A multimodality therapeutic application on Toxoplasma gondii encephalitis utilizing Spiramycin and 'de novo' Ferula asafetida in immunodeficient mice

This study investigated a 'de Novo' medicinal herb, Ferula asafetida (FA), against toxoplasma encephalitis either alone or combined with spiramycin (SP). Female Swiss-Webster mice (n = 72) were divided into three batches. Batch-I received no DMS to serve as an immunocompetent control, batch-II was immune-suppressed with the DMS (0.25 mg/g/day) for 14 days pre-infection, whilst batch-III was immune-suppressed with the DMS on the same day of infection. All experimental mice were inoculated with Toxoplasma gondii ME49 cysts (n = 75). Each batch was split into four subgroups: Mono-SP, mono-FA, combined drug (SP + FA), or neither. Therapies were administered on day zero of infection in batches (I and II) and 35 days post-infection in batch (III). Treatments lasted for 14 days, and mice were sacrificed 60 days post-infection. Histopathological changes, cysts load, and CD4 and CD8 T-cells were counted in brain tissues. The cyst-load count in mice receiving SP + FA was significantly (p < .0001) the least compared to the mono treatments in all protocols. Interestingly, the combined therapy demolished the T-cell subsets to zero in immunocompetent and immunocompromised infected mice. In conclusion, F. asafetida might be a powerfully natural, safe vehicle of SP in the digestive system and/or across the brain-blood barrier to control toxoplasmosis even through immunodeficient conditions.

Animal Models for Toxoplasma gondii Infection

Toxoplasma gondii is an obligate intracellular protozoan parasite that commonly infects mammals and birds throughout the world. This protocol describes murine models of acute T. gondii infection, toxoplasmic encephalitis and toxoplasma retinochoroiditis. T. gondii infection in severe combined immunodeficient (SCID) mice, deficient in T and B cells, has allowed for the study of T cell-independent mechanisms of defense against intracellular organisms, as described here. The uracil auxotroph strain cps1-1 and temperature-sensitive mutant strains of T. gondii induce protection against challenge with virulent strains of the parasite. They have allowed studies of immunization and adoptive-transfer experiments. A protocol is provided for infection with these mutant strains. The EGS strain of T. gondii has the unique feature of spontaneously forming tissue cysts in cell culture. Dual fluorescent reporter stains of this strain have allowed the study of tachyzoite to bradyzoite transitions in vitro and in vivo. A protocol for in vitro and in vivo growth of this strain and tissue cyst isolation is provided. Genetic manipulation of T. gondii and mice has led to the development of parasites that express fluorescent proteins as well as mice with fluorescently labeled leukocytes. This together with the use of T. gondii that express model antigens and transgenic mice that express the appropriate T cell receptor have facilitated the in vivo study of parasite host-interaction. In addition, parasites that express bioluminescent markers have made it possible to study the dynamics of infection in real time using bioluminescence imaging. Support protocols present methodology for evaluation of progression of infection and immune response to the parasite that includes these newer methodologies. In addition, support protocols address the maintenance of T. gondii tissue cysts and tachyzoites, as well as preparation of T. gondii lysate antigens. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Induction of acute T. gondii infection in mice Basic Protocol 2: Model of toxoplasmic encephalitis and toxoplasma retinochoroiditis in chronically infected mice Basic Protocol 3: Assessment of T. gondii invasion into neural tissue Basic Protocol 4: T. gondii infection in scid/scid (SCID) mice Basic Protocol 5: Infection with the uracil auxotroph strain CPS1-1 or the temperature-sensitive TS-4 strain of T. gondii Basic Protocol 6: In vivo and in vitro maintenance of the EGS strain of T. gondii Support Protocol 1: Assessment of progression of infection and immune response to T. gondii Support Protocol 2: Maintenance of a bank of T. gondii cysts of the ME49 strain Support Protocol 3: Maintenance of T. gondii tachyzoites using human foreskin fibroblasts Support Protocol 4: Maintenance of T. gondii tachyzoites in mice Support Protocol 5: Preparation of T. gondii lysate antigens Support Protocol 6: Isolation of T. gondii tissue cysts from brain.

