Global health inequalities of chronic kidney disease: a meta-analysis

BACKGROUND AND HYPOTHESIS

Chronic kidney disease (CKD) is a significant contributor to global morbidity and mortality. This study investigated disparities in age, sex and socio-economic status in CKD and updated global prevalence estimates through systematic review and meta-analysis.

METHODS

Five databases were searched from 2014 to 2022, with 14 871 articles screened, 119 papers included and data analysed on 29 159 948 participants. Random effects meta-analyses were conducted to determine overall prevalence, prevalence of stages 3-5 and prevalence in males/females. Influences of age, sex and socio-economic status were assessed in subgroup analyses, and risk of bias assessment and meta-regressions were conducted to explore heterogeneity.

RESULTS

Overall prevalence of CKD was 13.0% (11.3-14.8%) and 6.6% (5.6-7.8%) for stages 3-5. Prevalence was higher in studies of older populations (19.3% for stages 1-5, 15.0% for stages 3-5) and meta-regression demonstrated association of age, body mass index, diabetes and hypertension with prevalence of stages 3-5. The prevalence of CKD stages 1-5 was similar in males and females (13.1% versus 13.2%) but prevalence of stages 3-5 was higher in females (6.4% versus 7.5%). Overall prevalence was 11.4%, 15.0% and 10.8% in low, middle and high-income countries respectively; for stages 3-5 prevalence was 4.0%, 6.7% and 6.8%, respectively. Included studies were at moderate-high risk of bias in the majority of cases (92%), and heterogeneity was high.

CONCLUSION

This study provides a comprehensive assessment of CKD prevalence, highlighting important disparities related to age, sex and socio-economic status. Future research should focus on targeted screening and treatment approaches, improving access to care and more effective data monitoring, particularly in low or middle income countries.

Phenotypic variability and identification of novel YARS2 mutations in YARS2 mitochondrial myopathy, lactic acidosis and sideroblastic anaemia

Background

Mutations in the mitochondrial tyrosyl-tRNA synthetase (YARS2) gene have previously been identified as a cause of the tissue specific mitochondrial respiratory chain (RC) disorder, Myopathy, Lactic Acidosis, Sideroblastic Anaemia (MLASA). In this study, a cohort of patients with a mitochondrial RC disorder for who anaemia was a feature, were screened for mutations in YARS2.

Methods

Twelve patients were screened for YARS2 mutations by Sanger sequencing. Clinical data were compared. Functional assays were performed to confirm the pathogenicity of the novel mutations and to investigate tissue specific effects.

Results

PathogenicYARS2 mutations were identified in three of twelve patients screened. Two patients were found to be homozygous for the previously reported p.Phe52Leu mutation, one severely and one mildly affected. These patients had different mtDNA haplogroups which may contribute to the observed phenotypic variability. A mildly affected patient was a compound heterozygote for two novel YARS2 mutations, p.Gly191Asp and p.Arg360X. The p.Gly191Asp mutation resulted in a 38-fold loss in YARS2 catalytic efficiency and the p.Arg360X mutation did not produce a stable protein. The p.Phe52Leu and p.Gly191Asp/p.Arg360X mutations resulted in more severe RC deficiency of complexes I, III and IV in muscle cells compared to fibroblasts, but had relatively normal YARS2 protein levels. The muscle-specific RC deficiency can be related to the increased requirement for RC complexes in muscle. There was also a failure of mtDNA proliferation upon myogenesis in patient cells which may compound the RC defect. Patient muscle had increased levels of PGC1-α and TFAM suggesting mitochondrial biogenesis was activated as a potential compensatory mechanism.

Conclusion

In this study we have identified novel YARS2 mutations and noted marked phenotypic variability among YARS2 MLASA patients, with phenotypes ranging from mild to lethal, and we suggest that the background mtDNA haplotype may be contributing to the phenotypic variability. These findings have implications for diagnosis and prognostication of the MLASA and related phenotypes.

