Radiofrequency treatments: what can we expect?

Among non-ablative procedures in aesthetic medicine, the radiofrequency (RF) is one of the most popular for the treatment of face and body skin laxity. It can be classified as a physical bio-stimulation that produces a temperature increase on biological structures, using electromagnetic waves. The term encompasses devices having substantial differences in energy, wavelengths, handpieces dimension and structure. Moreover, for some of these, the protocols are only partially defined. The aim of this short review is to clarify some aspecst of the RF therapy starting from the physics, passing through the mechanism of action and finally, with the most suitable protocols. Contrary to mechanic waves, electromagnetic waves, physics are always transversal to the impulse and this leads to the different energy distribution in capacitive (monopolar) or resistive (bi- or multi-polar) applications. The thermal damage as therapeutic effect is a postulate that needs to be discussed and the same is true for the terms “non-surgical” and “non-ablative”, often recurrent in the scientific literature. Protocols must be optimized according to the machine and the patient, keeping in mind the possibilities of biostimulation in terms of immediate improvement and of long lasting investment in skin rejuvenation. It is mandatory to understand the possibilities and limitations of each device to perform useful, safe and correct medical treatments.

THE THEORIES OF AGING: REACTIVE OXYGEN SPECIES AND WHAT ELSE?

This manuscript is a short review on the theories of aging, focusing mainly on the balance between the nutrient and the oxygen intake necessary for energy metabolism and the processes for neutralizing the negative consequences of energy production. The first section entitled “Why” provides brief historical details regarding the main group of aging theories, firstly the evolutionary theories and secondly the theories of aging related to humans, cells and biomolecules are discussed. The second section entitled ‘Where’ includes brief summaries of the many cellular levels at which aging damage can occur: replicative senescence with its genetic and epigenetic implications, cytoplasmic accumulation, mitochondrial respiratory chain dysfunction, peroxisome and membrane activity. In the third section entitled ‘How’ the linking mechanisms between the caloric restriction and the antioxidant intake on lifespan and aging in experimental models are discussed. The role of ROS is evaluated in relation to the mitochondria, the AMPK activated sirtuins, the hormesis, the target of rapamicin and the balance autophagy/apoptosis.

HYALURONIC ACID: THE USE OF ITS PRECURSOR IN SKIN BIO-STIMULATION

Bio-stimulation is an injective therapy aimed to boost the anabolic functions of dermal fibroblasts to obtain skin improvement. It can be achieved with multiple intradermal injections (0.05–0.1 ml each) of a solution of 400 mg (3 ml) of injectable glucosamine sulphate, plus 5.623 mg (3 ml) of polideoxyribonucleotide, 1 ml of lidocaine and 0.5–1 ml of sodium bicarbonate, to repeat every 7, 14, 21, and 28 days. The administration of glucosamine sulphate to skin fibroblasts is believed to lead to its incorporation in glycosaminoglycans, and thereby to the stimulation of extracellular matrix synthesis, whereas polideoxyribonucleotide possesses anti-inflammatory and regenerative capability. This study aims to elucidate the in-vitro effects of this treatment by studying what happens to several genes related to connective tissue integrity. Human dermal fibroblasts were seeded in a culture medium enriched with either two drugs alone or combined: glucosamine sulphate and/or polideoxyribonucleotide. After the end of the exposure time of 24 h, 48 h, and 72 h, the cells were trypsinized and lysed for RNA extraction. Reverse transcription to cDNA was performed directly from cultured cell lysate. Finally, the cDNA was amplified by real-time PCR and a panel of genes involved in dermal integrity was tested. Gene expression of Hyaluronan synthase 1 (HAS1), Elastine (ELN), Insulin like growth factor 1 (IGF1), Growth differentiation factor 6 (GDF6) and of a series of catabolic enzymes, such as Metalloproteases (MMP) 2, 3 and 13, the neutrophyl expressed Elastase (ELANE) and the Hyaluronidase 1 (HYAL1) were tested after 24, 48 and 72 hours of exposure to glucosamine sulphate and polideoxyribonucleotide alone or combined. All the tested genes but one were up-regulated. A negative synergism on several enzymes (particularly appreciable for Insulin-like growth factor 1 and metalloprotease 13) was observed when the two drugs were delivered together. Glucosamine sulphate acts not only as building block in the biosynthesis of glycosaminoglycan chains, but also as a booster of hyaluronan synthase 1. The association of glucosamine sulphate and polideoxyribonucleotide, used in bio-stimulation therapy protocol, has a negative synergism on catabolic genes in dermal fibroblast cultures. The present observations produce further insight into the effects of glucosamine sulphate in the biosynthesis of glycosaminoglycan chains.

