Immunoendocrine mechanisms associated with resistance or susceptibility to parasitic diseases during pregnancy

Season affects the estrogen system and the immune response of common carp

The physiology of ectothermic animals, including fish, is strictly regulated by season-related external factors such as temperature or photoperiod. The immune response and the production of hormones, such as estrogens, are therefore also subject to seasonal changes. This study in common carp aimed to determine how the season affects the estrogen system and the immune response, including the antibacterial response during Aeromonas salmonicida infection. We compared the immune reaction in spring and autumn in the head kidney and liver and found that carp have higher levels of blood 17β-estradiol in autumn, while in the liver of these fish there is a higher constitutive expression of genes encoding vitellogenin, estrogen receptors and Cyp19 aromatase than in spring. Fish sampled in autumn also exhibited higher expression of immune-related genes in the liver. In contrast, in the head kidney from fish sampled in the autumn, the expression of genes encoding estrogen receptors and aromatase was lower than in spring, and a similar profile of expression was also measured in the head kidney for inos, arginases and il-10. In turn, during bacterial infection, we observed higher upregulation of the expression of inos, il-12p35, ifnγ-2, arginase 2 and il-10 in the liver of carp sampled in spring. In the liver of carp infected in spring a higher upregulation of the expression of the genes encoding CRPs was observed compared to fish infected during autumn. The opposite trend occurred in the head kidney, where the upregulation of the expression of the genes involved in the immune response was higher in fish infected in autumn than in those infected in spring. During the infection, also season-dependent changes occurred in the estrogen system. In conclusion, we demonstrated that season differentially affects the estrogenic and immune activity of the head kidney and liver. These results reinforce our previous findings that the endocrine and immune systems cooperate in maintaining homeostasis and fighting infection.

Toxoplasmosis Screening during Pregnancy in a Romanian Infectious Diseases Tertiary Center: Results of a 15 Years Follow-Up Program

Maternal infection with Toxoplasma gondii during pregnancy may have serious consequences for the fetus. In Romania, screening for toxoplasmosis is included in the first antenatal visit. A retrospective study was performed on all toxoplasmosis antenatal screening patients between May 2008 and February 2023. Twenty-seven thousand one hundred sixty-nine (27,169) pregnant women presented for prenatal screening once (22,858) or several times: during the same pregnancy (209) or during multiple pregnancies (4102). Thirty-one thousand six hundred fifty-eight (31,658) tests for IgM and IgG antibodies were performed. Nine thousand eighty-three (9083) tests (28.69%), corresponding to 7911 women (29.12%), were positive for IgG antibodies. The seroprevalence increased with patients' age, decreased in time intervals, and was more frequently associated with rural residence. At risk for acquiring the infection during the pregnancy were women with negative anti-Toxoplasma IgG antibodies (70.88%), but only 0.9% of them presented for rescreening during the same pregnancy. Acute Toxoplasma infection (ATI) was suspected in 44 patients (0.16%) due to IgG seroconversion and/or low or borderline IgG avidity. A questionnaire follow-up interview was performed, and no congenital toxoplasmosis was identified in children born from mothers with probable ATI. Our study demonstrates poor compliance with the screening program in the Romanian population.

Association of gastrointestinal parasite burden, serum cytokines and hormones concentrations, and pregnancy in Angus-cross beef cows

