Early acute kidney injury after tacrolimus administration in heart transplant recipients receiving basiliximab induction therapy.

OBJECTIVE: In this study, we aimed to analyze the association among the timing of tacrolimus initiation, time required to reach the target blood concentration, and early acute kidney injury (AKI) after tacrolimus administration in heart transplant recipients who received basiliximab induction therapy. MATERIALS AND METHODS: 88 patients treated with tacrolimus-based immunosuppressive therapy were retrospectively reviewed. Induction therapy was administered to 52 patients. AKI was evaluated within 7 days of tacrolimus administration. RESULTS: The rate of increase in tacrolimus trough concentration to the target trough concentration of 10 µg/mL early after its administration was set to be similar in the basiliximab induction and non-induction group; 8 and 2 patients developed AKI in the induction and non-induction group, respectively. In the induction group, there was no significant difference in the timing of tacrolimus initiation and the time required to reach the target concentration between patients who developed and did not develop AKI. In contrast, the cumulative incidence of AKI was significantly different between patients with an estimated glomerular filtration rate below and those with an estimated glomerular filtration rate above 43 mL/min/1.73m2 at the start of tacrolimus administration (37.5% and 11.4%, respectively; p = 0.045). CONCLUSION: In patients receiving basiliximab induction therapy, the timing of tacrolimus initiation and the time to reach the target concentration are unlikely to be associated with early AKI after tacrolimus administration. However, the recovery of sufficient renal function after heart transplantation is important for determining the start time of tacrolimus.

SIPA1L1/SPAR1 Interacts with the Neurabin Family of Proteins and is Involved in GPCR Signaling.

Signal-induced proliferation-associated 1 (SIPA1)-like 1 (SIPA1L1; also known as SPAR1) has been proposed to regulate synaptic functions that are important in maintaining normal neuronal activities, such as regulating spine growth and synaptic scaling, as a component of the PSD-95/NMDA-R-complex. However, its physiological role remains poorly understood. Here, we performed expression analyses using super-resolution microscopy (SRM) in mouse brain and demonstrated that SIPA1L1 is mainly localized to general submembranous regions in neurons, but surprisingly, not to PSD. Our screening for physiological interactors of SIPA1L1 in mouse brain identified spinophilin and neurabin-1, regulators of G-protein-coupled receptor (GPCR) signaling, but rejected PSD-95/NMDA-R-complex components. Furthermore, Sipa1l1-/- mice showed normal spine size distribution and NMDA-R-dependent synaptic plasticity. Nevertheless, Sipa1l1-/- mice showed aberrant responses to α2-adrenergic receptor (a spinophilin target) or adenosine A1 receptor (a neurabin-1 target) agonist stimulation, and striking behavioral anomalies, such as hyperactivity, enhanced anxiety, learning impairments, social interaction deficits, and enhanced epileptic seizure susceptibility. Male mice were used for all experiments. Our findings revealed unexpected properties of SIPA1L1, suggesting a possible association of SIPA1L1 deficiency with neuropsychiatric disorders related to dysregulated GPCR signaling, such as epilepsy, attention deficit hyperactivity disorder (ADHD), autism, or fragile X syndrome (FXS).SIGNIFICANCE STATEMENT Signal-induced proliferation-associated 1 (SIPA1)-like 1 (SIPA1L1) is thought to regulate essential synaptic functions as a component of the PSD-95/NMDA-R-complex. In our screening for physiological SIPA1L1-interactors, we identified G-protein-coupled receptor (GPCR)-signaling regulators. Moreover, SIPA1L1 knock-out (KO) mice showed striking behavioral anomalies, which may be relevant to GPCR signaling. Our findings revealed an unexpected role of SIPA1L1, which may open new avenues for research on neuropsychiatric disorders that involve dysregulated GPCR signaling. Another important aspect of this paper is that we showed effective methods for checking PSD association and identifying native protein interactors that are difficult to solubilize. These results may serve as a caution for future claims about interacting proteins and PSD proteins, which could eventually save time and resources for researchers and avoid confusion in the field.

Unnaturally Distorted Hexagonal Protein Ring Alternatingly Reorganized from Two Distinct Chemically Modified Proteins.

In this study, we constructed a semiartificial protein assembly of alternating ring type, which was modified from the natural assembly state via incorporation of a synthetic component at the protein interface. For the redesign of a natural protein assembly, a scrap-and-build approach employing chemical modification was used. Two different protein dimer units were designed based on peroxiredoxin from Thermococcus kodakaraensis, which originally forms a dodecameric hexagonal ring with six homodimers. The two dimeric mutants were reorganized into a ring by reconstructing the protein-protein interactions via synthetic naphthalene moieties introduced by chemical modification. Cryo-electron microscopy revealed the formation of a uniquely shaped dodecameric hexagonal protein ring with broken symmetry, distorted from the regular hexagon of the wild-type protein. The artificially installed naphthalene moieties were arranged at the interfaces of dimer units, forming two distinct protein-protein interactions, one of which is highly unnatural. This study deciphered the potential of the chemical modification technique that constructs semiartificial protein structures and assembly hardly accessible by conventional amino acid mutations.

