Association of MMP-2 and MMP-9 with clinical outcome of neurocysticercosis

Understanding the mechanisms underlying the disruption of the blood-brain barrier in parasitic infections

Parasites have a significant impact on the neurological, cognitive, and mental well-being of humans, with a global population of over 1 billion individuals affected. The pathogenesis of central nervous system (CNS) injury in parasitic diseases remains limited, and prevention and control of parasitic CNS infections remain significant areas of research. Parasites, encompassing both unicellular and multicellular organisms, have intricate life cycles and possess the ability to infect a diverse range of hosts, including the human population. Parasitic illnesses that impact the central and peripheral nervous systems are a significant contributor to morbidity and mortality in low- to middle-income nations. The precise pathways through which neurotropic parasites infiltrate the CNS by crossing the blood-brain barrier (BBB) and cause neurological harm remain incompletely understood. Investigating brain infections caused by parasites is closely linked to studying neuroinflammation and cerebral impairment. The exact molecular and cellular mechanisms involved in this process remain incomplete, but understanding the exact mechanisms could provide insight into their pathogenesis and potentially reveal novel therapeutic targets. This review paper explores the underlying mechanisms involved in the development of neurological disorders caused by parasites, including parasite-derived elements, host immune responses, and modifications in tight junctions (TJs) proteins.

What Causes Seizures in Neurocysticercosis?

Neurocysticercosis (NCC) is the most prevalent parasitic infection of the central nervous system. It is caused by the presence of larvae of the cestode Taenia solium in the brain. The most common symptom of NCC is seizures, and it is widely considered the world’s leading cause of preventable epilepsy. Despite the prevalence and impact of NCC, a thorough, mechanistic understanding of seizure generation is still lacking. In this review, we address the question “What causes seizures in NCC?” by summarizing and discussing the major theories that seek to explain the seizurogenic and epileptogenic processes in this disorder. In addition, we highlight the potential for recent advances in disease modeling to help accelerate progress in this area.

Clinical significance of matrix metalloproteinase-9 in Fragile X Syndrome

High plasma matrix metalloproteases-9 (MMP-9) levels have been reported in Fragile X Syndrome in a limited number of animal and human studies. Since the results obtained are method-dependent and not directly comparable, the clinical utility of MMP-9 measurement in FXS remains unclear. This study aimed to compare quantitative gel zymography and ELISA and to determine which method better discriminates abnormal MMP-9 levels of individuals with FXS from healthy controls and correlates with the clinical profile. The active and total forms of MMP-9 were quantified respectively, by gel zymography and ELISA in a cohort of FXS (n = 23) and healthy controls (n = 20). The clinical profile was assessed for the FXS group using the Aberrant Behavior Checklist FXS adapted version (ABC-C_FX), Adaptive Behavior Assessment System (ABAS), Social Communication Questionnaire (SCQ), and Anxiety Depression and Mood Scale questionnaires. Method comparison showed a disagreement between gel zymography and ELISA with a constant error of − 0.18 [95% CI: − 0.35 to − 0.02] and a proportional error of 2.31 [95% CI: 1.53 to 3.24]. Plasma level of MMP-9 active form was significantly higher in FXS (n = 12) as compared to their age-sex and BMI matched controls (n = 12) (p = 0.039) and correlated with ABC-C_FX (r_s = 0.60; p = 0.039) and ADAMS (r_s = 0.57; p = 0.043) scores. As compared to the plasma total form, the plasma MMP-9 active form better enables the discrimination of individuals with FXS from controls and correlates with the clinical profile. Our results highlight the importance of choosing the appropriate method to quantify plasma MMP-9 in future FXS clinical studies.

The Role of Tissue Inhibitor of Metalloproteinase-1 and 2 in Echinococcus granulosus senso lato-Induced Human Hepatic Fibrosis

INTRODUCTION

The main mechanism underlying hepatic fibrosis is the imbalance between tissue Matrix Metalloproteinases (MMPs) and Tissue Inhibitors of Metalloproteinases (TIMPs). This study aimed to investigate the potential role of TIMP-1 and TIMP-2 in the process of hepatic fibrosis caused by Echinococcus granulosus senso lato (E. granulosus s.l.).

METHODS

The expressions levels of TIMP-1 and TIMP-2 mRNAs were evaluated in fibrotic and normal hepatic tissues of 30 patients with Cystic Echinococcus (CE) using qRT-PCR. Moreover, their serum levels of TIMP-1 were assessed before CE cyst removal and 6 months after surgery using ELISA.

RESULTS

The qRT-PCR results showed that the expression levels of TIMP-1 and TIMP-2 mRNAs were significantly higher in the fibrotic hepatic tissue compared to the normal liver tissue, in a way that the TIMP-1 and TIMP-2 mRNA expression levels were 19.07 and 6.58 folds higher in the fibrotic tissue compared to the normal liver tissue. Among these TIMPs, TIMP-1 exhibited the higher area under the curve (AUC) value for predicting liver fibrosis. However, we could not find a significant difference in the serum levels of TIMP-1 before and after the cyst removal procedure (p = 0.48).

CONCLUSIONS

For the first time, our study showed that the significant overexpression of both TIMP mRNAs in the fibrotic liver tissue of the CE patients may be due to the increased expression of MMPs in the peri-cystic tissue. However, we could not find a significant difference in the pre- and post-operative TIMP-1 levels, which may be due to recurrence or heterogeneity in the cyst type. Therefore, performing further studies with a larger sample size of the CE patients is recommended.

Epileptogenesis in Common Parasitic Infections

Purpose of the review

Neurocysticercosis (NCC) has been well recognized as a leading cause of epilepsy. More recently, studies of other parasitic diseases such as cerebral malaria (CM) and onchocerciasis are yielding novel insights into the pathogenesis of parasite-associated epilepsy. We compare the clinical and electrophysiological findings in epilepsy associated with these highly prevalent parasites and discuss the mechanisms involved in epileptogenesis.

Recent Findings

Electrophysiological and imaging biomarkers continue to emerge, and individuals who are at-risk of developing parasite-associated epilepsies are being identified with greater reliability. While both Taenia solium and Plasmodium falciparum directly affect the brain parenchyma, Onchocerca volvulus is not known to invade the central nervous system. Thus, the causal association between O. volvulus and epilepsy remains controversial.

Summary

Both NCC and CM have a well-defined acute phase when the parasites directly or indirectly invade the brain parenchyma and lead to local inflammatory changes. This is followed by a chronic phase marked by recurrent seizures. However, these stages of epileptogenic process have not been identified in the case of O. volvulus.

Investigation on Risk Stratification and the Prognostic Value of hs-TnT Combined with MMP-2 in Patients with Acute Coronary Syndrome

Objective

The aim of this study was at investigating the risk stratification and prognostic value of hypersensitive troponin T (hs-TnT) combined with matrix metalloproteinase 2 (MMP-2) in patients with acute coronary syndrome (ACS).

Methods

80 patients with coronary syndrome admitted to our hospital from January 2019 to January 2020 and 40 healthy people (control group) in the same period were selected. According to different types of diseases, the patients were divided into an acute group (n = 40) and stable group (n = 40). Besides, they all were monitored by the hs-TnT value, serum MMP-2, and coronary angiography at admission and the comparative analysis was carried out. The patients in both groups were followed up for 30 days, and the incidence of adverse cardiovascular events in the patients during this period was recorded.

Results

Compared with those in the control group, the MMP-2 and hs-TnT levels in the acute group and the stable group were significantly higher and the MMP-2 and hs-TnT levels in the acute group were significantly higher than those in the stable group, with statistically significant differences (P < 0.05). The 30-day follow-up results showed that the incidence of adverse cardiovascular events in the acute group was significantly higher than that in the stable group, with statistically significant differences (P < 0.05). The hs-TnT and MMP-2 levels in the acute myocardial infarction (AMI) group were significantly higher than those in the unstable angina pectoris (UAP) group, with statistically significant differences (P < 0.01). The hs-TnT and MMP-2 levels in the non-single-vessel group were significantly higher than those in the single-vessel group, with statistically significant differences (P < 0.01).

Conclusion

The hs-TnT and MMP-2 high expression levels are closely associated with myocardial injury, and they can effectively predict the severity of patients' disease. In addition, the hs-TnT and MMP-2 elevated levels can be considered as an important index to judge the short-term treatment efficacy and the risk stratification of early ACS, playing an important role in clinical treatment and rehabilitation in the later stage.

My experience on taeniasis and neurocysticercosis

Taeniasis and neurocysticercosis (NCC) are major public health problems in developing countries. NCC is the leading cause of community-acquired active epilepsy. NCC may present as a medical emergency, especially when there is cysticercotic encephalitis or raised intracranial hypertension. Systematic community-based studies on taeniasis and NCC are lacking. We studied taeniasis and NCC-related active epilepsy disease burden in the pig farming community of Lucknow district, Uttar Pradesh, India. Based on the 30 cluster sampling approach as recommended by the World Health Organization, we estimated the prevalence of taeniasis, NCC-related active epilepsy, and silent NCC in the community. We also estimated the prevalence of swine cysticercosis. Taeniasis was detected in 18.6% of populations. Expulsions of tapeworm segments in stool, consumption of undercooked pork, age above 15 years, and handwash with clay or plain water after defecation were associated with taeniasis. On molecular analyses of positive stool samples, T. solium was identified in 40% and Taenia asiatica in 60% of cases. Active epilepsy was identified in 5.8% of subjects; 48% of them had NCC. On neuroimaging, NCC was detected in 15% of asymptomatic individuals. We observed that host genetic factors such as toll-like receptor-4, matrix metalloproteinase-9, intercellular adhesion molecule-1, and glutathione-S transferase gene polymorphisms were associated with seizure in NCC. When peripheral blood mononuclear cells (PBMCs) from NCC subjects were exposed to cysticerci fluid antigens in-vitro, PBMCs from symptomatic and asymptomatic subjects showed significantly higher Th 1 and Th 2 cytokines response respectively, symptomatic patients had significant Th-1 cytokines response, while asymptomatic individuals showed Th-2 response. Porcine cysticercosis was detected in 26% of swine; 38% of them had cysticerci in the brain. Swine with brain involvement showed clinical signs such as excessive salivation, excessive blinking and tearing, and subconjunctival nodule. On molecular analysis, 15% of cysticerci in swine were identified as T. asiatica. Infected swine when treated with albendazole plus/minus steroid, the response rate of cysticerci (either dead or resolved lesion) was 100% in albendazole-treated group and 71% in albendazole plus steroid-treated group. The above studies suggest that taeniasis and NCC are alarmingly high in the pig farming community of North India. Taeniasis in human and cysticercosis in swine due to T. asiatica call for further studies on this parasite.

Helminth Coinfection Is Associated With Enhanced Plasma Levels of Matrix Metalloproteinases and Tissue Inhibitor of Metalloproteinases in Tuberculous Lymphadenitis

Matrix metalloproteinases (MMPs) are crucial for tissue remodeling and repair and are expressed in diverse infections, whereas tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors of MMPs. However, the interaction of MMPs and TIMPs in tuberculous lymphadenitis (TBL), an extra-pulmonary form of tuberculosis (EPTB) and helminth (Hel+) coinfection is not known. Therefore, this present study investigates the levels of circulating MMPs (1, 2, 3, 7, 8, 9, 12, 13) and TIMPs (1, 2, 3, 4) in TBL individuals with helminth (Strongyloides stercoralis [Ss], hereafter Hel+) coinfection and without helminth coinfection (hereafter, Hel-). In addition, we have also carried out the regression analysis and calculated the MMP/TIMP ratios between the two study groups. We describe that the circulating levels of MMPs (except MMP-8 and MMP-12) were elevated in TBL-Hel+ coinfected individuals compared to TBL-Hel- individuals. Similarly, the systemic levels of TIMPs (1, 2, 3, 4) were increased in TBL-Hel+ compared to TBL-Hel- groups indicating that it is a feature of helminth coinfection per se. Finally, our multivariate analysis data also revealed that the changes in MMPs and TIMPs were independent of age, sex, and culture status between TBL-Hel+ and TBL-Hel- individuals. We show that the MMP-2 ratio with all TIMPs were significantly associated with TBL-helminth coinfection. Thus, our results describe how helminth infection has a profound effect on the pathogenesis of TBL and that both MMPs and TIMPs could dampen the immunity against the TBL-Hel+ coinfected individuals.

