Hepatic microcirculation and cholangiocyte physiopathology

BACKGROUND

The peribiliary plexus (PBP) plays a fundamental role in supporting the functions of the biliary epithelium. After common bile duct ligation (BDL) progressive PBP proliferation is demonstrated. We have, recently, demonstrated that the biliary epithelium express Vascular Endothelial Growth Factor (VEGF), both subtype -A and -B and VEGF receptors. Taking in consideration the wide extension of PBP during BDL, aim of our study is to investigate the role of VEGF in stimulating angiogenesis and also in the modulation of epithelial cells proliferation.

MATERIAL AND METHODS

Experimental studies were performed by evaluating the effects of: a) endogenous VEGF neutralization by chronic administration of anti VEGF-C antibody on cholangiocyte proliferation in BDL rats and; b) the hepatic artery ligation (HAL) immediately after BDL followed by treatment (7 days) with a recombinant of VEGF-A (administered through IP implanted minipumps) on cholangiocyte proliferative activities.

RESULTS

Both administration of antiVEGF-C antibody and HAL decreases cholangiocyte proliferation. The decrease of cholangiocyte proliferation was associated with depressed VEGF-A protein expression. The administration of rVEGF-A to BDL, hepatic artery ligated rats prevented the decrease of cholangiocyte proliferation and VEGF-A expression as compared to BDL control rats.

CONCLUSION

These data suggest that VEGF-C modulates the proliferative activities of cholangiocytes in experimental cholestasis and that circulating factors (i.e., VEGF) in the blood supply of the intra-hepatic biliary epithelium, play an important role in the balance between cholangiocyte proliferation/loss.

[Neuroplasticity and depression]

Early hypotheses on the pathophysiology of mood disorders were based on aberrant intrasynaptic concentrations of the neurotransmitters serotonin and norepinephrine. However, recent neuroimaging and post mortem morphometric studies demonstrated selective structural and morphological (macroscopic and microscopic) changes across various limbic and non-limbic circuits in the brains of depressed patients. Recently, these two types of observations seem to converge at the cellular and molecular level. It has been revealed, that stress and antidepressant treatment have an opposite effect on the intracellular signaling, transcription factors and target genes. In some cases, the factors that are influenced by antidepressants (e.g. cAMP-CREB cascade, BDNF) have also been identified as important mediators of learning and memory. An evolving new hypothesis in the pathophysiology and treatment of depression involves adaptation or plasticity of neural systems. Depression could result from an inability to make the appropriate adaptive responses to stress or aversive stimuli. It is possible that antidepressant treatment could oppose these adverse cellular effects, which may be regarded as a loss of neural plasticity, by blocking or reversing the atrophy of neurons and by increasing cell survival and function.

Estrogenic restoration of functional pancreatic islet cytoarchitecture in diabetes (db/db) mutant C57BL/KsJ mice: relationship to estradiol localization, systemic glycemia, and persistent hyperinsulinemia

The diabetes (db/db) genotype mutation induces a hyperglycemic-hyperinsulinemic endometabolic state in C57BL/KsJ mice, manifesting a type 2 NIDDM diabetes-obesity syndrome (DOS) in this hyperphagic, leptin receptor (lf) defective model. The severity of the DOS induced by the single gene, homozygous-recessive mutation may be therapeutically moderated by gonadal steroids and pre-steroidal metabolites. The current studies define the estradiol (E2)-modulated phenotypic, systemic, cytochemical, and cellular metabolic responses to db/db mutation expression as compared to littermate control (+/?) indices. The db/db mutation induced dramatic age- and DOS severity-related increases in body weights, blood glucose, and serum insulin concentrations relative to +/? indices between 4-week-old (i.e., initial onset stage of DOS phenotype) and 16-week-old (i.e., chronic stage of DOS) groups. Chronic, low-dose (0.1 microg/3.5 days) E2 treatment (E2-HRx) significantly reduced the obesity mass and blood glucose levels of db/db mutants relative to oil-HRx groups. Similarly, E2-HRx maintained pancreatic glucose utilization rates and pancreatic tissue weights in db/db mutants to near +/? indices. Concurrent amelioration of db/db-enhanced pancreatic lipogenesis and islet hypercytolipidemia occurred following E2-HRx. Pancreatic islet lipo-deposition was markedly reduced in db/db mutants following E2-HRx, and the restoration of islet size and cellular insulin concentrations correlated with beta-cell cytoplasmic regranulation of insulin secretory vesicles. In chronic E2-HRx db/db groups, autoradiographic localization of (3)H-E2 was demonstrated in the nuclear compartments of regranulated, nonhypertrophic islet cell populations, including insulin-containing beta-cells. In chronic E2-HRx db/db mutants, beta-cell insulin granulation was prominent in mildly hypertrophic pancreatic islets, with cytodistribution patterns and concentrations comparable to normal +/? indices. In contrast, E2-HRx maintained the systemic hyperinsulinemia characteristic of oil-HRx db/db mutants. The results of these studies indicate that the severity of the type 2 NIDDM endometabolic syndrome induced by the db/db genotypic mutation may be influenced by E2-HRx, including reduction of the islet hypercytolipidemia and hypertrophic atrophy which are indicators of impending pancreatic involution in this mutant model. The hypercytolipidemia-induced demise of beta-cell cytoarchitecture was reduced by E2-HRx, including the reestablishment of islet beta-cell cytogranulation. These data suggest that the severity of genomic db/db-mutation expression may be modified by E2-HRx, with the gonadal steroid probably acting as a nuclear-specific stimulatory transcriptional modulator of cellular glucometabolic cascades in the absence of leptin-directed homeostatic influences.

