Recent increase in non-tuberculous mycobacterial infection in patients with connective tissue diseases in Japan.

BACKGROUND: Non-tuberculous mycobacterial (NTM) infection is currently a growing health concern due to the increasing incidence and the need for prolonged therapy. In patients with connective tissue diseases, use of immunosuppressants may lead to an increased risk of NTM infection. However, few studies have examined the recent incidence of NTM infection among connective tissue diseases patients. This study investigated recent trends in NTM infection among connective tissue diseases patients. METHODS: We included adult patients from whose cultures NTM were isolated between January 2009 and October 2017 in our hospital. By reviewing their medical records, connective tissue diseases patients were identified. Types of connective tissue disease, NTM species, and treatment of NTM infection were extracted. RESULTS: NTM was isolated from 657 patients during the period. Among these, 24 patients had connective tissue diseases. The number and rate of NTM isolates from connective tissue diseases patients increased during the period, with 4 patients 2009 to 2012 (1.9%), and 20 patients from 2013 to 2017 (3.3%; P = 0.04). The proportion of Mycobacterium avium complex (MAC) to total NTM tended to be lower among connective tissue diseases patients (58.3%) than among non-connective tissue disease-patients (72.8%), but the difference was not significant (P = 0.20). Mycobacterium xenopi was significantly more frequent in connective tissue disease patients than in non-connective tissue diseases patients (P < 0.01). CONCLUSION: The recent increase in the incidence of NTM infections in connective tissue diseases patients was larger than that in the total population. NTM species other than MAC were isolated from connective tissue diseases patients.

The prevalence of low serum free testosterone and the short-term effect of anti-retroviral therapy in male Japanese treatment-naïve HIV patients.

OBJECTIVES: The prevalence of hypogonadism in HIV patients is still a matter of debate. Today, serum free testosterone (fTST) is thought to be more important than serum testosterone in the diagnosis of hypogonadism in patients with HIV. This study aimed to determine the prevalence of low fTST levels and the effects of anti-retroviral therapy (ART) on fTST levels in treatment-naïve male Japanese patients with HIV. METHODS: Patients who visited Teikyo University Hospital, Japan between 2010 and 2016 were enrolled. Patients' fTST levels were evaluated twice with a radioimmunoassay in the morning, at the onset of ART and one year later. Clinical factors were also reviewed. The patients were divided into two groups ('hypogonadism' and 'normal') based on Japanese criteria. To determine factors related to low fTST in treatment-naïve patients, the Mann-Whitney U test and a multiple-regression analysis were used. Changes in fTST levels after ART initiation were evaluated with a paired t-test. RESULTS: Data from 25 patients were collected. Their median age was 36.0 years, and the median fTST level was 8.00 pg/ml in the treatment-naïve state. Thirteen patients (52%) were in the hypogonadism group. Low levels of fibroblast growth factor 23 were significantly related to low fTST levels. After the start of ART, fTST levels increased significantly (median 8.00 interquartile range [6.40-9.70] to 9.60 [7.60-13.10] pg/ml, p = 0.0081). CONCLUSIONS: Subnormal fTST levels occurred frequently among the present study patients in treatment-naïve settings. Free testosterone levels in patients with HIV were significantly increased one year after the start of ART.

Efficacies of atovaquone, pentamidine, and trimethoprim/sulfamethoxazole for the prevention of Pneumocystis jirovecii pneumonia in patients with connective tissue diseases.

