Effects of Bedaquiline on Antimicrobial Activity and Cytokine Secretion of Macrophages Infected with Multidrug-Resistant Mycobacterium tuberculosis Strains.

Background: Bedaquiline (Bdq) exerts bactericidal effects against drug-susceptible and drug-resistant Mycobacterium tuberculosis strains, including multidrug-resistant M. tuberculosis strains (MDR-MTBs). However, few reported investigations exist regarding Bdq effects on MDR-MTBs-infected macrophages activities and cytokine secretion. Here, Bdq bactericidal activities against MDR-MTBs and related cellular immune mechanisms were explored. Methods: Macrophages infected with MDR-MTBs or H37Rv received Bdq treatments (4 h/8 h/24 h/48 h) at 1 × the minimum inhibitory concentration (1 × MIC), 10 × MIC and 20 × MIC. Intracellular colony-forming units (CFUs) and culture supernatant IL-12/23 p40, TNF-α, IL-6, and IL-10 were determined using the Luminex® 200TM system. Normally distributed continuous data (mean ± standard deviation) were analyzed using t-test or F-test (SPSS 25.0, P < 0.05 deemed statistically significant). Results: (1) 100% of Bdq-treated macrophages (all doses applied over 4-48 h) survived with 0% inhibition of proliferation observed. (2) Intracellular CFUs of Bdq-treated MDR-MTBs-infected macrophages decreased over 4-48 h of treatment, were lower than preadministration and control CFUs, decreased with increasing Bdq dose, and resembled H37Rv-infected group CFUs (48 h). (3) For MDR-MTBs-infected macrophages (various Bdq doses), IL-12/23 p40 levels resembled preadministration group levels and exceeded controls (4 h); TNF-α levels exceeded preadministration group levels (24 h/48 h) and controls (24 h); IL-12/23 p40 and TNF-α levels resembled H37Rv-infected group levels (4 h/8 h/24 h/48 h); IL-6 levels exceeded preadministration and H37Rv-infected group levels (24 h/48 h) and controls (24 h); IL-10 levels resembled preadministration and H37Rv-infected group levels (4 h/8 h/24 h/48 h) and were lower than controls (24 h/48 h); IL-12/23 p40 and IL-10 levels remained unchanged as intracellular CFUs changed, with IL-12/23 p40 levels exceeding controls (4 h) and IL-10 levels remaining lower than controls (24 h/48 h); TNF-α and IL-6 levels increased as intracellular CFUs decreased (24 h/48 h) and exceed controls (24 h). Conclusion: Bdq was strongly bactericidal against intracellular MDR-MTBs and H37Rv in a time-dependent, concentration-dependent manner. Bdq potentially exerted immunomodulatory effects by inducing high-level Th1 cytokine expression (IL-12/23 p40, TNF-α) and low-level Th2 cytokine expression (IL-10).

Prolonged use of bedaquiline in two patients with pulmonary extensively drug-resistant tuberculosis: Two case reports.

BACKGROUND: Bedaquiline is among the prioritized drugs recommended by the World Health Organization for the treatment of extensively drug-resistant tuberculosis (XDR-TB). Many patients have not achieved better clinical improvement after bedaquiline is stopped at 24 wk. However, there is no recommendation or guideline on bedaquiline administration beyond 24 wk, which is an important consideration when balancing the benefit of prognosis for XDR-TB against the uncertain safety concerning the newer antibiotics. CASE SUMMARY: This paper reported 2 patients with XDR-TB (a female of 58 years of age and a female of 18 years of age) who received bedaquiline for 36 wk, as local experience to be shared. The 2 cases had negative cultures after 24 wk of treatment, but lung imaging was still positive. After discussion among experts, the consensus was made to bedaquiline prolongation by another 12 wk. The 36-wk prolonged use of bedaquiline in both cases achieved a favorable response without increasing the risk of cardiac events or new safety signals. CONCLUSION: Longer regimen, including 36-wk bedaquiline treatment, might be an option for patients with XDR-TB. More studies are needed to explore the effectiveness and safety of prolonged use of bedaquiline for 36 wk vs standard 24 wk in the treatment of multidrug-resistant/XDR-TB or to investigate further the biomarkers and criteria indicative for extension of bedaquline to facilitate clinical use of this novel drug.