Suppressive effect of green tea catechins on morphologic and functional regression of the brain in aged mice with accelerated senescence (SAMP10)

Green tea catechins (GT-catechins) have been reported to have an antioxidative effect. We investigated the effect of long-term GT-catechin intake on aging and oxidative damage using aged mice with accelerated senescence (SAMP10), a model of brain senescence with cerebral atrophy and cognitive dysfunction. Major atrophy was observed in the rhinencephalon, hippocampus and striatum of 12-month-old untreated SAMP10 mice. Similarly, levels of 8-oxodeoxyguanosine (8-oxodG), a marker of oxidative DNA damage, were higher in these parts of the cerebrum than in the cerebral cortex and liver. GT-catechin intake effectively suppressed such atrophy in 12-month-old SAMP10 mice. A preventive effect of GT-catechin intake on oxidative DNA damage was also observed in the rhinencephalon (an area particularly susceptible to atrophy) at 6 months of age, i.e. during the early stages of atrophy. A suppressive effect of GT-catechin intake on cognitive dysfunction, as determined by the learning time needed to acquire an avoidance response and assessments of working memory in a Y-maze, was also found in 12-month-old mice. These results suggest that GT-catechin intake partially improves the morphologic and functional alterations that occur naturally in the brains of aged SAMP10 mice.

Exogenous testosterone prevents motoneuron atrophy induced by contralateral motoneuron depletion

Gonadal steroids exhibit neuroprotective and neurotherapeutic effects. The lumbar spinal cord of male rats contains a highly androgen-sensitive population of motoneurons, the spinal nucleus of the bulbocavernosus (SNB), whose morphology and function are dependent on testosterone in adulthood. Unilateral SNB motoneuron depletion induces dendritic atrophy in contralateral SNB motoneurons, but this atrophy is reversed in previously castrated males treated with testosterone. In the present experiment we test the hypothesis that the morphology of SNB motoneurons is protected from atrophy after contralateral motoneuron depletion by exogenous testosterone alone (i.e., with no delay between castration and testosterone replacement). We unilaterally depleted SNB motoneurons by intramuscular injection of cholera toxin conjugated saporin. Simultaneously, some saporin-injected rats were castrated and immediately given replacement testosterone. Four weeks later, contralateral SNB motoneurons were labeled with cholera toxin conjugated HRP, soma sizes were measured, and dendritic arbors were reconstructed. Contralateral SNB motoneuron depletion induced somal atrophy and dendritic retraction, but testosterone treatment prevented both of these effects. Thus, the presence of high-normal levels of testosterone prevents motoneuron atrophy induced by contralateral motoneuron depletion. These data support a therapeutic role for testosterone in preventing atrophy induced by motoneuron injury.

