Tomato paste rich in lycopene protects against cutaneous photodamage in humans in vivo: a randomized controlled trial.

BACKGROUND: Previous epidemiological, animal and human data report that lycopene has a protective effect against ultraviolet radiation (UVR)-induced erythema. OBJECTIVES: We examined whether tomato paste--rich in lycopene, a powerful antioxidant--can protect human skin against UVR-induced effects partially mediated by oxidative stress, i.e. erythema, matrix changes and mitochondrial DNA (mtDNA) damage. METHODS: In a randomized controlled study, 20 healthy women (median age 33 years, range 21-47; phototype I/II) ingested 55 g tomato paste (16 mg lycopene) in olive oil, or olive oil alone, daily for 12 weeks. Pre- and postsupplementation, UVR erythemal sensitivity was assessed visually as the minimal erythema dose (MED) and quantified with a reflectance instrument. Biopsies were taken from unexposed and UVR-exposed (3 × MED 24 h earlier) buttock skin pre- and postsupplementation, and analysed immunohistochemically for procollagen (pC) I, fibrillin-1 and matrix metalloproteinase (MMP)-1, and by quantitative polymerase chain reaction for mtDNA 3895-bp deletion. RESULTS: Mean ± SD erythemal D(30) was significantly higher following tomato paste vs. control (baseline, 26·5 ± 7·5 mJ cm(-2); control, 23 ± 6·6 mJ cm(-2); tomato paste, 36·6 ± 14·7 mJ cm(-2); P = 0·03), while the MED was not significantly different between groups (baseline, 35·1 ± 9·9 mJ cm(-2); control, 32·6 ± 9·6 mJ cm(-2); tomato paste, 42·2 ± 11·3 mJ cm(-2)). Presupplementation, UVR induced an increase in MMP-1 (P = 0·01) and a reduction in fibrillin-1 (P = 0·03). Postsupplementation, UVR-induced MMP-1 was reduced in the tomato paste vs. control group (P = 0·04), while the UVR-induced reduction in fibrillin-1 was similarly abrogated in both groups, and an increase in pCI deposition was seen following tomato paste (P = 0·05). mtDNA 3895-bp deletion following 3 × MED UVR was significantly reduced postsupplementation with tomato paste (P = 0·01). CONCLUSIONS: Tomato paste containing lycopene provides protection against acute and potentially longer-term aspects of photodamage.

A short-term screening protocol, using fibrillin-1 as a reporter molecule, for photoaging repair agents.

Photoaged skin is characterized by coarse and fine wrinkles. The mechanisms of wrinkle formation are undetermined, but appear to be due to changes within the matrix of the dermis and at the dermal-epidermal junction. Previous studies have identified marked reductions in procollagens I and III, collagen VII, and the fibrillin-rich microfibrillar apparatus in this area. Topically applied all-trans retinoic acid can repair photoaged dermal matrix, but this takes at least 6 mo of treatment. In this study, we have examined the abundance and distribution of fibrillin-1 prior to, and following, 192 wk of all-trans retinoic acid treatment. We have further developed a short-term protocol to determine the utility of potential repair agents, using fibrillin-1 as the marker for outcome. Individuals with clinically assessed severe photoaging were recruited to the study (n = 8). 0.025% all-trans retinoic acid, 5% sodium lauryl sulfate (irritant control), or vehicle were applied under occlusion to photoaged extensor forearm. A fourth control area was also occluded. After 96 h, punch biopsies were taken under local anesthesia and processed for either transmission electron microscopy or snap frozen. Frozen sections were prepared for immunohistochemistry and in situ hybridization immunohistochemistry. Electron microscopy revealed aberrant elastic fibers in the papillary dermis of photoaged forearm skin, with sparse microfibrillar apparatus and interstitial collagen. After application of 0.025% all-trans retinoic acid, there was increased deposition of both these dermal matrix components, with the aberrant elastic fibers no longer apparent. Significant increases (p < 0.05) were observed at the protein and mRNA levels for fibrillin-1 following all-trans retinoic acid and sodium lauryl sulfate treatments, with all-trans retinoic acid having a significantly greater effect than irritant control (p < 0.001); however, neither application had significant effect on the abundance of collagen VII or its mRNA. Investigation of collagen I synthesis revealed no difference following treatments. To ascertain the clinical relevance of using fibrillin-1 as a marker for photoaging, facial skin was biopsied at baseline and after long-term (192 wk) topical all-trans retinoic acid treatment (n = 5). Biopsies were wax-embedded and sections prepared for immunohistochemistry for fibrillin-1. Significant increases in the abundance of the microfibrillar apparatus was observed proximal to the dermal- epidermal junction (p < 0.001) following long-term all-trans retinoic acid application. This study indicates that all-trans retinoic acid can significantly affect fibrillin-1 content in photoaged skin. Furthermore, fibrillin-1 can be used as a "reporter" molecule in short-term protocols for testing the utility of topical agents in the repair of photoaged skin.