Role of antioxidants in dermal aging: an in vitro study by q-RT-PCR

BACKGROUND

Reactive oxygen species production is the final step in skin aging. These unstable molecules can damage and destroy DNA, proteins, and membrane phospholipids. The aim of this study was to test the in vitro effect of an antioxidant precursor, N-acetylcysteine (NAC), on human dermal fibroblasts. NAC alone and a solution of NAC and amino acids together, used in aesthetic medicine as intradermal injection treatment, were tested.

METHODS

The expression levels of some connective related genes (HAS1, HYAL1, ELN, ELANE, DSP, GDF6, and IGF1) were analyzed on cultures of dermal fibroblasts using real-time reverse-transcription polymerase chain reaction (real time RT-PCR).

RESULTS

All genes were upregulated after 24 h of treatment.

CONCLUSIONS

An interesting effect of gene induction by administration of NAC and amino acids in vitro was demonstrated. Upregulation of elastin-, hyaluronic acid-, and GDF6-encoding genes supports the evidence of clinical improvement induced by NAC biostimulation in the prevention and correction of skin aging.

Immunochemical localization of calcium/calmodulin-dependent protein kinase I

Ca2+/calmodulin-dependent protein kinase I (CaM kinase I) was originally identified in rat brain based on its ability to phosphorylate site 1 of synapsin I. Recently a cDNA for the rat brain enzyme has been cloned and the primary structure elucidated [Picciotto et al. (1993), J. Biol. Chem., 268:26512-26521]. The rat cDNA encoded a protein of 374 amino acids with a calculated M(r) of 41,636. Antibodies have now been raised against the recombinant kinase expressed in E. coli as a glutathione-S-transferase fusion protein. Immunoblot analysis of rat cortex lysates revealed two major immunoreactive bands of approximately M(r) 38,000 and 42,000. Minor immunoreactive species of slightly lower M(r) were also detected. Two distinct CaM kinase I activities were partially purified from rat brain and shown to correspond to the two major immunoreactive species. A variety of immunoreactive species of M(r) 35-43,000 were detected in "brain" tissue from cow, zebra finch, goldfish, Xenopus, lamprey, and Drosophila. In rat brain, immunocytochemistry revealed strong staining in cortex, hippocampus, amygdala, hypothalamus, brain stem, and choroid plexus. The labelling was mainly observed in neuropil but clusters of intensely labelled neuronal cell bodies were also detected all along the neuraxis. Neuronal nuclei and glial cells did not appear to be stained. Subcellular fractionation studies confirmed the cytosolic localization of the kinase in the brain. In various rat non-neuronal tissues and in a number of cell lines, immunoreactive species of approximately M(r) 38,000 and approximately 42,000 were detected at lower levels than that detected in brain. The M(r) 38,000 and 42,000 species were also found in different ratios and at different levels in the non-neuronal tissues. These results support a role for CaM kinase I in the regulation of multiple neuronal processes. Furthermore, the widespread cell and tissue distribution suggests that CaM kinase I may function as a ubiquitous multi-functional protein kinase. Finally, the multiple immunoreactive species may represent isoforms of CaM kinase I.

