Doxycycline-treated Group Research Articles

Possible beneficial effects of nano chitosan against doxycycline toxicity in Nile tilapia (Oreochromis niloticus)

In aquaculture, improper and illogical antibiotic use could yield negative outcomes. Therefore, this study investigates the ameliorative effects of chitosan (CS) and chitosan nanoparticles (CSNPs) against the toxicity of the antibiotic doxycycline in Nile tilapia fish. The fish were divided into four distinct categories: the first group served as the control, the second group was subjected to doxycycline (40 mg/L), the third group experienced doxycycline (40 mg/L) and CS (0.5% in fish diet), and the fourth group was exposed to doxycycline (40 mg/L) with CSNPs (0.5% in fish diet) for 15 days. Levels of creatinine, uric acid, and aspartate aminotransferase activities notably elevated (p < 0.05) in the doxycycline-treated group when compared with the control group. Meanwhile, fish in the doxycycline-exposed group demonstrated significantly lower (p < 0.05) levels of red blood cells, hemoglobin, packed cell volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and neutrophils. Conversely, mean corpuscular volume, platelets, white blood cells, and lymphocytes exhibited notably higher (p < 0.05) levels in the doxycycline group. Other hematological indicators, including monocytes and eosinophils, showed no notable variances (p > 0.05) among the studied groups. Fish treated with doxycycline exhibited notably higher (p < 0.05) interleukin-1β and interleukin-6 activity in comparison to the control group. Additionally, histopathological changes were detected in the gills, liver, and kidney tissues of doxycycline-exposed fish when contrasted with the control group. Co-exposure of CS and CSNPs significantly restored most hematological, biochemical, and immunological parameters, as well as histopathological indices, in the fish, aligning these values closer to those observed in the control group in comparison to the fish treated solely with doxycycline. In conclusion, both CS and CSNPs played an important role in moderating the negative effects of doxycycline on fish, through improving hematological indices, reductions in creatinine, uric acid, and aspartate aminotransferase activity, as well as anti-inflammatory action through reductions in interleukin-1β and interleukin-6 activity.

Abstract PR018: Neuropeptide Y as a metastatic factor

Abstract Although neuropeptide Y (NPY) is known mainly as a sympathetic neurotransmitter, growing evidence indicates its role in tumor biology. Previous studies from our laboratory and other groups suggested associations of high expression of NPY and its Y5 receptor (Y5R) with invasive and metastatic phenotypes of various tumor types; yet the direct evidence for the metastatic activity was lacking. Our recent work began to fill this gap. Using Ewing sarcoma (ES) as a model of NPY-rich tumor, we identified the NPY/Y5R axis as a crucial pathway responsible for hypoxia-induced ES bone metastasis. This osseous dissemination was driven by hypoxia-dependent over-activation of the NPY/Y5R/RhoA pathway, which led to cytokinesis defects and formation of the aneuploid ES cell population with high propensity to bone metastasis. Here, we sought to determine the impact of the Y5R signaling on overall, hypoxia-independent metastatic capabilities of ES cells. To this end, a doxycycline-inducible CRIPSR/Cas9 system was used to knockout Y5R in ES orthotopic xenografts and test its impact on metastasis and cell migration assessed by a transwell assay. The frequency of the NPY5R gene modifications was determined by sequencing and confirmed by immunohistochemistry. FISH was used to identify NPY5R gene gains in ES xenografts. RhoA activity was measured by immunocytochemistry and pull-down assay. As expected, ES/Y5R-sgRNA primary tumors in doxycycline-treated mice consisted of a heterogeneous ES cell population with variable Y5R levels. In contrast, metastases developing from these xenografts were primarily initiated by ES clones with an intact NPY5R gene. The frequency of NPY5R gene modifications in metastases from the doxycycline-treated group was markedly reduced, as compared to the primary tumors. No metastases arising from ES clones lacking intact NPY5R gene were detected. Similarly, metastasis from wild type ES xenografts was associated with a selection of clones with the NPY5R gene gain that was present in a small percent of the parental cells. Subsequent in vitro assays implicated Y5R-dependent ES cell motility driven by the activation of a key cytoskeleton regulator, RhoA, as the mechanism underlying the metastatic effects of NPY. The above results, along with our previously published data, provide direct evidence for the crucial role of the NPY/Y5R axis in metastasis. We have shown that under basal conditions the NPY/Y5R/RhoA axis promotes tumor cell motility and overall cancer cell dissemination, while over-activation of this pathway under hypoxic conditions leads to genomic instability and bone metastasis. While our study focused on ES due to its high endogenous expression of NPY and its receptors, our findings may be relevant to other malignancies rich in NPY and Y5R, such as neuroblastoma, breast and prostate cancer. Given availability of the FDA approved Y5R antagonist, NPY/Y5R pathway may be a promising target for therapies preventing cancer progression. Yet, further research is required to establish effectiveness of such pharmacological interventions. Citation Format: Mina Adnani, Sung-Hyeok Hong, Susana Galli, Akanksha Mahajan, Nouran Abualsaud, Lindsay Caprio, Jason U. Tilan, Olga Rodriguez, Hingkun Wang, Christopher Albanese, Luciane R. Cavalli, Joanna Kitlinska. Neuropeptide Y as a metastatic factor [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr PR018.