Sialic acid removal by trans-sialidase modulates MMP-2 activity during Trypanosoma cruzi infection

Matrix metalloproteinases (MMPs) not only play a relevant role in homeostatic processes but are also involved in several pathological mechanisms associated with infectious diseases. As their clinical relevance in Chagas disease has recently been highlighted, we studied the modulation of circulating MMPs by Trypanosoma cruzi infection. We found that virulent parasites from Discrete Typing Units (DTU) VI induced higher proMMP-2 and MMP-2 activity in blood, whereas both low (DTU I) and high virulence parasites induced a significant decrease in proMMP-9 plasma activity. Moreover, trans-sialidase, a relevant T. cruzi virulence factor, is involved in MMP-2 activity modulation both in vivo and in vitro. It removes α2,3-linked sialyl residues from cell surface glycoconjugates, which then triggers the PKC/MEK/ERK signaling pathway. Additionally, bacterial sialidases specific for this sialyl residue linkage displayed similar MMP modulation profiles and triggered the same signaling pathways. This novel pathogenic mechanism, dependent on sialic acid removal by the neuraminidase activity of trans-sialidase, can be exploited by different pathogens expressing sialidases with similar specificity. Thus, here we present a new pathogen strategy through the regulation of the MMP network.

Strongyloides stercoralis Coinfection Is Associated With Greater Disease Severity, Higher Bacterial Burden, and Elevated Plasma Matrix Metalloproteinases in Pulmonary Tuberculosis

BACKGROUND

Helminths and tuberculosis (TB) largely overlap at the population level. Whether helminth infections influence disease severity and bacterial burdens in TB is not well understood.

METHODS

This study was conducted to examine the disease severity in a cohort of pulmonary TB (PTB) individuals with (Ss+) or without (Ss-) seropositivity for Strongyloides stercoralis infection.

RESULTS

Ss+ was associated with increased risk of cavitation (odds ratio [OR], 4.54; 95% confidence interval [CI], 2.33-9.04; P < .0001) and bilateral lung involvement (OR, 5.97; 95% CI, 3.03-12.09; P < .0001) in PTB individuals. Ss+ was also associated with higher bacterial burdens (OR, 7.57; 95% CI, 4.18-14.05; P < .0001) in PTB individuals. After multivariate analysis adjusting for covariates, Ss+ was still associated with greater risk of cavitation (adjusted OR [aOR], 3.99; 95% CI, 1.73-9.19; P = .0014), bilateral lung involvement (aOR, 4.09; 95% CI, 1.78-9.41; P = .0011), and higher bacterial burden (aOR, 9.32; 95% CI, 6.30-13.96; P < .0001). Finally, Ss+ was also associated with higher plasma levels of matrix metalloproteinases ([MMP]-1, -2, -7, -8, and -9) in PTB individuals.

CONCLUSIONS

Therefore, our data demonstrate that coexistent Ss infection is associated with greater disease severity and higher bacterial burden in PTB. Our data also demonstrate enhanced plasma levels of MMPs in coinfected individuals, suggesting a plausible biological mechanism for these effects.

Zoonotic and vector-borne parasites and epilepsy in low-income and middle-income countries

Zoonotic and vector-borne parasites are important preventable risk factors for epilepsy. Three parasitic infections - cerebral malaria, Taenia solium cysticercosis and onchocerciasis - have an established association with epilepsy. Parasitoses are widely prevalent in low-income and middle-income countries, which are home to 80% of the people with epilepsy in the world. Once a parasitic infection has taken hold in the brain, therapeutic measures do not seem to influence the development of epilepsy in the long term. Consequently, strategies to control, eliminate and eradicate parasites represent the most feasible way to reduce the epilepsy burden at present. The elucidation of immune mechanisms underpinning the parasitic infections, some of which are parasite-specific, opens up new therapeutic possibilities. In this Review, we explore the pathophysiological basis of the link between parasitic infections and epilepsy, and we consider preventive and therapeutic approaches to reduce the burden of epilepsy attributable to parasitic disorders. We conclude that a concerted approach involving medical, veterinary, parasitological and ecological experts, backed by robust political support and sustainable funding, is the key to reducing this burden.

Unique Characteristics of Epilepsy Development in Neurocysticercosis

The parasitic helminth infection neurocysticercosis (NCC) is the most common cause of adult-acquired epilepsy in the world. Despite the serious consequences of epilepsy due to this infection, an in-depth review of the distinct characteristics of epilepsy due to neurocysticercosis has never been conducted. In this review, we evaluate the relationship between NCC and epilepsy and the unique characteristics of epilepsy caused by NCC. We also discuss recent advances in our understanding of NCC-related epilepsy, including the importance of anti-inflammatory therapies, the association between NCC and temporal lobe epilepsy, and the recent discovery of biomarkers of severe epilepsy development in individuals with NCC and seizures.

