Zinc Modulates Glutamine Metabolism in T Cells

SCOPE

Zinc and glutamine are well known to be essential for the function and polarization of immune cells. TH 17 cells are more frequently induced during zinc deficiency and cover their energy requirement mainly through glutaminolysis. A dysregulation of TH 17 cells can contribute to the development of autoimmune diseases. Both inhibition of glutaminolysis and zinc supplementation suppress experimental autoimmune encephalomyelitis in mice. Therefore, the aim of this study is to investigate whether zinc modulates glutaminolysis in T cells.

METHODS AND RESULTS

CD3/CD28 stimulation and mixed lymphocytes culture are used as in vitro models for T cell activation. Then, the glutaminolysis is investigated on mRNA, protein, and functional level. Zinc deficiency and glutaminase (GLS) inhibition decrease immune responses in vitro. Furthermore, extracellular zinc and glutamine levels both modulate glutaminolysis by changing the expression of glutamine transporters and key enzymes. Intriguingly, zinc directly interferes with the activity of GLS both in a cell free system and in the cytosol.

CONCLUSION

Besides T cell subset differentiation, zinc also impacts on the cellular metabolism by inhibiting glutaminolysis. This suggests that zinc deficiency can contribute to the development of autoimmune diseases whereas zinc supplementation can support their therapy.

Zinc Levels Affect the Metabolic Switch of T Cells by Modulating Glucose Uptake and Insulin Receptor Signaling

SCOPE

T cell activation requires a metabolic reprogramming from oxidative phosphorylation to aerobic glycolysis to rapidly provide substrates for biosynthesis. An individual's zinc status plays an important role in balancing the activation of T cells and is required for a proper function of immune cells. Furthermore, zinc plays an important role during effector T cell polarization to T helper cell subsets or regulatory T cells, with effector T cells relying on glycolysis and regulatory T cells on oxidative phosphorylation. Therefore, we aimed to analyze if zinc also impacts on T cell activation on the level of intracellular metabolism.

METHODS AND RESULTS

We used mixed lymphocyte culture and anti-CD3/CD28 stimulation as in vitro models for T cell activation to investigate the effect of zinc supplementation and deprivation on metabolic switching. We observed promoted glucose uptake, insulin receptor expression and signaling in both zinc conditions, whereas key metabolic enzymes were stimulated mainly by zinc deprivation. Alterations in cytokine production suggest an immune-activating effect of zinc deprivation and a balancing effect of zinc supplementation.

CONCLUSION

Our results suggest a supportive effect of both zinc supplementation and deprivation on the metabolic switch during T cell activation, adding another level of immune regulation by zinc. This article is protected by copyright. All rights reserved.

Dietary and Physiological Effects of Zinc on the Immune System

Evidence for the importance of zinc for all immune cells and for mounting an efficient and balanced immune response to various environmental stressors has been accumulating in recent years. This article describes the role of zinc in fundamental biological processes and summarizes our current knowledge of zinc's effect on hematopoiesis, including differentiation into immune cell subtypes. In addition, the important role of zinc during activation and function of immune cells is detailed and associated with the specific immune responses to bacteria, parasites, and viruses. The association of zinc with autoimmune reactions and cancers as diseases with increased or decreased immune responses is also discussed. This article provides a broad overview of the manifold roles that zinc, or its deficiency, plays in physiology and during various diseases. Consequently, we discuss why zinc supplementation should be considered, especially for people at risk of deficiency. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Zinc supplementation ameliorates lung injury by reducing neutrophil recruitment and activity

INTRODUCTION

Zinc is well known for its anti-inflammatory effects, including regulation of migration and activity of polymorphonuclear neutrophils (PMN). Zinc deficiency is associated with inflammatory diseases such as acute lung injury (ALI). As deregulated neutrophil recruitment and their hyper-activation are hallmarks of ALI, benefits of zinc supplementation on the development of lipopolysaccharides (LPS)-induced ALI were tested.

METHODS

64 C57Bl/6 mice, split into eight groups, were injected with 30 µg zinc 24 hours before exposure to aerosolised LPS for 4 hours. Zinc homoeostasis was characterised measuring serum and lung zinc concentrations as well as metallothionein-1 expression. Recruitment of neutrophils to alveolar, interstitial and intravascular space was assessed using flow cytometry. To determine the extent of lung damage, permeability and histological changes and the influx of protein into the bronchoalveolar lavage fluid were measured. Inflammatory status and PMN activity were evaluated via tumour necrosis factor α levels and formation of neutrophil extracellular traps. The effects of zinc supplementation prior to LPS stimulation on activation of primary human granulocytes and integrity of human lung cell monolayers were assessed as well.

