Effect of antibiotics on the generation of reactive oxygen species

Forget me not: The effect of doxycycline on human declarative memory

Investigations into neuroprotective drugs are in high demand for the treatment of neurodegenerative diseases, such as multiple sclerosis or Alzheimer's disease, but also psychiatric disorders, such as depression, trauma, and substance use. One potential drug class being investigated are tetracyclines impacting on a variety of neuroprotective mechanisms. At the same time, tetracyclines like doxycycline have been suggested to affect human fear and spatial memory as well as reducing declarative memory retention. Based on the assumed necessity for synaptic consolidation in hippocampus-dependent learning, we hypothesised declarative memory may be similarly impaired by doxycycline as fear and spatial memory. Therefore, in this study we investigate the potential diminishing effects of doxycycline on consolidation of declarative memory in healthy humans. Additionally, to test for effect specificity we assessed motor memory, sustained attention, and processing speed. We administered a neuropsychological test battery in three independent randomized placebo-controlled double-blind trials (RCTs), in which healthy young volunteers (total N = 252) either received a single oral dose doxycycline (200 mg, n = 126) or placebo (n = 126) in a between-subject design. We found no evidence for a detrimental effect of doxycycline on declarative memory; instead, doxycycline improved declarative learning (p-value=0.022, Cohen's d=0.15) and memory consolidation (p=0.040, d=0.26). Contrarily, doxycycline slightly reduced motor learning (p=0.001, d=0.10) but subtly strengthened long-term motor memory (p=0.001, d=0.10). These results suggest that doxycycline can improve declarative learning and memory without having long term negative effects on other cognitive domains in healthy humans. Our results give hope to further investigate doxycycline in neuroprotective treatment applications.

Neomycin inhibits Megalocytivirus infection in fish by antagonizing the increase of intracellular reduced glutathione

Infectious spleen and kidney necrosis virus (ISKNV) is the type species of the Megalocytivirus genus that infects a number of marine and freshwater fishes, causing huge economic losses in aquaculture. The ISKNV infection leads to increase of reducing power in cells. As the antibiotic neomycin can promote the production of reactive oxygen species (ROS) in animal cells, in the current study, the potential therapeutic effect of neomycin on ISKNV infection was explored. We showed that neomycin could decrease the reducing power in cultured MFF-1 cells and inhibit ISKNV infection by antagonizing the shift of the cellular redox balance toward reduction. In vivo experiments further demonstrated that neomycin treatment significantly suppresses ISKNV infection in mandarin fish. Expression of the major capsid protein (MCP) and the proportion of infected cells in tissues were down-regulated after neomycin treatment. Furthermore, neomycin showed complex effects on expression of a set of antiviral related genes of the host. Taking together, the current study suggested that the viral-induced redox imbalance in the infected cells could be used as a target for suppressing ISKNV infection. Neomycin can be potentially utilized for therapeutic treatment of Megalocytivirus diseases by antagonizing intracellular redox changes.

A Randomized, Controlled Trial of Intense Pulsed Light in combination with Minocycline Hydrochloride for the Treatment of Inflammatory Acne Vulgaris

BACKGROUND

It has been a long-term debate over the concomitant treatment of inflammatory acne vulgaris using Intense Pulsed Light (IPL) and minocycline due to the photosensitivity of minocycline.

OBJECTIVE

We aimed to evaluate the safety and efficiency of IPL combined with minocycline in treating acne vulgaris in a randomized trial.

METHODS

A total of 40 patients were enrolled and randomly assigned into two groups which were either given minocycline (100 mg per day) for 8 weeks with IPL treatments for three times at the weeks of 0, 4, and 8, or the same dosage of minocycline only. The evaluations for inflammatory lesion count, Investigator Global Assessment of Acne (IGA), erythema and purpura indexes were taken before treatment and at the weeks of 4, 8, and 16.

RESULTS

There were significant improvements in inflammatory lesion count, IGA scores, and purpura index in both groups as compared with the baseline at the week of 16 (p < 0.02). The concomitant therapy, but not minocycline only, significantly improved erythema index (p=0.40) at the 16^th week as compared with the baseline. The group with combined treatment showed significantly continuous improvements in inflammatory lesion counts (p < 0.04) and IGA scores (p ≤ 0.02) at the week of 4, 8, and 16 as compared with the group given by minocycline only. No severe adverse effects were observed during the trial.

CONCLUSION

IPL in combination with minocycline shows a better clinical efficacy for treatment of inflammatory acne vulgaris than minocycline alone, and it is safe.

What Are Reactive Oxygen Species, Free Radicals, and Oxidative Stress in Skin Diseases?

Oxygen in the atmosphere is a crucial component for life-sustaining aerobic respiration in humans. Approximately 95% of oxygen is consumed as energy and ultimately becomes water; however, the remaining 5% produces metabolites called activated oxygen or reactive oxygen species (ROS), which are extremely reactive. Skin, the largest organ in the human body, is exposed to air pollutants, including diesel exhaust fumes, ultraviolet rays, food, xenobiotics, drugs, and cosmetics, which promote the production of ROS. ROS exacerbate skin aging and inflammation, but also function as regulators of homeostasis in the human body, including epidermal keratinocyte proliferation. Although ROS have been implicated in various skin diseases, the underlying mechanisms have not yet been elucidated. Current knowledge on ROS-related and oxidative stress-related skin diseases from basic research to clinical treatment strategies are discussed herein. This information may be applied to the future treatment of skin diseases through the individual targeting of the ROS generated in each case via their inhibition, capture, or regulation.

A case of orofacial granulomatosis evolving into Melkersson Rosenthal syndrome in a child treated with a steroid free regimen of Clofazimine and Minocycline

Orofacial granulomatosis (OFG) is a rare disorder with varied etiological, immunological and infectious mechanisms implicated and is believed to be a umbrella term which includes Melkersson Rosethal syndrome (MRS). We describe a 17 year old female who was diagnosed with OFG and was successfully treated with a combination of minocycline and clofazimine without oral steroids with significant improvement within 1 month of therapy.

Similarity and difference between palmoplantar pustulosis and pustular psoriasis

Palmoplantar pustulosis is a chronic inflammatory disorder characterized by sterile pustules predominantly involving the palms and soles. Palmoplantar pustulosis has many similar aspects to psoriasis, either plaque and pustular type, namely familial occurrence between palmoplantar pustulosis and psoriasis, the appearance of the Köbner phenomenon, joint involvement, and nail involvement. Pustular psoriasis is classified into generalized and localized types, and there are a number of papers regarding palmoplantar pustulosis as an acral variant of localized pustular psoriasis. Many Japanese dermatologists consider palmoplantar pustulosis to be a distinct entity from pustular psoriasis, and the coexistence of palmoplantar pustulosis and psoriasis is rare. However, outside Japan, palmoplantar pustulosis is often considered to be palmoplantar psoriasis or palmoplantar pustular psoriasis, and extra-palmoplantar lesions are also considered to be psoriasis. The purpose of the current review is to compare the similarities and differences between palmoplantar pustulosis and generalized/localized pustular psoriasis. Japanese patients with palmoplantar pustulosis have a close relationship with focal infection, and the associated bone-joint manifestation exclusively involves the anterior chest wall. Furthermore, pediatric occurrence of palmoplantar pustulosis is extremely rare, and difference of genetic background between palmoplantar pustulosis and psoriasis has also been reported. Treatment of focal infection often results in dramatic effects on both cutaneous lesions and joint pain of palmoplantar pustulosis. Those findings suggest that palmoplantar pustulosis should be separately considered from either palmoplantar psoriasis or palmoplantar pustular psoriasis. The clinicopathological features and therapeutic approach of both diseases are discussed.

Identifying bioaccessible suspect toxicants in sediment using adverse outcome pathway directed analysis

Chemical mixtures are a common occurrence in contaminated sediment and determining causal relationship between sediment contamination and adverse outcomes is challenging. The bioavailability and choice of bioassay endpoints played important roles in elucidating causality. As such, bioaccessibility-based XAD extraction and adverse outcome pathway (AOP) guided bioassays were incorporated into an effect-directed analysis to more effectively determine sediment causality. XAD extracts of sediments from urban waterways in Guangzhou, China were examined using cell viability bioassays with four human tumor cells from lung, liver, breast, and bone marrow. Pronounced effects to SH-SY5Y cells were noted, thus neurotoxicity was subsequently focused in the AOP-guided bioassays. Intracellular calcium influx, mitochondrial membrane potential inhibition, reactive oxygen species generation, and cell viability were utilized as evidence for neurotoxicity AOP-guided analysis. Suspect toxicants were identified in active fractions using GC-MS. Toxicity confirmation was performed by evaluating toxicity contributions of the candidates to the pathway. Cypermethrin, bisphenol A, galaxolide, tonalide, and versalide were found as the major stressors across key events of the studied pathway. Moreover, good correlations among key events validated the feasibility of method to predict in vivo response, suggesting that considering bioavailability and AOP improved environmental relevance for toxicant identification in a complex mixture.

The Case for a More Holistic Approach to Dry Eye Disease: Is It Time to Move beyond Antibiotics?

Dry eye disease (DED) is one of the most frequent presentations to optometrists with over 16 million US adults (6.8% of adult population) diagnosed as having this disorder. The majority of associated marketed products offer relief from symptomatology but do not address aetiology. DED harbours many distinguishing features of a chronic inflammatory disorder. The recent explosion in human microbiome research has sparked interest in the ocular microbiome and its role in the preservation and extension of ocular surface health and in the contribution of the gut microbiome to chronic systemic inflammation and associated "Western life-style" diseases. With a significant lack of success for many patients using currently available DED treatments, in this era of the microbiome, we are interested in exploring potential novel therapies that aim to reconstitute healthy bacterial communities both locally and distally (in the gut) as a treatment for DED. Although this direction of investigation is in its infancy, burgeoning interest makes such a review timely. This paper considers a number of studies into the use functional foods and associated products to ameliorate dry eye.