Toxoplasmosis in patients with an autoimmune disease and immunosuppressive agents: A multicenter study and literature review

Background

Cases of Toxoplasma reactivation or more severe primary infection have been reported in patients receiving immunosuppressive (IS) treatment for autoimmune diseases (AID). The purpose of this study was to describe features of toxoplasmosis occurring in patients with AID treated by IS therapy, excluded HIV-positive and transplant patients.

Methods

A multicenter descriptive study was conducted using data from the French National Reference Center for Toxoplasmosis (NRCT) that received DNA extracts or strains isolated from patients, associated with clinical data. Other cases were retrieved through a questionnaire sent to all French parasitology and internal medicine departments. Furthermore, a systematic literature review was conducted.

Results

61 cases were collected: 25 retrieved by the NRCT and by a call for observations and 36 from a literature review. Half of the cases were attributed to reactivation (50.9%), and most of cases (49.2%) were cerebral toxoplasmosis. The most common associated AID were rheumatoid arthritis (28%) and most frequent treatments were antimetabolites (44.3%). Corticosteroids were involved in 60.7% of cases. Patients had a favorable outcome (50.8%) but nine did not survive. For 12 cases, a successful Toxoplasma strain characterization suggested the possible role of this parasitic factor in ocular cases.

Conclusion

Although this remains a rare condition, clinicians should be aware for the management of patients and for the choice of IS treatment.

Inhibition of Toxoplasma gondii Growth by Dihydroquinine and Its Mechanisms of Action

Toxoplasma gondii is a zoonotic parasite that infects the brain of humans and causes cerebral toxoplasmosis. The recommended drugs for the treatment or prophylaxis of toxoplasmosis are pyrimethamine (PY) and sulfadiazine (SZ), which have serious side effects. Other drugs available for toxoplasmosis are poorly tolerated. Dihydroquinine (DHQ) is a compound closely related to quinine-based drugs that have been shown to inhibit Plasmodium falciparum and Plasmodium berghei in addition to its anti-arrhythmia properties. However, little is known about the effect of DHQ in T. gondii growth and its mechanism of action in vitro. In this study, we report the anti-Toxoplasma and anti-invasion properties of DHQ. DHQ significantly inhibited T. gondii tachyzoite growth with IC50s values of 0.63, 0.67, and 0.00137 µM at 24, 48, and 72 h, respectively. Under similar conditions, SZ and PY, considered as the gold standard drugs for the treatment of toxoplasmosis, had IC50s values of 1.29, 1.55, and 0.95 and 3.19, 3.52, and 2.42 µM, respectively. The rapid dose-dependent inhibition of T. gondii tachyzoites by DHQ compared to the standard drugs (SZ and PY) indicates that DHQ has high selective parasiticidal effects against tachyzoite proliferation. Remarkably, DHQ had an excellent selectivity index (SI) of 149- and 357-fold compared to 24- and 143-fold for PY and SZ, respectively, using fibroblast cells. In addition, DHQ disrupted T. gondii tachyzoite mitochondrial membrane potential and adenosine triphosphate (ATP) production and elicited high reactive oxygen species (ROS) generation. Taking all these findings together, DHQ promises to be an effective and safe lead for the treatment of toxoplasmosis.

Brain lesions in a patient with rectal cancer: mind your step

Cerebral toxoplasmosis is a potentially fatal infection most commonly seen in immunocompromised patients. We present a patient on long-term immunosuppressive therapy after kidney transplantation and a recent history of oligometastatic rectal cancer, with cerebral lesions as a result of toxoplasmosis. Heightened awareness of the occurrence of opportunistic infections in patients with cancer who are taking immunosuppressive drugs is needed among clinicians.

Immunodiagnostics of cerebral toxoplasmosis depending on permeability of blood-brain barrier

OBJECTIVE

The aim of the work was to detect a diagnostic value of CNSToxoIndex - index of correlation between albumin concentration and anti-toxoplasma antibodies, which reflects local production of anti-toxoplasma IgG in CNS compared with their level in blood.