RESULTS

Injecting zinc 24 hours prior to LPS-induced ALI indeed significantly decreased the recruitment of neutrophils to the lungs and prevented their hyperactivity and thus lung damage was decreased. Results from in vitro investigations using human cells suggest the transferability of the finding to human disease, which remains to be tested in more detail.

CONCLUSION

Zinc supplementation attenuated LPS-induced lung injury in a murine ALI model. Thus, the usage of zinc-based strategies should be considered to prevent detrimental consequences of respiratory infection and lung damage in risk groups.

[Coronary angiography and change in antioxidative status]

PATIENTS AND METHODS

In a prospective study in 53 patients with stable angina pectoris symptoms the antioxidant status (glutathione peroxidase, glutathione, superoxid dismutase, malondialdehyde and selenium in serum and whole blood) was determined before and 4 to 6 hours after coronary angiography. According to the results of the coronary angiography the patients were classified in a group with "severe" (n = 16) and another with "moderate" coronary alterations.

RESULTS

In both groups there was a significant reduction of selenium in serum and whole blood. The enzymes glutathione peroxidase and superoxide dismutase as well as glutathione and malondialdehyde changed only slightly.

CONCLUSION

These results can be the cause of an increase of the formation of free radicals during coronary reperfusion (PTCA, implantation of stents in the group with "severe" coronary alterations) but could also be seen as a sign of formation of radicals by the method itself (in patients with "moderate" coronary alterations). Further investigations are indicated. Furthermore the amelioration of the antioxidant status of the organism by scavenger substances (vitamins A, B, C and selenium) should be discussed.

[Experimental and clinical studies on the relevance of proton spin tomography in patients with coxarthrosis]

We examined 2 in formalin fixed hip specimens from a corpse, 27 patients with coxarthrosis and 3 healthy young volunteers with MRT concerning the illustration of the hip joint and pathological changes by coxarthrosis. Specimen of the femoral head after endoprosthetic operation could be achieved in 18 cases for comparison with MRT. All pathological alterations as cartilage alterations, sclerosis, cysts, effusion, edema, fibrosis were figured with high sensitivity. Cartilage was figured much better by gradient echo sequence with short echo time than by spin echo sequence. Gradient echo sequence made it possible to figure and quantify thinning of cartilage with high sensitivity. Both sequences showed artefacts because of the chemical shift in the area of the cartilage-bone boundary, which impaired especially the judgement of cartilage by spin echo sequence. Gradient echo sequence allowed because of the phase-contrast effect the distinction of hematopoietic and fatty bone marrow and possibly the delineation of bone marrow edema.

MR mammographic localization. Work in progress

The authors present phantom test results for a stereotaxic device that may permit simple, rapid, and accurate needle biopsy and localization of breast lesions detected at contrast material-enhanced magnetic resonance (MR) mammography. The mechanical accuracy of this prototype MR breast localizer is approximately plus or minus 3.5 mm at 5 cm.

Identification of the 408 valine to methionine mutation in the low density lipoprotein receptor in a German family with familial hypercholesterolemia

Familial hypercholesterolemia (FH) is caused by different mutations in the gene encoding the low density lipoprotein receptor (LDLR). In Caucasian patients, at least three single point mutations have been identified causing FH. The asparagine206 to glutamine, and valine408 to methionine mutations were originally described in Afrikaners and recently identified in Dutch FH patients. The proline664 to leucine mutations was previously identified in an FH homozygote of Asian Indian origin and later identified in patients from London. Any of these mutations can be identified using direct amplification of genomic DNA by the polymerase chain reaction (PCR) and restriction enzyme digestion of PCR products. In this study, 100 unrelated German FH patients were screened for these three mutations. The valine408 to methionine mutation was identified in one individual and subsequently in the hypercholesterolemic child of the proband. Haplotype analysis with 7 restriction fragment length polymorphisms (RFLPs) revealed that the mutant allele carried the same haplotype as the previously described patients in South Africa and the Netherlands. Our finding supports the previous assumption of the European origin of the mutation.

Identification of a 76-year-old patient with compound heterozygous familial hypercholesterolemia by haplotype analysis of the LDL receptor gene

In a large family with clinical characteristics of heterozygous familial hypercholesterolemia (FH) seven restriction fragment length polymorphisms (RFLP) were used to determine low-density-lipoprotein receptor (LDLR) gene haplotypes. Following the inheritance of the LDL receptor genes characterized by their seven RFLP haplotypes, two different alleles were found to cosegregate with elevated cholesterol levels within this family. In a 76-year-old man both alleles identified as defective were present, thus classifying this individual as heterozygous compound for FH. In five heterozygous family members one allele was associated with 38% higher cholesterol levels when compared to the other mutant allele in two heterozygous family members. Cosegregation of hypercholesterolemia with the apolipoprotein B (apoB) gene and apolipoprotein E (apoE) gene was excluded by genotyping all individuals for the apoB XbaI RFLP and apoE polymorphisms. These findings are consistent with variable phenotypic expression of the mutant LDLR gene alleles.