Daily short-period gravitation can prevent functional and structural changes in arteries of simulated microgravity rats

This study was designed to clarify whether simulated microgravity-induced differential adaptational changes in cerebral and hindlimb arteries could be prevented by daily short-period restoration of the normal distribution of transmural pressure across arterial vasculature by either dorsoventral or footward gravitational loading. Tail suspension (Sus) for 28 days was used to simulate cardiovascular deconditioning due to microgravity. Daily standing (STD) for 1, 2, or 4 h, or +45° head-up tilt (HUT) for 2 or 4 h was used to provide short-period dorsoventral or footward gravitational loading as countermeasure. Functional studies showed that Sus alone induced an enhancement and depression in vasoconstrictor responsiveness of basilar and femoral arterial rings, respectively, as previously reported. These differential functional alterations can be prevented by either of the two kinds of daily gravitational loading treatments. Surprisingly, daily STD for as short as 1 h was sufficient to prevent the differential functional changes that might occur due to Sus alone. In morphological studies, the effectiveness of daily 4-h HUT or 1-h STD in preventing the differential remodeling changes in the structure of basilar and anterior tibial arteries induced by Sus alone was examined by histomorphometry. The results showed that both the hypertrophic and atrophic changes that might occur, respectively, in cerebral and hindlimb arteries due to Sus alone were prevented not only by daily HUT for 4 h but also by daily STD even for 1 h. These data indicate that daily gravitational loading by STD for as short as 1 h is sufficient to prevent differential adaptational changes in function and structure of vessels in different anatomic regions induced by a medium-term simulated microgravity.

Protective Effects of Vitamin A and Vitamin E Succinate against 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD)-Induced Body Wasting, Hepatomegaly, Thymic Atrophy, Production of Reactive Oxygen Species and DNA Damage in C57BL/6J Mice

The protective effect of vitamin A and vitamin E succinate against 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced acute toxicity and measures of oxidative stress was studied. Ten mice were treated with either vitamin A (50 mg/kg every other day for eight days) or vitamin E succiante (150 mg/kg/day followed by a dose of 40 mg/kg/day for five additional days). Half of each of the above groups of animals received TCDD on day 4. Five mice received corn oil or TCDD alone. After five days of TCDD treatment, antioxidant combination treatment with vitamin A and TCDD or vitamin E succinate and TCDD resulted in a significant reduction in indicators of acute toxicity including the decrease in total body and thymus weight as compared to TCDD alone (P<0.05). The combination treatment produced also a significant reduction in the increase in liver weight as compared to TCDD only (P<0.05). Following one day of treatment with 50 microg TCDD/kg, vitamin A and vitamin E succinate produced a significant decrease in the production of superoxide anion by peritoneal lavage cells (P<0.05) and in DNA-single strand breaks in the same cells (P<0.05) as assessed by the reduction of cytochrome c and the alkaline elution technique, respectively. A significant decrease in DNA-single strand breaks in peritoneal lavage cells was observed following 5 days treatment with 50 microg TCDD/kg (P<0.05). The results indicate a potential role for oxidative stress in the acute toxicity of TCDD and a protective effect for vitamin A and vitamin E succinate in the overall toxicity of TCDD including measures of oxidative stress.

Diabetes (db/db) mutation-induced female reproductive tract hypercytolipidemia: estrogenic restoration of utero-ovarian indices

The diabetes (db/db) mutation (leptin-receptor defect) induces a hyperglycemic-hyperinsulinemic endometabolic environment that promotes hypercytolipidemic, utero-ovarian involution in C57BL/KsJ mice, resulting in reproductive sterility and eventual organoatrophy. The effectiveness of low-dose, 17-B-estradiol therapy (E2-HRx), initiated prior to the genetic expression of the overt diabetes-obesity syndrome (DOS) on preventing female reproductive tract involution was evaluated by analysis of cytochemical, endocrine and tissue lipo-metabolic indices relative to oil (O)-vehicle treated (HRx) control (+/?) and (db/db) groups. All HRx treatments started at 4 weeks of age (i.e., pre-overt DOS stage) and continued through 16 weeks of age (i.e., chronic DOS expression) when tissue parameters were evaluated. The DOS promoted a dramatic increase in phenotypic obesity, hyperglycemia and hyperinsulinemia in (db/db) groups, relative to (+/?) indices, throughout the experimental period. In contrast, utero-ovarian weights were dramatically reduced in (db/db) groups relative to (+/?). Chronic low-dose E2-HRx moderated these DOS-induced trends in (db/db) groups, maintaining lowered body weights and normoglycemic parameters while stimulating utero-ovarian weight indices. In addition, E2-HRx prevented the dramatic hypercytolipidemic condition which promotes utero-ovarian involution in (db/db) mice as evidenced by the maintenance of normal reproductive cytoarchitecture. The concurrent moderation of tissue lipase activity and stimulated glucose uptake rates by (db/db) utero-ovarian compartments, under persistent hyperinsulinemic influences, indicated that E2-HRx effectively reduced both the structural and endometabolic consequences of the DOS from promoting (db/db)-associated reproductive organoatrophy. These results indicate that the pathophysiological alterations induced by the (db/db) mutation may be ameliorated through low-dose steroidal therapy, the efficacy of which is suspected to occur via membrane metabolic cascade induction mechanisms or by direct nuclear transcription modulation in reproductive target cells. The subsequent re-establishment of insulin-coupled glucose utilization and suppressed caloric shunting towards lipogenesis promotes the normalization of utero-ovarian structural and metabolic homeostasis in C57BL/KsJ-db/db mutants.