PATIENTS AND METHODS

Materials and methods: 30 HIV-infected persons with the IV clinical stage (16 man and 14 women) aged from 25 to 49 years with clinical and instrumental signs of cerebral toxoplasmosis were selected from the general array of the patients treated in the Regional Clinical Infectious Hospital. A retrospective parallel detection of IgG T. gondii was performed in serum and CSF in patients, whose results of ELISA or PCR on T. gondii were positive. Blood serum and CSF were obtained from patients at the same time. All samples for analysis were stored at -20 °C and then tested on the RT-2100C Rayto Life and Analytical Sciences Co., Ltd (China) immunoassay analyser for quantitative detection of the level of specific anti-Toxicoplasma IgG. Detection of albumin concentration in serum and CSF was performed on the Chemray-120 Automated Biochemical Analyzer Rayto Life and Analytical Sciences Co., Ltd (China) using the Liquick Cor-ALBUMIN Diagnostic Kit.

RESULTS

Results: Specific IgG to T. gondii in blood plasma was found in 27 patients (90%) while in CSF only in 7 (23 %). The results of the research in this group of patients were represented by the following parameters: patient 1 (blood antiToxo IgG - 200 IU/ml, blood albumin - 36 g/l, CSF antiToxo IgG - 10 IU/ml, CSF albumin - 0.8 g/l, CNSToxolndex - 2.3); patient 2 (150 / 40 / 90 / 0.7 / 34.3, respectively); patient 3 (90 / 35 / 64 / 0.25 / 99.6); patient 4 (140 / 39/ 10/ 0.19/ 14.7); patient 5 (88 / 52 / 48 / 0.21 / 135.1); patient 6 (160 / 48 / 50 /0.15 / 100.0); patient 7 (122 / 42 / 15 / 0.17 / 30.4). Consequently, taking into consideration the diagnostic marker CNSToxolndex more than 10.0, cerebral toxoplasmosis was diagnosed only in six patients from seven, in whom anti-toxoplasma antibodies in CSF were detected. Patient 1, despite clinical symptoms similar to cerebral toxoplasmosis, and substitute signs of cerebral toxoplasmosis detected with the help of neuroimaging methods (volumetric formation of the right frontal lobe with a ring-shaped enhancement), availability of specific anti-toxoplasma antibodies in blood serum and CSF, diagnosis of cerebral toxoplasmosis has not been confirmed. M. tuberculosis DNA was found in CSF by PCR.

CONCLUSION

Conclusions: CNSToxoIndex allows evaluating the local production of anti-toxoplasmic IgG in CNS and their diffusion from blood as a result of the blood-brain barrier damageand it is a powerful method of cerebral toxoplasmosis diagnostics in HIV-positive people as well.

Evaluating of Wistar rat and BALB/c mouse as animal models for congenital, cerebral and ocular toxoplasmosis

This study was conducted to evaluate the potential of cyst production by Toxoplasma (T.) gondii, RH strain, in Wistar rat and BALB/c mouse and the purpose of this study was to introduce an animal model suitable for congenital, cerebral, and ocular toxoplasmosis. The mice and rats, considered as cerebral and ocular toxoplasmosis models, were intraperitoneally infected by different number of the parasite and their eyes and brain were evaluated for the presence of T. gondii cyst using the microscopic examination and the bioassay method. Moreover, the pregnant mice and rats, considered as congenital toxoplasmosis models, were intraperitoneally infected by different number of the parasite and their infants were examined by the method mentioned above. The best result for the cerebral toxoplasmosis model was observed in the rats infected with the 107 parasites, so that all infants (100%) were infected with the parasite when examined using the bioassay method. Furthermore, the best result was observed for the congenital cerebral toxoplasmosis model with 100% infection rate in the infants born to mothers infected with the 107 parasites. Overall, just few the ocular samples were positive using bioassay method. The best result in the current study was for the congenital cerebral toxoplasmosis model where the pregnant rats were infected with the 107 parasites and all infants were infected (100%). Therefore, these infants can be used as a congenital cerebral toxoplasmosis model when they are in the fetal stage, and can be used as a cerebral toxoplasmosis model one month after birth.