Y Chromosome Genes May Play Roles in the Development of Neural Rosettes from Human Embryonic Stem Cells.

The human Y chromosome harbors genes that are mainly involved in the growth, development, sexual dimorphism, and spermatogenesis process. Despite many studies, the function of the male-specific region of the Y chromosome (MSY) awaits further clarification, and a cell-based approach can help in this regard. In this study, we have developed four stable transgenic male embryonic stem cell (ESCs) lines that can overexpress male-specific genes HSFY1, RBMY1A1, RPS4Y1, and SRY. As a proof of principle, we differentiated one of these cell lines (RPS4Y1 over-expressing ESCs) to the neural stem cell (rosette structure) and characterized them based on the expression level of lineage markers. RPS4Y1 expression in the Doxycycline-treated group was significantly higher than control groups at transcript and protein levels. Furthermore, we found Doxycycline-treated group had a higher differentiation efficiency than the untreated control groups. Our results suggest that the RPS4Y1 gene may play a critical role in neurogenesis. Also, the generated transgenic ESC lines can be widely employed in basic and preclinical studies, such as sexual dimorphism of neural and cardiac functions, the development of cancerous and non-cancerous disease models, and drug screening.

Postoperative Doxycycline Did Not Improve Early Postoperative Outcomes in Hip Arthroscopy Patients: A Retrospective Cohort Study

AbstractDoxycycline has been shown to reduce fibroblast activity in the treatment of multiple pathologies, and was utilized as part of the postoperative medication protocol to help prevent adhesions from developing after hip arthroscopy. The purpose of this study was to compare early postoperative pain outcomes between consecutive case series of femoroacetabular impingement syndrome (FAIS) patients treated with or without a 7-day postoperative course of doxycycline following hip arthroscopy. We hypothesized that the doxycycline-treated group would have superior patient-reported outcomes at 6 weeks, and the effect would be more pronounced for patients with low preoperative mental health scores.Our institutional review board–approved prospective outcomes registry was queried for patients who had undergone arthroscopic femoral osteochondroplasty and/or labral repair or reconstruction secondary to FAIS performed by a single, fellowship-trained surgeon. A 7-day postoperative course of doxycycline was initiated in 2018. Six-week postoperative Hip Disability and Osteoarthritis Outcome Score (HOOS) global (HOOSglobal) and International Hip Outcome Tool (iHOT) scores were compared between the consecutive series treated with versus without doxycycline. Additional subgroup analysis was performed on patients with low preoperative Veterans RAND 12-Item Health Survey (VR-12) mental component scores to determine possible additional benefit of postoperative doxycycline in this group.A total of 134 patients (98 female, 36 male, age = 36.2 ± 13.4 years, body mass index [BMI] = 27.2 ± 5 kg/m2) were identified between 2013 and 2020. There were no differences between the control (n = 84) and doxycycline group (n = 50) in age, sex, or BMI. Postoperative HOOSglobal scores (control = 58.5 ± 13.1, doxycycline = 58.7 ± 14.7, p = 0.96) and iHOT scores (control = 54.4 ± 22.2, doxycycline = 52.3 ± 24.8, p = 0.61) did not differ between groups. The subset of 83 patients with low preoperative mental scores showed no differences in HOOSglobal (control = 51.6 ± 13.3, doxycycline = 57.3 ± 7.4, p = 0.12) or iHOT scores (control = 45.5 ± 20.3, doxycycline = 53.6 ± 23.1, p = 0.250).Our results do not support the hypothesis that postoperative doxycycline leads to significant improvement in early postoperative pain scores or functional outcomes in patients undergoing hip arthroscopy for FAIS.

Role of adjunctive therapy with subantimicrobial doses of doxycycline in glycemic control (HbA1c) in patients with diabetes and endo-periodontal lesions to prevent sinus complications.

