Steroid hormone alterations following induction of chronic intraperitoneal sepsis in male rats

Navigating Post-Traumatic Osteoporosis: A Comprehensive Review of Epidemiology, Pathophysiology, Diagnosis, Treatment, and Future Directions

Post-traumatic osteoporosis (PTO) presents a significant challenge in clinical practice, characterized by demineralization and decreased skeletal integrity following severe traumatic injuries. This literature review manuscript addresses the knowledge gaps surrounding PTO, encompassing its epidemiology, pathophysiology, risk factors, diagnosis, treatment, prognosis, and future directions. This review emphasizes the complexity of the etiology of PTO, highlighting the dysregulation of biomineralization processes, inflammatory cytokine involvement, hormonal imbalances, glucocorticoid effects, vitamin D deficiency, and disuse osteoporosis. Moreover, it underscores the importance of multidisciplinary approaches for risk mitigation and advocates for improved diagnostic strategies to differentiate PTO from other musculoskeletal pathologies. This manuscript discusses various treatment modalities, including pharmacotherapy, dietary management, and physical rehabilitation, while also acknowledging the limited evidence on their long-term effectiveness and outcomes in PTO patients. Future directions in research are outlined, emphasizing the need for a deeper understanding of the molecular mechanisms underlying PTO and the evaluation of treatment strategies' efficacy. Overall, this review provides a comprehensive overview of PTO and highlights avenues for future investigation to enhance clinical management and patient outcomes.

Sepsis-Induced Myocardial Dysfunction (SIMD): the Pathophysiological Mechanisms and Therapeutic Strategies Targeting Mitochondria

Sepsis is a lethal syndrome with multiple organ failure caused by an inappropriate host response to infection. Cardiac dysfunction is one of the important complications of sepsis, termed sepsis-induced myocardial dysfunction (SIMD), which is characterized by systolic and diastolic dysfunction of both sides of the heart. Mechanisms that contribute to SIMD include an excessive inflammatory response, altered circulatory, microvascular status, nitric oxide (NO) synthesis impairment, endothelial dysfunction, disorders of calcium regulation, cardiac autophagy anomaly, autonomic nervous system dysregulation, metabolic reprogramming, and mitochondrial dysfunction. The role of mitochondrial dysfunction, which is characterized by structural abnormalities, increased oxidative stress, abnormal opening of the mitochondrial permeability transition pore (mPTP), mitochondrial uncoupling, and disordered quality control systems, has been gaining increasing attention as a central player in the pathophysiology of SIMD. The disruption of homeostasis within the organism induced by mitochondrial dysfunction may also be an important aspect of SIMD development. In addition, an emerging therapy strategy targeting mitochondria, namely, metabolic resuscitation, seems promising. The current review briefly introduces the mechanism of SIMD, highlights how mitochondrial dysfunction contributes to SIMD, and discusses the role of metabolic resuscitation in the treatment of SIMD.

Sirtuin 4 Regulates Lipopolysaccharide Mediated Leydig Cell Dysfunction

Bacterial lipopolysaccharide (LPS) is the most important contributing factor in pathogenesis of bacterial infection in male accessory glands; and it has shown to inhibit testicular steroidogenesis and induce apoptosis. The present study demonstrates that LPS causes mitochondrial dysfunction via suppression of sirtuin 4 (SIRT4); which in turn affects Leydig cell function by modulating steroidogenesis and apoptosis. LC-540 Leydig cells treated with LPS (10 µg/ml) showed impaired steroidogenesis and increased cellular apoptosis. The mRNA and protein expression of SIRT4 were decreased in LPS treated cells when compared to controls. The obtained data suggest that the c-Jun N-terminal kinase (JNK) activation suppresses SIRT4 expression in LPS treated Leydig cells. Furthermore, the overexpression of SIRT4 prevented LPS induced impaired steroidogenesis and cellular apoptosis by improving mitochondrial function. These findings provide valuable information that SIRT4 regulates LPS mediated Leydig cell dysfunction.

Bacterial lipopolysaccharide differently modulates steroidogenic enzymes gene expressions in the brain and testis in rats

Bacterial lipopolysaccharide (LPS) is a major component of the cell wall of gram negative bacteria contributing to the pathogenesis of bacterial infection, in particular in those diseases affecting central nervous system and reproductive tissues. The present work is an attempt to study the regulation of steroidogenic enzymes gene expression in the brain and testis in LPS induced rats. Adult male albino rats were administered LPS (5mg/kg BW) to induce acute inflammation. LPS administration induced severe oxidative damage in the brain and testicular tissue which was evident from decreased activities of enzymic antioxidants and increased lipid peroxidation levels. The mRNA expression of 3β-hydroxysteroid dehydrogenase (3β-HSD), 17β-hydroxysteroid dehydrogenase (17β-HSD) and androgen receptor corepressor-19kDa (ARR19) in the brain and testis were determined. The mRNA expression of 3β-HSD and 17β-HSD was increased in the brain with significant decrease in the testis at 24h and 48h in LPS treated animals. The results also demonstrated an interesting finding that LPS treatment completely represses ARR19 in the brain, while not in the testis. These findings show ARR19 might play a crucial role in regulation of neuronal and testicular steroidogenesis in inflammatory diseases.

