Efficacy and Safety of Tirzepatide in Adults With Type 2 Diabetes: A Perspective for Primary Care Providers

This article reviews the efficacy and safety data of tirzepatide, a once-weekly, novel glucose-dependent insulinotropic polypeptide and glucagon-like peptide 1 (GLP-1) receptor agonist approved in the United States, the European Union, and other regions for the treatment of type 2 diabetes. All doses of tirzepatide demonstrated superiority in reducing A1C and body weight from baseline versus placebo or active comparators. The safety profile of tirzepatide was consistent with that of the GLP-1 receptor agonist class, with mild to moderate and transient gastrointestinal side effects being the most common adverse events. With clinically and statistically significant reductions in A1C and body weight without increased risk of hypoglycemia in various populations, tirzepatide has demonstrated potential as a first-in-class treatment option for many people with type 2 diabetes.

Prevalence of undiagnosed stage 3 chronic kidney disease in France, Germany, Italy, Japan and the USA: results from the multinational observational REVEAL-CKD study

OBJECTIVES

REVEAL-CKD aims to estimate the prevalence of, and factors associated with, undiagnosed stage 3 chronic kidney disease (CKD).

DESIGN

Multinational, observational study.

SETTING

Data from six country-specific electronic medical records and/or insurance claims databases from five countries (France, Germany, Italy, Japan and the USA [two databases]).

PARTICIPANTS

Eligible participants (≥18 years old) had ≥2 consecutive estimated glomerular filtration rate (eGFR) measurements (calculated from serum creatinine values, sex and age) taken from 2015 onwards that were indicative of stage 3 CKD (≥30 and <60 mL/min/1.73 m²). Undiagnosed cases lacked an International Classification of Diseases 9/10 diagnosis code for CKD (any stage) any time before, and up to 6 months after, the second qualifying eGFR measurement (study index).

MAIN OUTCOME MEASURES

The primary outcome was point prevalence of undiagnosed stage 3 CKD. Time to diagnosis was assessed using the Kaplan-Meier approach. Factors associated with lacking a CKD diagnosis and risk of diagnostic delay were assessed using logistic regression adjusted for baseline covariates.

RESULTS

The prevalence of undiagnosed stage 3 CKD was 95.5% (19 120/20 012 patients) in France, 84.3% (22 557/26 767) in Germany, 77.0% (50 547/65 676) in Italy, 92.1% (83 693/90 902) in Japan, 61.6% (13 845/22 470) in the US Explorys Linked Claims and Electronic Medical Records Data database and 64.3% (161 254/250 879) in the US TriNetX database. The prevalence of undiagnosed CKD increased with age. Factors associated with undiagnosed CKD were female sex (vs male, range of odds ratios across countries: 1.29-1.77), stage 3a CKD (vs 3b, 1.81-3.66), no medical history (vs a history) of diabetes (1.26-2.77) or hypertension (1.35-1.78).

CONCLUSIONS

There are substantial opportunities to improve stage 3 CKD diagnosis, particularly in female patients and older patients. The low diagnosis rates in patients with comorbidities that put them at risk of disease progression and complications require attention.

TRIAL REGISTRATION

NCT04847531.

Living with Type 2 Diabetes: Podcast of a Patient-Physician Discussion

For patients with type 2 diabetes (T2D), the journey to diagnosis may not be straightforward. Patients can present with one of many diabetic complications before a diagnosis of T2D is made. These include heart disease and chronic kidney disease, in addition to cerebrovascular disease, peripheral vascular disease, retinopathy, and neuropathies, all of which can be asymptomatic in the early stages. In their clinical guidelines on standards of care in diabetes, the American Diabetes Association recommends regular screening for conditions such as kidney disease in patients with T2D. Furthermore, the frequent coexistence of diabetes and cardiorenal and/or metabolic conditions often requires a holistic approach to patient management, with specialists from multiple disciplines, including cardiologists, nephrologists, endocrinologists, and primary care physicians, working together. In addition to the use of pharmacological therapies, which can improve prognosis, the management of T2D should include attention to patient self-care, including appropriate dietary changes, consideration of continuous glucose monitoring, and advice on physical exercise. In this podcast, a patient and a clinician discuss a lived experience of the diagnosis of T2D, and the importance of patient education for understanding and managing T2D and its complications. The discussion highlights the central role of the Certified Diabetes Care and Education Specialist, and the role of ongoing emotional support in managing life with T2D, including patient education through reputable online resources and peer support groups. Podcast video with Pamela Kushner (PK) and Anne Dalin (AD) (MP4 92088 KB).