The present study aimed to analyze local and regional changes in regards to odontogenic sinusitis in subjects with endo-periodontal lesions and diabetes mellitus and to investigate the effect on the level of glycemic control (glycated hemoglobin) that could be generated by adjunctive therapy with subantimicrobial doses of doxycycline. This study was performed on 51 subjects with diabetes who were divided into two therapeutic groups: 31 patients with diabetes (the study group) who underwent conventional endo-periodontal therapy and subantimicrobial doses of doxycycline and 20 patients with diabetes who followed only conventional endo-periodontal therapy (the control group). Patients underwent endodontic and periodontal clinical examination, with retro-dental-alveolar radiographs and CBCT examinations. For each patient, glycated hemoglobin A1c (HbA1c) was determined. This evaluation was performed at the beginning of the study, as well as 3, 6 and 12 months after baseline. A significant percentage of patients, both in the study group and in the control group, showed radiological signs of odontogenic sinusitis, totaling 29 patients (56.86%). Periodontal parameters revealed lower levels in patients who underwent the regimen which consisted of subantimicrobial doses of doxycycline; these results were maintained over the study period. Moreover, we demonstrated significantly reduced glycated hemoglobin levels throughout the study (12 months) in the doxycycline-treated group. This fact has far-reaching effects in the sphere of loco-regional complications as well, and the risk of odontogenic sinusitis can be significantly reduced.

Doxycycline Toxicity in Rats: Clinicobiochemical and Histopathological Studies

Doxycycline (DOX) is one of widely used antibiotics for treatment of different diseases in human and animals. This study aimed to evaluate the toxic effects of DOX on different organs in rats. The experiment was carried out on forty albino rats, they were randomly divided into four equal groups (10/each): Group 1 served as control group, Group 2 received doxycycline hyclate 5 mg/Kg Bwt, Group 3 received doxycycline hyclate 25 mg/Kg Bwt and Group 4 received doxycycline hyclate 50 mg/Kg Bwt. DOX was given intragastrically twice daily (12 hours interval) for 4 weeks. The results revealed a significant increase in serum level of liver enzymes (aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and gamma-glutamyltransferase (GGT)), increased serum total protein, albumin and globulins, elevated serum levels of urea and creatinine, in addition to an increase in cardiac toxicity indicators (lactate dehydrogenase (LDH), and creatine kinase (CK)-MB enzymes and troponin-I). Also, there were significant increase in levels of malondialdehyde (MDA) and significant depletion of reduced glutathione (GSH) content besides various histopathological alterations in liver, kidneys and heart of DOX treated groups.

Clinical assessment of heartworm-infected Beagles treated with a combination of imidacloprid/moxidectin and doxycycline, or untreated.

BackgroundAdministration of moxidectin topically and doxycycline PO has been utilized experimentally as an alternative treatment for heartworm disease. However, clinical effects of this protocol remain poorly characterized.ObjectiveTo evaluate the clinical and postmortem findings associated with administration of doxycycline and monthly 10% imidacloprid + 2.5% moxidectin (IMD + MOX, Advantage Multi/Advocate) to Dirofilaria immitis‐experimentally infected as compared to nontreated control dogs.AnimalsSixteen purpose‐bred, female, Beagle dogs.MethodsProspective, blinded, experimental study. Animals with surgically transplanted adult heartworms were randomized into 2 study groups of equal size: a nontreated control group (n = 8) and an IMD + MOX and doxycycline‐treated group (n = 8). Randomization was performed using a complete block design according to circulating microfilarial concentrations, measured before treatment. Serum biochemical profiles, CBCs, thoracic radiographs and echocardiograms were performed prior to and 3 weeks after transplantation, and monthly for 10 months. Postmortem gross and histopathologic evaluations were performed.ResultsCompared to control animals, mean ± SD serum alanine aminotransferase (181 ± 203 U/L vs 33 ± 7 U/L; P < .0001) and alkaline phosphatase (246 ± 258 U/L vs 58 ± 19 U/L; P < .0001) activities were significantly higher in the treated group on day 28. Radiographic and echocardiographic evidence of heartworm disease was observed in both groups; however, no significant differences in these variables were noted between groups. Mean ± SD pulmonary arterial thrombus score was significantly higher in the treated vs nontreated group (3.9 ± 0.4 and 1.5 ± 2.1, respectively; P = .01).Conclusions and Clinical ImportanceThe treatment protocol was well‐tolerated with no clinically relevant adverse effects for any variable evaluated during the observational period.