Evidence for the Important Role of Oxidative Stress in the Pathogenesis of Acne

Acne vulgaris is a common inflammatory skin disorder which is recognizable by dermatological lesions and scars. In addition to some pathogenetic factors such as hyperkeratinization, upregulated sebum secretion, and immunoinflammatory reactions, recent studies have also connected oxidative stress to the pathogenesis of acne vulgaris. In this article, we will briefly review clinical studies that interrogated alterations in oxidative stress biomarkers by a systematic search conducted in PubMed, Web of Science, and Scopus using "acne", "oxidative stress", and "reactive oxygen species" keywords. Overall, studies have shown that oxidative biomarkers (e.g. lipid peroxidation final products) are higher in acne vulgaris lesions. A significant positive correlation has also been noted between acne severity and oxidative biomarkers. In contrast, diminished levels of antioxidant enzymes (e.g. superoxide dismutase and catalase) have been observed in acne. We propose four probable mechanisms for the role of reactive oxygen species (ROS) in acne pathogenesis. We believe that ROS can contribute significantly to the acne vulgaris pathobiology via toll-like receptor (TLR), peroxisome proliferator-activated receptor (PPAR), mTOR pathway, and innate immune system, resulting in inflammation by alterations in the generation of several proinflammatory cytokines including IL-1, IL-8, and TNF-α.

The interplay between neutrophils and microbiota in cancer

The role of the microbiota in many diseases including cancer has gained increasing attention. Paired with this is our expanding appreciation for the heterogeneity of the neutrophil compartment regarding surface marker expression and functionality. In this review, we will discuss the influence of the microbiota on granulopoiesis and consequent activity of neutrophils in cancer. As evidence for this microbiota-neutrophil-cancer axis builds, it exposes new therapeutic targets to improve a cancer patient's outcome.

Activation of Neutrophils via IP3 Pathway Following Exposure to Demodex-Associated Bacterial Proteins

Rosacea is a chronic inflammatory condition that predominantly affects the skin of the face. Sera from rosacea patients display elevated reactivity to proteins from a bacterium (Bacillus oleronius) originally isolated from a Demodex mite from a rosacea patient suggesting a possible role for bacteria in the induction and persistence of this condition. This work investigated the ability of B. oleronius proteins to activate neutrophils and demonstrated activation via the IP3 pathway. Activated neutrophils displayed increased levels of IP1 production, F-actin formation, chemotaxis, and production of the pro-inflammatory cytokines IL-1β and IL-6 following stimulation by pure and crude B. oleronius protein preparations (2 μg/ml), respectively. In addition, neutrophils exposed to pure and crude B. oleronius proteins (2 μg/ml) demonstrated increased release of internally stored calcium (Ca(2+)), a hallmark of the IP3 pathway of neutrophil activation. Neutrophils play a significant role in the inflammation associated with rosacea, and this work demonstrates how B. oleronius proteins can induce neutrophil recruitment and activation.

Critical data-based re-evaluation of minocycline as a putative specific microglia inhibitor

Minocycline, a second generation broad-spectrum antibiotic, has been frequently postulated to be a "microglia inhibitor." A considerable number of publications have used minocycline as a tool and concluded, after achieving a pharmacological effect, that the effect must be due to "inhibition" of microglia. It is, however, unclear how this "inhibition" is achieved at the molecular and cellular levels. Here, we weigh the evidence whether minocycline is indeed a bona fide microglia inhibitor and discuss how data generated with minocycline should be interpreted. GLIA 2016;64:1788-1794.

Minocycline protects against oxidative damage and alters energy metabolism parameters in the brain of rats subjected to chronic mild stress

Studies have been suggested that minocycline can be a potential new agent for the treatment of depression. In addition, both oxidative stress and energy metabolism present an important role in pathophysiology of depression. So, the present study was aimed to evaluate the effects of minocycline on stress oxidative parameters and energy metabolism in the brain of adult rats submitted to the chronic mild stress protocol (CMS). After CMS Wistar, both stressed animals as controls received twice ICV injection of minocycline (160 μg) or vehicle. The oxidative stress and energy metabolism parameters were assessed in the prefrontal cortex (PF), hippocampus (HIP), amygdala (AMY) and nucleus accumbens (Nac). Our findings showed that stress induced an increase on protein carbonyl in the PF, AMY and NAc, and mynocicline injection reversed this alteration. The TBARS was increased by stress in the PF, HIP and NAc, however, minocycline reversed the alteration in the PF and HIP. The Complex I was incrased in AMY by stress, and minocycline reversed this effect, however reduced Complex I activity in the NAc; Complex II reduced in PF and AMY by stress or minocycline; the Complex II-III increased in the HIP in stress plus minocycline treatment and in the NAc with minocycline; in the PF and HIP there were a reduced in Complex IV with stress and minocycline. The creatine kinase was reduced in AMY and NAc with stress and minocycline. In conclusion, minocycline presented neuroprotector effects by reducing oxidative damage and regulating energy metabolism in specific brain areas.