The effects of dexamethasone on the apoptosis and osteogenic differentiation of human periodontal ligament cells

PURPOSE

The purpose of the current study was to examine the effect of dexamethasone (Dex) at various concentrations on the apoptosis and mineralization of human periodontal ligament (hPDL) cells.

METHODS

hPDL cells were obtained from the mid-third of premolars extracted for orthodontic reasons, and a primary culture of hPDL cells was prepared using an explant technique. Groups of cells were divided according to the concentration of Dex (0, 1, 10, 100, and 1,000 nM). A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed for evaluation of cellular viability, and alkaline phosphatase activity was examined for osteogenic differentiation of hPDL cells. Alizarin Red S staining was performed for observation of mineralization, and real-time polymerase chain reaction was performed for the evaluation of related genes.

RESULTS

Increasing the Dex concentration was found to reduce cellular viability, with an increase in alkaline phosphatase activity and mineralization. Within the range of Dex concentrations tested in this study, 100 nM of Dex was found to promote the most vigorous differentiation and mineralization of hPDL cells. Dex-induced osteogenic differentiation and mineralization was accompanied by an increase in the level of osteogenic and apoptosis-related genes and a reduction in the level of antiapoptotic genes. The decrease in hPDL cellular viability by glucocorticoid may be explained in part by the increased prevalence of cell apoptosis, as demonstrated by BAX expression and decreased expression of the antiapoptotic gene, Bcl-2.

CONCLUSIONS

An increase in hPDL cell differentiation rather than cellular viability at an early stage is likely to be a key factor in glucocorticoid induced mineralization. In addition, apoptosis might play an important role in Dex-induced tissue regeneration; however, further study is needed for investigation of the precise mechanism.

Antimicrobial responses in the male reproductive tract of lipopolysaccharide challenged rats

PROBLEM

Innate immune machinery including the Toll-like receptors (TLRs) confers the first line of defense mechanisms to counter pathogenic microorganisms that enter the body. The male reproductive tract is vulnerable to infection and the role of TLRs and the antimicrobial responses that operate to counter infections in this organ system are poorly understood.

METHOD OF STUDY

Caput and cauda epididymides, testes and seminal vesicles were collected at 0, 3, 6, 9, 12, 15 and 24 h from rats injected intraperitoneally with a single dose of LPS. Plasma testosterone was measured using ELISA. Expression pattern of defensins and Spag11 isoforms were analysed using RT-PCR. Immunohistochemical analyses was performed to determine SPAG11E protein expression following LPS treatment.

RESULTS

We provide the first line of evidence that the male reproductive tract induces the expression of Sperm Associated Antigen 11 (Spag11) mRNA variants and defensins when challenged with lipopolysaccharide (LPS) with a concomitant increase in protein expression. However, there was an inverse relationship between induction of antimicrobial gene expression and plasma testosterone. An increase in the mRNA levels of proinflammatory cytokines was observed parallel to the induction of Spag11 variants and majority of defensin expression in the male reproductive tract.

CONCLUSION

The increase in Spag11 and defensin mRNA in response to LPS administration demonstrates their importance in protecting the male reproductive tract during infection. Results of this study help to understand male reproductive tract innate immune defense mechanisms and to design novel peptide antibiotics to prevent sexually transmitted diseases.

Norepinephrine induces systolic failure and inhibits antiapoptotic genes in a polymicrobial septic rat model

AIMS

We examined the effect of norepinephrine (NE) infusion on left ventricular function and apoptotic genes during progression of polymicrobial sepsis.

METHODS

Male Sprague-Dawley rats (350-400 g) were made septic by intraperitoneal (i.p.) administration of 200mg/kg cecal inoculum. Sham animals received 5% dextrose water, i.p. Echocardiography was performed at baseline, 3 days and 7 days post-sepsis/sham. NE (0.6 μgkg(-1)h(-1)) was infused for 2h, before the end of day 3 of echocardiography. At the end of day 7, rats were euthanized and heart tissues harvested for isolation of total RNA. PCR was performed using RT(2) profiler™ PCR array PARN-012 (Rat apoptosis array; SuperArray, MD) using RT(2) Real-Time™ SYBR Green PCR master mix PA-012.