Risk Assessment of Neutropenia during Low-Dose Valganciclovir Prophylaxis for Heart Transplant Recipients.

The aim of this study was to investigate whether low-dose valganciclovir (VGCV) prophylaxis for cytomegalovirus (CMV) infection increased the risk of developing neutropenia in heart transplant recipients (HTRs). Forty-three HTRs receiving VGCV were divided into two groups: those who received VGCV prophylaxis (n = 22) and those who did not (n = 21). Neutropenia was defined as an absolute neutrophil count ˂1500/µL and was monitored for approximately one year post-transplantation. In the prophylaxis group, 77.3% (17/22) of HTRs experienced neutropenia, which was significantly higher than that in the no prophylaxis group (42.9% [9/21], p = 0.031). No significant differences in the duration of VGCV administration and cumulative dose up to the first neutropenia episode were observed between the groups. Meanwhile, the cumulative dose of mycophenolate mofetil was significantly higher in the prophylaxis group than in the no prophylaxis group (p = 0.018); the daily maintenance dose and regularly measured area under the concentration-time curve (AUC) of mycophenolic acid did not significantly differ between groups. In conclusion, the risk of developing neutropenia was higher in HTRs receiving low-dose VGCV prophylaxis than it was in those not receiving prophylaxis, probably not attributed to dosing period and cumulative dose of VGCV until the onset of neutropenia.

Rebuilding Ring-Type Assembly of Peroxiredoxin by Chemical Modification.

Direct control of the protein quaternary structure (QS) is challenging owing to the complexity of the protein structure. As a protein with a characteristic QS, peroxiredoxin from Aeropyrum pernix K1 (ApPrx) forms a decamer, wherein five dimers associate to form a ring. Here, we disrupted and reconstituted ApPrx QS via amino acid mutations and chemical modifications targeting hot spots for protein assembly. The decameric QS of an ApPrx* mutant, wherein all cysteine residues in wild-type ApPrx were mutated to serine, was destructed to dimers via an F80C mutation. The dimeric ApPrx*F80C mutant was then modified with a small molecule and successfully assembled as a decamer. Structural analysis confirmed that an artificially installed chemical moiety potentially facilitates suitable protein-protein interactions to rebuild a native structure. Rebuilding of dodecamer was also achieved through an additional amino acid mutation. This study describes a facile method to regulate the protein assembly state.

Dysbiosis of Oral Microbiota Associated with Palmoplantar Pustulosis.

BACKGROUND: Dysbiosis of oral microbiota is implicated not only in oral inflammatory lesions, but also in a variety of extraoral diseases. The etiology of palmoplantar pustulosis (PPP) remains unclear; however, it has been suggested that chronic inflammation caused by periodontopathic bacterial infection may play a role. OBJECTIVES/METHODS: To determine whether patients with PPP have altered diversity and composition of oral microbiota, we conducted the 16S rDNA analysis using saliva samples collected from 21 outpatients with PPP and 10 healthy individuals. RESULTS: We found that the proportion of bacteria in the phylum Proteobacteria was significantly lower in PPP patients (p = 0.025). At the genus level, patients with PPP had a significantly lower abundance of Neisseria (p = 0.014), which best accounted for the observed decrease in Proteobacteria. We also identified multiple minor genera and species that were represented at a significantly higher level in the PPP group, several of which have been associated with periodontal diseases. CONCLUSION: Our results suggest a possible link between PPP and dysbiosis of oral microbiota, particularly the lower abundance of Neisseria, the most predominant genus of Proteobacteria in healthy oral microbiota. Probiotics that improves oral dysbiosis may be beneficial for patients with PPP as an adjunctive therapy.

Relationship between serum bepridil concentration and corrected QT interval.

OBJECTIVE: Bepridil prolongs the QT interval and can induce torsade de pointes. Although increased bepridil concentration may be a primary cause of prolonged QT, the relationship between serum bepridil concentration and prolonged QT remains unclear. We investigated the relationship between serum bepridil concentration and the corrected QT (QTc) interval in patients treated with bepridil. MATERIALS AND METHODS: A retrospective study was performed at the National Cerebral and Cardiovascular Center in Japan. Patients with atrial fibrillation who were treated with bepridil from January 2014 to December 2015 were enrolled in the study. Serum bepridil concentrations and electrocardiogram data collected more than 21 days after the initiation of bepridil were used for analysis. RESULTS: A total of 60 patients were included in this study. There was a significant difference in mean QTc interval before and after initiation of bepridil (p < 0.0001). A significant relationship was observed between bepridil dose (p = 0.014) or serum bepridil concentration (p < 0.001) and QTc interval. Additionally, a significant relationship was observed between serum bepridil concentration and ΔQTc (p = 0.034). In the study, 4 patients developed QTc prolongation ≥ 500 ms after the initiation of bepridil. Serum bepridil concentration in this group was significantly higher compared with the group that did not display prolonged QTc (973 ± 651 vs. 526 ± 310 ng/mL, p = 0.01). CONCLUSION: This study revealed that the QTc interval was significantly associated with serum bepridil concentration. Serum bepridil concentration beyond a therapeutic range may be a critical risk factor for developing QTc prolongation.

Discontinuation of oral amphotericin B therapy does not influence the pharmacokinetics of tacrolimus in heart transplant patients.

OBJECTIVE: Amphotericin B (AMPH-B) is used to prevent opportunistic infections associated with immunosuppressive therapy after heart transplantation (HTx), while the blood concentrations of tacrolimus (TAC) are carefully controlled. Although AMPH-B has the potential to inhibit TAC metabolism in in vitro studies, its interaction with clinically used AMPH-B oral suspension has not been investigated. In the present study, we examined whether oral AMPH-B therapy influences the pharmacokinetics of TAC in HTx patients. MATERIALS AND METHODS: A retrospective study was performed at the National Cerebral and Cardiovascular Center in Japan. All patients with HTx enrolled in the study received standard triple-drug immunosuppression therapy including the regular release of TAC, mycophenolate mofetil, and prednisolone as well as prophylactic therapy with AMPH-B oral suspension. Patient characteristics and clinical laboratory data were collected from the electronic medical record system. Blood concentrations of TAC were used for pharmacokinetic analysis. RESULTS: A total of 14 patients were enrolled in the study. There were no statistically significant differences in the variables except for serum creatinine levels and eGFR before and after discontinuation of oral AMPH-B therapy. The dose and trough concentrations of TAC and the area under the time-concentration curve and apparent oral clearance calculated from its concentrations were not influenced by discontinuation of AMPH-B treatment. CONCLUSION: The prophylactic treatment with AMPH-B oral suspension did not influence the pharmacokinetics of TAC and was demonstrated as a safe and easy method to prevent early post-HTx fungal infection.

Higher Prevalence of Nickel and Palladium Hypersensitivity in Patients with Ulcerative Colitis.

BACKGROUND: The etiology of ulcerative colitis (UC) remains elusive even though many genetic and environmental pathogenic factors have been reported. Aberrant inflammatory responses mediated by specific subsets of T cells have been observed in ulcerative lesions of UC patients. OBJECTIVES: To elucidate the involvement of a delayed-type hypersensitivity reaction in UC, we focused on dental metal hypersensitivity, a T cell-mediated, delayed-type allergic reaction that causes oral contact mucositis and systemic cutaneous inflammation. METHOD: We recruited 65 Japanese UC patients and 22 healthy controls (HC) and used the in vitro lymphocyte stimulation test to quantify their sensitivity to zinc, gold, nickel, and palladium - the metals that have been widely used in dentistry. All subjects were users of metallic dental implants and/or prostheses containing zinc, gold, nickel, and/or palladium as major constituents. RESULTS: Sixty percent of the UC patients were hypersensitive to at least one metal species, whereas 32% of the HC were hypersensitive to only a single metal species. The overall incidence of metal hypersensitivity was significantly higher for UC patients than for HC. Furthermore, a significantly greater proportion of UC patients were hypersensitive to nickel or palladium. The severity of the sensitivity to nickel and palladium was also significantly greater for UC patients than for HC. CONCLUSIONS: This pilot study demonstrates that UC patients have a significantly higher incidence of hypersensitivity to nickel and palladium, suggesting the possible involvement of dental metal hypersensitivity in UC pathogenesis.

Risk Factors for Skin Toxicities Associated with Bendamustine-Based Chemotherapy in Patients with Non-Hodgkin Lymphoma.

Bendamustine plays an especially important role as a treatment for non-Hodgkin lymphoma (NHL). However, patients administered bendamustine alone or in combination with rituximab (BR) may experience drug-associated skin toxicities that can profoundly impact their health-related QOL through both physical discomfort and psychological distress. Moreover, worsening skin symptoms may lead to dose reduction or termination in the management of cancer chemotherapy. We retrospectively investigated patient backgrounds and pretreatment characteristics from medical records of NHL patients treated with bendamustine alone or BR therapy and identified predictive factors for skin toxicities at the start of chemotherapy. Patients were eligible for the study if they were 20 years older, diagnosed with NHL, and received bendamustine alone or BR therapy at the Department of Hematology, Kobe City Medical Center General Hospital, between April 1, 2011, and March 31, 2018. This study included 95 patients with newly diagnosed or refractory or relapsed NHL. Multivariate stepwise logistic regression analysis with backward selection revealed that baseline non-prior chemotherapy (odds ratio (OR), 15.72; 95% confidence interval (CI), 4.24-83.13, p < 0.001) was a significant factor influencing the occurrence of skin toxicity. Our results demonstrated that non-prior chemotherapy was a significant risk factor for skin toxicities in patients with NHL receiving bendamustine alone or BR therapy. No patient experience serious side effects of grade 3 or higher and that bendamustine is very useful as a first-line treatment.