BACKGROUND: Pneumocystis jirovecii pneumonia (PCP) is an opportunistic infection in patients on steroid therapy for connective tissue diseases. The standard agent for primary PCP prophylaxis is trimethoprim/sulfamethoxazole (TMP-SMX), although this agent can cause common adverse reactions, including myelosuppression and renal toxicity, that result in cessation. Aerosolized pentamidine and oral atovaquone are alternatives for PCP prophylaxis. The efficacies of atovaquone, pentamidine, and TMP-SMX to prevent PCP in patients with connective tissue diseases have never been compared. METHODS: Hospitalized patients with connective tissue diseases who started steroid therapy and PCP prophylaxis were enrolled. PCP prophylaxis regimens were oral TMP-SMX, aerosolized pentamidine, or oral atovaquone. Information was retrospectively collected from medical records about laboratory findings, duration of PCP prophylaxis, and reasons for terminating PCP prophylaxis. RESULTS: Ninety-six patients received PCP prophylaxis. All of them were initially treated with TMP-SMX, but this was replaced during the study period with pentamidine in 33 patients and with atovaquone in 7. Forty-one (43%) patients discontinued TMP-SMX because of adverse events, and 5 (15%) also discontinued pentamidine. None of the patients discontinued atovaquone. The most frequent causes of TMP-SMX and pentamidine cessation were cytopenia (N = 15) and asthma (N = 2). The rates of continuing treatment with TMP-SMX, pentamidine, and atovaquone at one year after starting PCP prophylaxis were 55.3%, 68.6%, and 100%, respectively (P = 0.01). None of the patients developed PCP. CONCLUSION: Although TMP-SMX for PCP prophylaxis had to be discontinued in 43% of patients with connective tissue diseases, pentamidine and atovaquone were well tolerated.

Decreased serum bone specific alkaline phosphatase and increased urinary N-terminal telopeptide of type I collagen as prognostic markers for bone mineral density loss in HIV patients on cART.

OBJECTIVES: Bone mineral density (BMD) loss is a major chronic complication in HIV patients. We performed a prospective study to determine the time course of BMD changes and to find prognostic factors of BMD loss in HIV patients on combination antiretroviral therapy (cART). PATIENTS AND METHODS: Subjects were 54 male Japanese HIV patients who had been on cART ≥1 year with no therapeutic agents for osteoporosis. Patients were observed for ≥1 year (median 3.1 years) and underwent annual BMD analyses using dual energy X-ray absorptiometry. Changes in BMD at lumbar spine and femoral neck were calculated for each person-year of all the patients. Clinical factors were also collected simultaneously with BMD examinations to determine prognostic factors for BMD loss. RESULTS: In total, 173 person-years in 54 patients were observed. One third (19, 35.2%) and slightly over half (30, 55.6%) patients showed BMD decreases at lumbar spine and femoral neck, respectively. However, the median BMD changes at lumbar spine and femoral neck were 0.0% and -0.52% per year, respectively. Monovariant and mixed model analyses determined that decreased serum bone specific alkaline phosphatase (BAP, p = 0.0047) and increased urinary N-terminal telopeptide (uNTx, p = 0.0011) were prognostic factors for BMD loss at lumbar spine and femoral neck, respectively. CONCLUSIONS: BMD at both lumbar spine and femoral neck changed little on average in HIV patients on cART. Decreased serum BAP or increased uNTx may be helpful to predict progressive BMD loss in the following year and to select patients for BMD follow-up or initiation of anti-osteoporosis treatment.

Increase of 25-hydroxyvitamin D levels after initiation of combination antiretroviral therapy.

Although vitamin D deficiency in HIV patients reported worldwide, the mechanisms and the effect of combination antiretroviral therapy (cART) on vitamin D levels are unclear. Patients were 50 male Japanese with HIV who visited Teikyo University Hospital, Tokyo, Japan. Patients were divided into those receiving cART (cART-experienced group, n = 30) and those who had not received cART (cART-naïve group, n = 20). Patients in the cART-experienced group had received treatment with cART for more than one year and those in the cART-naïve group were just about to start cART at study entry. Patients underwent measurement of serum 25-hydroxyvitamin D (25(OH)D) levels and assessment of clinical factors twice at one year intervals. At study entry, 23 (76.7%) in the cART-experienced group and 19 (95.0%) in the cART-naïve group had vitamin D insufficiency or deficiency. Mean 25(OH)D values were significantly higher in the cART-experienced group (25.2 ng/ml vs. 19.3 ng/ml, p = 0.01). However, levels of 25(OH)D at one year increased more in the cART-naïve group (-1.1 ng/ml vs. 5.0 ng/ml, p = 0.01), with mean 25(OH)D values in the cART-naïve group increasing to match those in the cART-experienced group. HIV infected patients who initiated cART showed increases in vitamin D levels in one year.