The Role of the Antioxidative Defense System in Papulopustular Acne

Acne vulgaris frequently occurs in the second decade of life. The pathogenesis of the disease is multifactorial. In this study, we aimed to investigate the role of reactive oxygen species in inflammation of acne by determining the activity of antioxidant defense enzymes in leukocytes. Fifty-two patients with papulopustular type acne vulgaris and 36 healthy controls were enrolled. The severity of the disease was examined by the Global Acne Grading System, and the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) enzymes as well as the level of thiobarbituric acid reactive substance (TBARS) were detected in leukocytes. The activities of SOD and GSH-Px were significantly decreased in the acne group. CAT activity and TBARS level were higher in patients than controls. Only a poor correlation was detected between GSH-Px activity and severity of the disease. Antioxidative defense enzymes are impaired in papulopustular acne, and drugs with antioxidative effects might be valuable in treatment.

A new face for old antibiotics: tetracyclines in treatment of amyloidoses

The use of tetracyclines has declined because of the appearance of resistant bacterial strains. However, the indications of nonantimicrobial activities of these drugs have considerably raised interest and triggered clinical trials for a number of different pathologies. About 10 years ago we first reported that tetracyclines inhibited the aggregation of prion protein fragments and Alzheimer's β peptides, destabilizing their aggregates and promoting their degradation by proteases. On the basis of these observations, the antiamyloidogenic effects of tetracyclines on a variety of amyloidogenic proteins were studied and confirmed by independent research groups. In this review we comment on the data available on their antiamyloidogenic activity in preclinical and clinical studies. We also put forward that the beneficial effects of these drugs are a result of a peculiar pleiotropic action, comprising their interaction with oligomers and disruption of fibrils, as well as their antioxidant, anti-inflammatory, antiapoptotic, and matrix metalloproteinase inhibitory activities.

Acaricide, fungicide and drug interactions in honey bees (Apis mellifera)

Background

Chemical analysis shows that honey bees (Apis mellifera) and hive products contain many pesticides derived from various sources. The most abundant pesticides are acaricides applied by beekeepers to control Varroa destructor. Beekeepers also apply antimicrobial drugs to control bacterial and microsporidial diseases. Fungicides may enter the hive when applied to nearby flowering crops. Acaricides, antimicrobial drugs and fungicides are not highly toxic to bees alone, but in combination there is potential for heightened toxicity due to interactive effects.

Methodology/Principal Findings

Laboratory bioassays based on mortality rates in adult worker bees demonstrated interactive effects among acaricides, as well as between acaricides and antimicrobial drugs and between acaricides and fungicides. Toxicity of the acaricide tau-fluvalinate increased in combination with other acaricides and most other compounds tested (15 of 17) while amitraz toxicity was mostly unchanged (1 of 15). The sterol biosynthesis inhibiting (SBI) fungicide prochloraz elevated the toxicity of the acaricides tau-fluvalinate, coumaphos and fenpyroximate, likely through inhibition of detoxicative cytochrome P450 monooxygenase activity. Four other SBI fungicides increased the toxicity of tau-fluvalinate in a dose-dependent manner, although possible evidence of P450 induction was observed at the lowest fungicide doses. Non-transitive interactions between some acaricides were observed. Sublethal amitraz pre-treatment increased the toxicity of the three P450-detoxified acaricides, but amitraz toxicity was not changed by sublethal treatment with the same three acaricides. A two-fold change in the toxicity of tau-fluvalinate was observed between years, suggesting a possible change in the genetic composition of the bees tested.

Conclusions/Significance

Interactions with acaricides in honey bees are similar to drug interactions in other animals in that P450-mediated detoxication appears to play an important role. Evidence of non-transivity, year-to-year variation and induction of detoxication enzymes indicates that pesticide interactions in bees may be as complex as drug interactions in mammals.

What is behind the non-antibiotic properties of minocycline?

Minocycline is a second-generation, semi-synthetic tetracycline that has been in use in therapy for over 30 years for its antibiotic properties against both Gram-positive and Gram-negative bacteria. It displays antibiotic activity due to its ability to bind to the 30S ribosomal subunit of bacteria and thus inhibit protein synthesis. More recently, it has been described to exert a variety of biological actions beyond its antimicrobial activity, including anti-inflammatory and anti-apoptotic activities, inhibition of proteolysis, as well as suppression of angiogenesis and tumor metastasis, which have been confirmed in different experimental models of non-infectious diseases. There are also many studies that have focused on the mechanisms involved in these non-antibiotic properties of minocycline, including anti-oxidant activity, inhibition of several enzyme activities, inhibition of apoptosis and regulation of immune cell activation and proliferation. This review summarizes the current findings in this topic, mainly focusing on the mechanisms underlying the immunomodulatory and anti-inflammatory activities of minocycline.