[Nuclear magnetic resonance tomography of meniscus lesions]

In magnetic resonance imaging (MR) the use of suitable surface coils combined with high resolution makes it possible to obtain differentiated information on the condition of the menisci. In particular, the course and extent of cracks, degenerative changes, and the attachment zones of the menisci can be assessed. This paper describes MR and clinical findings in 58 patients and compares them with those in seven healthy subjects.

[Meniscus imaging in MR tomography using surface coils. Anatomy, areas of degeneration, laceration formation]

High resolution MR imaging using surface coils and thin-section techniques provides specific information when evaluating meniscal diseases. Extension and localisation of meniscal tears can be demonstrated as well as meniscal attachment areas. Diagnosis of degenerative changes is possible. We examined 7 healthy volunteers and 58 patients with suspected knee injuries. This study was done to discuss the use of MRI in the evaluation of meniscal diseases.

Angiography of histopathologic variants of synovial sarcoma

Synovial sarcomas are rare soft tissue tumors which histopathologically can be divided into monophasic, biphasic and mixed variants. As part of a protocol for intra-arterial chemotherapy 12 patients with biopsy proven synovial sarcoma underwent angiography. The angiograms on these patients were reviewed to determine whether synovial sarcomas and their variants demonstrated a characteristic angiographic appearance. Synovial sarcomas appeared angiographically as soft tissue masses which showed a fine network of tumor vessels with an inhomogeneous capillary blush. Their degree of vascularity varied according to their histopathology. Monophasic synovial sarcomas demonstrated in general a higher degree of neovascularity than the biphasic form. This finding was also suggested by histopathologic analysis of the vessels in the tumor. Although angiography did not show a distinctive vascular pattern it may be useful to evaluate tumor size and vascularity.

Multiple endocrine neoplasia type I. A case report

A case of multiple endocrine neoplasia (Men) consisting of an unusual combination of an insulin-producing islet cell tumour and an adrenal adenoma is reported. CT clearly demonstrated the adrenal mass whereas the pancreatic lesion remained questionable. Conversely angiography located the pancreatic tumour but the adrenal findings were subtle.

[Computerized tomography in endocrine ophthalmopathy with malignant exophthalmos]

CT scanning was done in 16 patients with deterioration of sight in endocrine ophthalmopathy. The assessment involved muscular changes and density of retrobulbar fat. Evaluation of muscular changes was staged. In addition, exophthalmus was graded and evaluated by staging. More than two thirds of patients showed pronounced muscular thickening whereas the remaining patients showed few or no muscular changes. Likewise, in a number of patients exophthalmus could hardly be demonstrated according to Hertel's values. Thus, clinical presentation in a number of patients is relatively mild. Pathophysiologic considerations as to the development of deterioration of sight mainly involve myogenic compression of the optic nerve at its orbital entry. This does not seem to hold true for patients without muscular thickening. In such patients optic nerve affection could be caused by increase of the volume of the fat body.

Angiography in soft tissue sarcomas

Angiography was performed in 41 patients with histologically proven soft tissue sarcomas that included tumors derived from a variety of cell types and locations. The leiomyosarcomas and sarcomas of uncertain or mixed origin showed extensive neovascularity. Liposarcomas, synovial cell sarcomas, and fibrous histiocytic sarcomas were moderately vascularized. Sarcomas originating from vascular, fibrous, neural, and osseous tissues had variable degrees of vascularity. In nearly all of the cases studied, angiography revealed tumor size, extent, source, and degree of vascularity and helped to determine the degree of malignancy. While angiography does not provide a histologic diagnosis, it plays an important role in patient management when a conservative therapy plan that uses several modalities is followed.

[Computer tomography in drusen of the optic papilla]

Drusen (astrocytic hamartoma) of the optic nerve are a rare eye disease produced by ocular calcification (inclusions containing calcium) at the optic disc surface. These drusen can lead to eye complaints as they grow bigger; in particular, they can cause loss of vision and can also limit the visual field. Ophthalmologically, they are characterised by an indistinct optic disc and/or ectasia of the optic disc which is sometimes combined with a poorly defined optic disc margin. Differential diagnosis must take into consideration the presence of space-occupying intracranial processes. The final diagnosis can be made via computerised tomography on the basis of a characteristic calcification pattern. Hence, the radiologist must be familiar with the disease pattern and must be able to differentiate this against other types of intraocular calcifications.