Pseudomonas putida bacteremia in adult patients: five case reports and a review of the literature.

Pseudomonas putida belongs to the fluorescent group of Pseudomonas species, a group of opportunistic pathogens that primarily cause nosocomial infections. However, few cases of P. putida bacteremia in adult patients have been reported. We report five cases of P. putida bacteremia in adult patients and review 23 previously reported cases. Our five patients consisted of three cases of catheter-related bloodstream infection (CRBSI), one case of indwelling biliary drainage tube-related cholangitis, and one case of cholecystitis. Many of the 23 previously reported cases also included CRBSI. Of the clinical backgrounds, in all 28 reported cases including ours, 24 (85.7%) were immunocompromised. Of the clinical management, in CRBSI, devices were removed in almost all cases (92.9%). Antibiotic susceptibility data of our five cases and another previous case showed that patients with bacteremia had a high susceptibility of P. putida to anti-pseudomonal ß-lactams. The prognosis for bacteremia with P. putida was good, as 26 (92.9%) of the total 28 cases were cured.

The usefulness of changing focus during examination using Gram staining as initial diagnostic clue for infective tuberculosis.

Gram staining is a useful technique for detecting bacteria but is highly questionable in detecting Mycobacterium tuberculosis. Its detection generally requires special staining, such as Ziehl-Neelsen staining. We experienced three cases in which tuberculosis was first suggested by Gram staining of sputum or pus, confirmed by Ziehl-Neelsen staining, and diagnosed by polymerase chain reaction or culture. To find colorless tubercle bacilli in clinical samples with various organisms, varying the focus to slightly longer and shorter during study of the slides is indispensable. We present criteria for detecting infective pulmonary tuberculosis in Gram staining. First, in the ordinary focus, weakly stained, thin, gram-positive bacilli are found; second, with a slightly longer focus distance, the thin, cord-like, conspicuous gram-positive bacilli can be observed; and third, with a shorter focus distance, the gram-positive bacilli have changed into the brightened, colorless, or ghost ones. Four laboratory technologists each evaluated 20 Gram-stained samples after being lectured on the criteria, with no prior information about the sample. They accurately evaluated the presence of the bacilli in Gram-stained preparations in more than 90% of samples containing 3+ bacilli on Ziehl-Neelsen staining. Gram staining is available as an easy and rapid initial clue to recognize highly infective tuberculosis.

Magnetic resonance imaging changes in Asian people living with HIV.

BACKGROUND: Previous studies have reported a significant increase in age-related magnetic resonance imaging (MRI) changes in relatively younger people living with HIV (PLWH). However, there is little data available for brain changes in Asian PLWH. The data to differentiate HIV specific brain change from usual aging change was also sparse. To clarify them, we assessed the presence of leukoaraiosis and brain atrophic changes on MRI in young and middle-aged Japanese PLWH. METHODS: We reviewed data from well-controlled PLWH (age: 20-64 years) and coeval controls. We evaluated the presence of leukoaraiosis, as well as the extent of whole-brain grey matter (GM) atrophy and parahippocampal atrophy on brain MRI and determined between-group differences. Moreover, we evaluated the severity of parahippocampal atrophy based on the voxel-based specific regional analysis system for Alzheimer's disease. RESULTS: We enrolled 40 PLWH and 33 controls (median age: 40.15 and 48.00 years, respectively, [p = .3585]). Leukoaraiosis was significantly more prevalent among the PLWH (20 cases [50%]) than in the controls (9 cases [27.3%]) (univariate: p = .0483, multivariate: p = .0206). The extent of whole-brain GM atrophy was significantly greater in the PLWH than in the controls (univariate: p < .001, multivariate: p = .0012). Contrastingly, there was no significant between-group difference in the extent and severity of parahippocampal atrophy. CONCLUSIONS: Aging changes in the brain were significantly more prevalent in well-controlled Japanese PLWH. However, the process of atrophic brain changes might differ between HIV and one of age-related diseases, Alzheimer's disease.