Impact of Disease-Modifying Therapies on Brain and Spinal Cord Atrophy in Multiple Sclerosis

Brain and spinal cord atrophy occur early in the course of multiple sclerosis (MS) and continue throughout this lifelong illness, resulting in substantial parenchymal tissue loss at later disease stages. Treatments that slow or prevent atrophy may reduce disability progression in the long term. Disease-modifying agents (DMAs) such as interferon beta-1b (IFNbeta-1b), IFNbeta-1a, and glatiramer acetate inhibit inflammatory events believed to initiate and perpetuate the disease process. DMAs have been shown to inhibit aspects of MS related to brain inflammation such as relapses and gadolinium-enhanced lesions. Because brain inflammation has been linked to irreversible brain tissue injury, DMAs should be effective in reducing the rate of brain atrophy progression. Weekly IFNbeta-1a (Avonex or Rebif) has been shown to slow the rate of brain atrophy; a large study of a frequent injection regimen with IFNbeta-1a (Rebif) showed continued atrophy progression despite IFNbeta-1a at a rate similar to placebo-treated patients. It is not clear why weekly treatment regimens with lower total doses of IFNbeta-1a would show beneficial effects on brain atrophy compared with frequent injections with larger weekly doses. This article reviews results of clinical trials that have examined the effects of DMAs on brain and spinal cord atrophy in patients with MS. Some of these agents have demonstrated positive effects in well-controlled studies, suggesting that anti-inflammatory therapy can delay or prevent the emergence of irreversible central nervous system pathology.

Topical instillation of ciliary neurotrophic factor inhibits retinal degeneration in streptozotocin-induced diabetic rats

Intraocular injections of ciliary neurotrophic factor (CNTF) or intraocular adenovirus-mediated CNTF gene transfer have been reported to inhibit retinal alterations in inherited retinal degeneration in mice strains. To investigate whether or not CNTF administered by eye drops prevents retinal degeneration in streptozotocin (STZ)-induced diabetic rats, recombinant CNTF was administered to eyes of diabetic rats (n=20) twice daily for 1 month after the onset of diabetes. The b-wave amplitude of electroretinogram in CNTF-administered diabetic rats was significantly larger than that of diabetic rats, and approached that of the controls. Atrophy of the inner plexiform layer, and cavity formation in the pigment epithelium, which were observed in diabetic rats, were prevented in CNTF-administered diabetic rats. These results indicate that CNTF administration by eye drops prevents retinal degeneration in STZ-induced diabetic rats.

Possible effects of melatonin on thymus gland after pinealectomy in rats

OBJECTIVES

The purpose of this study was to investigate the effects of pinealectomy and pinealectomy plus melatonin administration on thymus weight and histology in adult Wistar-albino rats.

METHODS

The animals were divided into three groups. Group I and Group II were designated as control (sham-pinealectomized) and pinealectomized rats, respectively. They received 10% ethanol (0.1 ml per day s.c.) alone. The rats in Group III were pinealectomized and daily injected with melatonin (3 mg/kg/0.1 ml 10% ethanol per day s.c.) commencing on the day seven after surgical operation. Injections were applied for two months.

RESULTS

The thymus atrophied and its weight decreased after pinealectomy (p<0.001). The cortico-medullary boundary could not be distinguished and in the thymus induced a loss of lymphoid elements, increased number of phagocytic macrophages and enlarged blood vessels. Melatonin prevented the thymic involution.

CONCLUSIONS

These results suggest that pinealectomy decreases thymus weight and that long-term administration of melatonin restores thymus weight to normal levels.