Cytotoxicity towards human endothelial cells, induced by neutrophil myeloperoxidase: protection by ceftazidime

We investigated the effects of the antibiotic ceftazidime (CAZ) on the cytolytic action of the neutrophil myeloperoxidase–hydrogen peroxide–chloride anion system (MPO/H₂O₂/Cl⁻). In this system, myeloperoxidase catalyses the conversion of H₂O₂ and CI⁻ to the cytotoxic agent HOCl. Stimulated neutrophils can release MPO into the extracellular environment and then may cause tissue injury through direct endothelial cells lysis. We showed that human umbilical vein endothelial cells (HUVEC) were capable of taking up active MPO. In presence of H₂O₂ (10⁻⁴ M), this uptake was accompanied by cell lysis. The cytolysis was estimated by the release of ⁵¹Cr from HUVEC and expressed as an index of cytotoxicity (IC). Dose dependent protection was obtained for CAZ concentrations ranging from 10⁻⁵ to 10⁻³ M;this can be attributed to inactivation of HOCl by the drug. This protection is comparable to that obtained with methionine and histidine, both of which are known to neutralize HOCl. This protection by CAZ could also be attributed to inactivation of H₂O₂, but when cytolysis was achieved with H₂O₂ or O₂^- generating enzymatic systems, no protection by CAZ was observed. Moreover, the peroxidation activity of MPO (action on H₂O₂) was not affected by CAZ, while CAZ prevented the chlorination activity of MPO (chlorination of monochlorodimedon). So, we concluded that CAZ acts via HOCl inactivation. These antioxidant properties of CAZ may be clinically useful in pathological situations where excessive activation of neutrophils occurs, such as in sepsis.

Novel therapeutic targets in depression: minocycline as a candidate treatment

Mood disorders are marked by high rates of non-recovery, recurrence, and chronicity, which are insufficiently addressed by current therapies. Several patho-etiological models have been proposed that are not mutually exclusive and include but are not limited to the monoamine, inflammatory, neurotrophic, gliotrophic, excitatory, and oxidative stress systems. A derivative of these observations is that treatment(s) which target one or more of these mechanistic steps may be capable of mitigating, or preventing, disparate psychopathological features. Minocycline is an agent with pleiotropic properties that targets multiple proteins and cellular processes implicated in the patho-etiology of mood disorders. Moreover, preclinical and preliminary clinical evidence suggests that minocycline possesses antidepressant properties. Herein, we provide the rationale for conducting a randomized, controlled trial to test the antidepressant properties of minocycline.

Nitric oxide--a versatile key player in cochlear function and hearing disorders

Nitric oxide (NO) is a signaling molecule which can generally be formed by three nitric oxide synthases (NOS). Two of them, the endothelial nitric oxide synthase (eNOS) and the neural nitric oxide synthase (nNOS), are calcium/calmodulin-dependent and constitutively expressed in many cell types. Both isoforms are found in the vertebrate cochlea. The inducible nitric oxide synthase (iNOS) is independent of calcium and normally not detectable in the un-stimulated cochlea. In the inner ear, as in other tissues, NO was identified as a multitask molecule involved in various processes such as neurotransmission and neuromodulation. In addition, increasing evidence demonstrates that the NO-dependent processes of cell protection or, alternatively, cell destruction seem to depend, among other things, on changes in the local cochlear NO-concentration. These alterations can occur at the cellular level or within a distinct cell population both leading to an NO-imbalance within the hearing organ. This dysfunction can result in hearing loss or even in deafness. In cases of cochlear malfunction, regulatory systems such as the gap junction system, the blood vessels or the synaptic region might be affected temporarily or permanently by an altered NO-level. This review discusses potential cellular mechanisms how NO might contribute to different forms of hearing disorders. Approaches of NO-reduction are evaluated and the transfer of results obtained from experimental animal models to human medication is discussed.

Rosacea: The cytokine and chemokine network

Rosacea is one of the most common dermatoses of adults. Recent studies have improved our understanding of the pathophysiology of rosacea. Current concepts suggest that known clinical trigger factors of rosacea such as UV radiation, heat, cold, stress, spicy food, and microbes modulate Toll-like receptor signaling, induce reactive oxygen species, as well as enhance antimicrobial peptide and neuropeptide production. Downstream of these events cytokines and chemokines orchestrate an inflammatory response that leads to the recruitment and activation of distinct leukocyte subsets and induces the characteristic histopathological features of rosacea. Here we summarize the current knowledge of the cytokine and chemokine network in rosacea and propose pathways that may be of therapeutic interest.

Evaluation of the antioxidant activity of tetracycline antibiotics in vitro

Tetracyclines are the second most common antibiotic family in medicine usage. These antibiotics exhibit antioxidant potential; however, the exact mechanism remains unclear. The antiradical activity of the seven tetracyclines (TCs; tetracycline, chlortetracycline, oxytetracycline, doxocycline, methacycline, demeclocycline, minocycline) was determined using the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH(•)) and hydroxyl radicals (HO(•)) generated in a Fenton reaction. Electron spin resonance (ESR), ESR spin-trapping, chemiluminescence and spectrophotometry techniques were applied. It was found that the TCs showed high DPPH antiradical activity in the range 26-96% at 2.5 mmol/L concentration. The second-order rate constants for the reaction between HO(•) and TCs were calculated, in the range (3.6-9.6) × 10(9)  L/mol/s. The tetracycline compounds also exhibited a strong decrease in light emission (range 61-85% at concentration of 1 mmol/L). This study also showed that TCs promote the generation of singlet oxygen in the presence of H(2)O(2) and Fe(II)/Fe(III) ions. Our findings suggest direct scavenging activity of the examined tetracyclines towards free radicals, and may be relevant to therapeutic strategy.