Doxycycline: An antibiotic with brain protective function in vanadium-intoxicated rats

Abstract Background: Exposure to vanadium exhibits deleterious neurotoxicity. Doxycycline is a potential antioxidant that prevents the progression of disease through inhibition of lipid peroxidation. Objectives: This research investigates the neuroprotective effects of doxycycline, in different rat brain areas in an animal model intoxicated with vanadium. Materials and Methods: Male Sprague-Dawley rats were equally divided into the following four groups: control group, doxycycline-treated group, vanadium-treated group, and concomitant doses of doxycycline plus vanadium-treated group, all given orally for 10 consecutive days. The animals were watched daily for any signs of neurological defects. They were sacrificed by decapitation 24 h after the last dose. Brain was removed rapidly and dissected into cerebral cortex, cerebellum, and brain stem. Biochemical studies including the concentrations of phospholipids, cholesterol, cerebrosides, glutathione (GSH), acetylcholinesterase (AChE) activity, gangliosides, ascorbic acid, calcium, and lipid peroxidation levels were determined. Results: The results revealed that vanadium produced significant reduction in body and absolute brain weight, with neurological function deficits. Vanadium significantly decreased the concentrations of phospholipids, cholesterol, cerebrosides, and GSH and inhibited AChE activity together with significant increase in gangliosides, ascorbic acid, calcium, and lipid peroxidation levels compared to saline controls. Animals which were given the combined treatment of vanadium and doxycycline regained weight and became normal. Moreover, doxycycline reversed the effect of vanadium on the metabolic variables and inhibited lipid peroxidation nearing to normal levels to that of saline controls. Conclusion: These findings demonstrated the antioxidant or chelating action of doxycycline against vanadium neurotoxicity and its therapeutic potential to avert neurodegenerative changes in different rat brain areas.

Matrix Metalloproteinase Inhibition With Doxycycline Affects the Progression of Posttraumatic Osteoarthritis After Anterior Cruciate Ligament Rupture: Evaluation in a New Nonsurgical Murine ACL Rupture Model

Background: Doxycycline has broad-spectrum activity as a matrix metalloproteinase (MMP) inhibitor and thus could reduce the progression of posttraumatic osteoarthritis (PTOA) after anterior cruciate ligament (ACL) rupture. Hypothesis: Doxycycline would inhibit progression of PTOA in a murine ACL rupture model. Study Design: Controlled laboratory study. Methods: For the in vitro study, cadaveric C57BL/6 male mice knees (N = 108) were used for the development of a nonsurgical ACL rupture model. For the in vivo study, 24 C57BL/6 male mice then underwent ACL rupture with our manual procedure and were divided into 4 groups: untreated control; doxycycline, 10 mg/kg/d; doxycycline, 50 mg/kg/d; and doxycycline, 100 mg/kg/d. Doxycycline was administered in drinking water beginning immediately after ACL rupture. Radiographic imaging and paw prints were evaluated at 3, 7, 14, and 28 days. The foot length and toe spread were analyzed as measures of function. Histology and MMP-13 immunohistochemistry were done at 4 weeks. Results: Radiographs demonstrated anterior tibial subluxation and meniscal extrusion after ACL rupture, confirming knee joint instability without fractures. Statistically significant differences in gait were found between the intact and experimental groups. Histologic examination demonstrated cartilage damage, meniscal tears, and mild osteoarthritis after ACL rupture, similar to what occurs in human patients. Hypertrophy of the posterior horn of the medial and lateral meniscus was found, and tears of the posterior horn of the menisci were common. All doxycycline groups had a lower score than the untreated control group, indicating less cartilage damage. The posterior tibia of the untreated group had the most cartilage damage as compared with the 3 doxycycline groups, with a significant difference between the untreated and 50-mg/kg/d doxycycline groups, suggesting that the latter dose may protect against proteoglycan loss and decrease the progression of osteoarthritis. The nondoxycycline group had the highest synovial inflammation score among all groups, indicating that doxycycline has an inhibitory effect on synovitis. There was significantly lower MMP-13 expression on the tibia in the doxycycline-treated groups, with a positive correlation between doxycycline concentration and MMP-13 inhibition. Conclusion: Modulation of MMP-13 activity by doxycycline treatment may offer a novel biological pathway to decrease the progression of PTOA after ACL rupture. Clinical Relevance: Doxycycline is an approved, readily available drug with infrequent side effects of photosensitivity and gastrointestinal symptoms. Future clinical trials could evaluate doxycycline to reduce or prevent progressive cartilage damage after ACL rupture.