Preliminary evidence that estrogen protects against age-related hippocampal atrophy

Few studies have examined gender differences in hippocampal volumes, and the potential effect of estrogen on these measures has not been well studied. We used MRI to measure hippocampal volumes in elderly Mexican American men and women subjects in order to determine if there were gender differences and if estrogen replacement therapy (ERT) had an effect on hippocampal volume in postmenopausal women. MRI measures of hippocampal volumes (normalized to intracranial volume) were compared in 59 women and 38 men. Further comparisons were made between men subjects, women subjects taking ERT, and women subjects not taking ERT. There were no significant effects of gender on normalized hippocampal volumes. However, women subjects taking ERT had larger right hippocampal volumes than women subjects not taking ERT and larger anterior hippocampal volumes than men subjects and women subjects not taking ERT. These findings suggest a neuroprotective effect of estrogen.

The effect of a soy rich diet on the vaginal epithelium in postmenopause: a randomized double blind trial

BACKGROUND

A traditional asiatic phytoestrogen-rich diet is associated with a lower incidence of estrogen-dependent cancers and clinical consequences of postmenopausal estrogen deficiency. First Wilcox in 1990, showed an increase of the vaginal cell maturation with phytoestrogens on postmenopausal women, but this has not been confirmed in some subsequent studies.

METHODS

In this study, we analyzed the effects of a 6-month soy-rich diet on the vaginal epithelium of asymptomatic postmenopausal women in a randomized clinical trial. 187 women were recruited for the study and divided into three groups: a phytoestrogen rich diet group; a hormonal replacement group, and a control group. A vaginal sample for hormonal cytology was taken before and at the end of the study, and sent unnamed to a cytologist.

RESULTS

The karyopycnotic index (KI) increased significantly in the diet group and in the HRT group but not in the control group. The maturation value (MV) had an identical trend to the KI.

CONCLUSION

We conclude that a soy rich diet is efficacious in increasing the maturation indices of vaginal cells. This effect could be a useful marker of the efficacy of a dietary intervention with phytoestrogen rich foods, and should be considered during preventive interventions against menopausal effects and vaginal atrophy.

Aortic regurgitation in the heterotopic rat heart transplant: effect on ventricular remodeling and diastolic function

OBJECTIVES

Use of the heterotopic rat cardiac isograft model is limited by ventricular atrophy attributable to the left ventricle's non-working state. Previous studies indicate that increased left ventricular pressure-volume work minimizes atrophy. We used a simpler approach to increase ventricular work, imposing aortic regurgitation on the transplant. We hypothesized that this would prevent atrophy and preserve left ventricular compliance.

METHODS

We analyzed heterotopic transplants with aortic valvotomy and without aortic valvotomy (controls). Recipient native hearts served as separate controls. After 15 to 25 days, we measured cardiac wet weight, dry weight, and water content of all groups and measured echocardiographic left ventricular wall thickness and end-diastolic and end-systolic diameters in both transplant groups. Left ventricular volume infusions yielded pressure-volume data that we analyzed using regression methods.

RESULTS

Aortic regurgitant transplants weighed more than control transplants (dry weight, 0.109 +/- 0.013 g vs 0.097 +/- 0.016 g; p = 0.020, 2-way analysis of variance), but all transplants weighed less than native hearts weighed (p = 0.001). Control transplants were less compliant than regurgitant transplants (p = 0.002), but the latter were similar to their own native hearts (p = 0.34). Wall thickness decreased in regurgitant vs control transplants (p = 0.020, Student's t-test), but end-diastolic and end-systolic diameters increased (p < or = 0.001).

CONCLUSIONS

Aortic regurgitation in heterotopic transplants improves left ventricular compliance through chamber dilatation without preventing atrophy. Moderate acute aortic regurgitation affects ventricular remodeling more than it stimulates myocardial hypertrophy. Smaller end-diastolic diameter, greater wall thickness, and myocardial edema may explain decreased compliance in non-working transplants.