[Radiotherapy in endocrine ophthalmopathy--evaluation of 56 cases]

The authors present the radiotherapeutic results achieved in 56 patients with endocrine ophthalmopathy, 15 out of them with severe, so-called malignant course. All patients were irradiated conventionally with small doses between 3 and 10 Gy at the surface. For this purpose, a deep therapy unit with 250 kV was used. The X-ray irradiation produced an improvement in 62% of the cases; the separate evaluation of cases with malignant course showed an improvement in nine cases. Thus the results produced by this method are as good as those of high doses, the greater possibilities in case of recurrence, however, are to be considered as an advantage. The irradiation should be applied early, and the simultaneous administration of a cortisone preparation is preferred by our team.

[Dose distribution during irradiation of the retrobulbar space--results of measurements on a phantom]

The transverse dose distribution in case of X-ray and cobalt irradiation of the retrobulbar space was measured in a water phantom. As expected, the crystalline lens receives a smaller dose by cobalt irradiation with lead shielding in front of the eye than by X-irradiation. In case of cobalt irradiation, the dorsal portions lying within the hypophyseal region can only be sufficiently protected by a special block cast by us in a divergent form and surrounding the irradiation field. If X-ray irradiation is performed with a field size of 2 X 4 cm2, the 50% isodose encloses just the complete retrobulbar space. Taking into consideration a second contralateral field, the crystalline lens is exposed to less than 10% of the maximum dose. Thus the doses applied usually in radiotherapy of endocrine ophthalmopathy, i.e. 15 to 20 Gy, lead to an unproblematic crystalline lens exposure of 150 to 200 rad.

[Computer tomography of esthesioneuroblastoma]

Aesthesioneuroblastomas are rare malignant nasal tumours of neural origin. Clinical symptoms depend upon the extent of the lesion. Five cases of tomography visualised the tumours as non-homogeneous soft tissue masses in the nasal cavity and the ethmoid cells with a varying infiltration of the adjacent paranasal sinuses. Radical surgery and radiation therapy are recommended. CT should be an integral part of annual follow-up studies.

[Computer tomography image of a triple anlage of the stomach]

A triple stomach in a 22 year old patient was evaluated by CT. In addition to the main stomach two cystic formations containing gastric mucosa were found. These accessory stomachs did not fill following ingestion of oral contrast medium. In the CT diagnosis of cystic masses of the upper abdomen multiple gastric formations should be considered.

[Computer tomography aspects in the diagnosis of tuberculosis in the area of the abdomen and urogenital tract]

The morphologic aspect of abdominal tuberculosis are evaluated by C.T. The necrotising tuberculosis of the genitourinary tract presents course cystic lesions of fluid density. Similar morphologic criteria are seen in ileocecal tuberculosis. The peritoneal tuberculosis is characterized by large soft tissue masses of a high density which can be found in nearly all areas of the abdomen. The increased morbidity of tuberculosis in people from foreign countries living in the Federal Republic of Germany is pointed out.

[Radiologic diagnosis of adrenal cyst]

Computed tomography did not lead to the correct diagnosis in a 40-year-old female patient with an adrenal cyst on the right side. Sonography permitted differentiation of the tumour from the surroundings. However, only angiography showed quality and precise localization of the tumour. Thus, in certain cases, angiography cannot be replaced despite the large diagnostic value of the other methods.

[Computer tomographic study of acute renal tuberculosis]

The course of an acute renal tuberculosis was demonstrated by computed tomography. The kidney presented coarse cystic lesions which were of water density. Subsequently a non-specific abscess occurred in the opposite kidney with a significantly higher density following intravenous contrast injection.

[Malignant tumors of the upper urinary passages (author's transl)]

Malignant tumors of the upper urinary passages are more frequent than one had formerly thought. Eleven case reports are presented in order to explain X-ray and differential diagnosis. The treatment consists in surgical nephrourethrectomy with lymphadenectomy. There are only few reports about indication and value of radiotherapy. A postoperative irradiation of the primary tumor region and the lymphatic outflow region is recommended for the stages B, C and D (without remote metastases). The suggested target volumes and doses are described.

[Practical experience with video recorders during screening procedures (author's transl)]

As a result of increasing standardisation and simplification of video recorders, it has proved possible to use equipment made by various firms for electronic recording. Instead of an expensive central set-up, screening procedures could be recorded either dynamically or statically on mobile recorders in every x-ray room. The procedure is largely automated. Both tape and disc recorders were used in 625 and 1249 recordings respectively. In addition to shorter screening time, there were other advantages which are described.