Protection from ultraviolet damage and photocarcinogenesis by vitamin d compounds

© Springer Nature Switzerland AG 2020. Exposure of skin cells to UV radiation results in DNA damage, which if inadequately repaired, may cause mutations. UV-induced DNA damage and reactive oxygen and nitrogen species also cause local and systemic suppression of the adaptive immune system. Together, these changes underpin the development of skin tumours. The hormone derived from vitamin D, calcitriol (1,25-dihydroxyvitamin D3) and other related compounds, working via the vitamin D receptor and at least in part through endoplasmic reticulum protein 57 (ERp57), reduce cyclobutane pyrimidine dimers and oxidative DNA damage in keratinocytes and other skin cell types after UV. Calcitriol and related compounds enhance DNA repair in keratinocytes, in part through decreased reactive oxygen species, increased p53 expression and/or activation, increased repair proteins and increased energy availability in the cell when calcitriol is present after UV exposure. There is mitochondrial damage in keratinocytes after UV. In the presence of calcitriol, but not vehicle, glycolysis is increased after UV, along with increased energy-conserving autophagy and changes consistent with enhanced mitophagy. Reduced DNA damage and reduced ROS/RNS should help reduce UV-induced immune suppression. Reduced UV immune suppression is observed after topical treatment with calcitriol and related compounds in hairless mice. These protective effects of calcitriol and related compounds presumably contribute to the observed reduction in skin tumour formation in mice after chronic exposure to UV followed by topical post-irradiation treatment with calcitriol and some, though not all, related compounds

CAPTOPRIL COMPARED TO ATENOLOL IN MILD TO MODERATE HYPERTENSION IN A RANDOMIZED DOUBLE-BLIND CONTROLLED TRIAL

After screening a local population in the northern part of The Netherlands for hypertension, 125 patients (116 of whom had not previously used antihypertensive drugs) with a five times elevated diastolic pressure (DP) of between 95 and 130 mmHg were randomized and treated daily either with atenolol 50 mg o.d. (n = 62) or with captopril 25 mg b.i.d. (n = 63) for 2 months under double-blind conditions. During this period the DP fell by 9 mm under atenolol (from 107 +/- 8 to 98 +/- 8) and by 8 mm under captopril (from 107 +/- 7 to 99 +/- 9). The number of responders with a DP = <90 mmHg was 21% and 20%, respectively. After 2 months the double-blind period was ended and the patients were submitted to a medication protocol for another 4 months in which an increased dose and additional nifedipine were given to non-responders. The response rate rose to 76% (atenolol/nifedipine combination) and to 60% (captopril/nifedipine combination) - NS. It is concluded that low doses of atenolol and captopril are equally effective in lowering blood pressure in uncomplicated mild to moderate hypertension