KEY FINDINGS

NE-infusion resulted in a significant decrease in the left ventricular ejection fraction (EF) (62.56±2.07 from the baseline 71.11±3.23, p<0.05) and fractional shortening (FS) (39.90±2.64 from the sham group 54.41±2.19, p<0.05) at 7 days post-sepsis, respectively. Super Array data revealed that during sepsis, tumor necrosis factor (TNF-α) (2.85±0.07 fold, p<0.0001), anti-apoptotic molecules, Prok2 (16.07±0.48 fold, p<0.0001) and interleukin-10 (IL-10) (23.5±0.57 fold, p<0.0001) were up regulated at day 1. At 7-days post-sepsis, CD40l g (2.49±0.54 fold, p<0.08) and Birc1b (17.8±0.58 fold, p<0.0001) were up regulated compared to the sham, 1 and 3-days post-sepsis groups.

SIGNIFICANCE

The data suggest that upregulation of a series of pro-apoptotic molecules could be responsible for systolic and diastolic dysfunction during 3 and 7 days post sepsis.

Gender differences in skin: a review of the literature

BACKGROUND

There has been increasing interest in studying gender differences in skin to learn more about disease pathogenesis and to discover more effective treatments. Recent advances have been made in our understanding of these differences in skin histology, physiology, and immunology, and they have implications for diseases such as acne, eczema, alopecia, skin cancer, wound healing, and rheumatologic diseases with skin manifestations.

OBJECTIVE

This article reviews advances in our understanding of gender differences in skin.

METHODS

Using the PubMed database, broad searches for topics, with search terms such as gender differences in skin and sex differences in skin, as well as targeted searches for gender differences in specific dermatologic diseases, such as gender differences in melanoma, were performed. Additional articles were identified from cited references. Articles reporting gender differences in the following areas were reviewed: acne, skin cancer, wound healing, immunology, hair/alopecia, histology and skin physiology, disease-specific gender differences, and psychological responses to disease burden.

RESULTS

A recurring theme encountered in many of the articles reviewed referred to a delicate balance between normal and pathogenic conditions. This theme is highlighted by the complex interplay between estrogens and androgens in men and women, and how changes and adaptations with aging affect the disease process. Sex steroids modulate epidermal and dermal thickness as well as immune system function, and changes in these hormonal levels with aging and/or disease processes alter skin surface pH, quality of wound healing, and propensity to develop autoimmune disease, thereby significantly influencing potential for infection and other disease states. Gender differences in alopecia, acne, and skin cancers also distinguish hormonal interactions as a major target for which more research is needed to translate current findings to clinically significant diagnostic and therapeutic applications.

CONCLUSIONS

The published findings on gender differences in skin yielded many advances in our understanding of cancer, immunology, psychology, skin histology, and specific dermatologic diseases. These advances will enable us to learn more about disease pathogenesis, with the goal of offering better treatments. Although gender differences can help us to individually tailor clinical management of disease processes, it is important to remember that a patient's sex should not radically alter diagnostic or therapeutic efforts until clinically significant differences between males and females arise from these findings. Because many of the results reviewed did not originate from randomized controlled clinical trials, it is difficult to generalize the data to the general population. However, the pressing need for additional research in these areas becomes exceedingly clear, and there is already a strong foundation on which to base future investigations.

Influence of Gender on Outcome of Severe Sepsis

Whether gender influences the outcome of severe sepsis remains a matter of debate. Because many confounding variables may affect observed associations between gender and mortality, high-quality statistical analyses are essential to carefully adjust the two groups of patients. About 55% to 65% of patients with sepsis have chronic co-morbidities associated with immune dysfunction (e.g., chronic renal failure, diabetes mellitus, human immunodeficiency virus [HIV] infection, and alcohol abuse), which increase the susceptibility to sepsis [1]. Genetic polymorphisms that affect the susceptibility to infection and/or the severity of the systemic response to infection [2] may lead to variability among individuals and between males and females [3]. Access to healthcare, another determinant of the incidence and outcome of sepsis, varies according to age, ethnic group, and gender, although a recent study conducted in the USA found only relatively small quality-of-care differences between males and females or across income groups compared to the gap for each subgroup between observed and desirable quality of health care [4]. Here, we review the data on the existence of, and reasons for, associations between gender and outcome of severe sepsis (Fig. 1).

Cortisol levels and adrenal reserve after successful cardiac arrest resuscitation

The postresuscitation phase after out-of-hospital circulatory arrest shares similarities with severe sepsis. Corticosteroid replacement is beneficial in patients with septic shock and adrenal dysfunction. The goal of this study was to assess baseline cortisol and adrenal reserve of out-of-hospital circulatory arrest patients after recovery of spontaneous circulation. Thirty-three consecutive patients successfully resuscitated after cardiac arrest were prospectively included between March 2002 and June 2003. A serum cortisol assay and a corticotropin test (250 microg i.v.) were done 6 to 36 h after circulatory arrest. A cortisol increase smaller than 9 microg/dL after corticotropin (nonresponders) defined adrenal reserve insufficiency. Response status was compared in the three outcome groups: survival with full neurologic recovery (n = 4), early death from refractory shock (n = 10), or later death from neurologic dysfunction (n = 19). Patients who died of early refractory shock had lower baseline cortisol levels than patients who died of neurologic dysfunction (27 microg/dL [15-47] vs. 52 microg/dL [28-73], respectively; P < 0.01), suggesting an inadequate adrenal response to severe systemic inflammation. Corticotropin response status was not associated with standard severity markers and seemed uninfluenced by therapeutic hypothermia. In conclusion, patients who die of early refractory shock after cardiopulmonary resuscitation may have an inadequate adrenal response to the stress associated with this condition. Thresholds for cortisol levels at baseline and after corticotropin need to be determined in this clinical setting.