The effects of EPA, DHA, and aspirin ingestion on plasma lysophospholipids and autotaxin

Lysophophatidylcholine (LPC) and lysophosphatidic acid (LPA) are potent lysolipid mediators increasingly linked with atherosclerosis and inflammation. A current model proposing that plasma LPA is produced when LPC is hydrolyzed by the enzyme autotaxin has not been rigorously investigated in human subjects. We conducted a clinical trial of eicosapentaenoic acid/docosahexaenoic acid (EPA/DHA) and aspirin ingestion in normal volunteers. Fasting blood samples were drawn at baseline and after 4-week supplementation with EPA/DHA (3.4 g/d) with and without aspirin (650 mg). Plasma LPC and LPA species and autotaxin activity were measured. EPA-LPC and DHA-LPC concentrations increased significantly with EPA/DHA supplementation whereas EPA- and DHA-LPA did not. Autotaxin activity was unaffected by any treatment, and aspirin had no effect on any endpoint. Taken together, our data demonstrate that plasma LPC, but not LPA, species can be dynamically regulated by dietary supplementation, and argue against a simple model of LPA generation via LPC hydrolysis.

Quantitative linkage genome scan for atopy in a large collection of Caucasian families

Quantitative phenotypes correlated with a complex disorder offer increased power to detect linkage in comparison to affected-unaffected classifications. Asthma is a complex disorder characterized by periods of bronchial obstruction and increased bronchial hyper reactivity. In childhood and early adulthood, asthma is frequently associated also with quantitative measures of atopy. Genome wide quantitative multipoint linkage analysis was conducted for serum IgE levels and percentage of positive skin prick test (SPT(per)) using three large groups of families originally ascertained for asthma. In this report, 438 and 429 asthma families were informative for linkage using IgE and SPT(per) which represents 690 independent families. Suggestive linkage (LOD > or = 2) was found on chromosomes 1, 3, and 8q with maximum LODs of 2.34 (IgE), 2.03 (SPT(per)), and 2.25 (IgE) near markers D1S1653, D3S2322-D3S1764, and D8S2324, respectively. The results from chromosomes 1 and 3 replicate previous reports of linkage. We also replicate linkage to 5q with peak LODs of 1.96 (SPT(per)) and 1.77 (IgE) at or near marker D5S1480. Our results provide further evidence implicating chromosomes 1, 3, and 5q. The current report represents one of the biggest genome scans so far reported for asthma related phenotypes. This study also demonstrates the utility of increased sample sizes and quantitative phenotypes in linkage analysis of complex disorders.

A new dominant distal myopathy affecting posterior leg and anterior upper limb muscles

OBJECTIVE

To report a dominant, slowly progressive early onset distal myopathy with sparing of the tibialis anterior.

METHODS

Twelve affected and two possibly affected members from an Australian kindred were examined and investigated by EMG, imaging studies, histopathology, and genetic analysis.

RESULTS

Affected patients had a slowly progressive condition with symmetric, distal weakness and wasting of the anterior upper and posterior lower limbs, with sparing of tibialis anterior, even in advanced disease. All patients remained ambulant and there was no evidence of cardiac or respiratory muscle involvement. Serum creatine kinase levels were either normal or mildly elevated. Imaging studies showed widespread involvement of the posterior and lateral leg compartments. Proximal muscles were radiologically abnormal only in advanced disease. Muscles that were mildly affected clinically appeared normal on imaging. EMG in nine patients showed widespread myopathic changes. Muscle histopathology in four patients showed either end stage muscle or nonspecific myopathic findings without inflammation or vacuoles. Microsatellite markers for distal myopathy loci were analyzed and all known distal myopathy phenotype genes and linkage regions were formally excluded by multipoint analysis.

CONCLUSIONS

The affected patients in this kindred display a clinically distinct myopathy, with selective involvement of posterior lower and anterior upper limb muscles. The genetic analysis suggests the existence of one more distal myopathy locus.

Costs of running a universal adolescent hepatitis B vaccination programme

In the first UK study to examine feasibility and acceptability of universal adolescent hepatitis B vaccination, the costs associated with the administration and uptake (80.2 and 89.3% for three doses and at least two doses, respectively), of a three-dose regimen in pupils in Glasgow schools (2001/2002) were measured. These data were used to estimate the economic outlay for the delivery of a routine, ongoing three-dose and two-dose hepatitis B vaccine programme in schools. Vaccine, accounting for almost 70% of the overall costs, was the largest cost item for both the pilot and routine programmes, using either regimen. However, the ongoing, two-dose regimen was the cheapest option in this analysis, irrespective of vaccine price. Cost data from this study may be useful for other countries wishing to implement a similar programme.