Care of Patients With HIV Infection: Medical Complications and Comorbidities

Care of patients with HIV infection starts with diagnosis as soon as possible, preferably at or near the time of acute infection. Opportunistic infections, malignancies, and other conditions develop progressively over time, particularly in untreated patients. The AIDS-defining opportunistic infections most common in the United States include Pneumocystis jirovecii pneumonia, Candida esophagitis, toxoplasmic encephalitis, tuberculosis, disseminated Mycobacterium avium complex, cryptococcal meningitis, and cytomegalovirus retinitis. Specific prophylaxis regimens exist for several opportunistic infections, and effective antiretroviral therapy reduces the risk of most others. Other AIDS-defining conditions include wasting syndrome and HIV encephalopathy. AIDS-defining malignancies include Kaposi sarcoma, systemic non-Hodgkin lymphoma, primary central nervous system lymphoma, and invasive cervical cancer. Although not an AIDS-defining condition, anal cancer is common in patients with HIV infection. Other HIV-related conditions include thrombocytopenia, recurrent bacterial respiratory infections, HIV-associated nephropathy, and HIV-associated neurocognitive disorder.

[Diagnosis and treatment of major protozoal infections among acquired immune deficiency syndrome patients]

Protozoal infection is one of the most important opportunistic infections among patients with acquired immune deficiency syndrome (AIDS). In order to enhance the knowledge of protozoal infections in AIDS, the current status of diagnosis and treatment of toxoplasmic encephalitis, cryptosporidiosis, microsporidiosis and isosporiasis was reviewed in this paper.

Clinical and laboratory characteristics of hospitalised patients with neurological manifestations of HIV/AIDS at the Nairobi hospital

OBJECTIVE

To determine the profile of clinical and laboratory characteristics of hospitalised HIV positive patients with neurological complications at a private hospital in Nairobi, Kenya from January 2000 to June 2005.

DESIGN

Retrospective observational study.

SETTING

The Nairobi Hospital, Nairobi, Kenya.

SUBJECTS

One hundred and fifty hospitalised patients.

RESULTS

Records of 708 HIV positive hospitalised patients were reviewed, 150 patients had neurological complications; giving a six-year point prevalence of 21.2%. Males were 86 (57.3%) and females 64 (42.7%) M:F ratio = 1.3:1. Mean age was 38.84 years. The five commonest neurological complications were; cryptococcal meningitis 33 (22%), encephalitis 28 (18.7%), cerebral toxoplasmosis 19 (12.7%), stroke 19 (12.7%) and tuberculous meningitis 16 (10.7%). Overall, 72 patients (63%) had CD4+ counts done. Cryptococcal meningitis patients' CD4+ count, (mean 60, median 17, range 1-273/cmm). Encephalitis patients' CD4+count, (mean 82, median 54, range 3-495/cmm). Cerebral toxoplasmosis patients' CD4+count, (mean 59, median 58, range 11-120/cmm). Stroke patients' CD4+ count, (mean 120, median 30, range 15-394/cmm) and Tuberculous meningitis patients' CD4+ count, (mean 67, median 62 and range 12-154/cmm). The other rare neurological manifestations included peripheral neuropathy, HIV associated dementia (HAD), myelopathy and myopathy amongst others. One hundred and eight (72%) patients were on anti-retroviral therapy. The commonest drugs used in various regimen combinations included efavirenz and combivir. Fourteen (9.3%) patients died while in hospital; eight of them were among those with the top five neurological complications.

CONCLUSION

The findings show that patients come to hospital when severely immune compromised and hence have overwhelming opportunistic infections. The profile of opportunistic infection is comparable to that observed in studies elsewhere. Some of the facts observed here may not reflect the situation in public health institutions where resources are scarce.

RECOMMENDATION

To do a multi-centre prospective study of neurological manifestations of HIV/AIDS.

Neurologic manifestations of toxoplasmosis in AIDS

Central nervous system (CNS) toxoplasmosis is the most common cause of cerebral mass lesions in AIDS patients. Toxoplasma gondii is commonly acquired through ingestion of contaminated meats resulting in latent infection. With the onset of immunosuppression, it may preferentially infect the CNS, resulting in a wide range of clinical presentations. Effective antibiotic therapy is available and capable of producing rapid remission of active infection but must be continued throughout life to prevent recurrence. Characteristic presentations and rapid therapeutic response permit presumptive diagnosis and initiation of specific antibiotics in many cases; however, appropriate clinical and radiographic monitoring to detect alternative or mixed pathologies is necessary. Unusual presentations may hinder rapid diagnosis and should be considered in AIDS patients with cryptic CNS symptoms. Despite increasing attention to primary prophylaxis, the worldwide distribution of this parasite, its potential to be the presenting illness in previously unidentified human immunodeficiency virus-infected individuals, and failures of prophylaxis are likely to make toxoplasmosis an important continuing source of neurologic morbidity in AIDS.