Bacterial endotoxin lipopolysaccharide and reactive oxygen species inhibit Leydig cell steroidogenesis via perturbation of mitochondria

Chronic inflammatory disease and acute infection are well known to inhibit gonadal steroidogenesis. Previous studies have demonstrated that immune activation in response to lipopolysaccharide (LPS) results in reductions in serum testosterone, and this is a direct effect on the Leydig cell. We hypothesize that during the early onset of LPS endotoxemia in vivo, testicular macrophages produce reactive oxygen species (ROS) leading to perturbation of Leydig cell mitochondria and an inhibition in steroidogenesis. To investigate the mechanism of LPS inhibition of Leydig cell steroidogenesis, alterations in mitochondria and markers of oxi-dative stress were assessed in vivo and in Leydig cell pri- mary culture. After a single injection of mice with LPS, serum testosterone was significantly decreased within 2 h. LPS injection of mice resulted in significant reductions in steroidogenic acute regulatory protein (StAR) and 3beta-hydroxysteroid dehydogenase-Delta4-Delta5 isomerase (3beta-HSD) proteins. LPS significantly increased lipid peroxidation of Leydig cell membranes, indicating that LPS results in oxidative damage in vivo. Mitochondria in Leydig cells isolated from LPS-injected mice were disrupted and showed a marked reduction in the mitochondrial membrane potential (DeltaPsim). Similar to the effects of LPS, treatment of Leydig cells with hydrogen peroxide acutely inhibited steroidogenesis, reduced StAR and 3beta-HSD protein levels, and disrupted DeltaPsim. These results suggest that LPS acutely inhibits Leydig cell function by ROS-mediated disruption of Leydig cell mitochondria. Taken together, these results demonstrate the necessity of having respiring mitochondria with an intact DeltaPsim to facilitate StAR function and Leydig cell steroidogenesis. The acute effects of LPS demonstrate how sensitive Leydig cell mitochondrial steroidogenesis is to inflammation-induced oxidative stress.

Ethanol and burn injury: estrogen modulation of immunity

A good deal of clinical evidence supports the idea that ethanol exposure is a causative factor in the occurrence of burn or other traumatic injury. In addition, more recent evidence reveals that individuals who sustain injury while under the influence of ethanol suffer from increased morbidity and mortality compared with those with comparable injuries who did not consume ethanol. Many of the complications seen in ethanol-exposed, burn-injured subjects result from depressed immune responses, which render the host unable to fight off infectious organisms. Both injury and ethanol exposure independently affect cellular immune responses, including delayed-type hypersensitivity and splenocyte proliferative responses, and the combined insult of ethanol exposure and injury acts in conjunction to increase further the magnitude and duration of immunosuppression. It is interesting that these immune responses can be restored experimentally in male, but not in female, mice by administration of low, proestrous levels of estrogen. The complexity of the responses after injury in ethanol-exposed subjects is multiplied when the sex of the subjects is added to the equation. This is due, in part, to the effect of the combined insult of injury and ethanol on the production of gonadal steroid hormones in males and females and the direct effects of those hormones on cytokine gene expression in sensitive cell types such as the macrophage. Evidence seems to indicate that cellular immune responses after ethanol exposure and burn injury differ in kinetics and magnitude for male and female subjects, and, hence, the therapeutic interventions to treat burn-injured patients should take into account both sex and ethanol exposure.

Closure of Abdominal Wall Defects Using Acellular Dermal Matrix

BACKGROUND

After some abdominal surgical procedures, the abdominal wall defect may be too large for closure by tension-free approximation of the wound margins because of tissue loss or swelling of the abdominal viscera. A variety of absorbable and nonabsorbable prosthetic materials have been used for emergency abdominal wall reconstruction. Of these materials, polytetrafluoroethylene (PTFE) sheets have proved to be the most efficacious.

METHODS

This study compared the efficacy of allogenic acellular dermal matrix (ADM) and PTFE as prosthetic materials for wound closure in rats with surgical, full-thickness, 2 x 3-cm abdominal wounds. Healing was studied among animals with and those without experimentally induced peritonitis for 21 days after surgery.