The objective was to elucidate the relationships among gastrointestinal (GI) parasite load, serum cytokines (Th 1 - Interleukin (IL) 2, Interferon (IFN) γ and Tumor necrosis factor (TNF) α; Th 2- IL4, IL6, and IL10) levels, hormones (progesterone, cortisol, 8-epi-prostaglandin F2 alpha (isoprostane), prolactin, substance-p, and prostaglandin F metabolites) concentrations, and pregnancy in beef cattle. Angus-cross beef cows (n = 700; age, 3-8 y) were blocked by age and body condition score (BCS, 1-9), and were randomly assigned to treatment (n = 350, TRT, 50 mg of eprinomectin/50 kg BW, im) or control (n = 350, CON, no treatment) on Day -30. Cows were synchronized using Controlled Internal Drug Release insert (CIDR) + CO-Synch protocol and artificially inseminated at a fixed time on Day 0 (66 h after CIDR removal). Fecal samples were collected to determine fecal egg count per gram (FEG, McMaster method) on Days -30, -23, -16, -7, 7, 0, 16 and 23, and blood samples were collected on Days -7, 0, 7, 16 and 23. Serum cytokines were determined on Days -7, 0, 7, 16 and 23, and circulating hormones were measured on Day 16. BCS were recorded on Day 16 following artificial insemination (AI), and pregnancy status was diagnosed on Day 30 and 60. Pregnancy/AI varied among treatment groups on Day 30 [TRT, 62.0% (217/350); CON, 54.9% (192/350) (P = 0.05)] and Day 60 [TRT, 60.9% (213/350); CON, 51.7% (181/350) (P < 0.05)]. Pregnancy loss between 30 and 60 days for TRT and CON groups were 1.8% (4/217) and 5.7% (11/192), respectively (P < 0.05). The BCS on Day 16 did not differ among treatment groups (P> 0.1). Four groups of 40 cows were selected based on their pregnancy status and treatment: pregnant, TRT; non-pregnant, TRT; pregnant, CON; and non-pregnant, CON to compare the mean FEG, cytokines, and hormones levels. The FEG and cytokine concentrations were significantly (P < 0.05) influenced by treatment, pregnancy status, day, treatment by pregnancy status, and treatment by day. Day 16 hormone concentrations were considerably influenced by treatment, pregnancy status, and treatment by pregnancy. Although FEG on Day -30 did not differ among the groups (P> 0.1), it was lower in treated, pregnant cows compared with cows in other three groups from Day -23 onwards (P < 0.05). Overall and pairwise comparisons showed that serum concentrations of Type 1 cytokines, IL2, IFNγ, and TNFα were lower (P < 0.05) from gestational Day 7 onwards in treated, pregnant cows compared with cows in other three groups. In contrast, serum concentrations of Type 2 cytokines, IL4, IL6 and IL10 were greater (P < 0.05) from gestational Day 7 onwards in treated, pregnant cows compared with cows in other groups. Serum concentrations of progesterone was greater and other hormones were lower for pregnant cows in TRT group compared to cows in other groups on gestational Day 16. In conclusion, GI parasite load was reduced; Th 1 cytokines levels were decreased; Th 2 cytokines concentrations were increased; progesterone level was increased; and cortisol, substance-P, prolactin, isoprostane, and PGFM were decreased in pregnant, TRT cows. These changes also resulted in an increase in P/AI. It is plausible that direct and bidirectional host-parasite interactions mediated by cytokines and hormones may have promoted maternal tolerance of an immunologically diverse conceptus and the establishment of pregnancy.

Temporal and spatial dynamics of gastrointestinal parasite infection in Père David's deer

Background

The Père David's deer (Elaphurus davidianus) population was established from only a small number of individuals. Their genetic diversity is therefore relatively low and transmissible (parasitic) diseases affecting them merit further attention. Parasitic infections can affect the health, survival, and population development of the host. However, few reports have been published on the gastrointestinal parasites of Père David's deer. The aims of this study were: (1) to identify the intestinal parasites groups in Père David's deer; (2) to determine their prevalence and burden and clarify the effects of different seasons and regions on various indicators of Père David's deer intestinal parasites; (3) to evaluate the effects of the Père David's deer reproductive period on these parasites; (4) to reveal the regularity of the parasites in space and time.

Methods

In total, 1,345 Père David's deer faecal samples from four regions during four seasons were tested using the flotation (saturated sodium nitrate solution) to identify parasites of different genus or group, and the McMaster technique to count the number of eggs or oocysts.

Results

Four groups of gastrointestinal parasites were found, of which strongyles were dominant; their prevalence and burden were significantly higher than other groups. Significant temporal and spatial effects on gastrointestinal parasitic infection were found. Parasite diversity, prevalence, parasite burden, and aggregation were the highest in summer. Among the four regions, parasite diversity, prevalence, and burden were the highest in the Dongting Lake area. In addition, parasite diversity and burden during the reproductive period of Père David's deer was significantly higher than during the post-reproductive period.

Conclusions

The summer season and the reproductive period of Père David's deer had great potential for parasite transmission, and there is a high risk of parasite outbreaks in the Dongting Lake area.