The hypothalamic ventromedial nucleus sends a met-enkephalin projection to the preoptic area's periventricular zone in the female rat.

The female but not the male rat possesses a dense network of methionine enkephalin (m-Enk) fibers in the periventricular zone of the preoptic area (pePOA). The potential source of these fibers was determined by injection of the tracer fluorogold, FAu, into the preoptic area of adult female rats. Twenty-four hours before they were killed, the rats were administered colchicine (intraventricularly) to enable immunocytochemical visualization of m-Enk cells. Upon examination of the brains with fluorescence microscopy, double-labeled cells showing fluorogold and immunofluorescence for m-Enk were consistently observed in the preoptic area, the ventrolateral division of the ventromedial nucleus of the hypothalamus (VMHvl) and nearby medial tuberal area (MTA), the arcuate nucleus, periventricular area of the hypothalamus, perifornical area, and dorsomedial nucleus of the hypothalamus. A series of lesion and knife cut experiments using glass, Halasz, and wire knives determined that the pePOA m-Enk fibers arose from the hypothalamus, near or within the VMH. Ibotenic acid lesions further determined that the source of the m-Enk projection was the VMHvl with a possible additional contribution from the MTA.

The C-type natriuretic peptide receptor is the predominant natriuretic peptide receptor mRNA expressed in rat hypothalamus.

The natriuretic peptide receptors (NPR) are membrane-bound guanylate cyclases with extracellular binding domains specific for particular members of the natriuretic peptide family. NPR-A binds atrial natriuretic peptide (ANP) with high affinity, whereas the NPR-B appears to be specific for C-type natriuretic peptide (CNP). Previous data indicating extensive overlap between localization of ANP and CNP in hypothalamic neuroendocrine circuits suggest the importance of determining whether specificity of natriuretic peptide action may be conferred via receptor type present on target cells. To address this issue, we used in situ hybridization histochemistry to localize NPR-A and NPR-B mRNA in the hypothalamus. NPR-A mRNA was not found in substantial abundance in any hypothalamic nucleus; however, detectable NPR-A signal was observed in other brain regions, including the subfornical organ and medial habenula. In contrast, NPR-B mRNA was expressed throughout the hypothalamus, including neurons of the magnocellular and parvocellular paraventricular, the arcuate, and the supraoptic nuclei. Expression was also seen in other nuclei essential to neuroendocrine control, including the median preoptic, anteroventral periventricular, tuberomammilary, ventromedial and suprachiasmatic nuclei. NPR-B mRNA was also observed in the neural lobe of the pituitary gland, suggesting expression by pituicytes. The results suggest that NPR-B is the primary natriuretic peptide receptor in hypothalamus, and by inference indicate that CNP is the primary active natriuretic peptide in neuroendocrine regulation.

Colocalization of natriuretic peptide and estrogen receptor immunoreactivities in preoptic nuclei in the female rat.

Estrogen is known to play an important role in regulating reproductive function in female rats through actions exerted at the preoptic area, a part of the brain that is markedly sexually dimorphic and which contains abundant estrogen receptors. A critical question to our understanding of estrogen's action on the brain is to identify the types of neurons that contain estrogen receptors (ER). Previous studies have shown that atrial natriuretic peptide (ANP) is in abundance in the preoptic area, and that ANP and other natriuretic peptides are capable of regulating gonadotropin secretion. In an effort to determine whether ERs are present in natriuretic peptide-immunoreactive (NP-ir) neurons in the preoptic area of the rat, double label immunocytochemistry was performed. Since ER-ir, as demonstrated with antibody H222 is known to be localized predominantly in cell nuclei, while NP-ir is present in the cytoplasm, single cells can be double labeled. Diaminobenzidine tetrahydrochloride was used for localization of NP-ir neurons, while nickel-enhanced diaminobenzidine tetrahydrochloride was used for localization of ER-ir. The results revealed that many nuclei throughout the preoptic area contained neurons that were ER-ir or NP-ir and that a substantial number were double labeled. Cell counts in selected preoptic nuclei and components, including the anteroventral periventricular nucleus, periventricular preoptic nucleus, medial part of the medial preoptic nucleus, and central part of the medial preoptic nucleus revealed that 13.6%, 11.1%, 13.5%, and 24.4%, respectively, of the NP-ir neurons in these nuclei also contained ER-ir. Collectively, a total of 14.9% of the NP-ir neurons in these nuclei also contained ER-ir.(ABSTRACT TRUNCATED AT 250 WORDS)

Localization of C-type natriuretic peptide mRNA in rat hypothalamus.