Non-antibiotic properties of tetracyclines as anti-allergy and asthma drugs

All available therapies for human allergic disease target IgE mediated pathologic responses after IgE has been produced. We are developing tetracyclines as anti-allergy drugs to prevent IgE production, based on our findings that minocycline or doxycycline treatment of allergic asthmatic humans significantly improves their asthma symptoms, reduces their oral steroid requirements, and strongly suppresses their ongoing IgE responses (ELISA, mast cell mediated cutaneous late phase responses); the tetracyclines also strongly suppress peak IgE responses of BPO-KLH sensitized mice (ELISPOT assay, ELISA, skin tests). The antibiotic activity of the tetracyclines is not required for suppression of IgE responses; inclusion of minocycline or doxycycline in sterile culture prevents anti-CD40/IL-4 mediated induction of memory IgE responses by PBMC of allergic asthmatic patients (ELISA), and induction of specific memory IgE responses by spleen cells of BPO-KLH sensitized mice (ELISPOT assay, ELISA). The tetracyclines affect an epsilon specific pathway because IgM, IgG and IgA responses did not decrease. Further, in humans, DTH responses to recall antigens did not decrease. In related studies, we found that two distinct T cell subsets: CD4+CD60 negative and CD8+CD60+ (CD60 is a ganglioside) (humans) and CD4+ Asialo GM1 ganglioside negative and CD8+Asialo GM1 ganglioside+ (mice), both are required for induction of memory IgE responses. Phosphorylated (phos) p38 MAP kinase, but not phos ERK or phos JNK expression by CD4+ and CD8+, including CD8+CD60+, T cells is increased in allergic asthmatic humans, as is IL-4 and IL-10 production. The tetracyclines appear to target T cell pathways to induce suppression of IgE responses because they suppress phos p38 MAP kinase expression by both CD4+ and CD8+, including CD8+CD60+, T cell subsets, and IL-4 and IL-10, while upregulating IL-2 and IFN gamma, and suppressing IgE responses. Our finding that tetracyclines do not require antibiotic activity to suppress IgE responses opens the door to development of new tetracycline-based and other therapeutics for human allergic disease.

Clinical implications of lipid peroxidation in acne vulgaris: old wine in new bottles

Acne vulgaris is a common dermatological disorder, one that is frequently associated with depression, anxiety and other psychological sequelae. In recent years there has been an increasing focus on the extent to which oxidative stress is involved in the pathophysiology of acne. Emerging studies have shown that patients with acne are under increased cutaneous and systemic oxidative stress. Indeed, there are indications that lipid peroxidation itself is a match that lights an inflammatory cascade in acne. The notion that lipid peroxidation is a 'starter gun' in acne is not a new one; here we review the nearly 50-year-old lipid peroxidation theory and provide a historical perspective to the contemporary investigations and clinical implications.

In addition, we present a novel hypothesis in which lipid peroxidation may be priming an increased susceptibility to co-morbid depression and anxiety in those with acne. The emerging research on the systemic burden of oxidative stress in acne sheds further light on the brain-skin axis. The recent findings also suggest potential avenues of approach for the treatment of acne via specific nutrients, dietary modifications, oral and topical interventions.

Sodium L-ascorbyl-2-phosphate 5% lotion for the treatment of acne vulgaris: a randomized, double-blind, controlled trial

BACKGROUND

Antioxidants are becoming increasingly important in the treatment of skin disease. In addition to their known anti-inflammatory effects, antioxidants may act to prevent the oxidation of sebum which has been proposed to be comedogenic in acne patients. Sodium L-ascorbyl-2-phosphate (APS) is a stable vitamin C derivative and highly effective antioxidant that has demonstrated efficacy in acne in open label studies.

OBJECTIVE

To evaluate the efficacy and safety of APS 5% lotion for the treatment of acne in a blinded controlled study.

METHODS

A total of 50 subjects were randomized in a double-blind controlled trial to receive APS 5% lotion or vehicle for 12 weeks. Evaluation included an Investigator's Global Assessment Score, a Subjects' Global Assessment Score, lesion counts, cutaneous tolerability, and adverse events.

RESULTS

APS 5% lotion demonstrated statistically significant improvement when compared to vehicle in all of the parameters measured. The adverse event frequency and cutaneous tolerability profile for APS 5% lotion were similar to vehicle.

LIMITATIONS

Adjunctive topical or oral agents and their impact on acne were not studied in this trial.

CONCLUSIONS

This study demonstrates that 5% sodium L-ascorbyl-2-phosphate is efficacious as monotherapy for the treatment of acne. APS 5% lotion offers a novel addition to our current acne armamentarium.

