 6.2% (P = .008), repectively. D+/R- recipients developed CMV infection and disease within 6 months after transplantation. However, both CMV infection- and disease-free survival rates beyond 1 year post-transplantation defined as late-onset were stable in D+/R- recipients. Moreover, serum creatinine levels at 1 year post-transplantation were comparable between D+/R- and R+ recipients (1.45 ± 0.71 vs 1.16 ± 0.35 mg/dL, P = .26).

CONCLUSION

Our novel protocol prevented late-onset CMV infection and disease beyond 1 year post-transplantation in D+/R- recipients.

Determination of the hydrogen-bond network and the ferrimagnetic structure of a rockbridgeite-type compound, [Formula: see text]

Applying neutron powder diffraction, four unique hydrogen positions were determined in a rockbridgeite-type compound, [Formula: see text] [Formula: see text]. Its honeycomb-like H-bond network running without interruption along the crystallographic [Formula: see text] axis resembles those in alkali sulphatic and arsenatic oxyhydroxides. They provide the so-called dynamically disordered H-bond network over which protons are superconducting in a vehicle mechanism. This is indicated by dramatic increases of dielectric constant and loss factor at room temperature. The relevance of static and dynamic disorder of OH and HOH groups are explained in terms of a high number of structural defects at octahedral chains alternatingly half-occupied by [Formula: see text] cations. The structure is built up by unusual octahedral doublet, triplet, and quartet clusters of aliovalent 3d transition metal cations, predicting complicate magnetic ordering and interaction. The ferrimagnetic structure below the Curie temperature [Formula: see text]-83 K could be determined from the structure analysis with neutron diffraction data at 25 K.

Tau Fibril Formation in Cultured Cells Compatible with a Mouse Model of Tauopathy

Neurofibrillary tangles composed of hyperphosphorylated tau protein are primarily neuropathological features of a number of neurodegenerative diseases collectively termed tauopathy. To understand the mechanisms underlying the cause of tauopathy, precise cellular and animal models are required. Recent data suggest that the transient introduction of exogenous tau can accelerate the development of tauopathy in the brains of non-transgenic and transgenic mice expressing wild-type human tau. However, the transmission mechanism leading to tauopathy is not fully understood. In this study, we developed cultured-cell models of tauopathy representing a human tauopathy. Neuro2a (N2a) cells containing propagative tau filaments were generated by introducing purified tau fibrils. These cell lines expressed full-length (2N4R) human tau and the green fluorescent protein (GFP)-fused repeat domain of tau with P301L mutation. Immunocytochemistry and super-resolution microscopic imaging revealed that tau inclusions exhibited filamentous morphology and were composed of both full-length and repeat domain fragment tau. Live-cell imaging analysis revealed that filamentous tau inclusions are transmitted to daughter cells, resulting in yeast-prion-like propagation. By a standard method of tau preparation, both full-length tau and repeat domain fragments were recovered in sarkosyl insoluble fraction. Hyperphosphorylation of full-length tau was confirmed by the immunoreactivity of phospho-Tau antibodies and mobility shifts by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). These properties were similar to the biochemical features of P301L mutated human tau in a mouse model of tauopathy. In addition, filamentous tau aggregates in cells barely co-localized with ubiquitins, suggesting that most tau aggregates were excluded from protein degradation systems, and thus propagated to daughter cells. The present cellular model of tauopathy will provide an advantage for dissecting the mechanisms of tau aggregation and degradation and be a powerful tool for drug screening to prevent tauopathy.

Prediction of major complications after hepatectomy using liver stiffness values determined by magnetic resonance elastography

BACKGROUND

Liver fibrosis is a risk factor for hepatectomy but cannot be determined accurately before hepatectomy because diagnostic procedures are too invasive. Magnetic resonance elastography (MRE) can determine liver stiffness (LS), a surrogate marker for assessing liver fibrosis, non-invasively. The aim of this study was to investigate whether the LS value determined by MRE is predictive of major complications after hepatectomy.

METHODS

This prospective study enrolled consecutive patients who underwent hepatic resection between April 2013 and August 2016. LS values were measured by imaging shear waves by MRE in the liver before hepatectomy. The primary endpoint was major complications, defined as Clavien-Dindo grade IIIa or above. Logistic regression analysis identified independent predictive factors, from which a logistic model to estimate the probability of major complications was constructed.

RESULTS

A total of 96 patients were included in the study. Major complications were observed in 15 patients (16 per cent). Multivariable logistic analysis confirmed that higher LS value (P = 0·021) and serum albumin level (P = 0·009) were independent predictive factors for major complications after hepatectomy. Receiver operating characteristic (ROC) analysis showed that the best LS cut-off value was 4·3 kPa for detecting major complications, comparable to liver fibrosis grade F4, with a sensitivity of 80 per cent and specificity of 82 per cent. A logistic model using the LS value and serum albumin level to estimate the probability of major complications was constructed; the area under the ROC curve for predicting major complications was 0·84.

