Investigation of the skin microbiome: swabs vs. biopsies.

BACKGROUND: Human skin is populated by diverse bacteria and there is increasing evidence that resident bacteria play a key role initiating immune responses in cutaneous diseases such as atopic dermatitis, psoriasis and hidradenitis suppurativa. Bacteria are present at all layers of the skin but many studies have relied on swabs to profile the skin microbiota. OBJECTIVES: As the pathogenesis of many skin conditions is dermal, we wanted to compare the microbiota obtained in swabs (surface) and biopsies (dermis). METHODS: Using 16S rRNA gene sequencing we established the microbial profiles of skin swabs and skin biopsies in 16 patients. RESULTS: We found differences in both diversity and taxonomic composition of the microbiome obtained from swabs and biopsies of the same individual. Several taxa were found to be more abundant in the swabs, which displayed significantly higher community richness, but Clostridiales and Bacteroidetes were significantly enriched in the biopsies. Most published research on cutaneous microbiota has been based on skin swabs, which represent the surface of the skin. CONCLUSIONS: Our study demonstrated a clear difference between the microbiome observed from skin swabs and skin biopsies. These findings may be highly relevant in disorders such as psoriasis where pathogenesis arises in the dermis. What's already known about this topic? 16S RNA gene sequencing has facilitated study of the skin microbiome. Several studies have sequenced the microbiome sampled by skin swabs. What does this study add? The microbiome data obtained using swabs and biopsies were different. Diseases that are predominantly dermal should be studied using both swabs and biopsies.

An investigation into the nutritional composition and cost of gluten-free versus regular food products in the UK.

BACKGROUND: The gluten-free (GF) food market has expanded considerably, although there is limited comparative evidence for the nutritional quality and cost of GF food products. The present study aims to compare the nutrient composition and cost of GF and gluten-containing (regular) foods across 10 food categories in the UK. METHODS: Nutritional information and the cost of GF foods available in the UK (n = 679) and comparable regular foods (n = 1045) were systematically collected from manufacturer and supermarket websites. Foods were classified using UK front-of-pack labelling for content of fat, saturated fat, sugar and salt and nutrient content, and cost per 100 g were identified and compared between GF and regular foods. RESULTS: Overall, more GF foods were classified as containing high and medium fat, saturated fat, sugar and salt than regular foods, although this was not universally consistent. More GF bread and flour products contained high fat and sugar, whereas fewer GF crackers contained high fat and sugar compared to regular foods. High salt content was found more frequently in GF than regular products. On average, GF products were 159% more expensive than regular (£0.44/100 g versus £1.14/100 g). GF items were also more likely to be lower in fibre and protein content than regular foods. CONCLUSIONS: Differences exist in the nutritional composition of GF and regular food. GF food is unlikely to offer healthier alternatives to regular foods, except for those who require a GF diet for medically diagnosed conditions, and it is associated with higher costs.

What are we injecting with our drugs?

In preparation for a case, an anaesthetist opened a 20 ml glass vial of propofol and aspirated the propofol into a syringe via a blunt drawing-up needle. Increased resistance was felt with aspiration. On inspection, a shard of glass was found at the tip of the drawing-up needle. The shard was presumed to be from the propofol ampoule, and to have fallen into the solution upon snapping open its glass tip. This illustrative case raises the issue of contamination of drugs by particles introduced during the drawing-up process. It also highlights the possibility that during the drawing-up process, intravenous drugs may become contaminated not just with particles, but with microorganisms on the surface of the particles. In this article, we discuss relevant recent research of the implications of this type of drug contamination. We draw attention to the need for meticulous care in drawing up and administering intravenous drugs during anaesthesia, particularly propofol.

Targeting retinal ganglion cell recovery.

Accumulating evidence from experimental and clinical studies suggest that retinal ganglion cells at least in the earlier stages of glaucoma have the capacity to recover function following periods of functional loss. The capacity for recovery may be negatively impacted by advancing age but can be boosted by interventions such as diet restriction and exercise.