Tetracycline-mediated IgE isotype-specific suppression of ongoing human and murine IgE responses in vivo and murine memory IgE responses induced in vitro

We previously reported that minocycline treatment of allergic asthmatic patients had oral steroid sparing effects and improved their clinical status and that minocycline suppressed in vitro induction of IgE responses by their PBMC. The effect of minocycline on human or animal IgE responses in vivo has not been studied. Allergic asthmatics (serum IgE: 505 +/- 535 IU ml(-1)) were given minocycline (150 mg po to 250 mg po BID) as add-on therapy to standard care for up to 10 months; control subjects (IgE: 405 +/- 472 IU ml(-1)) received standard care (n = 6 per group). Serum immunoglobulin (IgM, IgG, IgE and IgA) levels were determined monthly (Nephelometry, Unicap Total IgE Fluoroenzyme immunoassay). BALB/c mice (n = 6 per group) were injected intraperitoneally with benzylpenicilloyl(14)-Keyhole limpet hemocyanin (BPO(14)-KLH) in alum on days 0, 21 and 42, fed with minocycline or doxycycline (10-100 mg kg(-1)) on day 44 and numbers of BPO-specific IgG(1), IgE and IgA antibody-forming cell (AFC) in mesenteric LN and spleen and serum immunoglobulin levels were determined on days 46-70 (enzyme-linked immunosorbent spot assay, ELISA). The ability of minocycline or doxycycline to suppress in vitro induction of murine memory IgE responses also was investigated. Minocycline strongly suppressed serum IgE levels of allergic asthmatics (9% per month) (P = 0.012). Minocycline (and doxycycline) also strongly suppressed peak murine IgE AFC and serum IgE responses (>95, approximately 75%, respectively) and in vitro induction of memory IgE responses by murine mesenteric LN and spleen cells (>95%). Tetracycline suppression of all human and murine IgE responses was IgE isotype specific. Suppression of murine IgE responses in vivo was dose dependent and lasted 5-7 days.

The molecular pathology of rosacea

Rosacea is a common and chronic inflammatory skin disease that affects over 10 million Americans. Although the phenotypes of rosacea are clinically heterogeneous, they are all related by the presence of chronic facial skin inflammation. Until recently, the pathophysiology of this disease has been poorly understood and limited to descriptions of factors that exacerbate or improve this disorder. Recent molecular studies suggest that an altered innate immune response is involved in the pathogenesis of the vascular and inflammatory disease seen in patients with rosacea. These findings may help explain the benefits of current treatments and suggest new therapeutic strategies helpful for alleviating this disease. This article discusses the possible molecular mechanisms for the pathogenesis of rosacea from current clinical observations and laboratory research.

New insights into the management of acne: an update from the Global Alliance to Improve Outcomes in Acne group

The Global Alliance to Improve Outcomes in Acne published recommendations for the management of acne as a supplement to the Journal of the American Academy of Dermatology in 2003. The recommendations incorporated evidence-based strategies when possible and the collective clinical experience of the group when evidence was lacking. This update reviews new information about acne pathophysiology and treatment-such as lasers and light therapy-and relevant topics where published data were sparse in 2003 but are now available including combination therapy, revision of acne scarring, and maintenance therapy. The update also includes a new way of looking at acne as a chronic disease, a discussion of the changing role of antibiotics in acne management as a result of concerns about microbial resistance, and factors that affect adherence to acne treatments. Summary statements and recommendations are provided throughout the update along with an indication of the level of evidence that currently supports each finding. As in the original supplement, the authors have based recommendations on published evidence as much as possible.

Minocycline-induced drug hypersensitivity syndrome followed by multiple autoimmune sequelae

BACKGROUND

Drug hypersensitivity syndrome (DHS) is a severe, multisystem adverse drug reaction that may occur following the use of numerous medications, including anticonvulsants, sulfonamides, and minocycline hydrochloride. Long-term autoimmune sequelae of DHS have been reported, including hypothyroidism.

OBSERVATIONS

A 15-year-old female adolescent developed DHS 4 weeks after starting minocycline therapy for acne vulgaris. Seven weeks later she developed autoimmune hyperthyroidism (Graves disease), and 7 months after discontinuing minocycline therapy she developed autoimmune type 1 diabetes mellitus. In addition, she developed elevated titers of several markers of systemic autoimmune disease, including antinuclear, anti-Sjögren syndrome A, and anti-Smith antibodies.

CONCLUSIONS

Minocycline-associated DHS may be associated with multiple autoimmune sequelae, including thyroid disease, type 1 diabetes mellitus, and elevated markers of systemic autoimmunity. Long-term follow-up is needed in patients with DHS to determine the natural history of DHS-associated sequelae.

TNF-alpha-induced up-regulation of intercellular adhesion molecule-1 is regulated by a Rac-ROS-dependent cascade in human airway epithelial cells