RESULTS

Acellular dermal matrix became vascularized and incorporated into the wound bed and was partially or fully epithelialized without the need for skin grafting. As a result, little superficial bleeding was seen, and ADM effectively closed the wounds even in the presence of peritonitis. Wounds treated with ADM also showed a significant reduction in wound area (sterile:p < 0.001; contaminated:p < 0.05). In contrast, PTFE temporarily closed the wounds, but was not incorporated into them. It consequently evoked the formation of extensive underlying granulation tissue that showed significant superficial bleeding when the PTFE was removed. Very limited wound contraction occurred in PTFE-treated wounds, and some instances of evisceration and fistula formation were observed. Wounds treated with both types of material showed significant amounts of adhesion to visceral organs underlying the wound site.

CONCLUSIONS

Acellular dermal matrix exhibits a number of favorable features relative to PTFE for closing sterile or contaminated full-thickness abdominal wall defects.

Intratesticular delivery of tumor necrosis factor-alpha and ceramide directly abrogates steroidogenic acute regulatory protein expression and Leydig cell steroidogenesis in adult rats

Systemic or intratesticular release of TNF alpha and IL1 beta have been implicated in the reduced testosterone biosynthesis and impaired production of competent spermatozoa found in human patients suffering from sepsis or chronic inflammation. Although in vitro and in vivo studies have demonstrated that TNF alpha and IL1 beta intercept the hypothalamic-pituitary testis axis at different levels, the site(s) of action and relative contribution of each cytokine to the overall testicular failure associated to systemic inflammatory processes remains poorly defined. In this study we show that intratesticular delivery of TNF alpha induced a rapid (4 h) and sustained (up to 24 h) reduction in steroidogenic acute regulatory (StAR) protein expression and testosterone biosynthesis in nonstimulated or human chorionic gonadotropin-treated intact or hypophysectomized rats. Bilateral treatment with cell-permeant short-chain ceramides (C2-cer or C6-cer) reproduced the early (4 h) inhibitory action of TNFalpha on testosterone biosynthesis and testicular StAR expression. The inhibitory action of C2-cer or C6-cer was not observed in animals treated with inactive analogs (dihydroceramide), phosphorylcholine, sphingosine, or sphingosine-1P. In sharp contrast to the previously described ability of IL1 beta to prevent human chorionic gonadotropin-stimulated Leydig cell steroidogenesis in vitro, serum testosterone and testicular StAR protein expression remained unchanged in animals bilaterally injected with this cytokine. These data support the concept that TNF alpha triggers different effector mechanisms to directly inhibit Leydig cell StAR expression and steroidogenesis, which ultimately contribute to the global reproductive failure associated with chronic inflammation and sepsis.

Metalloendopeptidase Inhibition Regulates Phosphorylation of p38???Mitogen-Activated Protein Kinase and Nitric Oxide Synthase in Heart After Endotoxemia

We tested the hypothesis that metalloendopeptidase inhibition using phosphoramidon during induction of endotoxemia 24 h later would down-regulate the protein expression of myocardial inducible nitric oxide synthase (iNOS) and phosphorylation of p38-mitogen-activated protein kinase (p38-MAPK). Male Sprague-Dawley rats (350-400 g) were randomly divided into sham-treated and LPS-treated groups (Escherichia. coli lipopolysaccharide [LPS] 2 mg/kg bolus + 2 mg/kg infusion for 30 min). The animals in each group were further subdivided into vehicle- and phosphoramidon (1 mg/kg bolus)-treated subgroups. Blood and heart samples were collected at 2- and 24-h postendotoxemia/phosphoramidon treatment. LPS at 2 h after its administration produced a significant decrease in mean arterial pressure that was blocked by phosphoramidon treatment. LPS at 2 and 24 h produced a significant elevation in the concentration of left ventricular endothelin-1 (ET-1) both in heart and plasma as compared with control group. This LPS-induced left ventricular ET-1 elevation at 24 h was significantly reduced by phosphoramidon. No significant alterations were observed in the myocardial protein expression of preproET-1, iNOS, and eNOS at 2 h post LPS. In 24-h post treatment groups phosphoramidon upregulated the expression of myocardial preproET-1 protein both in control and endotoxemic rat groups. Also, LPS-induced upregulated protein expression of myocardial-inducible nitric oxide synthase and increased levels of nitric oxide byproducts at 24 h were blocked by phosphoramidon. Phosphoramidon inhibited LPS-induced down-regulated expression of myocardial endothelial nitric oxide synthase and upregulated p38-MAPK phosphorylation. These results indicated that inhibition of metalloendopeptidase during induction of endotoxemia could regulate the phosphorylation of myocardial p38-MAPK and iNOS protein expression at 24-h post endotoxemia. We concluded that inhibition of metalloendopeptidases during early endotoxemia not only decreased the biosynthesis of ET-1 in heart locally but also simultaneously down-regulated myocardial protein expression of iNOS and p38-MAPK phosphorylation in the later stage of endotoxemia.