Osteomyelitis and pyomyositis due to Staphylococcus aureus in an osteomalacic adult with multiple fractures.

Multifocal osteomyelitis and pyomyositis usually arise from hematogenous dissemination, especially in patients with immunodeficiency, trauma, or injection drug abuse. We report the case of a 75-year-old man with multifocal pyomyositis and osteomyelitis, which were due to Staphylococcus aureus and were presumably related to multiple fractures. The patient had no risk factors for these hematogenous infections. He was treated with antibiotic therapy for about 80 days and drainage of the abscesses. Regarding the cause of his multipe fractures, he was found to have hypophosphatemia and eventually diagnosed as osteomalacia. To our best knowledge, this case was the first report on multifocal osteomyelitis and pyomyositis around the fracture sites in an osteomalacic adult. Osteomalacia should be considered as one of the differential diagnoses when osteoarticular infection with multifocal fractures is detected.

Cryptococcal pleuritis containing a high level of adenosine deaminase in a patient with AIDS: a case report.

Cryptococcal infection is the 4th most common opportunistic infection in patients with acquired immune deficiency syndrome (AIDS). Although pleural effusion alone is an unusual presentation, we present a case of cryptococcal pleuritis in an AIDS patient which was initially difficult to discriminate from tuberculous pleuritis because of the high level of pleural adenosine deaminase (ADA). Cryptococcus neoformans was detected in the culture of the pleural effusion after the initiation of antituberculous treatment. High levels of ADA in the pleural fluid can be observed in patients with cryptococcal pleuritis, and longer incubation of pleural fluid should be performed in all patients who present with pleuritis associated with a high ADA level as the only significant finding.

Clinical Efficacy of Baloxavir Marboxil in the Treatment of Seasonal Influenza in Adult Patients: A Prospective Observational Study.

PURPOSE: Baloxavir marboxil, a recently developed antiviral drug, has been used to treat influenza in some countries including Japan. The aim of this study was to determine the clinical efficacy of the drug, which currently remains unclear. PATIENTS AND METHODS: Overall, 43 adult patients with seasonal influenza who visited the outpatient clinic of Teikyo University Hospital in Tokyo during the winter of 2018-2019 were enrolled. Of them, 14, 13, and 16 were prescribed baloxavir marboxil (40 or 80 mg once), oseltamivir (75 mg twice daily for 5 days), and laninamivir (40 mg once), respectively. A questionnaire was used to collect data about symptoms, and the Medical Outcome Study 8-Items Short Form Health Survey was employed to examine health-related quality-of-life (HRQOL) before and 7 days after admission. The main study endpoints included time to defervescence and the extent of improvement in HRQOL after treatment initiation. The data were analyzed with Welch's t-test and Fisher's exact test using StatFlex version 6. RESULTS: No significant differences in clinical background characteristics were observed among the patients. The mean time to defervescence in the baloxavir group (median [interquartile range]; 1.0 [1.0-2.0] days) was significantly shorter than that in the laninamivir group (2.0 [1.5-3.5] days; p=0.0322). No significant differences in mean time to defervescence, change in HRQOL, and time for resolution of other symptoms were observed between the groups. CONCLUSION: The results suggest that baloxavir marboxil has a better antipyretic effect than oseltamivir and laninamivir. Moreover, baloxavir marboxil might be clinically more valuable than the other two drugs owing to higher medication adherence among patients.

Prevalence of and Risk Factors for Low Free Testosterone Levels in Japanese Men with Well-controlled Human Immunodeficiency Virus Infection.