Up-regulation of intercellular adhesion molecule-1 (ICAM-1) in the lung airway epithelium is associated with the epithelium-leukocyte interaction, critical for the pathogenesis of various lung airway inflammatory diseases such as asthma. However, little is known about how ICAM-1 is up-regulated in human airway epithelial cells. In this study, we show that tumor TNF-alpha induces monocyte adhesion to A549 human lung airway epithelium and also up-regulation of ICAM-1 expression. These effects were significantly diminished by pre-treatment with diphenyliodonium (DPI), an inhibitor of NADPH oxidase-like flavoenzyme. In addition, the level of reactive oxygen species (ROS) was increased in response to TNF-alpha in A549 cells, suggesting a potential role of ROS in the TNF-alpha-induced signaling to ICAM-1 expression and monocyte adhesion to airway epithelium. Further, we found out that expression of RacN17, a dominant negative mutant of Rac1, suppressed TNF-alpha-induced ROS generation, ICAM-1 expression, and monocyte adhesion to airway epithelium. These findings suggest that Rac1 lies upstream of ROS generation in the TNF-alpha-induced signaling to ICAM-1 expression in airway epithelium. Finally, pretreatment with pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-kappaB, reduced TNF-alpha-induced ICAM-1 expression and both DPI and RacN17 significantly diminished NF-kappaB activation in response to TNF-alpha. Together, we propose that Rac1-ROS-linked cascade mediate TNF-alpha-induced ICAM-1 up-regulation in the airway epithelium via NF-kappaB-dependent manner.

Azithromycin may reduce cholestasis in primary sclerosing cholangitis: a case report and serendipitous observation

The newer macrolides have been shown to exert additional anti-inflammatory effects. We report the possible effect of azithromycin on primary sclerosing cholangitis in a patient treated with the drug for severe asthma. A 45-year-old woman with Crohn?s disease and primary sclerosing cholangitis, also suffering from severe asthma, was treated with azithromycin 500 mg OD for 3 consecutive days a week because of the clinical suspicion of bronchiectasis and the severity of her asthma. When the therapy was discontinued, her urine again became darker, pruritus reappeared with the usual severity and laboratory parameters, evaluated after 6 weeks without azithromycin, also worsened. For these reasons macrolide treatment was re-established. Cholestasis-related symptoms and the dark colour of the urine were again reduced 6 weeks later and laboratory parameters were again reversed. We are therefore tempted to speculate that azithromycin may have an effect on primary sclerosing cholangitis on the basis of its anti-inflammatory properties.

A role for non-antimicrobial actions of tetracyclines in combating oxidative stress in periodontal and metabolic diseases: a literature review

This review addresses the role of adjunctive tetracycline therapy in the management of periodontal diseases and its efficacy in reducing inflammatory burden, oxidative stress and its sequelae in patients with coexisting features of metabolic syndrome. Removal of the dimethylamine group at C4 of the tetracycline molecule reduces its antibiotic properties, enhancing its non-antimicrobial actions; this strategy has aided the development of several chemically modified tetracyclines such as minocycline and doxycycline, by altering different regions of the molecule for focused action on biological targets. Tetracyclines are effective in reducing inflammation by inhibiting matrix metalloproteinases, preventing excessive angiogenesis, inhibiting apoptosis and stimulating bone formation. There are important applications for tetracyclines in the management of diabetic, dyslipidaemic periodontal patients who smoke. The diverse mechanisms of action of tetracyclines in overcoming oxidative stress and enhancing matrix synthesis are discussed in this review.

Pathological investigation of oxidative stress in the post-genomic era

Aerobes, including humans, are consistently exposed to oxidative stress by consuming oxygen. The biological significance of oxidative stress via reactive oxygen and nitrogen species consists of two stages: reversible redox regulation and irreversible oxidative molecular damage, which are sometimes intermingled. During the past decade, many signaling cascades associated with oxidative stress have been discovered. An interaction between Keap1 and the Nrf2 transcription factor is among the most fundamental mechanisms of the defense system against oxidative or similar stress. Furthermore, it became apparent that reactive oxygen species are actively produced through enzymes such as xanthine oxidoreductase and nicotinamide adenine dinucleotide phosphate, reduced (NADPH) oxidases in non-phagocytic cells as well. The role of alpha-tocopherol solely as an anti-oxidant was also questioned. Now there is a long list of pathological states implicating oxidative stress. At the same time, genome projects on various species have been completed. These efforts convincingly led to a new era of oxidative stress investigation, contributing powerful strategies to select candidate genes or biomolecules. Herein are reviewed recent advances and novel concepts in this field, including oxygenomics. These fruitful results may lead to more accurate and useful pathological diagnosis and more efficient prophylaxis and therapeutic interventions on human diseases.

Subantimicrobial Dose Doxycycline for Acne and Rosacea

Acne vulgaris and rosacea present therapeutic challenges due to their chronicity, potential for disfigurement, and psychosocial impact. Although pathophysiologically distinct, both conditions have major inflammatory components. Consequently, topical and systemic antimicrobial agents are routinely prescribed for extended periods. Emergence of resistant strains of Propionibacterium acnes, adverse events, and compliance issues associated with chronic systemic tetracycline use have led to new treatment approaches. At subantimicrobial doses, tetracyclines reduce inflammation via anticollagenolytic, antimatrix-degrading metalloproteinase, and cytokine down-regulating properties. Subantimicrobial dose (SD) doxycycline (Periostat 20 mg) has clinical utility in periodontitis and has been investigated in a double-blind, placebo-controlled trial in the treatment of moderate facial acne as well as in an open label study in the treatment of rosacea. The results of subantimicrobial dose doxycycline treatment in early trials support its benefits and further investigation in acne and rosacea.