The use of non-steroidal anti-inflammatory drugs (NSAIDs) in COVID-19

Early in the COVID-19 pandemic, anecdotal reports emerged suggesting non-steroidal anti-inflammatory drugs (NSAIDs) may increase susceptibility to infection and adversely impact clinical outcomes. This narrative literature review (March 2020–July 2021) attempted to clarify the relationship between NSAID use and COVID-19 outcomes related to disease susceptibility or severity. Twenty-four relevant publications (covering 25 studies) reporting original research data were identified; all were observational cohort studies, and eight were described as retrospective. Overall, these studies are consistent in showing that NSAIDs neither increase the likelihood of SARS-CoV-2 infection nor worsen outcomes in patients with COVID-19. This is reflected in current recommendations from major public health authorities across the world, which support NSAID use for analgesic or antipyretic treatment during COVID-19. Thus, there is no basis on which to restrict or prohibit use of these drugs by consumers or patients to manage their health conditions and symptoms during the pandemic.

DCRM Multispecialty Practice Recommendations for the management of diabetes, cardiorenal, and metabolic diseases

Type 2 diabetes (T2D), chronic kidney disease (CKD), atherosclerotic cardiovascular disease (ASCVD), and heart failure (HF)-along with their associated risk factors-have overlapping etiologies, and two or more of these conditions frequently occur in the same patient. Many recent cardiovascular outcome trials (CVOTs) have demonstrated the benefits of agents originally developed to control T2D, ASCVD, or CKD risk factors, and these agents have transcended their primary indications to confer benefits across a range of conditions. This evolution in CVOT evidence calls for practice recommendations that are not constrained by a single discipline to help clinicians manage patients with complex conditions involving diabetes, cardiorenal, and/or metabolic (DCRM) diseases. The ultimate goal for these recommendations is to be comprehensive yet succinct and easy to follow by the nonexpert-whether a specialist or a primary care clinician. To meet this need, we formed a volunteer task force comprising leading cardiologists, nephrologists, endocrinologists, and primary care physicians to develop the DCRM Practice Recommendations, a multispecialty consensus on the comprehensive management of the patient with complicated metabolic disease. The task force recommendations are based on strong evidence and incorporate practical guidance that is clinically relevant and simple to implement, with the aim of improving outcomes in patients with DCRM. The recommendations are presented as 18 separate graphics covering lifestyle therapy, patient self-management education, technology for DCRM management, prediabetes, cognitive dysfunction, vaccinations, clinical tests, lipids, hypertension, anticoagulation and antiplatelet therapy, antihyperglycemic therapy, hypoglycemia, nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH), ASCVD, HF, CKD, and comorbid HF and CKD, as well as a graphical summary of medications used for DCRM.

Investigating the global prevalence and consequences of undiagnosed stage 3 chronic kidney disease: methods and rationale for the REVEAL-CKD study

Background

Timely diagnosis and treatment of stage 3 chronic kidney disease (CKD) can prevent further loss of kidney function and progression to kidney failure. However, contemporary data on the global prevalence of undiagnosed stage 3 CKD are scarce. REVEAL-CKD is a multinational, multifocal and observational study aiming to provide insights into undiagnosed stage 3 CKD in a large population.

Methods

Patients (aged ≥18 years) with data in selected secondary databases from 11 countries will be included if they have at least two estimated glomerular filtration rate (eGFR) measurements from 2015 onwards that are ≥30 and <60 mL/min/1.73 m², recorded >90 and ≤730 days apart. Undiagnosed cases are those without an International Classification of Diseases 9/10 diagnosis code for CKD (any stage) any time before and up to 6 months after the second qualifying eGFR measurement. Time to diagnosis will be assessed using a Kaplan–Meier approach; patient characteristics associated with undiagnosed CKD will be assessed using adjusted logistical regression analyses.

Results

REVEAL-CKD will assess the point prevalence of undiagnosed stage 3 CKD and time to CKD diagnosis in initially undiagnosed cases overall and in individual countries. Trends in undiagnosed CKD prevalence by calendar year will be assessed. Patient characteristics, healthcare resource utilization, adverse clinical outcomes, and CKD management and monitoring practices in patients with versus without a CKD diagnosis will be compared.