Efficacy and side effects of doxycycline versus minocycline in the three-dose melarsomine canine adulticidal heartworm treatment protocol

BackgroundThe American Heartworm Society currently recommends the use of a monthly macrocyclic lactone, a 28-day course of 10 mg/kg doxycycline BID, and the 3-dose protocol of melarsomine dihydrochloride for the treatment of canine heartworm disease. Doxycycline is necessary for the reduction of the bacterium Wolbachia, found in all heartworm life-stages. Previous price increases and decreasing availability prompted us to evaluate alternative tetracycline antibiotics, i.e. minocycline, for the reduction of Wolbachia during canine heartworm treatment.MethodsThirty-two heartworm-positive dogs were randomized to receive 10 mg/kg or 5 mg/kg of either doxycycline or minocycline for 28 days BID, for a total of 8 dogs per experimental group. All dogs received 6 months of Heartgard Plus® (ivermectin/pyrantel) and the 3-dose protocol of 2.5 mg/kg melarsomine dihydrochloride. Blood samples were collected prior to the initiation of treatment, every 7 days throughout tetracycline treatment, and then monthly thereafter until the dog tested negative for the presence of heartworm antigen. DNA was isolated from circulating microfilarial samples and qPCR was performed on each sample.ResultsA greater number of dogs in the 10 mg/kg doxycycline and minocycline treated groups experienced gastrointestinal side effects as compared to the 5 mg/kg doxycycline and minocycline treated groups. All eight dogs in the 10 mg/kg doxycycline-treated group tested negative for the presence of Wolbachia DNA by 28 days post-tetracycline treatment. A total of two dogs in both the 5 mg/kg doxycycline- and 10 mg/kg minocycline-treated groups and three dogs in the 5 mg/kg minocycline-treated group remained positive for the presence of Wolbachia DNA by the end of tetracycline treatment.ConclusionsNo lung pathology was assessed in this clinical trial, therefore the clinical effect of the remaining Wolbachia DNA in the 10 mg/kg minocycline-, 5 mg/kg doxycycline- and 5 mg/kg minocycline-treated groups cannot be determined. Owner compliance in the proper administration of these tetracyclines may be impacted by the increased severe gastrointestinal side effects reported for the 10 mg/kg doxycycline- and minocycline-treated groups. We recommend that veterinarians prescribe the recommended 10 mg/kg doxycycline for canine heartworm treatment and reduce the dosage to 5 mg/kg in cases of severe gastrointestinal side effects in order to improve owner compliance in administration of medications.

Effect of Subgingival Doxycycline Placement on Clinical and Microbiological Parameters in Inflammatory Periodontal Disease: Bothin Vivoandin VitroStudies

To eva luate the effect of subgingival placement of doxycy-cline in the form of a resorbable membrane on the clinical and microbiological parameters in the treatment of inflammatory periodontal disease. Material and methods; We evaluated the effects of a controlled release system containing doxycycline both in vivo and in vitro conditions. Drug systems were prepared for both, and a total of 19 patients were included in the study with age range from 35 to 50 years. Clinical parameters like gingival index, probing depth, attachment loss, and gingival shrinkage were evaluated along with microbiological evaluation as well for a period of 10 weeks. In vitro study showed that the doxycycline hydroxy-propyl methylcellulose films are capable of releasing the drug in a sustained way with respect to time. It was observed that the gingival index score, periodontal probing depth, and gingival shrinkage showed low levels at the doxycycline-treated sites as compared to the placebo group. The microbial culture results also showed a marked reduction in the total anaerobic count post-treatment and till the end of the 10 week study period in the doxycycline-treated group. Thus, overall results showed that 30% doxycycline methylcellulose strips have significant effects and benefits on clinical and microbial parameters in more than 5 mm deep periodontal pockets. We conclude that 30% doxycycline both in vivo and vitro study has proven to be an effective antibiotic of choice both clinically and microbiologically. Doxycycline has proven to have great promise as an antibiotic of choice. Thus, there is a significant advantage in the clinical use of doxycycline formulation for both the therapist and the patient. It can help dental professionals as an additional means to maintain an improved clinical health in periodontal problems of their patients. With this new therapeutic modality, we can augment the ability to treat periodontitis more effectively.

In Vitro Activity of Tigecycline Against Orientia tsutsugamushi.

Scrub typhus is a zoonosis caused by Orientia tsutsugamushi (O. tsutsugamushi) occurring mainly in autumn in Korea. The need of new antibiotics has arisen with a report on strains resistant to antibiotics and chronic infection. This study aims to identify susceptibility of tigecycline in-vitro as a new therapeutic option for O. tsutsugamushi. Antibacterial activity of tigecycline against the O. tsutsugamushi was compared with doxycycline using flow cytometry assay. The inhibitory concentration 50 (IC50) was 3.59×10-3 µg/mL in doxycycline-treated group. Whereas in 0.71×10-3 µg/mL tigecycline-treated group. These findings indicate that tigecycline may be a therapeutic option for the treatment of scrub typhus.

Dengue Patients Treated with Doxycycline Showed Lower Mortality Associated to a Reduction in IL-6 and TNF Levels.

