Chronic liver injury in mice promotes impairment of skin barrier function via tumor necrosis factor-alpha

Skin dryness induced in the KK-Ay/TaJcl type 2 diabetes mouse model deteriorates following dapagliflozin administration

Various diabetic drugs have been developed as the number of patients with type 2 diabetes has increased. Sodium-glucose cotransporter (SGLT)-2 inhibitors have been developed as novel therapeutic agents. However, SGLT-2 inhibitors cause skin dryness. The mechanism through which SGLT-2 inhibitors cause skin dryness is unknown. The purpose of this study was to investigate the mechanism through which dapagliflozin, a SGLT-2 inhibitor, induces skin dryness. Specific pathogen-free KK-Ay/TaJcl (type 2 diabetes model) mice were orally administered with SGLT-2 inhibitor (dapagliflozin) daily for 4 weeks at a dose of 1 mg/kg/day. Skin dryness induced in KK-Ay/TaJcl mice became severe after dapagliflozin administration. Dapagliflozin treatment decreased collagen type I and hyaluronic acid levels in mice; additionally, it affected the TGF-β/hyaluronan synthase pathway, further reducing hyaluronic acid levels. The results indicate that the reduction in hyaluronic acid levels plays an important role in the occurrence of dry skin in diabetes.

Alcohol in Psoriasis-From Bench to Bedside

Alcohol affects the symptoms, compliance and comorbidities as well as the safety and efficacy of treatments in psoriatic patients. In this review, we aim to summarize and link clinical observations with a molecular background, such as signaling pathways at the cellular level and genetic variations, and to provide an overview of how this knowledge could influence our treatment selection and patient management.

A decrease in the tear secretion volume in a mouse model with ulcerative colitis

PURPOSE

Dry eye syndrome is known to develop from several systemic inflammatory diseases. Although dry eye may develop due to extraintestinal complications of ulcerative colitis (UC), the pathogenesis is not well-known. This study aimed to investigate whether there was decrease in the tear secretion volume in a mice model with UC; the difference between the control and dextran sodium sulphate (DSS)-treated group was also determined.

MATERIALS AND METHODS

This study included a mice model with UC induced by the oral administration of 5.0% DSS for 7 days. Following the DSS treatment, the tear volume was measured using the Schirmer's test. The colon and ocular tissues, including the lacrimal gland, were evaluated using histological and protein analyses. Additionally, tumour necrosis factor (TNF)-α and interleukin (IL)-6 in the plasma were determined. Differences between groups (DSS-treated versus control mice) were determined using Student's t-test.

RESULTS

The tear volume in DSS-treated mice was decreased compared to that in the control mice. Plasma levels of TNF-α and IL-6 in DSS-treated mice was higher than that of control. Morphological change was observed with the invasion of the inflammatory cell in the lacrimal gland of DSS-treated mice. Terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labelling (TUNEL)-positive cells were increased in the lacrimal glands of DSS-treated mice compared with control group. The distribution of aquaporin-5 expressed in the lacrimal gland of DSS-treated mice was decreased compared to that in the control group.

CONCLUSIONS

These findings suggest that a decrease in the tear volume in UC was associated with a functional decline in the inflamed lacrimal gland. This result therefore provides useful information that could contribute to the development of treatment approaches for dry eye associated with UC.