Bedaquiline-containing regimens in patients with pulmonary multidrug-resistant tuberculosis in China: focus on the safety.

BACKGROUND: World Health Organization recommends countries introducing new drug and short treatment regimen for drug resistant tuberculosis (DR-TB) should develop and implement a system for active pharmacovigilance that allows for detection, reporting and management of adverse events. The aim of the study is to evaluate the frequency and severity of adverse events (AEs) of bedaquiline-containing regimen in a cohort of Chinese patients with multidrug-resistant (MDR)/extensively drug-resistant (XDR)-TB based on active drug safety monitoring (aDSM) system of New Drug Introduction and Protection Program (NDIP). METHODS: AEs were prospectively collected with demographic, bacteriological, radiological and clinical data from 54 sites throughout China at patient enrollment and during treatment between February, 2018 and December, 2019. This is an interim analysis including patients who are still on treatment and those that have completed treatment. A descriptive analysis was performed on the patients evaluated in the cohort. RESULTS: By December 31, 2019, a total of 1162 patients received bedaquiline-containing anti-TB treatment. Overall, 1563 AEs were reported, 66.9% were classified as minor (Grade 1-2) and 33.1% as serious (Grade 3-5). The median duration of bedaquiline treatment was 167.0 [interquartile range (IQR): 75-169] days. 86 (7.4%) patients received 36-week prolonged treatment with bedaquiline. The incidence of AEs and serious AEs was 47.1% and 7.8%, respectively. The most frequently reported AEs were QT prolongation (24.7%) and hepatotoxicity (16.4%). There were 14 (1.2%) AEs leading to death. Out of patients with available corrected QT interval by Fridericia's formula (QTcF) data, 3.1% (32/1044) experienced a post-baseline QTcF ≥ 500 ms, and 15.7% (132/839) had at least one change of QTcF ≥ 60 ms from baseline. 49 (4.2%) patients had QT prolonged AEs leading to bedaquiline withdrawal. One hundred and ninety patients reported 361 AEs with hepatotoxicity ranking the second with high occurrence. Thirty-four patients reported 43 AEs of hepatic injury referred to bedaquiline, much lower than that referred to protionamide, pyrazinamide and para-aminosalicylic acid individually. CONCLUSIONS: Bedaquiline was generally well-tolerated with few safety concerns in this clinical patient population without any new safety signal identified. The mortality rate was generally low. These data inform significant positive effect to support the WHO recent recommendations for the wide use of bedaquiline.

The Activities and Secretion of Cytokines Caused by Delamanid on Macrophages Infected by Multidrug-Resistant Mycobacterium tuberculosis Strains.

