Ability of innate defence regulator peptides IDR-1002, IDR-HH2 and IDR-1018 to protect against Mycobacterium tuberculosis infections in animal models.

Tuberculosis is an ongoing threat to global health, especially with the emergence of multi drug-resistant (MDR) and extremely drug-resistant strains that are motivating the search for new treatment strategies. One potential strategy is immunotherapy using Innate Defence Regulator (IDR) peptides that selectively modulate innate immunity, enhancing chemokine induction and cell recruitment while suppressing potentially harmful inflammatory responses. IDR peptides possess only modest antimicrobial activity but have profound immunomodulatory functions that appear to be influential in resolving animal model infections. The IDR peptides HH2, 1018 and 1002 were tested for their activity against two M. tuberculosis strains, one drug-sensitive and the other MDR in both in vitro and in vivo models. All peptides showed no cytotoxic activity and only modest direct antimicrobial activity versus M. tuberculosis (MIC of 15-30 µg/ml). Nevertheless peptides HH2 and 1018 reduced bacillary loads in animal models with both the virulent drug susceptible H37Rv strain and an MDR isolate and, especially 1018 led to a considerable reduction in lung inflammation as revealed by decreased pneumonia. These results indicate that IDR peptides have potential as a novel immunotherapy against TB

Effect of IDR peptides on the growth of <i>M. tuberculosis</i> and cytotoxicity in monocytic cells.

<p>(A) <i>Mycobacterium tuberculosis</i> strain H37Rv was incubated with increasing concentrations of the indicated peptides in doubling dilutions ranging from 128 to 8 µg/mL to determine the minimal inhibitory concentration (MIC). (B) The effect on monocyte viability was assessed by incubating increasing concentrations of these peptides with cells and assessing the integrity of the cytoplasmic membrane. The data is expressed as means ± standard deviation of 6 independent experiments with each one performed in duplicate.</p

Protection by peptide HH2 against an invasive <i>Staphylococcus aureus</i> infection in mice, compared to a negative control peptide HH17.

<p>Mice were pretreated with saline (control) or 4 mg/kg peptide (IP) in saline, and infected 4 hours later with approximately 1.0×10⁹ CFU of <i>S. aureus</i>. Twenty-four hours post infection, mice were euthanized and the peritoneal lavage taken, and plated on Mueller Hinton agar. The graph is representative data from a series of 2 independent experiments. *represents p<0.05.</p

Direct antimicrobial activity of the IDR peptides vs. Gram negative pathogen <i>Pseudomonas aeruginosa</i> and Gram positive pathogen.

<p><i>Staphylococcus aureus</i> - Mean of three independent experiment.</p>1<p>Taken from Wieczorek et al <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0059119#pone.0059119-Wieczorek1" target="_blank">[19]</a>.</p

Immunomodulatory activities of peptides IDR-HH2, IDR-1002 and IDR 1018 in human peripheral blood mononuclear cells (PBMC).

<p>Cells were stimulated with 20 µg/ml of peptide.</p>1<p>Experiments were performed 2–4 times and means are presented. All values for peptide treated cells represent significant induction relative to the untreated control (p<0.05) for the two chemokines MCP-1 and Gro-α, and significant reduction in LPS stimulated TNF-α relative to the LPS-treated but peptide-untreated control. There was no significant induction of TNF-α by the peptides themselves. The data for IDR-1018 are consistent with those presented in Wieczorek et al <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0059119#pone.0059119-Wieczorek1" target="_blank">[19]</a>.</p

Effect of antimicrobial peptide treatment on pulmonary bacilli burdens and tissue damage (pneumonia) during experimental tuberculosis kinetic.

<p>(A) Mice were infected with the drug-sensitive H37Rv Mtb strain, and after 60 days were treated, three times per week, with ∼1 mg/kg of the indicated peptide in 100 mL of saline solution. HH2 and 1018 decreased the lung bacillary loads in comparison with untreated mice, whereas 1002 showed no significant changes. (B) Percentage of the lung surface affected by pneumonia as determined by automated morphometry. Results are expressed as means ± standard deviations, P<0.05 * or P<0.01** were considered statistically significant. Both 1018 and HH2 peptides significantly decreased the pneumonic area when compared with the control group. The graph is representative data from a series of 3 independent experiments.</p

Effect of antimicrobial peptides on the treatment of mice infected with a drug-resistant strain.

<p>(A) Animals were infected with the MDR strain and after 60 days treated three times per week with 32 µg in 100 µL of saline solution of the indicated peptide. Compared to the control untreated animals, IDR peptides HH2 and 1018 induced a significant decrease in lung bacillary loads. (B) Measurement of the area of consolidation of pneumonia showed that only HH2 and 1018 significantly reduced the pneumonic areas when compared with control mice. The data is expressed as means ± standard deviation of 3 independent experiments; p<0.01 indicated with a bar and **over the two bars was considered statistically significant.</p

Representative electron microscopy micrographs of <i>Mycobacterium tuberculosis</i> strain H37Rv treated with high concentrations of IDR peptides.

<p>(A) Control bacteria show thick homogeneous electron lucent cell wall (asterisk) and cytoplasm with some electron dense granules (63,000x); (B) Incubation with peptide 1002 induces abnormalities in the cell wall, such as thinning, budding and partial dissolution (arrows) (100,000x). (C) Peptide HH2 induces complete disappearance of the cell wall with electron lucent cytoplasm (asterisks) or homogenous cell wall thinning and condensation (arrows) with slight electron lucent change of the cytoplasm (80,000x). (D) Incubation with peptide 1018 produced a peripheral electron dense rim with areas of rupture and dissolution (arrows) in the cell wall, which also have irregular electron dense condensations (asterisk) and an electron lucent halo around the cytoplasm (100,000x). All bars in the figures represent 5 µm. The micrographs are representative of 2 independent experiments.</p

Global economic burden of unmet surgical need for appendicitis

Background There is a substantial gap in provision of adequate surgical care in many low- and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially

Global economic burden of unmet surgical need for appendicitis

Background There is a substantial gap in provision of adequate surgical care in many low- and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially