Persistent release of IL-1s from skin is associated with systemic cardio-vascular disease, emaciation and systemic amyloidosis: the potential of anti-IL-1 therapy for systemic inflammatory diseases.

The skin is an immune organ that contains innate and acquired immune systems and thus is able to respond to exogenous stimuli producing large amount of proinflammatory cytokines including IL-1 and IL-1 family members. The role of the epidermal IL-1 is not limited to initiation of local inflammatory responses, but also to induction of systemic inflammation. However, association of persistent release of IL-1 family members from severe skin inflammatory diseases such as psoriasis, epidermolysis bullosa, atopic dermatitis, blistering diseases and desmoglein-1 deficiency syndrome with diseases in systemic organs have not been so far assessed. Here, we showed the occurrence of severe systemic cardiovascular diseases and metabolic abnormalities including aberrant vascular wall remodeling with aortic stenosis, cardiomegaly, impaired limb and tail circulation, fatty tissue loss and systemic amyloid deposition in multiple organs with liver and kidney dysfunction in mouse models with severe dermatitis caused by persistent release of IL-1s from the skin. These morbid conditions were ameliorated by simultaneous administration of anti-IL-1α and IL-1β antibodies. These findings may explain the morbid association of arteriosclerosis, heart involvement, amyloidosis and cachexia in severe systemic skin diseases and systemic autoinflammatory diseases, and support the value of anti-IL-1 therapy for systemic inflammatory diseases

KCASP1Tg and KIL-18Tg(+) mice showed emaciation and altered lipid metabolism in addition to dermatitis.

<p><b>A</b>) KCASP1Tg mice had erosive dermatitis at week 8, which spread across the entire face and trunk when mice were 5-months old. KIL-18Tg mice showed no dermatitis at 6 months of age, KIL-18Tg(−). Weight loss began at 10 weeks in KCASP1Tg mice, but not in age matched KIL-18Tg mice (n = 10, each group). The left Y-axis shows body weight and the right Y-axis shows the percentage of dermatitis. KIL-18Tg mice developed dermatitis at 1-year old, followed by weight loss, KIL-18Tg(+) (n = 7, each group) (*p<0.05, **p<0.001, ***p<0.0001). <b>B</b>) CT scan of KCASP1Tg mice at 6 months of age revealed a dramatic decrease in visceral fat as shown in yellow compared to normal control or KIL-18Tg(−) mice. Eighteen-year old KIL-18Tg(+) showed decreased visceral fat. Subcutaneous fat (in orange color) was also decreased in KCASP1Tg and KIL-18Tg(+). <b>C</b>) A comparison of the somatic fat ratio across the three groups determined by CT scan at 2, 4 and 6 months of age, and a decrease was observed in KCASP1Tg mice compared to the other two groups (n = 6, each group). <b>D</b>) Six-month-old KCASP1Tg mice showed decreased plasma HDL cholesterol and leptin levels, as well as increased triglyceride levels. LDL cholesterol and adiponectin levels remained normal. Eighteen-months old KIL-18Tg(+) mice showed decreased leptin levels. No significant change was identified in the triglyceride, HDL and LDL cholesterol, and adiponectin levels in KIL-18Tg(+) mice. <b>E</b>) Plasma IL-1α and β levels were elevated in 6-months old KCASP1Tg mice. IL-1 levels were under the detection limit in KIL-18Tg(−) mice, but were elevated in 18-months old KIL-18Tg(+) mice. Plasma IL-18 levels were increased in both KCASP1Tg and KIL-18Tg mice (n = 10).</p

KCASP1Tg and KIL-18Tg(+) mice developed amyloidosis in the liver, kidney and spleen.

<p><b>A</b>) Histological analyses showed loss of normal architecture: hepatocytes were replaced by dense deposits in the liver, the glomeruli and renal tubules were damaged in the kidney, and lymph-follicles were absent in the spleen. Dense amyloid deposition was detected in KCASP1Tg and KIL-18Tg(+) mice by Congo-red staining. <b>B</b>) KCASP1Tg mice showed mild liver and kidney dysfunction while renal function had significantly deteriorated in KIL-18Tg(+) mice (n = at least 7).</p

High serum amyloid A protein and organomegaly in KCASP1Tg and KIL-18Tg(+) mice.