Distribution of protein phosphatase inhibitor-1 in brain and peripheral tissues of various species: comparison with DARPP-32

The distribution of inhibitor-1, a cyclic AMP-regulated inhibitor of protein phosphatase-1, was analyzed in various brain regions and peripheral tissues of various species by immunolabeling of sodium dodecyl sulfate-poly-acrylamide gel transfers using specific antibodies. The distribution of inhibitor-1 was directly compared to that of DARPP-32, a structurally related cyclic AMP-regulated inhibitor of protein phosphatase-1. In rat CNS, a single immunoreactive protein of M(r) 30,000, identified as inhibitor-1, was widely distributed. In contrast, DARPP-32 was highly concentrated in the basal ganglia. Inhibitor-1 was detected in brain tissue from frog (M(r) 27,000), turtle (M(r) 29,000/33,000), canary (M(r) 26,000), pigeon (M(r) 28,000), mouse (M(r) 30,500), rabbit (M(r) 26,500), cow (M(r) 27,000), and monkey (M(r) 27,500), but not from goldfish. Inhibitor-1 was detected at various levels in most peripheral tissues of the species studied; however, it was not detectable in certain tissues of particular species (e.g., rat and cow liver). DARPP-32 was detected in brain tissue of all the species tested except frog and goldfish, but was not detectable in most peripheral tissues. Both inhibitor-1 and DARPP-32 were concentrated in the cytosol and synaptosomal cytosol of rat striatum. The developmental expressions of inhibitor-1 and DARPP-32 in rat striatum differed: the level of inhibitor-1 peaked in the first postnatal week and then declined by the third postnatal week, whereas the level of DARPP-32 increased to a peak level by the third postnatal week and remained elevated thereafter.(ABSTRACT TRUNCATED AT 250 WORDS)

Phosphorylation of the cystic fibrosis transmembrane conductance regulator

Regulation of epithelial chloride flux, which is defective in patients with cystic fibrosis, may be mediated by phosphorylation of the cystic fibrosis transmembrane conductance regulator (CFTR) by cyclic AMP-dependent protein kinase (PKA) or protein kinase C (PKC). Part of the R-domain of CFTR (termed CF-2) was expressed in and purified from Escherichia coli. CF-2 was phosphorylated on seryl residues by PKA, PKC, cyclic GMP-dependent protein kinase (PKG), and calcium/calmodulin-dependent protein kinase I (CaM kinase I). Direct amino acid sequencing and peptide mapping of CF-2 revealed that serines 660, 700, 737, and 813 as well as serine 768, serine 795, or both were phosphorylated by PKA and PKG, and serines 686 and 790 were phosphorylated by PKC. CFTR was phosphorylated in vitro by PKA, PKC, or PKG on the same sites that were phosphorylated in CF-2. Kinetic analysis of phosphorylation of CF-2 and of synthetic peptides confirmed that these sites were excellent substrates for PKA, PKC, or PKG. CFTR was immunoprecipitated from T84 cells labeled with 32Pi. Its phosphorylation was stimulated in response to agents that activated either PKA or PKC. Peptide mapping confirmed that CFTR was phosphorylated at several sites identified in vitro. Thus, regulation of CFTR is likely to occur through direct phosphorylation of the R-domain by protein kinases stimulated by different second messenger pathways.

Protein phosphotyrosine in mouse brain: developmental changes and regulation by epidermal growth factor, type I insulin-like growth factor, and insulin

Using antiphosphotyrosine antibodies, we have investigated protein phosphorylation in mouse brain during development in intact animals and in reaggregated cerebral cultures. Under basal conditions, in vivo and in vitro, the levels of two main phosphoproteins, of Mr 120,000 and 180,000 (pp180), increased with development, reaching a maximum in the early postnatal period and decreasing thereafter. In adult forebrain, pp180 was still highly phosphorylated, but it was not detected in cerebellum or in peripheral tissues. In reaggregated cortical cultures, epidermal growth factor (EGF), type I insulin-like growth factor (IGF-I), and insulin enhanced protein tyrosine phosphorylation of several proteins, which were specific for EGF or IGF-I/insulin. In highly enriched neuronal or astrocytic monolayer cultures, some proteins phosphorylated in basal conditions, or in response to EGF and IGF-I, were found in both types of culture, whereas others appeared cell type specific. In addition, in each cell type, some proteins were phosphorylated under the action of both growth factors. These results indicate that tyrosine protein phosphorylation is maximal in mouse brain during development and is regulated by growth factors in neurons as well as in astrocytes.