In vitro model of postoncosphere development, and in vivo infection abilities of Taenia solium and Taenia saginata

Taenia solium is known to cause human cysticercosis while T. saginata does not. Comparative in vitro and in vivo studies on the oncosphere and the postoncospheral (PO) forms of T. solium and T. saginata may help to elucidate why cysticercosis can occur from one and not the other. The aim of this study was to use in vitro culture assays and in vivo models to study the differences in the development of the T. solium and T. saginata oncosphere. Furthermore, this study aimed to evaluate the expression of cytokines and metalloproteinases (MMPs) in human peripheral blood mononuclear cells (PBMCs), which were stimulated by these oncospheres and PO antigens. T. solium and T. saginata activated oncospheres (AO) were cultured in INT-407 and HCT-8 intestinal cells for 180 days. The T. solium began to die while the T. saginata grew for 180 days and developed to cysticerci in INT-407 cells. Rats were inoculated intracranially with AO and PO forms of either T. saginata or T. solium. Rats infected with T. solium AO and PO forms developed neurocysticercosis (NCC), while those infected with the T. saginata did not. Human PMBCs were stimulated with antigens of AO and PO forms of both species, and the production of cytokines and metalloproteinases (MMPs) was measured. The T. solium AO antigen stimulated a higher production of IL-4, IL-5, IL-13, IFN-γ, and IL-2 cytokines compared to T. saginata AO. In the PO form, the T. saginata PO antigen increased the production of IL-4, IL-5, IL-13, IFN-γ, IL-1β, IL-6, IL-10, TNF-α and IL-12 cytokines compared to T. solium, suggesting that this global immune response stimulated by different forms could permit survival or destruction of the parasite depending of their life-cycle stage. Regarding MMPs, T. solium AO antigen stimulated a higher production of MMP-9 compared to T. saginata AO antigen, which may be responsible for altering the permeability of intestinal cells and facilitating breakdown of the blood-brain barrier during the process of invasion of host tissue.

Taenia solium and Taenia saginata are two parasites that cause the tissue infection cysticercosis in their intermediate hosts, pigs and cows, respectively. One major difference between them is that T. solium can also cause neurocysticercosis in the human brain, while T. saginata cannot. Neurocysticercosis is thought to be the major cause of adult-onset seizures in developing countries. It is not well understood why only T. solium can survive in human tissue; however, the host inflammatory response likely plays an important role. The authors found that human immune cells stimulated with T. solium in the early stages of the parasite life cycle produced a more robust cytokine response than T. saginata. However, in the mature stage, which occurs once T. solium reaches the brain, T. solium antigens stimulated a lower inflammatory response compared to T. saginata, suggesting the parasite is able to manipulate the host immune response in some way to evade destruction. These findings may support the differences in growth observed by the authors when rat brains were inoculated with either parasite species. This study provides new insights into the different ways T. solium and T. saginata activate the immune response to survive and develop within the host.

Therapeutic Target and Cell-signal Communication of Chlorpromazine and Promethazine in Attenuating Blood-Brain Barrier Disruption after Ischemic Stroke

Ischemic stroke destroys blood–brain barrier (BBB) integrity. There are currently no effective treatments available in the clinical setting. Post-ischemia treatment with phenothiazine drugs [combined chlorpromazine and promethazine (C+P)] has been shown to be neuroprotective in stroke. The present study determined the effect of C+P in BBB integrity. Sprague-Dawley rats were divided into the following groups (n=8 each): (1) stroke, (2) stroke treated by C+P with temperature control, and (3) stroke treated by C+P without temperature control. Infarct volume and neurological deficits were measured to assess the neuroprotective effect of C+P. BBB permeability was determined by brain edema and Evans blue leakage. Expression of BBB integral molecules, including proteins of aquaporin-4 and -9 (AQP-4, AQP-9), matrix metalloproteinase-2 and -9 (MMP-2, MMP-9), zonula occludens-1 (ZO-1), claudin-1/5, occludin, and laminin were determined by Western blot. Stroke caused brain infarction and neurological deficits, as well as BBB damage, which were all attenuated by C+P through drug-induced hypothermia. When the reduced temperature was controlled to physiological levels, C+P still conferred neuroprotection, suggesting a therapeutic effect independent of hypothermia. Furthermore, C+P significantly attenuated the increase in AQP-4, AQP-9, MMP-2, and MMP-9 levels after stroke, and reversed the decrease in tight junction protein (ZO-1, claudin-1/5, occludin) and basal laminar protein (laminin) levels. This study clearly indicates a beneficial effect of C+P on BBB integrity after stroke, which may be independent of drug-induced hypothermia. These findings further prove the clinical target and cell-signal communication of C+P treatment, which may direct us closer toward the development of an efficacious neuroprotective therapy.

Inflammation is a key risk factor for persistent seizures in neurocysticercosis

Objective

We conducted a retrospective, case-control study of neurocysticercosis patients to ascertain early markers that identify subjects likely to develop treatment-resistant seizures.

Methods

Clinical histories and imaging studies from 38 neurocysticercosis patients who had been followed for 18 months after treatment were evaluated. Both pairwise and multifactorial analyses were conducted to identify factors associated with continued seizures.

Results

Eleven of 38 patients continued to have seizures during the follow-up period. On univariate analysis, the number of neurocysticercosis lesions, number of bands on the baseline neurocysticercosis western blot, edema volumes on follow-up MRI scans, edema volume changes between baseline and follow-up images, and proportion of calcified lesions with perilesional edema were all significantly increased in subjects who had persistent seizures during the 18-month follow-up period. On multivariate analyses using recursive partition and random forest algorithms, variables associated with persistent seizures included: the number of total and calcified lesions, presence of perilesional edema, the rate of change in the lesion and edema volumes from baseline to follow-up, and the number of bands on the neurocysticercosis western blot.

Interpretation

Measures of both inflammation and disease burden are key risk factors for persistent seizures despite anticonvulsant treatments in patients with neurocysticercosis. Inflammation is therefore a potentially modifiable risk factor for the frequently seen severe seizure disorders in patients with neurocysticercosis.

Dynamic contrast-enhanced (DCE) MRI derived kinetic perfusion indices may help predicting seizure control in single calcified neurocysticercosis

BACKGROUND

The factors responsible for seizure recurrence in patients with Solitary calcified neurocysticercosis (NCC) are not well understood. Blood brain barrier (BBB) breach may be associated with seizure recurrence. Dynamic contrast enhanced (DCE) MRI derived indices k_ep, k^trans and v_e are useful in quantifying BBB permeability. In this study, we assessed the possible role of DCE-MRI and matrix metalloproteinases (MMP)-9 levels in predicting seizure recurrence.