Interventions for the prevention of brain atrophy in multiple sclerosis : current status

The assessment of brain volume changes on serial magnetic resonance imaging (MRI) scans can provide an objective measure of the neurodegenerative component of multiple sclerosis (MS) pathology. Results from placebo-controlled and crossover clinical trials indicate that immunomodulating (e.g. recombinant interferon-beta [IFNbeta]-1a [Rebif] and IFNbeta-1b [Betaferon] and glatiramer acetate [Copaxone]) and immunosuppressive (e.g. cladribine and alemtuzumab) treatments for relapsing-remitting (RR) and secondary progressive MS lack substantial efficacy in preventing the development of brain atrophy, despite the marked effects of these treatments on clinical and MRI outcomes of disease activity. A modest but significant treatment effect on brain atrophy has been reported for patients with RRMS only in one trial of IFNbeta-1a (Avonex) and in another study of long-term corticosteroid therapy.Failure to find a significant treatment benefit in preventing brain atrophy might be the result of inadequate trial designs, including their relatively short durations, which may not be adequate to reveal beneficial effects in a chronic disease like MS. Alternatively, such a failure might indicate that treatments proven to be effective in reducing MS-related inflammation are unable to act with the same efficacy on the most severe and disabling pathological substrates of the disease. The modest correlation between MRI enhancement frequency and brain atrophy observed in the placebo groups of several trials also fits with the concept that the suppression of inflammatory activity in MS is not fully and rapidly associated with a similar effect on the global neurodegenerative process of the disease.

Effectiveness of intermittent -Gx gravitation in preventing deconditioning due to simulated microgravity

This study was designed to compare the effectiveness of daily short-duration -Gx gravity exposure in preventing adverse changes in skeletal and cardiac muscles and bone due to simulated microgravity. Tail suspension for 28 days was used to simulate microgravity-induced deconditioning effects. Daily standing (STD) at 1 G for 1, 2, or 4 h/day or centrifugation (CEN) at 1.5 or 2.6 G for 1 h/day was used to provide -Gx gravitation as a countermeasure. The results indicate that the minimum gravity exposure requirements vary greatly in different systems. Cardiac muscle is most responsive to such treatment: 1 h/day of -Gx gravitation by STD was sufficient to prevent adverse changes in myocardial contractility; bone is most resistant: 4 h/day of -Gx gravitation only partially alleviated the adverse changes in physical and mechanical properties of the femur. The responsiveness of skeletal muscle is moderate: 4 h/day of -Gx gravitation prevented mass reduction and histomorphometric changes in the soleus muscle during a 28-day simulation period. Increasing gravitational intensity to 2.6 G showed less benefit or no additional benefit in preventing adverse changes in muscle and bone. The present work suggests that system specificity in responsiveness to intermittent gravity exposure should be considered one of the prerequisites in proposing intermittent artificial gravity as a potential countermeasure.

Randomized prospective trial of the effect of induced hypergastrinemia on the prevention of pancreatic atrophy after pancreatoduodenectomy in humans

OBJECTIVE

To investigate whether gastrin has regenerative effect on the pancreas and in particular whether it prevents the atrophy of the distal pancreas after resection of pancreas in humans.

SUMMARY BACKGROUND DATA

Although pancreatic regeneration after resection is well documented in animals, atrophy rather than regeneration of the distal remnant pancreas commonly occurs following pancreatoduodenectomy in humans. Of the many factors involving pancreatic regeneration, gastrin has been shown to have trophic effect on the pancreas in an animal model.

METHODS

Between March 1999 and May 2000, a randomized prospective study was performed in 56 patients who underwent pylorus-preserving pancreatoduodenectomy for periampullary neoplasms. Patients were allocated to either a lansoprazole group or a control group. The lansoprazole members were given oral lansoprazole (30 mg/d) over 12 weeks postoperatively to induce hypergastrinemia. During the study period, 19 patients were excluded for different reasons; in the end a total of 37 patients (lansoprazole, n = 18; control, n = 19) were eligible for study. The volume of the distal pancreas as determined using thin-sectioned spiral CT data, nutritional status, and endocrine (insulin level, glucose tolerance test) and exocrine function (stool elastase) of the pancreas and serum gastrin levels were measured before surgery and 3 months after surgery. The two groups were clinically comparable.

RESULTS

Serum gastrin level was elevated in the lansoprazole group. In this group, the mean volume of the distal pancreas was reduced by 10% after pylorus-preserving pancreatoduodenectomy, whereas severe pancreatic atrophy occurred in the control group. Postoperative insulin and stool elastase levels were higher in the lansoprazole group than in the control group.

CONCLUSIONS

This study is the first prospective randomized trial of induced hypergastrinemia on the regeneration of the pancreas in humans. It may be possible to use induced hypergastrinemia in the treatment or prevention of pancreatic insufficiency following resection or injury.