BACKGROUND: The change in the prevalence of hypogonadism with age in men with human immunodeficiency virus (HIV) infection is subject to debate. OBJECTIVE: To address this issue, we diagnosed hypogonadism based on serum levels of free testosterone (fTST) rather than total testosterone which is thought to be an inaccurate indicator. We also determined the relationship between age and fTST levels and identified risk factors for hypogonadism in men with HIV infection. METHODS: We retrospectively reviewed fTST levels and associated clinical factors in 71 wellcontrolled HIV-infected men who were treated at Teikyo University Hospital between April 2015 and March 2016 and who had data available on serum fTST levels, measured >6 months after starting antiretroviral therapy. fTST was measured using radioimmunoassay on blood samples collected in the morning. Risk factors for hypogonadism were identified using Welch's t-test and multiple regression analysis. RESULTS: The men had a mean (± standard deviation) age of 47.4 ± 13.6 years, and mean (± standard deviation) serum fTST level of 13.0 ± 6.1 pg/mL. Fifteen (21.1%) men had hypogonadism based on a fTST <8.5 pg/mL. Serum fTST levels significantly decreased with age (-0.216 pg/mL/year). Older age and low hemoglobin levels were identified as risk factors for hypogonadism. CONCLUSION: The men in the study experienced a more rapid decline in fTST levels with age than men in the general population (-0.161 pg/mL/year). Serum fTST levels in men with HIV infection should be monitored, especially in older men and those with low hemoglobin levels.

Characteristics of pneumonia with negative chest radiography in cases confirmed by computed tomography.

Background: Chest radiography is commonly used for diagnosing community-acquired pneumonia (CAP). Computed tomography (CT) is not routinely recommended for initial assessment of CAP patients but is more sensitive and more specific than chest radiography. Objectives: To investigate characteristics of pneumonia with negative chest radiography in cases confirmed by CT. Methods: We included patients diagnosed with CAP in the emergency department, and chest radiography and CT were performed and sputum cultures were collected. The CR- group was defined as patients for whom infiltration of pneumonia was detected only on CT. The CR+ group was defined as patients for whom infiltration was detected on both chest radiography and CT. Data were collected retrospectively from medical records. Results: A total of 138 patients were included, with 58 patients in the CR- group and 80 patients in the CR+ group. Mean age was higher in the CR- group than in the CR+ group, and white blood cell counts and C-reactive protein (CRP) levels were lower in the CR- group than in the CR+ group (8.4 × 103/µL vs 12.4 × 103/µL, p = 0.01; 4.7 mg/dL vs 15.6 mg/dL, p < 0.001, respectively). Laterality of the infiltrated lungs differed between groups (right:left:bilateral = 14:30:14 vs 48:20:12, p = 0.006). Multivariate logistic analysis identified leukocytosis, elevated CRP levels (odds ratio (OR) 3.57, p = 0.003), laterality (OR 2.16, p = 0.006) as predictors of pneumonia in the CR- group. Conclusion: In pneumonia with negative chest radiography in cases confirmed by CT, milder inflammation and infiltration in the left lung tended to be seen.

Exposure to low temperatures suppresses the production of B-cell activating factor via TLR3 in BEAS-2B cells.

Acute viral respiratory tract infections (RTIs) are commonly associated with cold weather; however, the mechanism behind this is still unclear. Secretory IgA (sIgA) mainly contributes to the immune response against pathogenic microorganisms in the respiratory tract. Certain pathogen-associated molecular patterns (PAMPs) induce the expression of B-cell activating factor (BAFF) in epithelial cells, macrophages, and dendritic cells. BAFF transforms B cells into plasma cells, which leads to the mass production of immunoglobulins, including IgA, on the mucosal epithelium. However, no studies have described the relationship between cold exposure and BAFF and/or sIgA in RTI. The aim of our study was to determine this relationship in vitro by investigating the effect of low temperature on BAFF production by BEAS-2B cells after the addition of toll-like receptor (TLR) ligands. We showed stimulation of polyinosinic:polycytidylic acid (poly I:C), which led BEAS-2B to produce interferon (IFN)-ß. IFN-ß itself induced BEAS-2B cells to produce BAFF. Janus kinase inhibitor I decreased the amount of BAFF produced in BEAS-2B cells upon stimulation with IFN-ß and poly I:C. Significantly less BAFF was produced post-poly I:C stimulation in low-temperature conditions than in normal-temperature conditions (mean ± SD: 41.2 ± 23.3 [33 °C] vs. 138.3 ± 7.1 pg/mL [37 °C], P = 0.05). However, the low-temperature condition itself was not cytotoxic. The stimulation of poly I:C produced BAFF from BEAS2B cells via IFN-ß production and the JAK/signal transducer and activator of transcription pathway played an important role in BAFF production in BEAS-2B cells. Cold exposure reduced BAFF production by BEAS2B cells after stimulation with the TLR3 ligand. Cold exposure may, therefore, suppress the production of BAFF, resulting in the inhibition of IgA secretion in the bronchial epithelium, which explains the increased frequency of RTIs in cold weather.