METHODS

In this prospective-observational study, patients with new-onset seizures and a solitary calcified NCC were included. DCE-MRI was done to quantify BBB integrity. DCE-MRI parameters were measured as k_ep, k^trans and v_e. MMP-9 levels were estimated. Patients were followed for 1 year, when DCE-MRI and MMP-9 levels were repeated. Patients were classified into two groups on the basis of seizure recurrence, which was defined as the recurrence of an episode of seizure at least 1 week after the initiation of the anti-epileptic drugs. Logistic regression analysis was done.

RESULTS

At 1-year of follow up, 8 out of 32 patients had seizure recurrence. Baseline DCE-MRI derived k_ep (p = 0.015) and MMP-9 levels (p = 0.019) were significantly higher in the seizure "recurrence" group compared with the "no recurrence" group. On within-group analysis, a significant increase in k_ep (p = 0.012), v_e (p = 0.012), and MMP-9 levels (p = 0.017) was observed in the seizure "recurrence" group while a decrease was seen in v_e and MMP-9 levels in the "no recurrence" group.

CONCLUSION

Higher values of DCE-MRI indices and MMP-9 levels, with a corresponding trend in the follow-up, can be useful in predicting lesions with a higher propensity for seizure recurrence.

TNF-α blockade suppresses pericystic inflammation following anthelmintic treatment in porcine neurocysticercosis

Background

Neurocysticercosis (NCC) is an infection of the brain with the larval cyst of the tapeworm, Taenia solium. Cysticidal treatment induces parasite killing resulting in a post inflammatory response and seizures, which generally requires corticosteroid treatment to control inflammation. The nature of this response and how to best control it is unclear. We investigated the anti-inflammatory effects of pretreatment with etanercept (ETN), an anti-tumor necrosis factor agent, or dexamethasone (DEX), a high potency corticosteroid, on the post treatment inflammatory response in naturally infected pigs with neurocysticercosis after a single dose of the cysticidal drug praziquantel (PZQ).

Methodology/Principal findings

We followed the methods from a previously developed treatment model of NCC in naturally infected swine. The four study groups of infected pigs included 3 groups treated with PZQ on day 0: PZQ-treated alone (100 mg/kg PO; n = 9), pretreated with dexamethasone (DEX, 0.2 mg/kg IM administered on days -1, +1 and +3; n = 6), and pretreated with etanercept (ETN, 25 mg IM per animal on days -7 and 0; n = 6). The fourth group remained untreated (n = 3). As measured by quantitative RT-PCR, ETN pretreatment depressed transcription of a wide range of proinflammatory, regulatory and matrix protease encoding genes at 120 hr post PZQ treatment in capsules of cysts that demonstrated extravasated Evans Blue (EB) (a measure of blood brain barrier dysfunction) compared to animals not receiving ETN. Transcription was significantly depressed for the proinflammatory genes tumor necrosis factor (TNF)-α, and interferon (IFN)-γ; the inflammation regulating genes cytotoxic T-lymphocyte-associated protein (CTLA)4, interleukin (IL)-13 and transforming growth factor (TGF)-β; the tissue remodeling genes matrix metalloprotease (MMP)1 and 9, tissue inhibitors of metalloproteases (TIMP)1 and 2, and the genes regulating endothelial function vascular endothelial growth factor (VEGF)1, angiopoietin (Ang)1, Ang 2, and platelet endothelial cell adhesion molecule (PECAM)-1. In contrast, transcription was only modestly decreased in the DEX pretreated pigs compared to PZQ alone, and only for TNF-α, IL-6, IFN-γ, TGF-β and Ang1. IL-10 was not affected by either ETN or DEX pretreatments. The degree of inflammation, assessed by semi-quantitative inflammatory scores, was modestly decreased in both ETN and DEX pretreated animals compared to PZQ treated pigs whereas cyst damage scores were moderately decreased only in cysts from DEX pretreated pigs. However, the proportion of cysts with EB extravasation was not significantly changed in ETN and DEX pretreated groups.

Conclusions/Significance

Overall, TNF-α blockade using ETN treatment modulated expression of a large variety of genes that play a role in induction and control of inflammation and structural changes. In contrast the number of inflammatory cells was only moderately decreased suggesting weaker effects on cell migration into the inflammatory capsules surrounding cysts than on release of modulatory molecules. Taken together, these data suggest that TNF-α blockade may provide a viable strategy to manage post-treatment pericystic inflammation that follows antiparasitic therapy for neurocysticercosis.

Infection of the brain with larvae of the tapeworm Taenia solium is called neurocysticercosis (NCC), a disease with varied and serious neurological symptoms. Therapy requires antiparasitic drugs and corticosteroids to prevent seizures caused by treatment due to inflammation around dying parasites. The gene expression of the proinflammatory molecule tumor necrosis factor alpha (TNF-α) is increased in NCC. We treated three groups of naturally infected pigs with an antiparasitic drug: one group was also pretreated with an anti-TNF-α inhibitor, the second one with a corticosteroid, and the third was not pretreated. All pigs were infused with Evans blue dye (EB), which leaks where the blood brain barrier is damaged by inflammation around cysts. We compared the expression of several genes involved in inflammation, healing and fibrosis and regulation of vascular function in tissues surrounding cysts. In inflamed samples showing leaked EB, the inhibition of TNF-α suppressed nearly all the genes assessed, and this suppression was significantly stronger than the moderate decrease caused by corticosteroid pretreatment on most of the genes. On microscopic examination, the inflammation observed was slightly decreased with both pretreatments in relation to the group that was not pretreated. We believe that the inflammatory route that includes TNF-α should be further explored in the search for better management of inflammation directed to degenerating cysts.