Determinants of universal adolescent hepatitis B vaccine uptake

The UK is currently considering the introduction of universal hepatitis B vaccination. This study of determinants of vaccine uptake among school based adolescents shows that living in areas of high deprivation, commonly associated with injecting drug risk behaviours, was the most important factor, with statistically significant lower odds of receiving three doses. This was less pronounced for receipt of two doses. Thus, there are implications for future policy; if universal vaccination is approved, a licensed two dose schedule would be most appropriate in this setting.

Universal hepatitis B vaccination of UK adolescents: a feasibility and acceptability study

The feasibility of introducing universal hepatitis B immunisation was assessed by offering the vaccine to all 11-12 year old pupils in Greater Glasgow (approximately 10,800). Consent was received from 92% of the school roll, and 91.3%, 89.2% and 80.3% received at least 1, at least 2, and 3 doses respectively. The findings of this study constitute key evidence for the ongoing debate in the UK on hepatitis B vaccination.

PHA induces IL-2 receptors on B-CLL cells and is a potential biological response modifier for the LIL-2-diphtheria toxin, DAB486IL-2

DAB486IL-2 is an IL-2-diphtheria toxin conjugate which was developed to be specifically cytotoxic to cells bearing high affinity IL-2 receptors. The high affinity IL-2 receptor is a heterodimer comprising p55 and p75 subunits. While the p75 subunit appears to be ubiquitously expressed among the common North American leukemias and lymphomas, the p55 subunit is more restricted in its expression. To broaden the therapeutic relevance of the DAB486IL-2 we have sought physiologically feasible inducers of the p55 IL-2 receptor subunit. This report describes that PHA, in vitro, induces the p55 IL-2 receptor subunit on initially p55-negative B-CLL cells and converts toxin-insensitive leukemia cells to a toxin-sensitive state.

2',3'-Dideoxyadenosine is selectively toxic for TdT-positive cells

The 2',3'-dideoxynucleosides (ddNs) are currently undergoing clinical evaluation as antiretroviral agents in HIV-infected individuals. When phosphorylated, the ddNs (ddNTPs) function as chain-terminating substrate analogues with reverse transcriptase, thereby inhibiting HIV replication. These nucleoside analogues can also inhibit, by chain-terminating additions, the primitive lymphoid DNA polymerase, terminal deoxynucleotidyl transferase (TdT). To determine the effect of possible intracellular chain-terminating additions of ddNMPs by TdT, we exposed a series of TdT-positive and TdT-negative cell lines to 2',3'-dideoxyadenosine (ddA), a representative ddN. At ddA concentrations 25-fold higher than required for inhibition of HIV replication, progressive dose-related cytotoxicity was observed in the TdT-positive cell lines. This was accentuated by the adenosine deaminase inhibitor Coformycin (CF), presumably by enhancing the intracellular generation of ddATP from ddA. A central role of TdT in mediating the ddA/CF cytotoxicity was suggested by studies in a pre-B-cell line rendered TdT positive by infection with a TdT cDNA-containing retroviral vector. After a 48-hour continuous exposure period to 250 mumol/L ddA and 30 mumol/L CF, 30% cell death was observed in the TdT-negative parental line, whereas 90% cell death was observed in the TdT-positive daughter line. Exposure of fresh TdT-positive leukemic cells to ddA/CF for 72 hours ex vivo resulted in cytotoxicity (six cases of acute lymphocytic leukemia [ALL]) while not affecting TdT-negative acute leukemic cells (six cases). We conclude that ddA/CF selectively damages TdT-positive cells, presumably by chain-terminating additions of ddAMP, and that this may have therapeutic relevance in TdT-positive malignant disease.