[Multiple cerebral hydatic cysts of cardiac origin. A case report]

The hydatic cyst is a pathology observed in developing countries. Multiple cerebral localizations with a cardiac origin are exceptional and are sometimes diagnosed only after onset of complications. We present the case of a 22-year-old male student: the diagnosis of multiple cerebral hydatic cysts caused by rupture of a cardiac hydatic cyst was established after an episode of ischemia of the limbs with cerebral hemorrhage induced by heparin. One year later, the clinical situation consisted in intracranial hypertension, hemiplegia and convulsive seizures. We observed no cardiac symptoms. The brain CT showed 9 hydatic cysts and echocardiography showed a myxomatous cystic tumor. Abdominal CT detected renal and splenic hydatic cysts. The patient underwent total ablation of the cerebral and abdominal cysts and made a full recovery. After surgical removal of the cardiac cyst, the patient has been lost to follow-up. Cerebral hydatidosis of cardiac origin is highly exceptional and, due to nonspecific symptomatology, may go undiagnosed. In general, prognosis is good in case of a cerebral localization but the cardiac localization is associated with high mortality.

A strategy for immunohistochemical signal enhancement by end-product amplification

We report a novel strategy, called end-product (EP) amplification, capable of enhancing the sensitivity of immunohistochemical procedures by about an order of magnitude or more. The strategy employs an antibody (anti-EP) to the product generated by the action of horseradish peroxidase on 3,3'-diaminobenzidine (DAB), and can be extended to the products of other enzymes as well, e.g., alkaline phosphatase. Amplification is the consequence of the ability of anti-EP to detect the multiplicity of product moelcules resulting from the turnover of substrate by a single enzyme molecule. The subsequent detection of anti-EP was by biotinylated goat anti-rabbit antibody, followed by avidin-peroxidase and DAB or by avidin-alkaline phosphatase and Vector Red. Further amplification can be accomplished by repeated cycles of the protocol. Anti-EP was produced by immunization with a bovine serum albumin (BSA) conjugate of a soluble polymer of DAB, prepared by a carefully controlled reaction of DAB with horseradish peroxidase and hydrogen peroxide. Coupling to BSA (and to RSA) was accomplished with glutaraldehyde. The titer of anti-EP was established by ELISA. Formalin-fixed, paraffin-embedded sections of five cases of Hodgkin's disease and five tonsils with follicular hyperplasia were immunolabeled for the following lymphoid markers: CD3, CD20, CD30, CD45RA, and CD68. EP amplification with anti-EP was also applied to cases of CMV pneumonia and cerebral toxoplasmosis to determine whether this procedure could improve detection of the infectious agents. Immunolabeling of the primary antibody was performed by the avidin-biotin-peroxidase technique with DAB as the reaction substrate. The specificity of EP amplification was tested by demonstrating binding of anti-EP with Vector Red with the generation of a fluorescence end-point. There was complete congruence in the distribution of the DAB signal and the red immunofluorescence representing EP amplification. The intensity of the DAB signal was increased as much as 16-fold by EP amplification, making possible a reduction in the amount of the primary antibody by as much as 85-90%. Sensitivity also increased with respect to weakly expressed antigens and low concentrations of infectious agents.

[Cryopreservation of isolates of Toxoplasma gondii in cell culture]

For a better preservation and identification of Toxoplasma gondii isolates, we propose a new method of freezing of toxoplasma growth in THP-1 cell culture. A cystogenic strain isolated from foetal blood has been grown in these cells and frozen in liquid nitrogen. After thawing, toxoplasma recover the same growth rate and morphology in vitro and the same capacity to form brain cysts into mice compared to the initial strains. The freezing of the cell suspension provides a simple and appropriate method for preservation of Toxoplasma gondii within "bank" isolates.