Natural History of Patients With Perilesional Edema Around Taenia solium Calcified Granulomas

Background

The transient development of perilesional edema (PE) around ≥1 calcification (defined as 1 episode) occurs in about 50% of the patients with recurrent seizures in calcified neurocysticercosis (NCC). We determined the long-term clinical and radiological course of persons undergoing PE episodes.

Methods

Twenty-one persons with NCC who experienced ≥1 PE episode were followed for a median of 10.6 years (range, 0.4-29.2 years). Clinical evaluations and magnetic resonance imaging (MRI) were performed at the time of suggestive symptoms and during routine follow-up.

Results

PE episodes were documented 78 times, involving 50 of 729 calcifications. Episodes reoccurred in all but 3 persons. The pattern, rate, and number of episodes were variable, commonly chronic, and not significantly associated with time from treatment, number of calcifications, or sex. Seizure was the most common symptom, but almost 30% of episodes were asymptomatic and detected by MRI during routine follow-up. Persons with delayed recurrent episodes were significantly older (age, 42.3 vs 28.8 years; P = .045). Seizures continued to occur in 37.5%, and 2 persons had a severe disabling clinical course.

Conclusions

The number and timing of PE episodes in individuals with calcified NCC are variable and commonly chronic, sometimes recurring over decades. A minority of patients developed significant disability.

Pathogenesis of Taenia solium taeniasis and cysticercosis

Taenia solium infections (taeniasis/cysticercosis) are a major scourge to most developing countries. Neurocysticercosis, the infection of the human nervous system by the cystic larvae of this parasite, has a protean array of clinical manifestations varying from entirely asymptomatic infections to aggressive, lethal courses. The diversity of clinical manifestations reflects a series of contributing factors which include the number, size and location of the invading parasites, and particularly the inflammatory response of the host. This manuscript reviews the different presentations of T. solium infections in the human host with a focus on the mechanisms or processes responsible for their clinical expression.

Matrix metalloproteinase (MMP)-9: A realiable marker for inflammation in early human trichinellosis

Matrix Metalloproteinases (MMPs) are involved in many physiological and pathological processes. As regards parasitic infections, the role of these proteins has been particularly studied in malaria, neurocysticercosis and angiostrongyloidosis. Recently, we evaluated serum levels of MMP-9 and -2 (gelatinases) in mice experimentally infected with Trichinella spiralis or Trichinella pseudospiralis, which cause different degrees of myositis and we found their significant increase in the former and, at a lesser extent, in the latter, thus suggesting the possibility that these gelatinases, particularly MMP-9, represent a marker of inflammation. Our aim was to evaluate the levels of MMP-9 and 2 in trichinellosis patients, to assess their possible clinical significance. Serum samples from 31 Trichinella britovi-infected individuals (20 males and 11 females), living in Tuscany, Central Italy, were analysed for MMP-9 and MMP-2 serum levels. Patients acquired infection with Trichinella after consuming raw or undercooked meat of wild boar. Their median age was 49±0.33years (range from 7 to 91). Sera was collected before starting anti-inflammatory treatment, aliquoted and stored at -20°C until use. Sera from healthy subjects was considered as controls. The gelatinolytic activity of MMPs was analysed by gelatin zymography on 8% polyacrylamide-SDS gels containing 0.1% porcine gelatin, under non-reducing conditions. Clear bands corresponding to the digested areas were evaluated with an appropriate software. MMP-9 levels were additionally determined in 15 patients using a commercial ELISA kit for human MMP-9. The zymographic analysis of the gels showed the presence in serum samples of gelatinase bands at approximately 125-kDa, 92-kDa and 72-kDa, corresponding to the MMP-9/Neutrophil gelatinase-associated lipocalin (NGAL) complex and proenzyme forms of MMP-9 and MMP-2, respectively. A significant (p<0.01) increase in gelatinolytic activity in patients compared to the control group was observed for pro-MMP-9 in 25 out of 31. The mean increase in activity was 39.25%±16.67%. No significant differences were observed for pro-MMP-2 activity. The MMP-9 levels detected by ELISA showed significant correlation with zymographic data (r²=0.62, p<0.003) and were higher in more affected patients (suffering diarrhea, facial edemas and myalgia). In conclusion, MMP-9 might be considered as a marker of inflammation in T. britovi patients. On the contrary, MMP-2 did not result significantly different in patients, compared to controls.

Toll-like Receptor-4 Polymorphisms and Serum Matrix Metalloproteinase-9 in Newly Diagnosed Patients With Calcified Neurocysticercosis and Seizures

We evaluated seizure profile, Toll-like receptor (TLR)-4 polymorphisms, and serum matrix metalloproteinases (MMPs) in patients with calcified neurocysticercosis.One-hundred nine patients with calcified neurocysticercosis with newly diagnosed seizures and 109 control subjects were enrolled. TLR-4 Asp299Gly and Thr399Ile polymorphisms and serum MMP-9 levels were evaluated. The patients were followed for 1 year.Asp/Gly (P = 0.012) and Thr/Ile (P = 0.002), Gly (Asp/Gly plus Gly/Gly) (P = 0.008) and Ile (Thr/Ile plus Ile/Ile) (P = 0.003) genotypes were significantly associated with calcified neurocysticercosis compared with controls. Gly/Gly and Ile/Ile genotypes were not significantly associated (P = 0.529 for Gly/Gly, P = 0.798 for Ile/Ile) with either group. The levels of MMP-9 were higher in calcified neurocysticercosis (P =  < 0.001). The levels of MMP-9 were higher in patients with multiple calcified neurocysticercosis compared with single calcified neurocysticercosis (P =  < 0.001).Headache (P = 0.031), status epilepticus (P = 0.029), Todd paralysis (P = 0.039), lesion size >10 mm (P = 0.001), and perilesional edema (P =  < 0.001) were significantly associated with seizure recurrence. Heterozygous form Asp/Gly (P =  < 0.001) and heterozygous form Thr/Ile (P =  < 0.001) were significantly associated with seizure recurrence. The Gly (Asp/Gly plus Gly/Gly) (P =  < 0.001) and Ile (Thr/Ile plus Ile/Ile) (P =  < 0.001) genotypes were also significantly associated with seizure recurrence. Higher serum MMP-9 levels were significantly associated with seizure recurrence (P =  < 0.001).The TLR-4 gene abnormalities may trigger inflammation around calcified neurocysticercosis leading to an increase in perilesional edema and provocation of seizures.