CONCLUSION

The LS value determined by MRE in patients undergoing hepatectomy was an independent predictive factor for major complications.

Effective and Safe Reduction of Conventional Immunosuppressants Using Everolimus in Maintenance Kidney Transplant Recipients

BACKGROUND

Adverse events due to conventional immunosuppressive therapy decrease both graft and patient survival. We aimed to establish a new protocol using everolimus (EVR) to safely minimize conventional immunosuppressants in maintenance kidney transplant recipients.

METHODS

A total of 86 consecutive kidney transplant recipients with no complications were maintained with triple-drug combination therapy (conventional group). In case of complications, the administration of very low-dose tacrolimus (C₀: 5.0 to <3.0 ng/mL), reduced mycophenolate mofetil (1000-1500 to 500-1000 mg), and EVR (C₀: 3.0-5.0 ng/mL) and methylprednisolone withdrawal (2-4 to 0 mg) were simultaneously conducted (EVR group). Graft survival and acute rejection rate were compared between groups. Within the EVR group, the dose of conventional immunosuppressants was compared between pre- and post-EVR administration. Renal function was evaluated 1 year post-EVR administration.

RESULTS

All grafts survived in the conventional (n = 50) and EVR (n = 36) groups, and biopsy-proven acute rejection rate exhibited no significant difference between these groups (12% vs 17%; P = .55). Furthermore, no acute rejection occurred post-EVR administration. In the EVR group, all immunosuppressants significantly decreased post-EVR administration compared with those pre-EVR administration (P < .01), and serum creatinine significantly improved at postoperative year 1 (P = .031).

CONCLUSIONS

EVR administration enables very low-dose tacrolimus administration, helps reduce mycophenolate mofetil and steroid withdrawal, and ameliorates renal function in maintenance kidney transplant recipients experiencing complications associated with conventional immunosuppressive therapy.

A new species of the rare, deep-sea polychaete genus Benthoscolex from the Sea of Kumano, Japan (Annelida, Amphinomidae)

A new species of amphinomid polychaete, Benthoscolexseisuiaesp. n., is described from the Sea of Kumano, Japan, from depths of 487–596 m. The species is distinguishable from its congeners by the following features: i) palps 1.8 times as long as lateral antennae; ii) branchiae do not reach to the tip of the notochaetae. This is the first record of Benthoscolex from Japan. A partial mitochondrial cytochrome c oxidase subunit I gene sequence from the holotype of B.seisuiaesp. n. is provided for reliable species identification in the future.

Steroid Withdrawal Using Everolimus in ABO-Incompatible Kidney Transplant Recipients With Post-Transplant Diabetes Mellitus

BACKGROUND

The effectiveness of everolimus (EVR) for ABO-incompatible (ABOi) kidney transplantation is unknown. We evaluated outcomes of conversion from steroid to EVR in ABOi kidney transplant recipients.

METHODS

We performed a retrospective observational cohort study of 33 de novo consecutive adult ABOi living donor kidney transplant recipients. Desensitization was performed using 0 to 4 sessions of plasmapheresis and 1 to 2 doses of 100 mg rituximab according to the anti-A/B antibody titer. ABOi recipients were administered a combination of tacrolimus, mycophenolate mofetil, and methylprednisolone. Diabetic patients were converted from methylprednisolone to EVR at 1 to 15 months post-transplantation to prevent diabetes progression. Graft outcomes, hemoglobin A1c (HbA1c) levels, and cytomegalovirus infection rates were compared between the EVR (n = 11) and steroid (n = 22) groups.

RESULTS

Mean postoperative duration was 814 and 727 days in the EVR and steroid groups, respectively (P = .65). Between the 2 groups, graft survival rate (100% vs 95.5%, P > .99), acute rejection rate (9.1% vs 18.2%, P = .64), and serum creatinine levels (1.46 mg/dL vs 1.68 mg/dL, P = .66) were comparable. Although HbA1c levels were elevated in the steroid group (5.47%, 5.87%; P = .003), no significant deterioration was observed in the EVR group without additional insulin administration (6.10%, 6.47%; P = .21). Cytomegalovirus infection rate was significantly lower in the EVR group than in the steroid group (18.2% vs 63.6%, P = .026).

CONCLUSION

Conversion from steroid to EVR in ABOi kidney transplant recipients maintained excellent graft outcomes and avoided diabetes progression and cytomegalovirus infection.