Conclusions

REVEAL-CKD will increase awareness of the global clinical and economic burden of undiagnosed stage 3 CKD and provide valuable insights to inform clinical practice and policy changes.

Prevalence of and factors associated with undiagnosed stage 3 chronic kidney disease in patient with a history of heart failure: a report from REVEAL-CKD

Background

Chronic kidney disease (CKD) is a serious debilitating condition affecting 10% of the world's population, yet it remains largely under recognised even among patients with pre-existing comorbidities. Approximately 5% of patients with CKD have a history of heart failure (HF), however factors associated with undiagnosed CKD in patients with multimorbidity remain unclear.

Purpose

REVEAL-CKD is a multinational initiative to assess undiagnosed CKD. This analysis aims to assess prevalence and factors associated with undiagnosed stage 3 CKD in patients with heart failure.

Methods

From the US, we utilised TriNetX, a federated research network providing statistics on electronic health records. Adult patients, with two consecutive estimated glomerular filtration rate (eGFR) measurements ≥30 and &lt;60 mL/min/1.732 at least 90 days apart were identified between 2015–2020. HF status was ascertained by ICD codes prior to the index date (date of the second eGFR measurement). Patients with no ICD code for CKD at any time before or up to 6 months after the index date were considered to have undiagnosed CKD.

Results

The study cohort included 31,263 patients with eGFR values indicating stage 3 CKD and pre-existing HF with mean age of 72 years (standard deviation: 11 years). The overall prevalence of undiagnosed CKD was 48.5% (n=15,159, 95% Confidence Interval: 47.9–49.0). Prevalence of undiagnosed CKD increased with age, was greater than 50% in female patients and was between 38% and 46% in patients with other pre-existing comorbidities (Table 1). Compared to patients with diagnosed CKD, the undiagnosed group had more females (41% versus 60%) and a had higher proportion of patients in the older age group (≥75 years: 43% versus 52%). Fewer undiagnosed CKD patients had pre-existing comorbidities than those with diagnosed CKD.

Conclusion

This study suggests that a large proportion of either older or female patients with baseline HF comorbidity have undiagnosed CKD. These results suggest that an opportunity exists for more proactive CKD diagnosis and monitoring of patients with comorbidities

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): AstraZeneca

Global survey investigating causes of treatment inertia in type 2 diabetes cardiorenal risk management

AIM

To explore reasons behind treatment inertia in current approaches to early cardiorenal risk management in type 2 diabetes (T2D).

METHODS

A global, web-based, quantitative panel survey of primary care physicians (PCPs) and primary care diabetes specialists treating people living with T2D. The questions covered current management of T2D, particularly the use of sodium-glucose co-transporter 2 inhibitors, glucagon-like peptide-1 receptor agonists, and dipeptidyl peptidase-4 inhibitors as second-/third-line therapies.

RESULTS

Of 1677 respondents from 18 countries who completed the survey, 73.4% were responsible for second-/third-line therapy initiation. Two thirds had modified treatment decisions based on recent cardiovascular outcomes trials (CVOTs). Respondents cited restricted access to therapies and limits on regular appointments as the greatest barriers to second-/third-line therapy prescription. Although 81.6% agreed that early intensification to second-/third-line therapies is associated with clinical benefits, 46.1% of respondents still reserve these for later lines of therapy, and 23.8% would not consider changing therapeutic approach in patients with well-controlled T2D but increasing cardiovascular risk.

CONCLUSIONS

Substantial barriers still prevent optimization of primary setting T2D patient care. Education programs which enable PCPs to translate CVOT evidence into clinical benefits for patients with T2D could address many of the remaining knowledge gaps identified.

Practical guidance for using the FreeStyle Libre flash continuous glucose monitoring in primary care

Use of continuous glucose monitoring (CGM) improves clinical outcomes in type 1 diabetes, and significant benefits been demonstrated in patients with type 2 diabetes, including improved glycemic control, better treatment adherence, and an increased understanding of their treatment regimens. Currently, there are two types of CGM systems: real-time CGM (rtCGM) and flash CGM (FCGM). Retrospective analysis of CGM data allows patients and their clinicians to identify glycemic patterns that support and facilitate informed therapy decisions. With the increasing prevalence of diabetes, primary care physicians will be compelled to take on more responsibility for managing patients with diabetes. This article focuses on practical approaches and decision-making strategies for utilizing FCGM in primary care settings.