Predictors of helminth parasite infection in female chacma baboons (Papio ursinus)

Helminth parasite infection can impose major consequences on host fitness. Several factors, including individual characteristics of hosts, environmental conditions, and patterns of coinfection, are thought to drive variation in parasite risk. Here, we report on four key drivers of parasite infection-phase of reproduction, steroid hormone profiles, rainfall, and patterns of coinfection-in a population of wild female chacma baboons (Papio ursinus) in South Africa. We collected data on reproductive state and hormone profiles over a 3-year span, and quantified helminth parasite burdens in 2955 fecal samples from 24 female baboons. On a host level, we found that baboons are sensitive to parasite infection during the costliest phases of the reproductive cycle: pregnant females harbored higher intensities of Protospirura eggs than cycling and lactating females; lactating and cycling females had a higher probability of Oesophagostomum infection than pregnant females; and cycling females exhibited lower Trichuris egg counts than pregnant and lactating females. Steroid hormones were associated with both immunoenhancing and immunosuppressive properties: females with high glucocorticoid concentrations exhibited high intensities of Trichuris eggs but were at low risk of Oesophagostomum infection; females with high estrogen and progestagen concentrations exhibited high helminth parasite richness; and females with high progestagen concentrations were at high risk of Oesophagostomum infection but exhibited low Protospirura egg counts. We observed an interaction between host reproductive state and progestagen concentrations in infection intensity of Protospirura: pregnant females exhibited higher intensities and non-pregnant females exhibited lower intensities of Protospirura eggs with increasing progestagen concentrations. At a population level, rainfall patterns were dominant drivers of parasite risk. Lastly, helminth parasites exhibited positive covariance, suggesting that infection probability increases if a host already harbors one or more parasite taxa. Together, our results provide a holistic perspective of factors that shape variation in parasite risk in a wild population of animals.

Reduced gastrointestinal worm burden following long term parasite control improves body condition and fertility in beef cows

The objective of this study was to compare effects of gastrointestinal parasite control over a long vs short term (PC-LT vs. PC-ST) on fecal parasite load, body condition and pregnancy in beef cows. On Day 0, fecal samples were collected from Angus cross cows (n = 1462) and they were assigned a body condition score (BCS: 1, emaciated; 9, Obese) and randomly divided into two groups (within location) to receive extended-release eprinomectin [PC-LT; n = 749; 50 mg/50 kg body weight (BW)] or pour-on ivermectin (PC-ST; n = 713; 25 mg/50 kg BW). All cows were synchronized with CO-Synch + CIDR [100 μg GnRH + progesterone vaginal insert (CIDR) application on Day 20, CIDR removal +25 mg PGF2a on Day 27, and artificial insemination +100 μg GnRH on Day 30 (66 h after CIDR removal)] protocol, artificially inseminated (AI; Day 30) and on Day 44, exposed to breeding bulls (1:40 bull to cow ratio) for the remainder of the 85 day breeding season. On Day 90, a second fecal sample was collected from all cows and the cows were examined to determine pregnancy/AI (P/AI). All cows were assigned a BCS on Day 180 and re-examined to determine pregnancy/breeding season (P/BS). Worm egg count per gram of feces (FEG) was determined by McMaster method. There were no differences (P > 0.1) between PC-LT and PC-ST groups on Day 0 for FEG (46.9 ± 13.1 vs 42.6 ± 15.2, respectively; mean ± SEM) or BCS (5.95 ± 0.12 vs 6.00 ± 0.20). The mean FEG (PC-LT, 12.3 ± 4.7 vs. PC-ST, 131.3 ± 10.9) on Day 90 and BCS (PC-LT, 6.04 ± 0.07 vs. PC-ST, 5.79 ± 0.13) on Day 180 differed (P < 0.05) between the two groups. Mean P/AI [PC-LT, 62.9 %; (471/749) vs PC-ST, 57.4 %; (409/713)] and P/BS [PC-LT, 92.9 % (696/749) vs PC-ST, 90.0 (642/713)] also differed (P < 0.05). Lower FEG at Day 90 resulted in moderate to good body condition at Day 180 and cows with moderate to good body condition at Day 180 had higher P/BS. In conclusion, lower worm burden with long-term parasite control reduced FEG and improved BCS, P/AI and P/BS.

Increased Toxoplasma gondii Intracellular Proliferation in Human Extravillous Trophoblast Cells (HTR8/SVneo Line) Is Sequentially Triggered by MIF, ERK1/2, and COX-2

Macrophage migration inhibitory factor (MIF) is a potent pro-inflammatory cytokine, which mediates the regulation of diverse cellular functions. It is produced by extravillous trophoblastic cells and has been found to be involved in the pathogenesis of diseases caused by some protozoa, including Toxoplasma gondii. Previous studies demonstrated the ability of T. gondii to take advantage of MIF action in human trophoblast cells. However, MIF action in T. gondii-infected extravillous trophoblastic cells (HTR8/SVneo cell line) has not been fully investigated. The present study aimed to investigate the role of MIF in T. gondii-infected HTR8/SVneo cells and verify the intracellular signaling pathways triggered by this cytokine. We found that T. gondii increased MIF production by HTR8/SVneo cells, and by contrast, MIF inhibition, by ISO-1, led to a significant decrease in T. gondii proliferation and CD74 expression in HTR8/SVneo cells. Moreover, in infected HTR8/SVneo cells, the addition of recombinant MIF (rMIF) increased CD44 co-receptor expression, ERK1/2 phosphorylation, COX-2 expression, and IL-8 production, which favored T. gondii proliferation. Our findings indicate that T. gondii can use MIF to modulate important factors in HTR8/SVneo cells, being a possible explanation for the higher susceptibility of extravillous trophoblast cells than other trophoblast cell populations.

Role of Lactobacilli and Lactoferrin in the Mucosal Cervicovaginal Defense

The innate defense system of the female mucosal genital tract involves a close and complex interaction among the healthy vaginal microbiota, different cells, and various proteins that protect the host from pathogens. Vaginal lactobacilli and lactoferrin represent two essential actors in the vaginal environment. Lactobacilli represent the dominant bacterial species able to prevent facultative and obligate anaerobes outnumber in vaginal microbiota maintaining healthy microbial homeostasis. Several mechanisms underlie the protection exerted by lactobacilli: competition for nutrients and tissue adherence, reduction of the vaginal pH, modulation of immunity, and production of bioactive compounds. Among bioactive factors of cervicovaginal mucosa, lactoferrin, an iron-binding cationic glycoprotein, is a multifunctional glycoprotein with antibacterial, antifungal, antiviral, and antiparasitic activities, recently emerging as an important modulator of inflammation. Lactobacilli and lactoferrin are largely under the influence of female hormones and of paracrine production of various cytokines. Lactoferrin is strongly increased in lower genital tract mucosal fluid of women affected by Neisseria gonorrheae, Chlamydia trachomatis, and Trichomonas vaginalis infections promoting both innate and adaptive immune responses. In vaginal dysbiosis characterized by low amounts of vaginal lactobacilli and increased levels of endogenous anaerobic bacteria, the increase in lactoferrin could act as an immune modulator assuming the role normally played by the healthy microbiota in vaginal mucosa. Then lactoferrin and lactobacilli may be considered as biomarkers of altered microbial homeostasis at vaginal level. Considering the shortage of effective treatments to counteract recurrent and/or antibiotic-resistant bacterial infections, the intravaginal administration of lactobacilli and lactoferrin could be a novel efficient therapeutic strategy and a valuable tool to restore mucosal immune homeostasis.

Oral contraceptive pills: Risky or protective in case of Trichinella spiralis infection?

The aim of this study was to investigate how Trichinella spiralis infection can be affected by contraceptive pills in vivo. Methods included six groups of female Wistar rats; healthy, Trichinella infected, receiving combined contraceptive pills (COCPs), receiving progestin only pills (POPs), infected receiving COCPs and infected receiving POPs. Parasite burden was measured; adult worm counts, gravidity, larvae and reproductive capacity index). Histopathological examination, immunohistochemical detection of C-kit+ mast cells and Foxp3+ T-reg. cells in intestinal sections, eosinophils muscle infiltration and CPK level were performed. Rats infected and receiving COCPs showed a significant increase in parasitic burden, and infected receiving POPs showed a significant reduction compared to infected only, with a significant increase in nongravid females (Mean total worms=964.40±55.9, 742±52.63, 686±31.68, larvae/g=5030±198.75, 2490±143.18 and 4126±152,91, respectively). Intestinal sections from infected receiving COCPs showed intact mucosa (though the high inflammatory cells infiltrate), and significant increase in C-kit+ mast cells number and intensity (30.20±4.15 and 60.40±8.29), and Foxp3+ T-reg. cells (10±1.58). Infected receiving POPs showed a significantly less CPK (5886±574.40) and eosinophilic muscle infiltration (58±13.51). Oestrogen-containing pills established a favourable intestinal environment for Trichinella by enhancing Foxp+T-reg. cells and stabilizing C-kit+mast cells, while POPs gave a potential protection with less gravidity, larval burden and eosinophilic infiltrate.

The immunomodulatory role of the hypothalamus-pituitary-gonad axis: Proximate mechanism for reproduction-immune trade offs?

The present review discusses the communication between the hypothalamic-pituitary-gonad (HPG) axis and the immune system of vertebrates, attempting to situate the HPG-immune interaction into the context of life history trade-offs between reproductive and immune functions. More specifically, (i) we review molecular and cellular interactions between hormones of the HPG axis, and, as far as known, the involved mechanisms on immune functions, (ii) we evaluate whether the HPG-immune crosstalk serves as proximate mechanism mediating reproductive-immune trade-offs, and (iii) we ask whether the nature of the HPG-immune interaction is conserved throughout vertebrate evolution, despite the changes in immune functions, reproductive modes, and life histories. In all vertebrate classes studied so far, HPG hormones have immunomodulatory functions, and indications exist that they contribute to reproduction-immunity resource trade-offs, although the very limited information available for most non-mammalian vertebrates makes it difficult to judge how comparable or different the interactions are. There is good evidence that the HPG-immune crosstalk is part of the proximate mechanisms underlying the reproductive-immune trade-offs of vertebrates, but it is only one factor in a complex network of factors and processes. The fact that the HPG-immune interaction is flexible and can adapt to the functional and physiological requirements of specific life histories. Moreover, the assumption of a relatively fixed pattern of HPG influence on immune functions, with, for example, androgens always leading to immunosuppression and estrogens always being immunoprotective, is probably oversimplified, but the HPG-immune interaction can vary depending on the physiological and envoironmental context. Finally, the HPG-immune interaction is not only driven by resource trade-offs, but additional factors such as, for instance, the evolution of viviparity shape this neuroendocrine-immune relationship.

Host immune status and response to hepatitis E virus infection

Hepatitis E virus (HEV), identified over 30 years ago, remains a serious threat to life, health, and productivity in developing countries where access to clean water is limited. Recognition that HEV also circulates as a zoonotic and food-borne pathogen in developed countries is more recent. Even without treatment, most cases of HEV-related acute viral hepatitis (with or without jaundice) resolve within 1 to 2 months. However, HEV sometimes leads to acute liver failure, chronic infection, or extrahepatic symptoms. The mechanisms of pathogenesis appear to be substantially immune mediated. This review covers the epidemiology of HEV infection worldwide, the humoral and cellular immune responses to HEV, and the persistence and protection of antibodies produced in response to both natural infection and vaccines. We focus on the contributions of altered immune states (associated with pregnancy, human immunodeficiency virus [HIV], and immunosuppressive agents used in cancer and transplant medicine) to the elevated risks of chronic infection (in immunosuppressed/immunocompromised patients) and acute liver failure and mortality (among pregnant women). We conclude by discussing outstanding questions about the immune response to HEV and interactions with hormones and comorbid conditions. These questions take on heightened importance now that a vaccine is available.

Trophoblast cells are able to regulate monocyte activity to control Toxoplasma gondii infection

INTRODUCTION

Toxoplasma gondii is an intracellular parasite that causes severe disease when the infection occurs during pregnancy. Trophoblast cells constitute an important maternal-fetal barrier, with monocytes concentrating around them. Thus, interactions between trophoblasts and monocytes are important for maintaining a successful pregnancy, especially in cases of infection. This study aimed to evaluate the role of trophoblast cells (BeWo line) on monocyte (THP-1 line) activity in the presence or absence of T. gondii infection.

METHODS

THP-1 cells were stimulated with supernatants of BeWo cells, previously infected or not with T. gondii, and then infected with parasites. The supernatant of both cells were collected and analyzed for cytokine production and T. gondii proliferation in THP-1 cells was determined.