Immune-endocrine interactions and Leydig cell function: the role of cytokines

Inflammatory disease is known to affect male reproductive function and fertility. Male accessory gland infections (MAGI) account for almost 15% of all cases of male infertility seen in infertility clinics. Infections of the male accessory glands are associated with increased counts of white blood cells in semen and elevated levels of pro-inflammatory cytokines in the semen and the testis. Numerous studies have underscored the importance of cytokines in the regulation of testicular and glandular function during pathophysiological events as well as under normal physiological conditions when cytokines act as growth and differentiation factors. The purpose of this paper is to particularly review the role of cytokines in the regulation of Leydig cell function in the testis primarily under pathophysiological conditions, and also considers clinical investigations that help to improve the evaluation and treatment of male infertility.

Testicular macrophage modulation of Leydig cell steroidogenesis

This review will highlight recent advances in the study of the immuno-endocrinology of the testis, in particular how macrophage-derived inflammatory mediators affect Leydig cell functions. Both the beneficial and deleterious outcomes resulting from macrophage-Leydig cell interactions are discussed. A brief overview of testicular physiology is provided that discusses the functional and anatomical compartmentalization of the testis into the gamete and endocrine compartments where spermatogenesis and testosterone biosynthesis take place, respectively. The process of steroidogenesis including the activities of the steroidogenic enzymes and the role of steroidogenic acute regulatory protein (StAR) are described. The close physical association between Leydig cells and interstitial testicular macrophages suggests that these cells are functionally related. Under normal physiological and non-inflammatory conditions macrophages play an important role in Leydig cell development. If macrophages are absent from the testicular interstitium, Leydig cells fail to develop normally, which suggest that macrophages provide essential growth and differentiation factors for Leydig cells. In contrast, when macrophages are activated and elaborate inflammatory mediators, Leydig cell steroidogenesis is inhibited. Activated macrophages produce pro-inflammatory cytokines such as interleukin-1 (IL-1) and tumor necrosis factor (TNF) that are profoundly inhibitory to Leydig cells and appear to act as transcriptional repressors of steroidogenic enzyme gene expression. Macrophages also produce reactive oxygen species (ROS) such as hydrogen peroxide, which also inhibits Leydig cell functions. ROS appear to act acutely by perturbing Leydig cell mitochondria resulting in the inhibition of StAR protein expression. One important consequence of this immune modulation of Leydig cell function may be manifest behaviorally by switching the affected animal from 'testosterone' behavior, to 'sickness' behavior. Increased interest in immune-endocrine control of reproductive function over the past decade has stimulated research into the molecular and biochemical immunopathophysiology of the reproductive system. As investigations unravel mechanisms underlying reproductive dysfunction caused by inflammation and infection, an understanding of the role that immune-endocrine interactions play in the normal physiology of the reproductive system has emerged.

Sepsis-induced depressed contractile function of isolated ventricular myocytes is due to altered calcium transient properties

Chronic peritoneal sepsis in a rodent model produces myocardial dysfunction characterized by decreased rates of ventricular contraction and relaxation in the isolated heart preparation. However, it remains controversial whether the ventricular contractility is altered during sepsis. In the present study, we determined the effect of chronic peritoneal sepsis on the mechanical properties and intracellular Ca2+ handling of cardiac myocytes isolated from septic rats at 24 or 48 h. Mechanical properties were evaluated by use of an IonOptix MyoCam system. Myocytes were electrically stimulated at 0.5 Hz. The contractile properties analyzed included peak shortening (PS), time-to-peak shortening (TPS), time-to-90% relengthening (TR90), and maximal velocities of shortening and relengthening (+/-dL/dt). Intracellular Ca2+ handling was evaluated with fura-2 fluorescent dye. Myocytes obtained from 24-h postseptic animals exhibited a depressed PS (85% of control), normal TPS, prolonged TR90 (147% of control), and reduced +/-dL/dt (both 79% of control). Myocytes from 48-h postseptic animals also exhibited a reduced peak of intracellular Ca2+ sequestration (55% of control), but resting intracellular Ca2+ and Ca2+-transient decay were comparable with the values seen in myocytes from untreated rats. Myocytes from septic and control animals were equally responsive over a range of stimulation frequencies (0.1-5 Hz). Myocytes from septic animals were unresponsive (5% of control) to increase of extracellular Ca2+ (0.5-3 mM). These results demonstrate that sepsis produces substantial deficits in cardiac myocytes function that can be attributed to altered calcium transient properties.

Estrogen regulation of immune responses after injury

There is a naturally occurring gender difference in immune responses which persists after traumatic injury. Physiological levels of 17beta-estradiol (E(2)) are immunostimulatory, whereas high pregnancy and superphysiological levels are immunosuppressive. In contrast, at all concentrations, testosterone suppresses immune responses. Evidence from this laboratory and others suggest that the gender difference in immune responses after injury is mediated in part by alterations in the circulating levels of gonadal steroid hormones through modulation of production of inflammatory and immunoregulatory cytokines, including interleukin-6 (IL-6). Aberrant production of IL-6 is known to be an important mediator of immunity after injury. Since E(2) is a critical regulator of IL-6 production and overall immune function, it suggests gender specific therapies should be considered for the treatment of patients.