Microencapsulated tumor assay: new short-term assay for in vivo evaluation of the effects of anticancer drugs on human tumor cell lines

A new in vivo has been developed for evaluating the antitumor activity of chemotherapeutic drugs. The assay is based on a microencapsulation technology developed by Damon Biotech, Inc., Boston, MA, which makes it possible to encapsulate human tumor cells in small (about 1 mm in diameter) microcapsules with semipermeable membranes. Microcapsules containing human tumor cells were injected i.p. into nude or C57BL/6 mice and drugs were administered i.v. The microcapsules were recovered at various intervals following treatment and determinations of drug effects were made based on the differences in the number of tumor cells recovered from the treated and nontreated animals. Using this assay we found that (a) encapsulated tumor cells grew better in the in vivo system than in vitro under the conditions tested; (b) drugs crossed the capsular membrane and killed or inhibited the proliferation of tumor cells; and (c) the antitumor effect was consistent with the relative therapeutic efficacy of drugs or level of resistance of tumor cells detected by other in vitro or in vivo tests. The tumor microencapsulation assay offers several properties which make it attractive for use in new drug development: (a) the antitumor activity of drugs can be tested against human tumor cells under conditions which provide for three-dimensional growth and in vivo supply of nutrients; (b) the sensitivity of tumor cells can be assessed following exposure to drugs at concentrations which are achievable in vivo; (c) compounds requiring in vivo metabolic activation can be tested; (d) the effect of each drug injection can be quickly evaluated; (e) inhibition of tumor cell proliferation versus cytoreductive effects of drugs can be discriminated; (f) the test is applicable to virtually all histological types of human tumor cells; and (g) the tumor microencapsulation assay is a short-term, simple, and relatively inexpensive assay.

Determination of L-buthionine-(S,R)-sulfoximine in plasma by high-performance liquid chromatography with o-phthalaldehyde derivatization and fluorometric detection

The development of a high-performance liquid chromatography system for the analysis of L-buthionine-(S,R)-sulfoximine (BSO) in human plasma is described. o-Phthalaldehyde derivatization and fluorescence detection were used. The R- and S-BSO peaks were partially separated from each other and completely separated from the matrix components. The limit of detection for BSO was 2 micrograms/ml plasma.

A comparison of the fears of mildly retarded adults with children of their mental age and chronological age matched controls

Twenty mildly retarded adults were matched for chronological age and sex with twenty non-retarded children using the Peabody Picture Vocabulary Test. All 60 subjects were given an 89-item Fear Survey Schedule with a three-point rating scale. Mildly retarded adults were more fearful in general and showed a more intense level of fear than their chronological age matched controls. However, they reported less overall fear than their mental age matched controls. Differences in type of feared objects or situations were reported between groups. The importance of understanding the degree and types of fear in promoting de-institutionalization in the retarded is stressed.

Effects of experimental excision arthroplasty of the hip joint

The experimental results are reported on a series of sheep in which unilateral hip excision arthroplasty was performed. These sheep were slaughtered at regular postoperative intervals. Radiography and histology were performed on the normal and excised hip joints of the experimental sheep to provide information of the formation of the pseudarthrosis that develops following excision arthroplasty. The efficiency of the false joint that develops is good, judged on a clinical basis. Continuous remodelling of the acetabulum and resected face was noted throughout the experimental period. A sequence of degenerative changes in the acetabular cartilage was observed followed by filling in of the acetabular favity with new bone. New bone also developed on the cemoral component of the pseudarthrosis in the form of osteophytes situated around the perimeter of the resected surface. Growth deformities of the contralateral, nonoperated limb were induced.

Long term results of excision arthroplasty of the canine hip

An analysis has been made of the long term results of excision of the canine femoral head and neck. The most frequent postoperative findings include shortening of the operated limb and restricted movement of the hip pseudarthrosis. Although few dogs show lameness or pain in the operated hip, muscle atrophy is a frequent finding even after eight years. Difficulty in jumping and in climbing stairs are more commonly found postoperatively in the larger breeds of dog. Despite these noted abnormalities almost all owners expressed their satisfaction with the outcome of excision arthroplasty.