RESULTS

The results showed that after infection, the pattern of cytokines secreted by THP-1 and BeWo cells was characterized as a pro-inflammatory profile. Furthermore, supernatant of BeWo cells infected or not, was able to change the cytokine profile secreted by infected THP-1 cells, and this supernatant became THP-1 cells more able to control T. gondii proliferation than those that had not been stimulated.

DISCUSSION

This effect was associated with secretion of interleukin (IL)-6 by the THP-1 cells and soluble factors secreted by BeWo cells, such as IL-6 and MIF.

CONCLUSION

Together, these results suggest that trophoblast cells are able to modulate monocyte activity, resulting in the control of T. gondii infection and subsequent maintenance of pregnancy.

Progesterone induces mucosal immunity in a rodent model of human taeniosis by Taenia solium

More than one quarter of human world's population is exposed to intestinal helminth parasites. The Taenia solium tapeworm carrier is the main risk factor in the transmission of both human neurocysticercosis and porcine cysticercosis. Sex steroids play an important role during T. solium infection, particularly progesterone has been proposed as a key immunomodulatory hormone involved in susceptibility to human taeniosis in woman and cysticercosis in pregnant pigs. Thus, we evaluated the effect of progesterone administration upon the experimental taeniosis in golden hamsters (Mesocricetus auratus). Intact female adult hamsters were randomly divided into 3 groups: progesterone-subcutaneously treated; olive oil-treated as the vehicle group; and untreated controls. Animals were treated every other day during 4 weeks. After 2 weeks of treatment, all hamsters were orally infected with 4 viable T. solium cysticerci. After 2 weeks post infection, progesterone-treated hamsters showed reduction in adult worm recovery by 80%, compared to both vehicle-treated and non-manipulated infected animals. In contrast to control and vehicle groups, progesterone treatment diminished tapeworm length by 75% and increased proliferation rate of leukocytes from spleen and mesenteric lymph nodes of infected hamsters by 5-fold. The latter exhibited high expression levels of IL-4, IL-6 and TNF-α at the duodenal mucosa, accompanied with polymorphonuclear leukocytes infiltration. These results support that progesterone protects hamsters from the T. solium adult tapeworm establishment by improving the intestinal mucosal immunity, suggesting a potential use of analogues of this hormone as novel inductors of the gut immune response against intestinal helminth infections and probably other bowel-related disorders.

Neuroendocrine-immune interaction in fish: differential regulation of phagocyte activity by neuroendocrine factors

Coping with physical, chemical and biological disturbances depends on an extensive repertoire of physiological, endocrinological and immunological responses. Fish provide intriguing models to study bi-directional interaction between the neuroendocrine and the immune systems. Macrophages and granulocytes are the main actors in the first and rapid innate immune response. They are resident in different organs and are moreover rapidly recruited and activated upon infection. They act in response to recognition of pathogen-associated molecular patterns (PAMPs) via a repertoire of surface and intracellular receptors by inducing a plethora of defense reactions aiming to eradicate the pathogen. Subsequent production of inflammatory mediators stimulates other leukocytes required to develop an adaptive and specific antibody response. The type of phagocyte reaction will therefore depend on their differentiation state, specific receptor repertoire and their specific location. Apart from these pathogen induced responses, immune reactivity may be modulated by neuroendocrine factors. Over the last years we extensively studied changes in carp stress axis activity and the effect of its end-products on the immune system in an acute stress paradigm. We focus on specific neuroendocrine receptors on leukocytes and their effect on crucial phagocyte activities. We performed identification and functional analyses of different glucocorticoid, opioid and adrenergic receptors on carp phagocytes. Results show that their ligands of neuroendocrine origin may have substantial impact on specific phagocyte functions in a differential way. Inflammatory and microbicidal responses fight pathogens but may be detrimental to the host tissue. Neuroendocrine modulation may regulate inflammation to reach an optimum defense while preventing excessive host cell damage.

Reproductive immunology: a focus on the role of female sex hormones and other gender-related factors

Reproductive immunology has attracted the attention of researchers interested in fertility and pregnancy as well as those interested in immunity and autoimmunity. Over the past couple of decades, a wealth of data on the immune-reproductive interactions has been generated. This issue of the Journal will examine several topics including the role of immune factors in the induction of anti-Ro antibody-mediated autoimmunity in neonates and the immunological effects of gender and sex hormones. The possible implications of the research reviewed here for the development of novel therapeutic approaches are also addressed.