Expression of adhesion molecules, chemokines and matrix metallo- proteinases (MMPs) in viable and degenerating stage of Taenia solium metacestode in swine neurocysticercosis

Neurocysticercosis (NCC) is a parasitic infection of central nervous system (CNS). Expression of adhesion molecules, chemokines and matrix metalloproteinases (MMPs) were investigated on brain tissues surrounding viable (n=15) and degenerating cysticerci (n=15) of Taenia solium in swine by real-time RT-PCR and ELISA. Gelatin gel zymography was performed for MMPs activity. ICAM-1 (intercellular adhesion molecule-1), E-selectin, MIP-1α (macrophage inflammatory protein-1α), Eotaxin-1 and RANTES (regulated on activation, normal T cell expressed and secreted) were associated with degenerating cysticerci (cysts). However, VCAM-1 (vascular cell adhesion molecule-1), MCP-1 (monocyte chemotactic protein-1), MMP-2 and MMP-9 were associated with both viable and degenerating cysts. In conclusion, viable and degenerating cysticerci have different immune molecule profiles and role of these molecules in disease pathogenesis needs to be investigated.

Post-treatment vascular leakage and inflammatory responses around brain cysts in porcine neurocysticercosis

Cysticidal treatment of neurocysticercosis, an infection of humans and pig brains with Taenia solium, results in an early inflammatory response directed to cysts causing seizures and focal neurological manifestations. Treatment-induced pericystic inflammation and its association with blood brain barrier (BBB) dysfunction, as determined by Evans blue (EB) extravasation, was studied in infected untreated and anthelmintic-treated pigs. We compared the magnitude and extent of the pericystic inflammation, presence of EB-stained capsules, the level of damage to the parasite, expression of genes for proinflammatory and regulatory cytokines, chemokines, and tissue remodeling by quantitative PCR assays between treated and untreated infected pigs and between EB-stained (blue) and non stained (clear) cysts. Inflammatory scores were higher in pericystic tissues from EB-stained cysts compared to clear cysts from untreated pigs and also from anthelmintic-treated pigs 48 hr and 120 hr after treatment. The degree of inflammation correlated with the severity of cyst wall damage and both increased significantly at 120 hours. Expression levels of the proinflammatory genes for IL-6, IFN-γ, TNF-α were higher in EB-stained cysts compared to clear cysts and unaffected brain tissues, and were generally highest at 120 hr. Additionally, expression of some markers of immunoregulatory activity (IL-10, IL-2Rα) were decreased in EB-stained capsules. An increase in other markers for regulatory T cells (CTLA4, FoxP3) was found, as well as significant increases in expression of two metalloproteases, MMP1 and MMP2 at 48 hr and 120 hr post-treatment. We conclude that the increase in severity of the inflammation caused by treatment is accompanied by both a proinflammatory and a complex regulatory response, largely limited to pericystic tissues with compromised vascular integrity. Because treatment induced inflammation occurs in porcine NCC similar to that in human cases, this model can be used to investigate mechanisms involved in host damaging inflammatory responses and agents or modalities that may control damaging post treatment inflammation.

Neurocysticercosis is caused by infection of the brain with the larval (cyst) stage of the tape worm Taenia solium in humans and pigs. Antiparasitic drug treatment is compromised by worsening of neurological symptoms during therapy due to reactive inflammation triggered by the dying parasite. The immune mechanisms that cause this inflammation are poorly understood. In this study, we investigated the nature of inflammation after treatment in pigs naturally infected with T. solium cysts. Evans blue dye injected into infected pigs marks areas in the brain where the normally impermeable capillaries have become more permeable, allowing damaging cells and molecules to leak out into the brain. By microscopy and measurement of gene expression for inflammation-inducing immune mediators, we show that inflammation in the brain tissues around cysts is more severe with increased vessel leakage. Furthermore, the levels of these mediators increased after antiparasitic drug treatment. A significant implication of these findings is that it may be possible to inhibit the inflammation around parasites using drugs or biologics that inhibit these inflammatory pathways and, thereby, reduce local brain damage during treatment. These observations may also be applicable to other inflammatory conditions that affect the brain.

Clinical symptoms, diagnosis, and treatment of neurocysticercosis

The infection of the nervous system by the cystic larvae of Taenia solium (neurocysticercosis) is a frequent cause of seizure disorders. Neurocysticercosis is endemic or presumed to be endemic in many low-income countries. The lifecycle of the worm and the clinical manifestations of neurocysticercosis are well established, and CT and MRI have substantially improved knowledge of the disease course. Improvements in immunodiagnosis have further advanced comprehension of the pathophysiology of this disease. This knowledge has led to individualised treatment approaches that account for the involvement of parenchymal or extraparenchymal spaces, the number and form of parasites, and the extent of degeneration and associated inflammation. Clinical investigations are focused on development of effective treatments and reduction of side-effects induced by treatment, such as seizures, hydrocephalus, infarcts, and neuroinjury.

Immunology of Taenia solium taeniasis and human cysticercosis

The life cycle of Taenia solium, the pork tapeworm, is continuously closed in many rural settings in developing countries when free roaming pigs ingest human stools containing T. solium eggs and develop cysticercosis, and humans ingest pork infected with cystic larvae and develop intestinal taeniasis, or may also accidentally acquire cysticercosis by faecal-oral contamination. Cysticercosis of the human nervous system, neurocysticercosis, is a major cause of seizures and other neurological morbidity in most of the world. The dynamics of exposure, infection and disease as well as the location of parasites result in a complex interaction which involves immune evasion mechanisms and involutive or progressive disease along time. Moreover, existing data are limited by the relative lack of animal models. This manuscript revises the available information on the immunology of human taeniasis and cysticercosis.