Phospho-Tau Bar Code: Analysis of Phosphoisotypes of Tau and Its Application to Tauopathy

Tau is a microtubule-associated protein which regulates the assembly and stability of microtubules in the axons of neurons. Tau is also a major component of neurofibrillary tangles (NFTs), a pathological hallmark in Alzheimer's disease (AD). A characteristic of AD tau is hyperphosphorylation with more than 40 phosphorylation sites. Aggregates of hyperphosphorylated tau are also found in other neurodegenerative diseases which are collectively called tauopathies. Although a large number of studies have been performed on the phosphorylation of AD tau, it is not known if there is disease-specific phosphorylation among tauopathies. This is due to the lack of a proper method for analyzing tau phosphorylation in vivo. Most previous phosphorylation studies were conducted using a range of phosphorylation site-specific antibodies. These studies describe relative changes of different phosphorylation sites, however, it is hard to estimate total, absolute and collective changes in phosphorylation. To overcome these problems, we have recently applied the Phos-Tag technique to the analysis of tau phosphorylation in vitro and in vivo. This method separates tau into many bands during SDS-PAGE depending on its phosphorylation states, creating a bar code appearance. We propose calling this banding pattern of tau the "phospho-tau bar code." In this review article, we describe what is newly discovered regarding tau phosphorylation through the use of the Phos-Tag. We would like to propose its use for the postmortem diagnosis of tauopathy which is presently done by immunostaining diseased brains with anti-phospho-antibodies. While Phos-tag SDS-PAGE, like other biochemical assays, will lose morphological information, it could provide other types of valuable information such as disease-specific phosphorylation.

Isoform-independent and -dependent phosphorylation of microtubule-associated protein tau in mouse brain during postnatal development

Tau is a microtubule (MT)-associated protein that regulates MT dynamics in the axons of neurons. Tau binds to MTs via its C-terminal MT-binding repeats. There are two types of tau, those with three (3R) or four (4R) MT-binding repeats; 4R tau has a stronger MT-stabilizing activity than 3R tau. The MT-stabilizing activity of tau is regulated by phosphorylation. Interestingly, both the isoform and phosphorylation change at the time of neuronal circuit formation during postnatal development; highly phosphorylated 3R tau is replaced with 4R tau, which is less phosphorylated. However, it is not known how the transition of the isoforms and phosphorylation are regulated. Here, we addressed this question using developing mouse brains. Detailed analysis of developing brains revealed that the switch from 3R to 4R tau occurred during postnatal day 9 (P9) to P18 under the same time course as the conversion of phosphorylation from high to low. However, hypothyroidism, which is known to delay brain development, delayed the timing of tau dephosphorylation but not the exchange of isoforms, indicating that isoform switching and phosphorylation are not necessarily linked. Furthermore, we confirmed this finding by using mouse brains that expressed a single isoform of human tau. Human tau, either 3R or 4R, reduced phosphorylation levels during development even though the isoform did not change. We also found that 3R tau and 4R tau were phosphorylated differently in vivo even at the same developmental days. These results show for the first time that the phosphorylation and isoform alteration of tau are regulated differently during mouse development.

Polyunsaturated fatty acid deficiency during neurodevelopment in mice models the prodromal state of schizophrenia through epigenetic changes in nuclear receptor genes

The risk of schizophrenia is increased in offspring whose mothers experience malnutrition during pregnancy. Polyunsaturated fatty acids (PUFAs) are dietary components that are crucial for the structural and functional integrity of neural cells, and PUFA deficiency has been shown to be a risk factor for schizophrenia. Here, we show that gestational and early postnatal dietary deprivation of two PUFAs-arachidonic acid (AA) and docosahexaenoic acid (DHA)-elicited schizophrenia-like phenotypes in mouse offspring at adulthood. In the PUFA-deprived mouse group, we observed lower motivation and higher sensitivity to a hallucinogenic drug resembling the prodromal symptoms in schizophrenia. Furthermore, a working-memory task-evoked hyper-neuronal activity in the medial prefrontal cortex was also observed, along with the downregulation of genes in the prefrontal cortex involved in oligodendrocyte integrity and the gamma-aminobutyric acid (GABA)-ergic system. Regulation of these genes was mediated by the nuclear receptor genes Rxr and Ppar, whose promoters were hyper-methylated by the deprivation of dietary AA and DHA. In addition, the RXR agonist bexarotene upregulated oligodendrocyte- and GABA-related gene expression and suppressed the sensitivity of mice to the hallucinogenic drug. Notably, the expression of these nuclear receptor genes were also downregulated in hair-follicle cells from schizophrenia patients. These results suggest that PUFA deficiency during the early neurodevelopmental period in mice could model the prodromal state of schizophrenia through changes in the epigenetic regulation of nuclear receptor genes.