Polyploidization and Hemiploidization Induced by PUVA <i>in viv</i><i>o</i>

Abstract

To obtain additional information on the in vivo injury induced by PUVA treatment, primary cultures were initiated from biopsies of the uninvolved skin of 15 PUVA-treated psoriatic patients, and the cells generated were analysed for morphological and chromosomal modifications. Three biopsies were obtained from each patient, the first one before commencing PUVA therapy (control) and the other two during the course of therapy. It was found that PUVA treatment has diverse effects on the mitotic activity, mitotic mechanisms and chromosomes of the cutaneous cells: (1) an inhibition of cell proliferation during the early stages of therapy followed by a reversion to normal proliferation as the PUVA treatments were continued; the production of (2) cells with more than one nucleus, (3) macrocells, (4) cells with micronuclei, (5) polyploid cells, (6) haploid cells, (7) cells with 13 chromosomes denoting a twofold reduction in the normal number of metaphase chromosomes, (8) end-associations of the chromosomes as in the pachytene phase of meiosis (9) diplotene chromosomes, and (10) chromosomal translocations.

Long‐term growth arrest of PUVA‐treated fibroblasts in G2/M in the absence of p16INK4a, p21CIP1 or p53

“…The large proportion of cells < 4C at 28 days may be due to endoreduplication leading to polyploid fibroblasts with a 4C content. In fact, polyploidization has been described after PUVA treatment (3). Alternatively, as suggested by the results after blocking DNA replication by hydroxyurea this DNA synthesis may represent unscheduled DNA synthesis due to repair.…”

“…The planar structure of psoralens facilitates their intercalation between DNA base pairs and – after photocyclo‐addition reactions – their covalent binding to DNA upon photoexcitation. Therefore, in addition to oxidative damage psoralen photoactivation generates mono‐ and biadducts leading to DNA interstrand cross‐links with increased chromosome breakage and DNA fragmentation (2), poly‐ and hemiploidization (3).…”

“…Therefore, in addition to oxidative damage psoralen photoactivation generates mono-and biadducts leading to DNA interstrand cross-links with increased chromosome breakage and DNA fragmentation (2), poly-and hemiploidization (3).…”

Ultrastructural Studies on the Effect of Photoactivated 8‐methoxy Psoralen

“…While their report was mainly based on light microscopic examinations, we have studied the ultrastructural events. Examining the chromosomal alterations due to PUVA exposure, Omar et al ( 6 ) argue that multimicronucleate cells are formed by miotic division in G I phase of the cell cycle. At the ultrastructural level we found that multimicronucleate cells contain bizarre nuclear elements interconnected by heterochromatic extensions.…”

Labial Salivary Gland Polykaryocytes: Virus- or Hormone-Related Change?

“…Of note would also be that polykaryocytes may occur after PUVA (psoralen and ultraviolet A) therapy. 8 Although the patient was diagnosed with psoriasis vulgaris 15 years before the salivary gland biopsy, it is questionable whether an eventual PUVA treatment might have an impact on the present salivary gland lesions.…”