To determine the effect of doxycycline treatment on cytokine levels, including tumor necrosis factor (TNF) and interleukin 6 (IL-6), and mortality in dengue patients at high risk of complication. A group of dengue hemorrhagic fever patients (n=231) were randomized to receive either standard supportive care or supportive care in addition to oral doxycycline twice daily for 7 days. Dengue virus infection was confirmed by PCR using multiple primers. Serum samples were obtained at days 0, 3, 5 and 7 and tested for levels of TNF and IL-6. Doxycycline-treated group presented a 46% lower mortality than that observed in the untreated group (11.2% [13/116] vs 20.9% [24/115], respectively, p=0.05). Moreover, administration of doxycycline resulted in a significant (p<0.01) decrease in levels of TNF and IL-6 versus controls in the tests performed during follow-up (day 3, 5 and 7). Patients who died in both groups possessed significantly (p<0.01) higher levels of TNF and IL-6 compared to those who survived at all-time points. The above findings suggest that doxycycline can provide a clinical benefit to dengue patients at high risk of complications. This effect could be mediated by decreasing pro-inflammatory cytokine levels.

Doxycycline Leads to Sterility and Enhanced Killing of Female Onchocerca volvulus Worms in an Area With Persistent Microfilaridermia After Repeated Ivermectin Treatment: A Randomized, Placebo-Controlled, Double-Blind Trial.

Ivermectin (IVM) has been the drug of choice for the treatment of onchocerciasis. However, there have been reports of persistent microfilaridermia in individuals from an endemic area in Ghana after many rounds of IVM, raising concerns of suboptimal response or even the emergence of drug resistance. Because it is considered risky to continue relying only on IVM to combat this phenomenon, we assessed the effect of targeting the Onchocerca volvulus Wolbachia endosymbionts with doxycycline for these individuals with suboptimal response. One hundred sixty-seven patients, most of them with multiple rounds of IVM, were recruited in areas with IVM suboptimal response and treated with 100 mg/day doxycycline for 6 weeks. Three and 12 months after doxycycline treatment, patients took part in standard IVM treatment. At 20 months after treatment, 80% of living female worms from the placebo group were Wolbachia positive, whereas only 5.1% in the doxycycline-treated group contained bacteria. Consistent with interruption of embryogenesis, none of the nodules removed from doxycycline-treated patients contained microfilariae, and 97% of those patients were without microfilaridermia, in contrast to placebo patients who remained at pretreatment levels (P < .001). Moreover, a significantly enhanced number of dead worms were observed after doxycycline. Targeting the Wolbachia in O. volvulus is effective in clearing microfilariae in the skin of onchocerciasis patients with persistent microfilaridermia and in enhanced killing of adult worms after repeated standard IVM treatment. Strategies can now be developed that include doxycycline to control onchocerciasis in areas where infections persist despite the frequent use of IVM. ISRCTN 66649839.

Effect of probiotics on doxycycline disposition in gastro-intestinal tract of poultry

Poultry feed is often supplemented with probiotics in order to improve disease resistance and growth performance and to decrease undesirable effects of antibacterial therapy. Therefore this study was designed to evaluate the effect of probiotics such as Lactobacillus brevis, L. plantarum and L. bulgaricus on pharmacokinetics of doxycycline in healthy DUC broiler chickens. The treatment with doxycycline at a dose of 10 mg/kg body weight started on the 15 day after hatching for 5 days via drinking water. The probiotics treated group received Lactobacillus strains for 15 days, 5 days after hatching. Treatment with probiotics did not lead to statistically significant differences in serum concentrations of doxycycline between both groups of chickens. The value of Cmax was significantly higher in the liver of doxycycline + probiotics treated chickens (1.47 μg/mL) than in doxycycline-treated group (1.28 μg/mL). The same tendency was observed in the duodenum and jejunum of both groups of animals suggesting favourable results in the cure of bacterial diseases of the gastrointestinal tract of poultry.The selected dose was appropriate for treatment of infections caused by pathogens with MIC < 0.25 μg/mL irrespective of antibiotic administration alone or in combination with probiotics. The simultaneous treatment of chickens with probiotics and doxycycline did not entail changes in the dose regime of the antibiotic.