[Piperazinyl estrone prevents bone loss in ovariectomized rats]

AIM

To determine the effect of piperazinyl estrone, a new estrogen derivative, on bone turnover, bone mass and uteri in ovariectomized rats.

METHODS

Female Sprague-Dawley rats were ovariectomized (OVX) or sham operated (sham) at the age of 3 months and treated with estrone (E) at 0.75 mg.kg-1.d-1, or with piperazinyl estrone (P-E) at 1 or 10 mg.kg-1.d-1, orally, for 3 months. At the time of death, the uterine weight was measured. Bone histomorphometric analysis of proximal tibial metaphyses (PTM) was performed in undecalcified sections.

RESULTS

Bone histomorphometric data showed that the percent trabecular area (% Tb.Ar) of OVX rats with bone high turnover was significantly decreased. The uteri were atrophied. The percent trabecular area (% Tb.Ar) of estrone treated group was increased in decreasing bone turnover manner. But the size and weight of uteri in this group were increased vs OVX group. The bone loss induced by OVX was preserved by P-E treatment, but the mechanism of maintaining bone is different from that of E-treated rats. P-E treatment in low dose did not decrease any bone formation indices, such as percent labeling perimeter, bone formation rate per bone volume (BFR/BV), except bone mineral apposition rate (MAR) compared with E-treated group, and maintained them at OVX level. The uteri were found to be in atrophy compared with the match dose (0.75 mg) of E-treated OVX rats. But rats treated with high dose of P-E showed the same change like E-treated group.

CONCLUSION

The finding of this study shows that lower dosage of piperazinyl estrone has effect on preventing the bone losses in OVX rats, while the bone formation and the uterus are not affected, thus supporting the hypothesis that piperazinyl estrone has the potential to prevent postmenopausal bone loss in women with less side effects.

Enteral feeding and gut atrophy

PURPOSE OF REVIEW

Because of the hypothesis that enteral feeding prevents intestinal mucosal atrophy and bacterial translocation, when fasting or malnutrition is present, nutrition support by the enteral route is usually preferred, if it is available. If nutrients are provided only parenterally intestinal mucosal mass falls dramatically in rats, but the relevance of this finding to humans has not been documented. This article reviews findings in the last 2 years relating to this dilemma.

RECENT FINDINGS

Most work continues to be done in rats and pigs, two species that demonstrate mucosal atrophy with fasting. The earlier demonstration of effects of administration of hormones and glutamine have been corroborated, but proper controls for hormones (related peptides) or glutamine (most importantly glutamate) have usually not been included. In humans mucosal atrophy does not occur except modestly (approximately 10% decrease in thickness) in some reports during catabolic conditions, such as in critical-care units. Even so, no evidence for reversal by enteral feeding has as yet been provided. On the other hand, evidence for specific gene adaptation with or without mucosal atrophy has begun to appear in animals and humans.

SUMMARY

The focus on mucosal atrophy has obscured the adaptation that may occur simultaneously to minimize the atrophy. Attention to gene adaptation during fasting and malnutrition may provide evidence, in future, for appropriate therapeutic interventions.

Estradiol absorption from vaginal tablets in postmenopausal women

OBJECTIVE

To evaluate absorption of estradiol (E2) and compare two low doses of 17 beta-E2 (25 microgram and 10 microgram) in postmenopausal women with atrophic vaginitis.

METHODS

In a double-masked, randomized, parallel-group study, 58 postmenopausal women were treated with 25 microgram or 10 microgram of 17 beta-E2 for 12 weeks. We report data for 42 eligible subjects who had serum E2 concentrations below 20 pg/mL at baseline and complete data available at the baseline visit (30 minutes before tablet insertion) and weeks 2 and 12. Serum E2 and FSH concentrations were measured at specified intervals. The area under the curve, maximal concentration, and time to maximal concentration were measured for serum E2 concentrations. Maturation values of vaginal epithelial cells were assessed as indicators of change in vaginal epithelium condition in response to treatment.

RESULTS

After 12 weeks of treatment, the area under the curve, maximal and average over 24-hour E2 concentration were higher in the 25-microgram (563 pg. hour/mL, 49 and 23 pg/mL) than in the 10-microgram (264 pg. hour/mL, 22 and 11 pg/mL) group. Seventy-four percent in the 25-microgram and 96% in the 10-microgram groups had low systemic absorption of E2, that is, area under the curve (0-24 hour) less than 500 pg/mL. All but three women who received 25 microgram had mean FSH levels below 35 mIU/mL.