T1-weighted dynamic contrast-enhanced MR evaluation of different stages of neurocysticercosis and its relationship with serum MMP-9 expression

BACKGROUND AND PURPOSE

Epileptogenesis in NCC is associated with perilesional inflammation and disruption in BBB. We quantified BBB in different stages of NCC by using DCE-MR imaging to look for the differences in perfusion indices and to correlate these indices with serum MMP-9 expression.

MATERIALS AND METHODS

DCE-MR imaging along with conventional MR imaging was performed in 57 single cysticercous brain lesions to quantify the kep, K(trans), and ve around the lesions, which were in different stages of evolution. There were 6 lesions in the vesicular stage and 17 lesions each in the colloidal, granular-nodular, and calcified stages. Serum MMP-9 was quantified from all patients, whereas perfusion indices were quantified from all stages except for the vesicular stage.

RESULTS

We observed significant differences among the 3 stages of NCC in serum MMP-9 expression as well as DCE-derived kep values. In addition, kep showed a strongly significant positive correlation with MMP-9 expression when modeled with the individual stage of the disease as well as with all stages when pooled together. Other DCE-derived hemodynamic and pharmacokinetic parameters showed inconsistent differences with each stage of the disease. The correlation of DCE-derived parameters with serum MMP-9 expression and edema volume also showed inconsistency with the stage of the disease.

CONCLUSIONS

We conclude that kep correlates best with serum MMP-9 expression among the pharmacokinetic indices and most closely represents the degree of BBB breakdown, which is highest in the colloidal stage and lowest in the calcified stage. kep may be used as a noninvasive image biomarker of BBB breakdown in different stages of NCC.

The significance of matrix metalloproteinases in parasitic infections involving the central nervous system

Matrix metalloproteinases (MMPs) represent a large family of over twenty different secreted or membrane-bound endopeptidases, involved in many physiological (embryogenesis, precursor or stem cell mobilization, tissue remodeling during wound healing, etc.), as well as pathological (inflammation, tumor progression and metastasis in cancer, vascular pathology, etc.) conditions. For a long time, MMPs were considered only for the ability to degrade extracellular matrix (ECM) molecules (e.g., collagen, laminin, fibronectin) and to release hidden epitopes from the ECM. In the last few years, it has been fully elucidated that these molecules have many other functions, mainly related to the immune response, in consideration of their effects on cytokines, hormones and chemokines. Among others, MMP-2 and MMP-9 are endopeptidases of the MMP family produced by neutrophils, macrophages and monocytes. When infection is associated with leukocyte influx into specific organs, immunopathology and collateral tissue damage may occur. In this review, the involvement of MMPs and, in particular, of gelatinases in both protozoan and helminth infections will be described. In cerebral malaria, for example, MMPs play a role in the pathogenesis of such diseases. Also, trypanosomosis and toxoplasmosis will be considered for protozoan infections, as well as neurocysticercosis and angiostrongyloidosis, as regards helminthiases. All these situations have in common the proteolytic action on the blood brain barrier, mediated by MMPs.

Altered circulating levels of matrix metalloproteinases and inhibitors associated with elevated type 2 cytokines in lymphatic filarial disease

Background

Infection with Wuchereria bancrofti can cause severe disease characterized by subcutaneous fibrosis and extracellular matrix remodeling. Matrix metalloproteinases (MMPs) are a family of enzymes governing extracellular remodeling by regulating cellular homeostasis, inflammation, and tissue reorganization, while tissue-inhibitors of metalloproteinases (TIMPs) are endogenous regulators of MMPs. Homeostatic as well as inflammation-induced balance between MMPs and TIMPs is considered critical in mediating tissue pathology.

Methods

To elucidate the role of MMPs and TIMPs in filarial pathology, we compared the plasma levels of a panel of MMPs, TIMPs, other pro-fibrotic factors, and cytokines in individuals with chronic filarial pathology with (CP Ag+) or without (CP Ag−) active infection to those with clinically asymptomatic infections (INF) and in those without infection (endemic normal [EN]). Markers of pathogenesis were delineated based on comparisons between the two actively infected groups (CP Ag+ compared to INF) and those without active infection (CP Ag− compared to EN).

Results and Conclusion

Our data reveal that an increase in circulating levels of MMPs and TIMPs is characteristic of the filarial disease process per se and not of active infection; however, filarial disease with active infection is specifically associated with increased ratios of MMP1/TIMP4 and MMP8/TIMP4 as well as with pro-fibrotic cytokines (IL-5, IL-13 and TGF-β). Our data therefore suggest that while filarial lymphatic disease is characterized by a non-specific increase in plasma MMPs and TIMPs, the balance between MMPs and TIMPs is an important factor in regulating tissue pathology during active infection.

Lymphatic filariasis afflicts over 120 million people worldwide. While the infection is mostly clinically asymptomatic, approximately 40 million people suffer from overt, morbid clinical pathology characterized by swelling of the scrotal area and lower limbs (hydrocele and lymphedema). Host immunologic factors that influence the pathogenesis of disease in these individuals are not completely understood. Matrix metalloproteinases are a family of circulating and tissue proteins that influence the development of tissue fibrosis. They are regulated by another family of proteins called tissue inhibitors of metalloproteinases. The interplay between these proteins governs tissue fibrosis in a variety of conditions. In addition, certain cytokines are known to promote pro-fibrotic events. We have attempted to elucidate the role of the above-mentioned factors in disease pathogenesis by comparing the plasma levels of the various markers in four groups of individuals: chronic pathology individuals with or without active filarial infection; asymptomatic, filaria-infected individuals; and uninfected, endemic normal individuals. We show that altered ratios of the metalloproteinases and their inhibitors—as well as elevated levels of pro-fibrotic cytokines—characterize filarial infection-induced lymphatic pathology.