Central or peripheral administration of C-type natriuretic peptide (CNP) affects numerous neuroendocrine systems, including the hypothalamo-pituitary-gonadal, hypothalamo-pituitary-adrenocortical and hypothalamo-neurohypophysial axes. The present report characterizes the distribution of CNP mRNA in hypothalamus, providing the first definition of CNP-containing neuroendocrine circuits. In situ hybridization histochemical analysis revealed high expression of CNP mRNA in the anteroventral periventricular nucleus (AVPv) and in hypothalamic arcuate nucleus (ARC). Hybridization signals of significantly lower intensity were seen in the medial, median and periventricular preoptic area, the supraoptic, dorsomedial, ventral premammillary and lateral mammillary nuclei and in the posterior hypothalamic area. A few scattered CNP mRNA containing cells were visualized in the medial parvocellular paraventricular nucleus, posterior magnocellular paraventricular nucleus and lateral hypothalamic area. In the AVPv and ARC the pattern of CNP mRNA distribution paralleled that of ANP mRNA. The results indicate a distribution of CNP mRNA associated with key neuroendocrine systems, and underscores the potential importance of this novel natriuretic peptide in neuroendocrine regulation.

A [14C]2-deoxyglucose analysis of the functional neural pathways of the limbic forebrain in the rat. IV. A pathway from the prefrontal cortical-medial thalamic system to the hypothalamus.

The present study utilized the [14C]2-deoxyglucose (2-DG) cell labeling procedure to characterize a functional pathway from the prefrontal cortex (Pfc) and mediodorsal thalamic nucleus (MD) to the hypothalamus. Rats were injected with 2-DG prior to a 45 min experimental paradigm consisting of alternating 30 s on-off periods of electrical brain stimulation. Standard procedures were utilized for the removal and processing of brain tissue for X-ray autoradiography. In the first phase of this study, stimulation applied to the prefrontal cortex generally yielded a pattern of 2-DG distribution consistent with the findings of classical anatomical studies. Stimulation of the dorsomedial and ventromedial prefrontal cortex or the infralimbic cortex produced the most effective activation of the diencephalon. This activation was primarily limited to MD, with no involvement of any region of the hypothalamus. In the second phase of this study, brain regions activated following stimulation of sites along the rostro-caudal axis of MD were examined. Stimulation of MD resulted in the activation of the nucleus reuniens and other midline and non-specific thalamic nuclei. Stimulation of this nucleus also activated the ventromedial thalamic nucleus, medial aspects of the nucleus accumbens and the medial and sulcal prefrontal cortices. Again, in each of these cases, labeling within any region of the hypothalamus could not be detected. Since MD stimulation activated the midline thalamus, and the nucleus reuniens in particular, the last phase of this experiment involved stimulation of the nucleus reuniens in order to determine the source of medial thalamic inputs to the hypothalamus. Stimulation of the nucleus reuniens activated fibers which were distributed to both the medial and lateral hypothalamus. In addition, stimulation also activated the descending periventricular system, which could be followed to the level of the midbrain central gray and such limbic structures as the hippocampal formation, septal area, amygdala and prefrontal cortex. These findings indicate that Pfc-MD activation of the hypothalamus is achieved indirectly via interneurons within the nucleus reuniens.

A 14C-2-deoxyglucose analysis of the neural pathways of the limbic forebrain in the rat: II. The hypothalamus.

An attempt was made to characterize the nature of the functional organization of the hypothalamus by observing the patterns of uptake of 14C-2-deoxyglucose (2DG) following electrical stimulation of different regions within the preoptico-hypothalamus in the rat. The experimental paradigm consisted of electrical brain stimulation delivered continuously for periods of 30 sec on and 30 sec off for 45 minutes following injection of 2DG. Brains were removed and processed for autoradiography. Activation of the medial forebrain bundle was noted following stimulation of the nucleus accumbens and lateral preoptico-hypothalamus. Activated fibers could be followed only in a caudal direction through the medial forebrain bundle and into the ventral tegmental area as a result of nucleus accumbens stimulation. Stimulation of the lateral preoptic region or of the anterior half of lateral hypothalamus produced activation of the lateral septal nucleus, lateral habenular nucleus, perifornical region, midline thalamus and ventral tegmental area. Since stimulation of the perifornical hypothalamus significantly activated the rostro-caudal extent of the midbrain cental gray, it is suggested that impulses from the lateral hypothalamus reach the lower brainstem via its connections with the perifornical hypothalamus. Ventromedial hypothalamic stimulation activated only the lateral septal nucleus, cortico-medial amygdala and medial preoptico-hypothalamus, while medial preoptico-hypothalamic stimulation resulted in increased 2DG uptake in the midbrain central gray, thus suggesting that medial hypothalamic impulses reach the brainstem by first ascending to the level of the preoptico-hypothalamus. Mammillary body stimulation orthodromically activated fibers in the mammillothalamic and mammillotegmental tracts and antidromically fibers in the fornix for a short distance.