Background: Delamanid (Dlm) is an effective drug against drug-susceptible and drug-resistant Mycobacterium tuberculosis strains, including Multidrug-resistant Mycobacterium tuberculosis (MDR-MTB). There are few reports on the activity and secretion of cytokines caused by Dlm on macrophages infected by MDR-MTB strains. Therefore, this article aims to observe the bactericidal activity and secretion of cytokines of the macrophages infected by MDR-MTB strains after Dlm was administered, so as to provide a basis for further perfecting the mechanism of Dlm. Methods: Samples were respectively collected to count the intracellular colony-forming unit (CFU) of macrophages infected by MDR-MTB or H37Rv strains at 4, 8, 24, and 48 h after Dlm at MIC, 10MIC, and 20MIC were administered. Samples were respectively collected to detect the level of IL-12/23 p40, TNF-α, IL-6, and IL-10 in the culture supernatant of macrophages infected by MDR-MTB or H37Rv strains at 4, 24, and 48 h after Dlm at MIC were administered. The levels of four cytokines in the culture supernatant were measured using the Luminex® 200™ (Luminex, USA) according to the manufacturer's instructions. Data were analyzed by SPSS 25.0 software. The continuous data in normal distribution were expressed as mean ± standard deviation ( x¯ ± s) and analyzed by t or F test. P<0.05 was considered statistically significant. Results: (1) After Dlm was applied to macrophages infected by MDR-MTB strains:(A) The intracellular CFU gradually decreased, reached the lowest value at 48 h, and was lower than that of Dlm before administration and infection group (P<0.05). (B) The intracellular CFU was further reduced after increasing Dlm dose to 10MIC and 20MIC, and the latter was lower than that of the former (P<0.05). (C) The intracellular CFU of MDR-MTB group was higher than that of H37Rv group at 4~48 h after administration (P<0.05). (2) After Dlm at MIC dose was applied to macrophages infected by MDR-MTB strains: (A) The level of IL-12/23 p40 at any time didn't change compared with that of Dlm before administration (P>0.05), while the level of IL-12/23 p40 at 4 h was higher than that of the infection group (P<0.05). The levels of TNF-α at 24 and 48 h were higher than that of Dlm before administration (P<0.05), but were similar to that of the infection group (P>0.05). In addition, the levels of IL-12/23 p40 and TNF-α at any time were similar to that of the H37Rv group after administration (P>0.05). (B) The levels of IL-6 at 24 and 48 h were higher than that of Dlm before administration (P<0.05), but were similar to that of H37Rv group (P>0.05) and were lower than that of infection group (P<0.05). The level of IL-10 at any time didn't change compared with that of Dlm before administration (P>0.05), but was lower than that of the infection group at 4~48 h and was lower than that of the H37Rv group at 24 h (P<0.05). (C) The level of IL-12/23 p40 and IL-10 didn't change with the change of intracellular CFU (P<0.05), while the level of TNF-α and IL-6 increased with the intracellular CFU decreasing, and the increase level of TNF-α was lower than that of the infection group (P<0.05). Conclusions: Dlm had strong bactericidal activity against intracellular MDR-MTB, which was time-dependent and concentration-dependent. Its bactericidal activity against intracellular MDR-MTB strains was weaker than that against drug-susceptible tuberculosis strains. Dlm might have immunomodulatory effect, inducing low expression of Th2 cytokines IL-6 and IL-10 at different times after administration.

The China tuberculosis clinical trials consortium network: a model for international TB clinical trials capacity building.

BACKGROUND: With the second largest tuberculosis (TB) burden globally, China is committed to actively engage in international TB clinical trials to contribute to global TB research. However, lack of research capacity among local sites has been identified as a barrier. MAIN TEXT: The China Tuberculosis Clinical Trials Consortium (CTCTC) was initiated by Beijing Chest Hospital with investment from the US National Institutes of Health and technical support from Family Health International 360 in 2013, as a nationwide collaborative clinical trial network to strengthen selected clinical site research capacity and attract TB clinical trials. The program aims to: 1) recruit leading hospitals that care for TB patients; 2) conduct on-site assessment to identify capacity gaps and needs for improvement; 3) design and deliver capacity building activities; 4) attract and deliver high quality results for TB clinical trials. A total of 24 sites have joined CTCTC, covering 20 provinces in China. Twenty-two sites have been accredited by the National Medical Products Administration (NMPA) to be qualified to conduct TB clinical trials. The onsite assessment, extensive trainings among the CTCTC sites and young investigators have resulted in better understanding and improvement of the site capacity in conducting TB clinical trials. The establishment and growth of the CTCTC network has benefited from the good leadership, effective international cooperation and local commitment. Issues in human resources, regulatory environment and sustainability have been challenging the network from continuing growth. Clinical researchers have full-time clinical responsibilities in China and it is thus important to build a cadre of other human resources to assist. The regulatory environment is becoming friendlier in China to introduce international clinical trials to the CTCTC network. CONCLUSIONS: The CTCTC, with mature management structure and sustainable development model, which are distilled five key lessons for other developing countries or investigators of interest. They are the respectively using assessment-based approach to design tailored training package, understanding the availability of clinical researchers, providing solutions to maintain sustainability, understanding local regulatory environments and working with an international organization with local on-site team, respectively. Although, the experiences and capacity of China's TB hospitals in conducting clinical research vary. Considerable efforts to continue building the capacity are still needed, although the gap is smaller for a few top-tier hospitals.

[A mouse model of myelofibrosis induced by high dose of recombinant human erythropoietin].