CONCLUSION

Treatment with 25 or 10 microgram of 17 beta-E2 vaginal tablets resulted in low absorption of estrogen without systemic effects often associated with hormone replacement therapy. After 12 weeks of therapy for atrophic vaginitis, absorption patterns remained consistent, and women did not have accumulations of circulating E2.

Does nocturnal deactivation of the artificial urinary sphincter lessen the risk of urethral atrophy?

OBJECTIVES

To compare nocturnal deactivation with nocturnal activation of the artificial urinary sphincter (AUS) to determine whether nocturnal deactivation reduces the risk of urethral atrophy and subsequent recurrent incontinence. To the best of our knowledge, no review comparing these two approaches has been performed.

METHODS

At the Mayo Clinic, all patients are instructed to deactivate their AUS at night; at Baylor, all patients keep their AUS activated all the time. At each institution, a group of consecutive men with comparable severe urinary incontinence after radical retropubic prostatectomy were selected; 61 and 46 patients from the Mayo Clinic and Baylor, respectively, were available for review. All Mayo Clinic patients strictly adhered to nocturnal deactivation of their AUS and all 46 patients from Baylor kept their AUS activated at all times, except during voiding. Each patient was reviewed for the long-term risk of subsequent reoperation, especially regarding recurrent incontinence due to urethral atrophy.

RESULTS

Seventeen (27.8%) of the 61 patients from Mayo (mean follow-up 40 months) required a repeated operation. Of the 17 AUS failures, 6 (35%) were due to urethral atrophy. Of the 46 patients from Baylor (mean follow-up 28 months), 16 (34.7%) required a repeated operation. Of the 16 AUS failures, 10 (62%) were due to urethral atrophy. Overall, the patients who nocturnally deactivated their AUS had a 10% risk of atrophy-related incontinence compared with a 21% risk in the nocturnally activated group.

CONCLUSIONS

Although not statistically significant, nocturnal deactivation appears to decrease the risk of urethral atrophy and recurrent incontinence (10% versus 21%). Nocturnal deactivation should be considered in men who are dry at night and have sufficient motivation to lessen the risk of urethral atrophy secondary to cuff compression.

Fluoxetine inhibits dendrite atrophy of hippocampal neurons by decreasing nitric oxide synthase expression in rat depression model

AIM

To study the effect of fluoxetine on dendrite atrophy of hippocampal neurons in rat depression model.

METHODS

CMS (chronic mild stress), mimicking human depression, was used as the animal depression model. The neurons shape and numbers of nitric oxide synthase positive cells in the hippocampal subfields were measured by Nissl staining and histochemical staining of NADPH (nicotinamide adenine dinucleotide phosphate)-diaphorase respectively.

RESULTS

CMS deforms neurons in the hippocampal formation, and fluoxetine can renormalize the deformed neurons by inhibiting the nitric oxide synthase catalyzing the over-production of NO, which lead subsequently to the morphological abnormality in the circumscribed area of brain.

CONCLUSION

Fluoxetine, an antidepressant, renormalizes dendrite atrophy of hippocampal neurons by inhibiting nitric oxide synthase overexpression in rat chronic mild stress model.

[HRT: state of the art]

Hormone replacement therapy (HRT) in postmenopause represents the most advanced frontier of preventive medicine in a rapidly evolving society that aims to emphasise, today as in the past, the leading role of women. While modern medicine has extended the average life expectancy of women today, it is now the task to enhance the quality of these extra years. HRT prevents cardiovascular disease, osteoporosis, disorders relating to changes in pelvic connective tissue and genitourinary tissues, and it can also have a positive influence on the psycho-affective sphere and, perhaps, alterations in cognitive capacity. Cultural delays and alternate phases of optimism and alarm are not always backed by solid scientific knowledge. Epidemiological research over the past years has underlined the oncological risk of using estrogens, even if associated with progestin, without the necessary methodological clarity and efficacy. From the data reported in the international literature and on the basis of over ten years experience accumulated at Department B of Gynecology and Obstetrics of Turin University, it appears that the oncogenic risk in women taking HRT is not significantly higher if the indications are strictly respected and, when necessary, progestin is associated with estrogen.