Assessing the toxic effects of DMSO on cord blood to determine exposure time limits and the optimum concentration for cryopreservation.

BACKGROUND AND OBJECTIVES: Advantages of using cord blood (CB) over other sources of haematopoietic progenitor cells, such as bone marrow, include the ability to cryopreserve and bank the samples until requested for a transplant. Cryopreservation requires the addition of a cryoprotectant to prevent the formation of intracellular ice during freezing. Dimethyl sulphoxide (DMSO) is commonly used at a concentration of 10% (v/v); however, there is evidence to suggest this chemical is toxic to cells as well as to patients after infusion. MATERIALS AND METHODS: The toxic effects of DMSO were assessed through cell viability and in vitro functional assays in fresh and post-thaw CB samples before determining the maximum exposure time and optimal concentration for cryopreservation. RESULTS: A dose-dependent toxicity of DMSO was observed in fresh samples with 40% removing all viable and functional haematopoietic progenitor cells (HPC). In fresh and post-thaw analysis, minimal toxic effect was observed when cryopreservation was delayed for up to 1 h after 10% DMSO addition. After thawing, DMSO washout was superior to dilution or unmanipulated when maintained for long periods (advantage observed 1 h after thawing). Finally, the optimum concentration for cryopreserving CB was found to be 7.5 to 10% with detrimental effects observed outside of this range. CONCLUSION: These results support the use of 7.5-10% as the optimal DMSO concentration and the maximum exposure time should be limited to <1 h prior to freezing and 30 min post-thaw.

A retrospective survey of substance abuse in anaesthetists in Australia and New Zealand from 2004 to 2013.

A questionnaire on substance abuse was distributed electronically to the heads of 185 Australian and New Zealand College of Anaesthetists accredited anaesthesia departments in Australia and New Zealand. The response rate was 57%. From January 2004 to December 2013, 61 cases of substance abuse were identified, giving an estimated incidence of 1.2 cases per 1000 anaesthetist years. Of 44 detailed reports completed, the majority were aged between 30 and 49 years, were male and of specialist grade. However, when corrected for gender and grade, the estimated overall incidence was higher in females and twice as high for trainees compared with specialists. When compared with prior surveys, the pattern of substance abuse in Australia and New Zealand appears to have changed significantly, with a notable increase in propofol and alcohol abuse and a decrease in reported cases of opioid abuse. Common presenting features of abuse included intoxication and witnessed abuse. Seventy percent of cases had more than one comorbid condition, most frequently either mental health or family problems. Only 32% of abusers had made a long-term recovery within the specialty. Death was the eventual outcome in 18% overall, with a particularly high mortality associated with propofol abuse (45%). Trainee suicide from all causes was reported at three times the rate of specialists. The findings indicate that substance abuse remains a significant problem in Australia and New Zealand and is associated with a significant mortality rate.

Is chronic plaque psoriasis triggered by microbiota in the skin?

There is a known association between psoriasis and Crohn disease (CD). Patients with CD are five times more likely to develop psoriasis, and, conversely, patients with psoriasis are more likely to develop CD. Many gastroenterologists now accept that CD results from a breakdown of immune tolerance to the microbiota of the intestine in genetically susceptible individuals. The microbiota of the skin have recently been investigated in psoriasis. Firmicutes was the most common phylum, and Streptococcus the most common genus identified. Beta-haemolytic streptococci have been implicated in both guttate and chronic plaque psoriasis. Furthermore, the innate immune system has been shown to be activated in psoriasis, and many of the genes associated with the disease are concerned with the signalling pathways of the innate immune system, notably interleukin-23 and nuclear factor κB. Patients with psoriasis also have an increased incidence of periodontitis, a disease thought to be due to an abnormal response to normal oral commensals. Based on the similarities between CD and psoriasis, we propose that psoriasis is due to a breakdown of immune tolerance to the microbiota of the skin. In support of this hypothesis we provide evidence for microbiota in the skin, activation of the innate immune system, and genetic abnormalities involving the innate immune system.