<p><b>A</b>) Serum amyloid A protein (SAA) levels were significantly higher in KCASP1Tg mice than in normal control and 6-months old KIL-18Tg(−) mice. Eighteen-months old KIL-18Tg(+) mice also showed elevated SAA concentration (n = at least 7). <b>B</b>) <b>C</b>) The liver, kidney, and spleen of both KCASP1Tg and KIL-18Tg(+) mice were significantly enlarged compared to control and KIL-18Tg(−) mice.</p

Cardiovascular findings in KCASP1Tg and KIL-18Tg(+).

<p><b>A</b>) Six-months old KCASP1Tg mice had significantly heavier hearts compared to normal control and KIL-18Tg(−) mice. The heart weight of 18-months old KIL-18Tg(+) mice was also increased (n = 6, each group). <b>B</b>) The maximal tension produced in an 1 mm ring segment obtained from normal and KCASP1Tg mice is shown. The strength of the snapping point of the aorta ring from KCASP1Tg mice was significantly lower than in those from control mice (n = 12, each group). <b>C</b>) Thermography showed deterioration of peripheral blood circulation in the lower limbs and tail in 6-months old KCASP1Tg and 18-months old KIL-18Tg(+) mice. <b>D</b>) Both systolic and diastolic pressures were significantly lower in KCASP1Tg and KIL-18Tg(+) mice, (n = 10, each group) compared to control or KIL-18Tg(−) mice.</p

IL-1α and IL-1β trigger fat tissue remodeling.

<p><b>A</b>) KCASP1Tg mice were treated once-a-week with an intra-peritoneal injection of 10 µg anti-IL-1α and/or IL-1β neutralizing antibodies between 4 to 24 weeks of age. PBS-treated KCASP1Tg littermates were used as controls. The body weight loss was ameliorated by either anti-IL-1α, anti-IL-1β or anti-IL-1α/β administration, (n = 7, each group). <b>B</b>) Emaciation was reproduced by administering 1 µg of recombinant IL-1α or IL-1β protein 3 times per week from 6 to 16 weeks of age to wild type mice compared to PBS-injected mouse controls from 6 to 16 weeks (n = 6, each group). <b>C</b>) H&E staining of abdominal adipose tissue revealed that the adipocytes were large and plump in shape in normal control and 6-months old KIL-18Tg(−) mice; they were small and round, however, in 6-month-old KCASP1Tg and 18-months old KIL-18Tg(+) mice. The number of infiltrating mononuclear cells was similar among these groups (n = 7, each group). <b>D</b>) Cytokine levels in the skin culture supernatant were measured by flow cytometry. IL-1α and IL-1β were detected in conditioned medium from the skin culture of normal control mice and KIL-18Tg(−) mice, but was significantly higher in medium from skin culture of KCASP1Tg mice (n = 7, each group). <b>E</b>) Mouse adipose cells cultured in regular medium contained abundant lipid drops on day 14. The addition of supernatant from normal skin culture revealed a decrease in the number of plump adipocytes containing lipids as stained with oil red O, which was reversed by supplementing with supernatant from KCASP1Tg mice skin culture. The pretreatment of KCASP1Tg mice skin culture medium with anti-IL-1α or anti-IL-1β neutralizing antibodies partially ameliorated the inhibitory effects on adipose cells, which were almost abrogated by simultaneous treatment with both antibodies (n = 7, each group).</p

KCASP1Tg and KIL-18Tg(+) mice developed arteriosclerosis with impaired peripheral blood circulation.

<p><b>A</b>) H and E staining of aorta sections revealed stenosis in 6-months old KCASP1Tg and 18-months old KIL-18Tg(+) mice. EVG staining revealed no significant changes in terms of periaortic lesions or elastic fibers. <b>B</b>) Enhanced CT scans revealed the presence of aortic stricture in KCASP1Tg and KIL-18Tg(+) mice. <b>C</b>) The aorta diameter in KCASP1Tg and KIL-18Tg(+) mice was decreased compared to normal control and KIL-18Tg(−) mice (n = 6, each group). <b>D</b>) Three-dimensional CT images showed the presence of aortic stenosis in KCASP1Tg and KIL-18Tg(+) mice.</p