CHARACTERIZATION OF THK5117 BINDING IN AD BRAIN TISSUE: IMPLICATION FOR DEVELOPMENT OF PET TAU IMAGING

Background: Averting and clearing the aberrant accumulation of tau proteins in neurofibrillary tangles is the current focus of therapeutic strategies in Alzheimer’s disease (AD).New approaches for direct targeting of tau demand safe, non-invasive methods to detect and quantify tau in vivo [1, 2]. To assess tau progression together with the induced brain pathology, we longitudinally applied MRI on a conditional bigenic mouse model of tauopathy, rTg4510, in which tau expression can be supressedwith doxycycline [3].We investigated four, clinically relevant, quantitative techniques: cerebral blood flow (CBF) using arterial spin labelling (ASL); aggregated protein detection using amide proton transfer (APT); microstructural diffusion using diffusion tensor imaging (DTI), which were compared with the established gold standard structural MRI. Methods: 19 rTg4510, and 8 wild-type(WT) littermatched mice were imaged at baseline (4.5 months) using a 9.4T scanner for ASL, DTI, APT and structural data using parameters previously described [4,5]. 10 rTg4510 were then treated orally with doxycycline hyclate (10mg/kg) and maintained on a doxycycline diet for the remainder of the study to supress tau expression. The doxycycline-treated rTg4510, untreated rTg4510 and WT groups were imaged again at 5.5 and 7.5 months for longitudinal ASL, DTI, APTand structural data. During imaging, anaesthesia was maintained using 1.5-2% isoflurane and 1L/min O 2. Results:At 4.5 months, prior to doxycycline treatment, we observed marked changes in CBF, ATP and diffusion in rTg4510s due to increased tau pathology in comparison toWT controls. This was most apparent in the CBF study. Following only one month of treatment to supress tau, (imaging at 5.5 months), CBF had returned to control levels. This pattern was also observed for APT and diffusion imaging and the trend continued through to 7.5 months. Conclusions: This study demonstrates the sensitivity of multi-parametric MRI to the regulation of tau-driven pathological processes and provides an opportunity to assess novel therapeutic strategies. These approaches could give insights into the early onset of tauopathies, at a time when non-invasive imaging biomarkers are urgently needed for understanding the progressive pathology. This is the first demonstration that suppression of tau expression can be observed with the clinically relevant MRI parameters CBF, ATP and diffusion.

Doxycycline administration improves fascial interface in hernia repair

BackgroundDespite improvements in ventral hernia repair techniques, their recurrence rates are unacceptably high. Increased levels of matrix metalloproteinases (MMPs) and reduced collagen-1 to -3 ratios are implicated in incisional hernia formation. We have recently shown doxycycline treatment for 4 wk after hernia repair reduced MMP levels, significantly increased collagen-1 to -3 ratios, and increased tensile strength of repaired interface fascia. However, this increase was not statistically significant. In this study, we extended treatment duration to determine whether this would impact the tensile strength of the repaired interface fascia. Materials and methodsThirty-two male Sprague–Dawley rats underwent incision hernia creation and subsequent repair with polypropylene mesh. The animals received either saline (n = 16) or doxycycline (n = 16) beginning from 1 day before hernia repair until the end of survival time of 6 wk (n = 16) or 12 wk (n = 16). Tissue samples were investigated for MMPs and collagen subtypes using Western blot procedures, and tensiometric analysis was performed. ResultsAt both 6 and 12 wk after hernia repair, the tensiometric strength of doxycycline-treated mesh to fascia interface (MFI) tissue showed a statistically significant increase when compared with untreated control MFI. In both groups, collagen-1, -2, and -3 ratios were remarkably increased in doxycycline-treated MFI. At 6 wk, the doxycycline-treated MFI group showed a significant decrease in MMP-2, an increase in MMP-3, and no change in MMP-9. At 12 wk, MMP-9 showed a remarkable reduction, whereas MMP-2 and -3 protein levels increased in the doxycycline-treated MFI group. ConclusionsDoxycycline administration results in significantly improved strength of repaired fascial interface tissue along with a remarkable increase in collagen-1, -2, and -3 ratios.

Therapeutic effects of topical doxycycline in a benzalkonium chloride-induced mouse dry eye model.

We investigated the therapeutic effects and underlying mechanisms of topical doxycycline in a benzalkonium chloride (BAC)-induced mouse dry eye model. Eye drops containing 0.025%, 0.1% doxycycline or solvent were administered to a BAC-induced dry eye model four times daily. The clinical evaluations, including tear break-up time (BUT), fluorescein staining, inflammatory index, and tear volume, were performed on days 0, 1, 4, 7, and 10. Global specimens were collected on day 10 and processed for immunofluorescent staining, TUNEL, and periodic acid-Schiff assay. The levels of inflammatory mediators in the corneas were determined by real-time PCR. The total and phosphorylated nuclear factor-κB (NF-κB) were detected by Western blot. Both 0.025% and 0.1% doxycycline treatments resulted in increased BUT, lower fluorescein staining scores, and inflammatory index on days 4, 7, and 10, while no significant change in tear volume was observed. The 0.1% doxycycline-treated group showed more improvements in decreasing fluorescein staining scores, increasing Ki-67-positive cells, and decreasing TUNEL- and keratin-10-positive cells than other groups. The mucin-filled goblet cells in conjunctivas were increased, and the expression of CD11b and levels of matrix metalloproteinase-9, IL-1β, IL-6, TNF-α, macrophage inflammatory protein-2, and cytokine-induced neutrophil chemoattractant in corneas were decreased in both doxycycline-treated groups. In addition, doxycycline significantly reduced the phosphorylation of NF-κB activated in the BAC-treated corneas. Topical doxycycline showed clinical improvements and alleviated ocular surface inflammation on BAC-induced mouse dry eye, suggesting a potential as an anti-inflammatory agent in the clinical treatment of dry eye.