Isolation and preliminary characterization of temperature-sensitive mutants of measles virus

Twenty-four genetically stable temperature-sensitive mutants of measles virus were isolated after mutangenesis by 5-azacytidine, 5 fluorouracil, or proflavine. The restricted replication of all mutants at 39 C was blocked subsequent to cell penetration and could not be attributed to heat inactivation of virus infectivity. Complementation analysis was made possible through the use of poly-L-ornithine. The members of one complementation group exhibited wild-type RNA synthesis at the nonpermissive temperature and induced the synthesis of virus antigens. These mutants were found defective in both hemolysin antigen synthesis and cell fusion "from within," supporting the unitary hypothesis for these functions. The members of the other two complementation groups synthesized neither virion RNA nor detectable virus antigens at the nonpermissive temperature.

Experimental measles encephalitis: a genetic analysis

The encephalitogenic potential of nine temperature-sensitive mutants of measles virus was determined in newborn golden Syrian hamsters. The parental virus produced acute encephalitis without any prior adaptation. Six of the mutants were attenuated, two were virulent, and one was associated with hydrocephalus with acute onset. The attenuated mutants, blocked before measles virus antigen and ribonucleic acid synthesis at 39 C, were all members of one complementation group. The virulent temperature-sensitive mutants, defective in hemolysin antigen synthesis at 39 C, were members of a second complementation group. The hydrocephalus-inducing mutant was genetically distinct from the other mutants. The mechanism of attenuation most probably does not involve a temperature-induced inhibition of virus replication, but rather appears to be related to the partial defectiveness of the mutants under permissive conditions.

Quantitative assay for transformation of 3T3 cells by herpes simplex virus type 2

The interaction of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) with Swiss/3T3 cells was investigated. Virus-induced cytopathic effects developed in the absence of production of infectious virus. HSV-2 inactivated with UV light (2, 4, 6, and 8 min) also induced cell death in the absence of virus replication. Cell death was not detectable after infection by HSV-2 that had been inactivated by UV irradiation for 10, 12, and 14 min. 3T3 cells infected with UV-inactivated virus (10 and 12 min) continued to replicate past the contact-inhibited monolayer normally associated with these cells. Infection of 3T3 cells with UV-irradiated USV-2 also induced the development of transformed foci. Transformed cells with an epithelioid of fibroblastoid morphology were identified and isolated. All HSV-2-transformed cell lines contained HSV-2-specific antigens detectable by immunofluorescence techniques. The maximum frequency of HSV-2-induced transformation was 3 times 105 PFU per transformed focus, and the observed transformation could be inhibited by pretreatment of the virus with specific antiserum. No type C particles were detected within five cell culture passages after transformation by HSV-2. Type C virus particles were detected after 10 cell culture passages of the HSV-2-transformed cell lines.

Chromosome aberrations in Syrian hamster embryo cells transformed after exposure to ultraviolet-irradiated herpes simplex virus type 1 or 2

Six Syrian hamster embryo cell lines (14-012-8-1, KOS-6-1, 333-8-9, 333-2-29, MS-4-1, FR-6-1), developed after exposure of primary cultures to different strains of UV-irradiated herpes simplex virus (HSV) type 1 or 2, were analyzed for chromosome aberrations. All the cell lines showed chromosome stability (number of chromosomes were maintained within a narrow range of variation in the diploid region) and a low incidence of polyploids, endoreduplications, and metaphases with pulveration or extensively fragmented chromosomes. The cell lines, passaged over long periods of time in vitro, developed marker chromosomes that suggested a clonal-type evolution of the cell populations. Two cell lines, 333-8-9 and 14-012-8-1, showed two different marker chromosomes with large heterochromatic regions. Chromosomes with abnormal heterochromatic regions, which often appeared like prominent secondary constrictions, were found in all the cell lines we examined. The level of chromosome breakage was low in all the cell lines except the highly tumorigenic cell line 333-2-29, which had a high incidence of cells with single or double chromatinic bodies. The abnormal heterochromatic regions that occurred on marker chromosomes and prominent secondary constrictions were interpreted as a possible chromosomal effect of the HSV. The karyotypic stability and low incidence of open breaks might have been the result of UV irradiation of the HSV.