Cerebral blood flow in young and middle-aged people living with HIV.

Purpose: Neurocognitive disorder has been noted as a long-term complication in individuals with HIV. In people living with HIV, regardless of treatment, age-related changes like arteriosclerosis are well-known to be accelerated. Such accelerated aging changes may decrease cerebral blood flow in younger generations with HIV, increasing the rate of occurrence of neurocognitive disorders. We investigated regional cerebral blood flows in well-controlled Japanese people living with HIV under 65 years old to clarify whether age-related changes in regional cerebral blood flows are accelerated in people living with HIV.Method: Japanese male HIV patients >20 years old but <65 years old who visited Teikyo University Hospital between August 2013 and September 2015 were recruited to and enrolled in this study. Healthy coeval male volunteers during the same period were recruited as controls. Magnetic resonance imaging was performed. Twelve regional cerebral blood flows were calculated from pseudocontinuous arterial spine labelling data.Results: Participants in this study comprised 40 individuals with HIV (HIV-positive group) and 33 non-HIV individuals (Control group). Median age was 40.15 years [interquartile range (IQR), 32.80-50.55 years] for the HIV-positive group and 48.00 years [IQR, 37.75-59.25 years; p = 0.3585] for the Control group. No significant differences in regional cerebral blood flows were seen between groups. In the HIV-positive group, cerebral blood flows decreased with age in the neocortex, although no significant decrease was observed in any of the regions in the control group.Conclusions: Significant age-related declines in cerebral blood flows in the neocortex may occur earlier in HIV patients.

Evaluation of a new rapid molecular diagnostic system for Plasmodium falciparum combined with DNA filter paper, loop-mediated isothermal amplification, and melting curve analysis.

Falciparum malaria is a fatal infection without immediate diagnosability or treatment. There are shortages of clinicians and examiners skilled in the treatment of malaria in non-endemic countries, including Japan. This study was performed to evaluate a novel rapid molecular diagnostic system consisting of loop-mediated isothermal amplification (LAMP) combined with DNA filter paper (FTA card) and melting curve analysis. Combining LAMP with melting curve analysis enabled diagnosis of Plasmodium falciparum more accurately with relative ease. FTA cards could be used to clarify problems regarding storage, infectivity, and transportation. The LAMP assay was carried out at a constant temperature of 63 degrees C for 90 min. The diagnostic system (malaria-LAMP) accurately diagnosed malaria (47 samples from Thailand and 50 from Zimbabwe) with 97.8% sensitivity and 85.7% specificity as compared with microscopic methods, indicating the usefulness of this combined system.

[A case of disseminated nocardiosis followed by pneumocystis pneumonia in a patient prescribed corticosteroid and cyclosporin A and having elevated blood (1-->3)-beta-D-glucan].

A 78-year-old man administered prednisolone and cyclosporin A for bullous pemphigoid and found in computed tomography (CT) to have a left-lung nodule was suspected of having a fungal infection due to elevated blood (1-->3)-beta-D-glucan. Despite empirical antifungal therapy, however, the nodule grew, followed by new nodules in both lungs. Disseminated nocardiosis was eventually diagnosed based on sputum, blood, and skin cultures growing Nocardia sp. Antinocardial treatment with imipenem/cilastatin and amikacin was started. The patient then developed pneumocystis pneumonia for which pentamidine was added. He had recovered completely when antimicrobial therapy was completed. A wide variety of microorganisms may infect patients with impaired cellular immunity, simultaneously involving multiple organisms in some cases. Definitive microbiological diagnosis with culture or biopsy specimens is therefore crucial for appropriate management.