In vivo screening of five phytochemicals/extracts and a fungal immunomodulatory protein against colibacillosis in broilers

Five phytochemicals/extracts (an extract from Echinacea purpurea, a β-glucan-rich extract from Shiitake, betaine [Betain™], curcumin from Curcuma longa [turmeric] powder, carvacrol and also a recombinant fungal immunomodulatory protein [FIP] from Ganoderma lucidum) cloned and expressed in Escherichia coli were investigated for their anticolibacillosis potential in three chicken experiments, which were conducted in floor pens. Birds that were inoculated with E. coli intratracheally were treated with the phytochemicals/extracts or the FIP and compared with doxycycline-medicated and non-medicated infected broilers. Non-medicated and non-infected birds were used as negative controls. Mortality, colibacillosis lesions and body weight gains were used as parameters. Considering the sum of dead birds and chickens with generalized colibacillosis per group, there was no significant difference between the positive control groups and birds treated with phytochemicals/extracts or the FIP. In contrast, doxycycline-treated birds showed significantly lower mortality and generalized colibacillosis. Moreover, none of the phytochemicals/extracts and the FIP improved recovery from colibacillosis lesions, while all doxycycline-treated broilers recovered completely. The negative control birds and doxycycline-treated groups consistently showed the highest weight gains. Pulsed-field gel electrophoresis of reisolates showed that they were genetically indistinguishable from the inoculation strain. In conclusion, none of the tested phytochemicals/extracts and the FIP significantly reduced the E. coli-induced mortality and generalized colibacillosis, and nor did they improve recovery from colibacillosis lesions.

Abstract 3205: In vivo oncology target screening using a lentiviral inducible- shRNA knockdown system.

Abstract Background: Small RNAs are able to suppress expression of any gene through the endogenous RNA interference pathway and have been used to identify therapeutic targets in a variety of pathological conditions. In this project, we aimed to optimise a lentiviral inducible-knockdown small hairpin RNA (shRNA) system for efficient in vivo cancer target validation, using polo-like kinase 1 (PLK1), an essential cell-cycle protein, as a proof-of-concept target. Methods: An inducible shRNA construct targeting PLK1 or a control construct was transduced into the colon carcinoma cell line SW620. Inducible shRNA expression (marked by turbo-RFP) was monitored by fluorescence microscopy and flow cytometry in vitro and by spectrum CT in vivo. PLK1 gene expression was quantified by real-time PCR and protein expression was quantified by Western blotting in vitro or IHC ex vivo. Cell viability was assessed by MTT assays. Xenografts were established by subcutaneous injection of PLK1 inducible-knockdown cells into nude mice. Growth inhibitory effect was assessed by calliper measurement of tumour size and correlated with ex vivo assessment of gene and protein knockdown, and of cell proliferation as measured by Ki67 staining. Results: Cell viability assays demonstrated that concentrations of 2ug/ml of doxycycline or less did not result in cell death over an assay period of 7 days in both wild-type cells and cells transduced with a control shRNA construct. Following doxycycline treatment, PLK1 inducible-knockdown cells showed dose- and time-dependent shRNA induction with an increase in the level of shRNA expression and the percentage of positive cells. PLK1 down-regulation correlated with induction of shRNA expression reaching 80% gene knock-down and 60% protein knock-down 72 hours post-induction. The optimal delivery route of doxycycline via measurement of turbo-RFP induction and PK/PD measurements was assessed in vivo. In tumour-bearing mice treated with doxycycline, there was a decline in tumour growth rate in the PLK1 knockdown group compared with the control group. Ex vivo analysis showed significantly lower PLK1 gene and protein expression in the doxycycline-treated group compared with the control group which correlated with lower rates of cell proliferation in the treated group. Conclusion: The results support the anti-tumour effects of PLK1 down-regulation and confirm an efficient target validation methodology for cancer target screening using a lentiviral inducible-knockdown shRNA system. Citation Format: Yinfei Yin, Rajendra Kumari, Siddharth Subramaniam, Peter King, Sue Watson, Philip Mallinder, Anna Grabowska. In vivo oncology target screening using a lentiviral inducible- shRNA knockdown system. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3205. doi:10.1158/1538-7445.AM2013-3205