Oncogenic transformation of hamster embryo cells after exposure to inactivated herpes simplex virus type 1

The in vitro transformation of hamster embryo fibroblasts by herpes simplex virus type 1 (HSV-1) after exposure of the virus to UV irradiation is described. Cell transformation was induced by 2 out of 12 strains of HSV-1 that were tested for transforming potential. Cells transformed by the KOS strain of HSV-1 were not oncogenic when injected into newborn Syrian hamsters. However, cells transformed by HSV-1 strain 14-012 induced tumors in 47% of the newborn hamsters injected. HSV-specific antigens were found in the cytoplasm of cells transformed by both virus strains. Sera from tumor-bearing hamsters contained HSV-1- and HSV-2-neutralizing antibodies as well as antibodies which reacted specifically with HSV antigens by the indirect immunofluorescence technique. Hamster oncornavirus antigens were not detected by immunofluorescence methods. These observations represent the first evidence of the oncogenic potential of HSV-1.

Immunologic manipulation of metastases due to herpesvirus transformed cells

Herpes simplex virus type 1 (HSV-1), type 2 (HSV-2), and simian virus 40 (SV40) fail to induce immunity in weanling Syrian hamsters to transplant of hamster cells transformed by HSV-2. However, the development of metastatic tumors is markedly enhanced by prior immunization with HSV-1. Immunization with SV40, ultraviolet-irradiated tumor cells, or ultraviolet-irradiated normal hamster embryo cells inhibits the development of metastases. The HSV-hamster system appears a good one for the study of development, prevention, and control of metastases by mammalian cells transformed by a common human virus.

Production of mucopolysaccharides by normal and transformed cells

The rate of hyaluronic acid and sulfated mucopolysaccharide production was measured for hamster embryo fibroblasts and for general oncogenic lines derived by virus transformation. A striking increase in both the rate of hyaluronic acid synthesis and the amount of cell-associated polymer was observed after transformation by herpes simplex type-2 or SV40 virus. Although no corresponding change was observed for the sulfated polysaccharides, the proportion of heparan sulfate increased significantly after transformation.

Latency of human measles virus in hamster cells

A latent system employing measles virus (Schwarz strain) was developed in hamster embryo fibroblasts (HEF). Measles virus-specific antigen was detected by immunofluorescence in 30 to 50% of HEF cells, and these cells released infectious virus when co-cultivated with a susceptible monkey cell line, BSC-1 cells. No infectious virus could be detected in the cells when measures were taken to exclude passage of viable latent cells onto the indicator BSC-1 cells. Infectious center assays demonstrated that about 1 in 10 of the latently infected cells in the population could release infectious virus. Infectious virus appeared within 6 hr after co-cultivation of the HEF cells with BSC-1 cells, as compared to 24 hr required for normal replication of measles virus in the BSC-1 cells. Furthermore, labeling of progeny virus ribonucleic acid (RNA) by using tritiated uridine, and inhibition of RNA or protein synthesis by 5-azacytidine or cycloheximide suggested that neither additional RNA nor protein synthesis is required after co-cultivation of the cells to effect early virus release. It can therefore be postulated that there is a block at a late step in virus replication in the latently infected hamster cells. The most obvious site would concern maturation of infectious virions at the cell membrane.

Absence of leukosis virus markers in hamster cells transformed by herpes simplex virus type 2

Hamster cells which transformed after exposure to herpes simplex virus type 2 previously irradiated with ultraviolet light were tested for the presence of hamster leukosis viruses or their virus-specific antigens. Three techniques that were used did not detect the presence of either hamster C-type particles or antigens commonly associated with such structures. The implication of these findings to current concepts of virus oncology is discussed.

Properties of hamster embryo fibroblasts transformed in vitro after exposure to ultraviolet-irradiated herpes simplex virus type 2

An in vitro method which led to the transformation of hamster embryo fibroblasts after exposure to herpes simplex virus type 2 (HSV-2) inactivated with ultraviolet irradiation is described. The transformed cells (333-8-9) produced tumors when inoculated into newborn Syrian hamsters but not when injected into weanling Syrian hamsters of the same LSH inbred strain. However, after one in vivo passage, the 333-8-9 cells became highly oncogenic in weanling hamsters. No infectious virus was recovered from these cells. Herpes simplex virus antigens were detected in the transformed cells by the indirect immunofluorescence technique. Sera from tumor-bearing hamsters contained antibody with highly specific neutralizing activity against HSV-2. These studies indicate the continued involvement of the HSV-2 genome in an oncogenic cell line.