Serum Levels of Fibroblast Growth Factor 23 in People Living with HIV.

BACKGROUND: Fibroblast growth factor (FGF) 23 is a well-known phosphaturic hormone produced mainly by bone cells to maintain phosphate and mineral homeostasis. Serum FGF23 levels are elevated in patients with chronic kidney disease (CKD), and elevated FGF23 might increase the risk of cardiovascular disease (CVD). Several reports have documented an increased incidence of risk factors for osteopenia, CKD, and CVD in people living with HIV (PLWH). However, few reports related to FGF23 in PLWH have been published. METHODS: Male HIV patients who presented to the outpatient clinic of Teikyo University Hospital, Tokyo, Japan, in 2015 and were treated with antiretroviral therapy (ART) for > 6 months were enrolled in the study. In addition to serum FGF23 measurements, the clinical factors assessed included age, ART regimens, and laboratory data. Spearman correlation and multiple regression analysis were performed to determine factors significantly associated with FGF23. RESULTS: In total, 67 patients were enrolled in the present study. The median age was 43.7 years, the median CD4 count was 529 cells/µL, and the median serum FGF23 level was 36.0 pg/mL. Based on correlation and multiple regression analyses, serum FGF23 levels were significantly correlated with HIV RNA > 50 copies (correlation analysis: t = 3.4259, P = 0.0011 / multiple regression analysis: P = 0.00106) or abacavir (ABC)/lamivudine (3TC) use (t = 2.8618, P = 0.0057 / P = 0.02704). CONCLUSION: Factors significantly associated with elevated serum FGF23 levels included poor virologic control and ABC/3TC use.

Inhibition of osteoblast differentiation by ritonavir.

Osteoporosis is one of the chronic complications seen in human immunodeficiency virus (HIV)-infected patients, and affects patients at high prevalence. The causes of osteoporosis in HIV-infected patients are multiple, and include chronic HIV infection, living habits such as smoking and alcohol consumption, and antiretroviral drug use. Among antiretroviral drugs, protease inhibitors have been reported to be associated with osteoporosis. However, it remains to be determined how anti-HIV drugs affect osteoblast differentiation. In the current study, MC3T3-E1 cells, a mouse osteoblastic cell line, were cultured in osteoblast differentiation medium with or without different protease inhibitors (ritonavir, lopinavir, darunavir or atazanavir), and alkaline phosphatase (ALP) activity and the expression of Runt-related transcription factor 2 (Runx2) were analyzed. The ALP activity in MC3T3-E1 cells cultured with ritonavir was significantly reduced compared with that in cells in only osteoblast inducer reagent, indicating that ritonavir inhibited osteoblast differentiation. Meanwhile, ALP activity was not reduced in cells cultured with any of the other inhibitors. In addition, ritonavir inhibited the expression of Runx2, a key regulator of osteoblast differentiation, in the early period of osteoblast differentiation. To the best of our knowledge, this is the first study to demonstrate that ritonavir inhibits osteoblast differentiation in vitro. The present findings may explain the mechanism of osteopenia induced by combination antiretroviral therapy involving protease inhibitors.

Chlamydophilal antigens induce foam cell formation via c-Jun NH2-terminal kinase.

Chlamydophila pneumoniae is known to be associated with atherosclerosis. Recent studies have reported that components of Chlamydophila pneumoniae (chlamydophilal antigens) induce foam cell formation in macrophages. However, the mechanism of foam cell formation induced by chlamydophilal antigens has yet to be elucidated. In this paper, we first found that mitogen-activated protein kinases including extracellular signal-regulated kinase, p38 and c-Jun NH2 terminal kinase are phosphorylated after stimulation by chlamydophilal antigens. We then showed that chlamydophilal antigens induce foam cell formation mainly via c-Jun NH2 terminal kinase. Finally, we demonstrated that foam cell formation and phosphorylation of mitogen-activated protein kinases induced by chlamydophilal antigens are mainly recognized through Toll-like receptor 2. These results collectively indicated that chlamydophilal antigens induce foam cell formation mainly via Toll-like receptor 2 and c-Jun NH2 terminal kinase.