Tn order to set up a mouse model of myelofibrosis (MF) induced with high dose recombinant human erythropoietin (rhEPO). 60 mice were collected and divided into EPO and control groups, the former was injected with rhEPO and the latter with normal saline intraperitoneally. 5 mice from each group were executed on day 6, 30, 60, 90, 120 and 150 respectively. Their WBC count, Hb level, MCV, RDW and platelet amount were measured by automatic blood cell analyzer; CD34(+) cell ratio in bone marrow were analyzed by flow cytometry; liver and spleen coefficients were measured; pathological changes of liver, spleen, femur were observed by HE staining and reticular fibers staining; cortex thickness, femoral canal diameter and lumbar spine density were determined by computerized tomography (CT). The results indicated that as compared with normal control group in EPO induced group, WBC count was increased slightly in whole period, but without statistic significance (p > 0.05), Hb level and RDW increased at day 6 and 30 significantly (p < 0.05), MCV increased at day 6 significantly (p < 0.05), but platelet amount decreased significantly at all time points (p < 0.05). Most mice in EPO-induced group had hepatomegalia and their liver and spleen coefficient increased significantly at day 60 (p < 0.05), while most mice had splenomegaly and its coefficient was increased significantly at all time-points (p < 0.05). CD43(+) cell ratio of EPO group increased significantly in whole period (p < 0.05). CT scanning displayed femoral cortical thickening, medulla canal narrowing and lumbar spine density increasing at day 150, meanwhile, HE staining and reticular fiber staining showed the fatty degeneration or vacuolization in liver, splenomegaly with megakaryocytic proliferation, femur bone marrow fibrosis and osteosclerosis. It is concluded that the mouse induced by high dose of rhEPO displays the myelofibrosis associated with splenic extramedullary hemopoiesis, and this study is useful to establish a practical MF model, and to explore its pathological mechanism.

[Analysis of the antimycobacterial activities of rifabutin and the relationship between drug-resistance and rpoB mutations of Mycobacterium tuberculosis].

OBJECTIVE: To compare the antimycobacterial activities of rifampicin (RFP) and rifabutin (RBT), and to evaluate the correlation between RBT resistance and genetic alterations in the rpoB gene. METHODS: The microplate-based alamar blue assay (MABA) method was performed to detect the antimycobacterial activities of RFP and RBT in 168 strains of Mycobacterium tuberculosis (M. tuberculosis). Meanwhile, we also analyzed the 81 bp core region of rpoB gene by DNA sequencing. The rate of gene mutations was analyzed by chi-square test. RESULTS: RBT was sensitive for all of the 66 RFP-sensitive strains with no mutations in 81 bp core region of rpoB gene. But of the 102 RFP-resistant strains, 76 strains were also resistant to RBT. Cross resistance between RFP and RBT was 74.5% (76/102). Alterations at codons 516, 526, 531 in the rpoB gene correlated with resistance to both RFP and RBT. While point mutations at codons 511 and 533 possibly influenced the susceptibility to RFP but not to RBT. The mutation rate (92.1%, 70/76) of rpoB gene of RBT-resistant strains was significantly higher than that (23.9%, 22/92) of RBT-sensitive strains (χ(2) = 78.12, P < 0.05). CONCLUSIONS: RBT was more active against M. tuberculosis as compared to RFP. The RFP-resistant strains with MIC ≤ 4 mg/L were still susceptible to RBT. Our results suggest that analysis of genetic alterations in the rpoB gene is useful for predicting RFP-resistance, and may have implications for evaluating RBT-resistance.

[Intra-bone marrow infusion of human cord blood hematopoietic stem/progenitor cells improves hematopoietic reconstitution in NOD-SCID mice].