Nutrition and Psoriasis

Psoriasis is a chronic inflammatory skin disease characterized by accelerated tumor necrosis factor-α/interleukin-23/interleukin-17 axis, hyperproliferation and abnormal differentiation of epidermal keratinocytes. Psoriasis patients are frequently associated with obesity, diabetes, dyslipidemia, cardiovascular diseases, or inflammatory bowel diseases. Psoriasis patients often show unbalanced dietary habits such as higher intake of fat and lower intake of fish or dietary fibers, compared to controls. Such dietary habits might be related to the incidence and severity of psoriasis. Nutrition influences the development and progress of psoriasis and its comorbidities. Saturated fatty acids, simple sugars, red meat, or alcohol exacerbate psoriasis via the activation of nucleotide-binding domain, leucine-rich repeats containing family, pyrin domain-containing-3 inflammasome, tumor necrosis factor-α/interleukin-23/interleukin-17 pathway, reactive oxygen species, prostanoids/leukotrienes, gut dysbiosis or suppression of regulatory T cells, while n-3 polyunsaturated fatty acids, vitamin D, vitamin B12, short chain fatty acids, selenium, genistein, dietary fibers or probiotics ameliorate psoriasis via the suppression of inflammatory pathways above or induction of regulatory T cells. Psoriasis patients are associated with dysbiosis of gut microbiota and the deficiency of vitamin D or selenium. We herein present the update information regarding the stimulatory or regulatory effects of nutrients or food on psoriasis and the possible alleviation of psoriasis by nutritional strategies.

Irinotecan-Induced Skin Dryness Is Ameliorated By Orally Administered High-Dose Vitamin C In Mice

Background

Vitamin C plays a part in various roles in the human body. In this study, we examined the effect of oral administration of high-dose vitamin C on the skin dryness induced by irinotecan.

Methods

To establish the experimental model of irinotecan-induced skin dryness, the drug was intraperitoneally administered for four consecutive days. Simultaneously, oral administration of high-dose vitamin C (4 g/kg) was continued for 4 days.

Results

High-dose vitamin C administration ameliorated the skin dryness induced by irinotecan. The expression of caspase-3 and caspase-9, reactive oxygen species, and the number of TUNEL-positive cells increased in the skin of irinotecan-treated mice but were lowered by high-dose vitamin C administration. In contrast, fibroblasts and collagen type I decreased in the skin of the irinotecan-treated mice but was increased by high-dose vitamin C administration.

Conclusion

These results suggested that high-dose vitamin C administration can improve the skin dryness induced by irinotecan.

Psoriasis and alcohol

Psoriasis is a chronic inflammatory skin disease that may be triggered or worsened by several factors, including alcohol. A higher than average alcohol consumption is common among individuals with psoriasis. Neurobiological signaling affected by alcohol intake includes a range of neurotransmitters, such as the dopaminergic, serotonergic, and tachykinergic systems, involved in reward and drug-seeking. These neurotransmitters may also have an impact on the inflammatory processes per se in psoriasis. Future therapy may, therefore, be targeted at neurotransmitter networks involved with both alcohol intake and the inflammatory processes.

Role of mast cells in the induction of dry skin in a mouse model of rheumatoid arthritis

PURPOSE

Rheumatoid arthritis (RA) is known to induce dry skin as an extra-articular symptom. However, the mechanisms behind the induction are unclear. In this study, we utilized an arthritis mouse model to simulate RA to reveal the relationship between arthritis and dry skin.

MATERIALS AND METHODS

DBA/1JJmsSlc control mice (n = 5) and DBA/1JJmsSlc collagen-induced arthritis mouse model (arthritis mice; n = 5) were used. We measured transepidermal water loss (TEWL) and capacitance to reveal the effect of arthritis on skin barrier function. In addition, we measured the expression of biomarkers of skin barrier function.

RESULTS

We found that the hind limb volume of the arthritis mice was higher than that of the control mice. Our results showed that the arthritis mice had higher TEWL and lower capacitance when compared to the control mice. When compared to that of the control mice, the skin of the arthritis mice was thicker with more leukocyte infiltration. In the skin of arthritis mice, we observed lower expression of type I and IV collagens, but higher expression of matrix metalloproteinases (MMP)-1 and -9 when compared to that of the control mice. The levels of mast cells, histamine, substance P, and tryptase were higher in the arthritis mice than in the control mice. This study showed that the arthritis mice exhibited a disruption of skin barrier function (i.e. dry skin), which was improved following treatment with a mast cell inhibitor.

CONCLUSIONS

Our results on mast cells suggested that an improvement of dry skin is important for RA management.