Induction of peritoneal sepsis increases the susceptibility of isolated hearts to a calcium paradox-mediated injury

The present study was designed to test the hypothesis that induction of chronic peritoneal sepsis in rats would produce a more severe calcium paradox-mediated myocardial injury in isolated heart preparation than is seen in normal hearts, and that this would be inhibited by sucrose as in normal hearts. Male Sprague-Dawley rats were made septic using 200 mg of cecal material (obtained from a donor rat) suspended in 5 mL of 5% dextrose in sterile water D5 W/kg. In septic animals, the cecal material was injected in the peritoneum, while sham-septic animals received only D5 W/kg (5 mL/kg). A third group consisting of normal rats (no surgery) group was also included. Hearts were harvested from all three groups and were subjected to a calcium paradox-mediated injury in an isolated heart preparation. Hearts were perfused with Krebs-Henseleit (KH) medium and were allowed to stabilize, followed by a perfusion with Ca2+-free KH for 10 min. After this 10-min Ca2+-free KH perfusion, rats were reperfused with KH medium for 60 min. Ca2+-free KH medium was used in control experiments, while sucrose experiments were conducted with the same medium except that 150 mM sucrose replaced 75 mM NaCl. A marked decrease in ATP and phosphocreatine occurred during Ca2+ reperfusion in all hearts in absence of sucrose. In the presence of the disaccharide, no change in high-energy phosphate (HEP) levels was observed in normal hearts, while lower ATP concentrations were seen in sham and septic hearts. Thus, sucrose did not inhibit cellular injury in sham and septic hearts as it did in normal hearts, and this might be due to a smaller HEP availability. Control studies with normal, sham, and septic hearts exhibited cessation of contractions in the absence of Ca2+, and appearance of large amounts of cytosolic protein in the effluent perfusate during Ca2+ reperfusion. With normal hearts, perfusion with sucrose caused a 96% inhibition of the total creatine kinase (CK) release observed in control experiments. With sham hearts, 32% of CK release was inhibited by sucrose, while 68% of the CK release was attributed to stress associated with surgery performed in the sham-septic group. In septic hearts, only 8% of the CK release was inhibited by sucrose, suggesting that more severe myocardial injury occurs when septic hearts are subjected to a calcium paradox as compared to other groups. It is evident that sucrose can inhibit a small fraction of the CK release from septic hearts during the calcium paradox as compared to the large CK loss associated with sham sepsis. We have concluded that induction of sepsis made the heart more susceptible to a calcium paradox-mediated myocardial injury.

Diametric effects of bacterial endotoxin lipopolysaccharide on adrenal and Leydig cell steroidogenic acute regulatory protein

Immune activation results in the activation of adrenal steroidogenesis and inhibition of gonadal steroidogenesis. Previous studies indicated that these effects were caused primarily by activation and suppression of the secretion of ACTH and LH, respectively. However, other evidence indicated a direct effect of the immune system on the gonads. In this study, serum testosterone, quantitated by RIA after lipopolysaccharide injection, showed a significant decrease within 2 h. Parallel measurement of serum LH showed no change. There were no differences in LH receptor or cAMP produced in Leydig cells between vehicle- and lipopolysaccharide-injected mice. The 30-kDa form of the steroidogenic acute regulatory (StAR) protein was quantitated, by Western blot, in Leydig cells and was found to decrease in a time-dependent manner. No change in StAR protein messenger RNA (mRNA) was detected by Northern analysis during this time, nor were any changes found in the levels of mRNA for the steroidogenic enzymes P450scc, 3beta-hydroxysteroid dehydrogenase delta4-delta5-isomerase, or P450c17. In the adrenal, StAR protein was increased, as was StAR protein mRNA. No changes were observed in the levels of mRNA for P450scc, 3beta-hydroxysteroid dehydrogenase delta4-delta5-isomerase, or P450c21. Thus, although the mechanisms of regulation differ, changes in the levels of StAR protein are a sensitive indicator of the steroidogenic capacity of these two tissues.

Testosterone receptor blockade after trauma and hemorrhage attenuates depressed adrenal function

Although the testosterone receptor antagonist flutamide restores the depressed immune function in males after trauma and hemorrhage, it remains unknown whether this agent has any salutary effects on adrenal function. To study this, male rats underwent laparotomy and were bled to and maintained at a blood pressure of 40 mmHg until 40% of the shed blood volume was returned in the form of Ringer lactate. Animals were then resuscitated and flutamide (25 mg/kg body wt) was administered subcutaneously. Plasma adrenocorticotropic hormone (ACTH) and corticosterone, as well as adrenal corticosterone and cAMP were measured 20 h after resuscitation. In additional animals, ACTH was administered and ACTH-induced corticosterone release and adrenal cAMP were determined. The results indicate that adrenal contents of corticosterone and cAMP were significantly decreased and morphology was altered after hemorrhage. Administration of flutamide improved corticosterone content, restored cAMP content, and attenuated adrenal morphological alterations. Flutamide also improved the diminished ACTH-induced corticosterone release and adrenal cAMP response at 20 h after hemorrhage and resuscitation. Furthermore, the diminished corticosterone response to ACTH stimulation in the isolated adrenal preparation was improved with flutamide. These results suggest that flutamide is a useful adjunct for improving adrenal function in males following trauma and hemorrhage.