The purpose of this study was to explore the effect of intra-bone marrow infusion (iBMI) of cord blood (CB)-derived hematopoietic stem/progenitor cells (HS/PCs) on human hematopoietic reconstitution in xenotransplanted NOD-SCID mouse model. Aliquots containing 5 x 10(5) CB CD34(+) cells were transplanted into sublethally irradiated NOD-SCID mouse via intravenous infusion (iVI) or iBMI routes. 64 female NOD-SCID mice were divided randomly into 3 groups: iBMI group, iVI group and negative control group. The engraftment levels of human hematopoietic cells at 3, 5 and 8 weeks after xenotransplantation were detected by fluorescence-activated cell sorter (FACS), polymerase chain reaction (PCR), immunohistochemistry and HPC colony formation assay, and long-term hematopoietic reconstitution capacity of HSC was tested by secondary transplantation. The results showed that the percentages of human CD45(+) cells in bone marrow, peripheral blood and spleen of recipient in iBMI group at 8 weeks after xenotransplantation were significantly higher than those in iVI group (p < 0.05). HS/PCs given through both iVI and iBMI methods had the ability of multilineage differentiation, the percentages of CD45(+)CD19(+) cells, CD45(+)CD33(+) cells, CD45(+)CD56(+) cells and CD45(+)CD34(+) cells of recipient bone marrow in iBMI group at 8 weeks after xenotransplantation were significantly higher than those in iVI group (p < 0.05), while other lineages in iBMI group were also higher than that in iVI group (p > 0.05). alpha-satellite-specific fragment of human chromosome 17 could be detected by PCR in liver, spleen, lung, peripheral blood and bone marrow cells of long-term survival recipients in both iVI and iBMI groups. Human CD45 antigen could be detected by immunohistochemical method in spleen, liver and lung of recipients in iBMI group at 8 weeks after xenotransplantation. Total colony count in iBMI group at 8 weeks after xenotransplantation was significantly higher than that in iVI group (p < 0.05). alpha-satellite-specific fragment of human chromosome 17 could be detected in all above organs of both group recipients at 6 weeks after secondary xenotransplantation. It is concluded that iBMI of CB CD34(+) cells improves hematopoietic reconstitution in xenotransplanted NOD-SCID mouse model.

[Study on the mechanism of enhancing homing efficiency of human hematopoietic stem/progenitor cells into bone marrow after manipulation with tumor necrosis factor alpha in xenotransplanted BALB/c mouse model].

OBJECTIVE: To investigate the role of tumor necrosis factor (TNF) alpha on the homing efficiency of hematopoietic stem/progenitor cells (HS/PC) into bone marrow and its mechanism. METHODS: CFSE-labeled umbilical cord blood (UCB) CD34+ cells were transplanted into irradiated (control group) or combined with TNF alpha prepared (experimental group) BALB/c recipient mice. The distribution in peripheral blood, liver, lung and homing characteristics in bone marrow and spleen of UCB CD34+ cells, in BALB/c recipient mice were determined 20 hours after xenotransplantation by flow cytometry (FACS) and their homing efficiency was calculated. ELISA was used to measure serum SDF-1 alpha level. CXCR4 expression levels of on UCB CD34+ cells were assessed by FACS pre-/post-manipulation with TNF alpha. SDF-1 alpha expression level in bone marrow and spleen was tested by immunohistochemistry. RESULTS: UCB CD34+ cells mainly home into recipient mice bone marrow and spleen; The homing efficiency in experimental group bone marrow [(0.65 +/- 0.13)%] was significantly higher than that in control ones [(0.30 +/- 0.09)%, P < 0.01], whereas the homing efficiency in experimental group spleen was dramatically lower than that in control ones (P < 0.01); Treatment with TNF alpha did not affect recipient serum SDF-1 alpha level; After 18 hours co-cultured with TNF alpha, the CXCR4e expression level on UCB CD34+ cells was similar to that on fresh ones; TNF alpha treatment induced significantly higher SDF-1 alpha expression on osteoblastic and stromal cells in bone marrow, and reversed spleen SDF-1 alpha gradient that was originally favorable for CD34+ cells homing. CONCLUSION: TNF alpha enhances the homing efficiency of HS/PC via up-regulating SDF-1 alpha gradient in bone marrow, and might be an useful enhancer for HS/PC homing in clinical practice.

[The observation of engraftment of human umbilical cord blood-derived hematopoietic stem/progenitor cells in xenotransplanted NOD/SCID mouse model by intra-bone marrow injection].

