Molecular mechanisms of vasculopathy and coagulopathy in COVID-19.

COVID-19 primarily affects the respiratory system and may lead to severe systemic complications, such as acute respiratory distress syndrome (ARDS), multiple organ failure, cytokine storm, and thromboembolic events. Depending on the immune status of the affected individual early disease control can be reached by a robust type-I-interferon (type-I-IFN) response restricting viral replication. If type-I-IFN upregulation is impaired, patients develop severe COVID-19 that involves profound alveolitis, endothelitis, complement activation, recruitment of immune cells, as well as immunothrombosis. In patients with proper initial disease control there can be a second flare of type-I-IFN release leading to post-COVID manifestation such as chilblain-like lesions that are characterized by thrombosis of small vessels in addition to an inflammatory infiltrate resembling lupus erythematosus (LE). Mechanistically, SARS-CoV-2 invades pneumocytes and endothelial cells by acting on angiotensin-II-converting enzyme 2 (ACE2). It is hypothesized, that viral uptake might downregulate ACE2 bioavailability and enhance angiotensin-II-derived pro-inflammatory and pro-thrombotic state. Since ACE2 is encoded on the X chromosome these conditions might also be influenced by gender-specific regulation. Taken together, SARS-CoV-2 infection affects the vascular compartment leading to variable thrombogenic or inflammatory response depending on the individual immune response status.

Sex-difference in expression and function of beta-adrenoceptors in macrovessels: role of the endothelium.

Estrogen modulates adrenergic reactivity of macrovessels, resulting in weaker α-adrenergic vasoconstriction in females than males. However, the mechanisms governing this important sex-specific difference are not well understood. We hypothesized that vessels of females express more dilatory ß-adrenoceptors, which counteract constrictive effects of α-adrenoceptors. This hypothesis was tested using aortas of normotensive (WKY) and hypertensive rats (SHR), along with human mammary artery. Selective blockade of ß1 (CGP20712) or ß3 (SR59230A), but not ß2 (ICI118,551) adrenoceptors, greatly increased α-adrenergic constriction (norepinephrine) of aorta in female SHRs, but not in male SHRs at 12 weeks of age. Consistently, the selective ß1/ß2 (isoproterenol) and ß3-adrenergic (BRL37344) relaxation was stronger in female SHRs than in males. Removal of endothelium and use of L-NMMA abolished sex-difference in α-adrenergic constriction and ß-adrenergic relaxation. Immunostainings revealed endothelial localization of ß1- and ß3-adrenoceptors. mRNA levels of aortic ß1- and ß3-, but not ß2-adrenoceptors were markedly higher in female than in male SHRs. The sex-specific differences in α-adrenergic constriction and ß-adrenoceptor mRNA levels were age-dependent, predominantly present up to 29 weeks and disappeared at 36 weeks of age. The sex-specific difference was not strain-dependent and was similarly present in normotensive WKY rats. Human mammary artery of women showed a weaker α-adrenergic constriction than arteries of men. This sex-specific difference was prominent at 45-65 years and disappeared with aging. Our results convincingly demonstrate that female macrovessels express more dilatory ß1- and ß3-adrenoreceptors than male vessels with a predominant endothelial localization. This sex-specific difference is functionally relevant in young adults and is attenuated with aging.

Sex-specific differences in age-dependent progression of aortic dysfunction and related cardiac remodeling in spontaneously hypertensive rats.

Evidence of sex-specific differences in renin-angiotensin-system (RAS) and arterial pressure has been shown in many mammals, including spontaneously hypertensive rats (SHRs). Although SHRs have been used extensively as a leading experimental model of hypertension, the effects of sex-specific differences in RAS on aortic function and related cardiac remodeling during aging and hypertension have not been documented in detail. We examined structural and functional changes in aorta and heart of female and male SHRs at the ages of 5, 14, 29, and 36 wk. SHRs of both sexes were hypertensive from 14 wk. Aortic endothelial dysfunction and fibrosis, left ventricular (LV) hypertrophy, and cardiac fibrosis were evident at the age of 29 wk in male SHRs but first appeared only at the age of 36 wk in female SHRs. There was a pronounced delay of matrix metalloproteinase-2 activity in the aorta and heart of female SHRs, which was associated with preservation of 40% more elastin and less extensive cardiac fibrosis than in males. At 5, 29, and 36 wk of age, female SHRs showed higher levels of aortic and myocardial AT2R and MasR mRNA and decreased ANG II-mediated aortic constriction. Although female SHRs had increased relaxation to AT2R stimulation at 5 and 29 wk compared with males, this difference disappeared at 36 wk of age. This study documents sex-specific differences in the temporal progression of aortic dysfunction and LV hypertrophy in SHRs, which are independent of arterial pressure and are apparently mediated by higher AT2R expression in the heart and aorta of female SHRs.

[Localized scleroderma]. / Lokalisierte Sklerodermie.

Localized scleroderma (LS), also called circumscribed scleroderma or morphea, comprises a heterogeneous group of diseases that can be classified into four subtypes: limited, linear, generalized, and mixed LS. All manifestations are primarily due to chronic progressive fibrosis of the skin or structures close to the skin. Involvement of internal organs or the transition to systemic sclerosis is excluded by definition. A distinction is made between forms that primarily affect the skin (up to the dermis) or that severely involve subcutaneous fat tissue, muscle fascia or muscles. A detailed examination is required for clinical diagnosis. In order to improve comparability of findings, photo documentation and the use of clinical scores should be carried out. For superficial subtypes the use of topical glucocorticosteroids, calcineurin inhibitors or phototherapy is initially recommended, whereas for severe forms with deep involvement or overall therapy refractoriness, the diagnosis should first be expanded and systemic therapy initiated at an early stage. Especially, in cross joint or extremity-dominant forms of linear LS or in cases with head and neck involvement, such as en coup de sabre, Parry-Romberg syndrome and other subtypes with a prominent musculoskeletal affection, an MRI examination should be arranged. Depending on location, an ophthalmological, neurological, orthodontic, rheumatological or orthopedic consultation may be necessary. For systemic therapy, methotrexate alone or in combination with systemic glucocorticosteroids as pulse therapy is recommended as first-line treatment.