Concepts in psoriasis: psoriasis and the extracellular matrix.

Post-streptococcal guttate psoriasis only sometimes progresses to the persistent plaque psoriasis. We have previously proposed that psoriasis is driven by multiple extradomain A+ fibronectin (EDA+ FN) 'feedback loops'. The psoriasis-specific loop, the 'keratinocyte loop', depends upon expression by keratinocytes of α5ß1 integrin. In normal skin, α5ß1 expression is minimal or absent in resting epithelial cells, where basal cells are anchored to the laminin component of the basement membrane (via integrins α6ß4 and α3ß1). However, when the laminin layer is disrupted, due to wounding for instance, α5ß1 is then strongly expressed by basal cells as a means for anchoring. At uninvolved skin sites in patients with psoriasis the laminin layer within the basement membrane is disrupted, with a consequential increase in the expression by basal keratinocytes of EDA+ FN and α5ß1. We are postulating that in guttate psoriasis streptococcal lytic enzymes, and in particular streptokinase, may - via plasminogen activation - initiate a disruption of the laminin layer in the basement membrane. It is also possible that the expression by proliferating keratinocytes of plasminogen-activating factor might result in additional laminin digestion. The suggestion is that progression of guttate psoriasis to full-blown plaque psoriasis, or to its spontaneous resolution, is governed largely by the triggering of humoral immune responses. Thus, if streptococcal lytic enzymes are neutralized by host antibodies in advance of irreversible and lasting damage to the basement membrane of the dermal papillae, then guttate psoriasis will resolve spontaneously. In contrast, if permanent damage is induced prior to effective neutralization of the relevant bacterial toxins, then keratinocytes will become chronically destabilized. The consequence will be to liberate keratinocytes to proliferate in response to various stimuli, and to continue to elaborate plasminogen activation enzymes; the combined effect being, in concert with immunological priming, to precipitate and sustain plaque psoriasis.

Psoriasis and extra domain A fibronectin loops.

We have previously postulated that as well as T-helper (Th) 1 and Th17 cells, the transforming growth factor (TGF)-beta/fibronectin (FN)/alpha5beta1 pathway is central to psoriasis pathogenesis. EDA+ FN refers to an alternatively spliced isoform of FN with an additional domain known as extra domain A. EDA+ FN has two important properties pertinent to psoriasis lesions: it stimulates keratinocyte hyperproliferation, and, through stimulation of Toll-like receptor (TLR) 4, stimulates production of proinflammatory cytokines. EDA+ FN production induced by TGF-beta stimulation can be maintained in psoriasis lesions via two main feedback loops. Firstly, EDA+ FN stimulates proliferation of keratinocytes, which, in an autocrine fashion, will release more EDA+ FN. Secondly, EDA+ FN stimulates TLR4 expressed by antigen-presenting cells resulting in the production of proinflammatory cytokines such as tumour necrosis factor-alpha, interleukin (IL)-1, IL-6 and IL-12. The resultant promotion of cutaneous inflammation results in the recruitment of Th1 cells, which also produce EDA+ FN. We propose that these 'FN loops' contribute to the maintenance and progression of psoriatic lesions. Finally, although the association between psoriasis and heart/thrombotic disease remains unclear one plausible link may be the promotion of atherosclerosis and thrombotic heart disease by EDA+ FN.

Bile leak from the duct of Luschka.

A 64-year-old diabetic man underwent an open cholecystectomy for acute necrotizing cholecystitis. Post-operatively he developed a biloma which was drained percutaneously. A bile leak was suspected and he underwent an ERCP. Initial cholangiography was normal, but upon continued injection of contrast agent, a bile leak originating from a branch of the right hepatic duct or duct of Luschka became evident. A sphincterotomy was performed and a plastic stent was placed into the common bile duct. The leak resolved and the plastic stent was removed 6 weeks later.