OBJECTIVE: To explore whether intra-bone marrow injection strategy could promote the engraftment of human umbilical cord blood derived hematopoietic stem/progenitor cells (HS/PC) in xenotransplanted NOD/SCID mouse model. METHODS: Aliquots containing 1 x 10(3), 1 x 10(4), 0.5 x 10(5), 1 x 10(5) and 5 x 10(5) human umbilical cord blood (hUCB) CD34+ cells were transplanted into sublethally irradiated NOD/SCID mice via intra-venous (i.v.) and intra-bone marrow (iBM) injection. The homing and long-term engraftment capabilities of hUCB CD34+ cells from right tibia, right femur, left tibia, left femur and spleen were detected by PCR 24h after xenotransplantation and by FACS 8-week after xenotransplantation. RESULTS: Tissues of liver, spleen, lungs, or cells from peripheral blood, right tibia, right femur, left tibia and left femur 24 hours after xenotransplantation in iBM injecting 5 x 10(5) CD34+ cells recipients expressed human chromosome 17 specific alpha-satellite fragment. 8-week engraftment of human cells was observed and engraftment level indicated dose-dependent effect in injected bone (right tibia) as well as non-injected bones (including right femur, left tibia and left femur), spleen and peripheral blood in all iBM recipients. 8-week engraftment levels of human cells were (44.063 +/- 20.095)% and (45.881 +/- 22.316)% for i.v. and iBM groups respectively, when transplanted with 1 x 10(5) hUCB CD34+ cells, being no statistical difference (P >0.05). More superior 8-week engraftment levels of human cells were observed in iBM recipients [(54.019 +/- 31.338)%] than in i.v. recipients [(12.197 +/- 10.350)%] when transplanted with 1.0 x 10(4) CD34 cells (P<0.01). Human cell engraftment was observed in iBM but not in i.v. recipients when transplanted with 1.0 x 10(3) CD34+ cells, and was usually observed in non-injected bones. CONCLUSION: Intra-bone marrow strategy can efficiently increase the engraftment of umbilical cord blood derived hematopoietic stem/progenitor cells in xenotransplanted NOD/SCID mouse model.

Ultrastructural characteristics of nucleated cells in bone marrow of patients with acquired aplastic anemia.

The objective of this study was to investigate the ultrastructural characteristics of nucleated cells in the bone marrow of patients with aplastic anemia (AA). This was done by observing the morphology of nucleated cells in bone marrow aspirates from 20 patients with AA by transmission electron microscopy. Erythroblasts were decreased in all cases and not observed in 6 cases. Nuclear abnormalities, such as pyknosis, karyolysis, karyorrhexis, apoptosis, and "Swiss cheese"-like changes, were found in 10 cases. Focal cytoplasmic necrotic changes and cytolysis were found in 3 cases. There were more megaloblasts in 4 cases. Abnormalities of granulocytes were found in 12 out of 18 cases. Megakaryocytes showed focal cytoplasmic necrotic changes. Most monocytes had dendritic features, including excessive cytoplasm, processes, and large round nuclei in all cases. Other monocytes illustrated typical monocytic features with twisted nuclei, plentiful RER, vacuoles, lysosomes, and prominent Golgi apparatus. Macrophages and hemophagocytes occurred in all cases. The incidence of lymphocytes was high in 17 out of 20 cases and occasionally lymphocytes were enlarged in 8 cases. More plasmacytes and plasmacytoid lymphocytes were found in 5 and 3 cases, respectively. The observations suggest that (1) the universal nuclear injury of erythroblasts may be related to the pathogenetic pathway of AA development; (2) the dendritic cells and hemophagocytes from the mononuclear phagocyte system may play a more critical role in hematopoietic failure of AA, directly and/or indirectly; and (3) besides T lymphocytes, increasing numbers of plasmacytes or plasmacytoid lymphocytes are associated with AA in some cases.

Congenital dyserythropoietic anemia in a Chinese family with a mutation of the CDAN1-gene.

Congenital dyserythropoietic anemia I (CDA I) is a well-defined entity within the heterogeneous group of the CDAs. So far, most CDA cases were reported from Europe and Israel. A homozygous mutation of the CDAN1-gene was identified from a founder population observed in Bedouin tribes in Israel, and many different mutations in additional cases from Europe were reported. Few cases of CDA I were presented from Asian regions so far, mostly without convincing data and only one case in which a mutation of the CDAN1-gene was detected. Here, the first Chinese family with the typical hematological phenotype, osseous syndactyly and with a compound heterozygous CDAN1-gene mutation is described. Prevalence data of CDA I from Asian countries are not known, but experiences from Europe suggest that in many families the disorder remains undiagnosed.