Adrenocorticosterone alterations in male, albino mice treated with Trichopus zeylanicus, Withania somnifera and Panax ginseng preparations

The levels of corticosterone were estimated by the HPLC method in the adrenal glands of stressed (5 h constant swimming) male albino mice treated with Trichopus zeylanicus, Withania somnifera and Panax ginseng preparations and compared with non-treated stressed and normal controls. The treatments increased the corticosterone levels in all the groups. The physical endurance (increased survival time) of swimming mice also increased in all the treated groups, except in the group treated with Withania somnifera powder (500 mg/kg, p.o.).

Role of cytokines in testicular function

Inflammatory disease has been established to affect male reproductive function and fertility. Relevant inflammatory diseases include general and chronic infectious diseases as well as localized acute or chronic infections of the male genitourinary tract. Male accessory gland infections account for almost 15% of all cases of male infertility seen in infertility clinics while fertility usually is not a clinical objective among patients with acute systemic infections such as Gram-negative sepsis. Infections of the male accessory glands frequently are associated with increased counts of white blood cells in semen and elevated levels of proinflammatory cytokines in semen and the testis. There is a mounting body of evidence that demonstrates the importance of cytokines and chemokines in the regulation of testicular and glandular function during pathophysiological states as well as under normal physiological conditions when cytokines act as growth and differentiation factors. The purpose of this review is to examine the role of cytokines in the regulation of steroidogenesis and spermatogenesis in the testis under physiological and pathophysiological conditions and considers clinical investigations that help to improve the evaluation and treatment of male infertility.

Protective roles of nitric oxide and testosterone in endotoxemia: evidence from NOS-2-deficient mice

Lipopolysaccharide (LPS)-induced septic shock, which triggers nitric oxide (NO) overproduction, multiple organ dysfunction, and death, can be affected by gender and sex hormones. We hypothesized that NO is beneficial during endotoxemia and that this beneficial effect is influenced by sex hormones. C57BL/6 wild-type (WT) mice and congenic inducible NO synthase knockout (KO) mice were injected with LPS, and mortality was recorded for 4 days. After 5 mg/kg LPS, female KO mice had significantly higher mortality than WT. After 12.5 mg/kg LPS, both male and female KO mice had significantly higher mortality than WT. Ovariectomy did not alter mortality, but orchiectomy dramatically increased mortality in KO mice. After 5 mg/kg LPS, exogenous testosterone completely prevented the increased mortality in KO female and orchiectomized KO male mice. WT survival was not affected by exogenous testosterone. After 12.5 mg/kg LPS, exogenous testosterone significantly improved survival of female KO mice. Serum enzymes and organ edema, which may not correlate with mortality, were significantly and similarly increased in both WT and KO endotoxemic mice; however, edema was not observed in KO hearts. Thus, NO plays a protective role in endotoxemia while having differential effects on different organs. Importantly, testosterone is beneficial in endotoxemia when NO production is deficient, and may be therapeutic in certain septic patients.

Adenosine receptor antagonism affects regional resting vascular resistance during rat peritoneal sepsis

BACKGROUND

To identify vascular beds where endogenous adenosine plays a significant role as a mediator of resting perfusion alterations associated with sepsis, we tested the hypothesis that adenosine receptor blockade would cause differential regional increases in vascular resistance during intraperitoneal (ip) sepsis in the rat.

MATERIALS AND METHODS

Rats (250-350 g) were catheterized and randomized to septic or nonseptic groups. Sepsis was induced with an ip injection of cecal slurry (150 mg/kg in D5W; 5 ml/kg), and baseline hemodynamics, cardiac output (CO), and blood flows (microspheres) were measured 24 h later. Animals then received the adenosine receptor antagonist 8-phenyltheophylline (8-PTH; 10 mM, 1.5 ml/kg), its vehicle (1.5 ml/kg), or normal saline (1.5 ml/kg), iv, and measurements were repeated.

RESULTS

Septic animals treated with 8-PTH had a significant increase in skeletal muscle, hepatic portal, and cerebral vascular resistance with concomitant decreases in CO when compared with vehicle at 1 min. No significant resistance changes were observed in the renal, adipose, or coronary vasculatures. Adenosine receptor blockade caused a significant increase in +dP/dt and -dP/dt during sepsis, indicating that the reduced CO was not secondary to myocardial depression.

CONCLUSIONS

These data suggest that adenosine receptor-mediated actions during sepsis affect vascular beds selectively and indicate a significant role for adenosine in resting perfusion redistribution in sepsis.