Benefits/risks of sodium-glucose co-transporter 2 inhibitor canagliflozin in women for the treatment of Type 2 diabetes

Sodium-glucose co-transporter 2 (SGLT2) inhibitors, such as canagliflozin, are used in patients with Type 2 diabetes mellitus (T2DM). In clinical studies, canagliflozin significantly reduced A1C, bodyweight and blood pressure, and was generally well tolerated with no increased risk of hypoglycemia. Most common adverse effects observed were genital mycotic infections and urinary tract infections, and increased urination. Approximately 10% of women treated with canagliflozin experienced a genital mycotic infection compared with 3% treated with placebo; those with a prior history were at greater risk. Approximately 9% of women treated with canagliflozin reported a urinary tract infection compared with 7% treated with placebo. Most adverse events were considered mild to moderate in intensity and responded to standard therapy. Treatment with canagliflozin was effective and generally well tolerated in both women (and men) with T2DM.

Recognizing and minimizing hypoglycemia: The need for individualized care

Hypoglycemia is a condition known to disrupt many everyday activities and is associated with increased risks of hospitalization, falls, motor vehicle accidents and mortality. Many patients with diabetes have an increased risk of hypoglycemia due to interventions targeting glycemic control. In these patients, hypoglycemia and fear of hypoglycemia may further reduce adherence to glucose-lowering regimens, contributing to the further aggravation of diabetes-related complications. Avoiding hypoglycemia should be one of the principal goals of any treatment strategies employing agents that can induce hypoglycemia in order to prevent the occurrence of associated symptoms and consequences. The education of patients and their families is an important feature of individualized management strategies in order to prevent, mitigate and treat hypoglycemic episodes. Patients with diabetes need to be made aware of how to recognize the signs of hypoglycemia and of the simple, highly effective steps that they can take to self-manage hypoglycemic episodes. Clinicians should be familiar with the risk factors for hypoglycemia, especially the profiles of the different classes of glucose-lowering medications such as the sulfonylureas and insulin. This article aims to review the risk factors for hypoglycemia and its implications for patients and healthcare systems, and provide practical advice for minimizing the risk of hypoglycemia and its consequences.

Type 2 diabetes comorbidities and treatment challenges: rationale for DPP-4 inhibitors

The management of type 2 diabetes is designed to reduce disease-related complications and improve long-term outcomes. Achieving glycemic control is a critical component of this process. The selection of drug therapy for reducing blood glucose is made more challenging when patients already have complications or comorbid conditions (eg, high risk for hypoglycemia, obesity, renal impairment). Dipeptidyl peptidase-4 (DPP-4) inhibitors are a new class of antihyperglycemic drugs that block degradation of incretin hormones. By enhancing and prolonging incretin effects, DPP-4 inhibitors stimulate glucose-dependent insulin secretion and also reduce glucagon secretion. This results in improved glycemic control, as reflected by decreases in glycated hemoglobin (HbA1c), fasting plasma glucose, and postprandial plasma glucose. Dipeptidyl peptidase-4 inhibitors also have the potential to improve beta-cell function. In randomized clinical trials, the DPP-4 inhibitors saxagliptin and sitagliptin reduced HbA1c by 0.5% to 0.8%, compared with placebo, whether used as monotherapy or in combination with another agent. As initial combination therapy with metformin, saxagliptin and sitagliptin have demonstrated reductions in HbA1c of 2.5% and 1.9%, respectively. The efficacy of the DPP-4 inhibitors was maintained during treatment for up to 2 years, and did not differ in the elderly compared with younger adults. Dipeptidyl peptidase-4 inhibitors offer efficacy similar to other drug classes, and are well tolerated with a lower risk of hypoglycemia, weight-neutral effects, and a low propensity for drug-drug interactions. On the basis of their clinical profiles, the DPP-4 inhibitors are emerging as an attractive option for improving glycemic control in patients with type 2 diabetes. Saxagliptin and sitagliptin are approved for use as initial therapy in combination with metformin, as monotherapy, as well as in combination with metformin, a sulfonylurea, or a thiazolidinedione in patients not adequately controlled by these agents alone.

Minimizing the risk of hypoglycemia in patients with type 2 diabetes mellitus

Hypoglycemia is a major barrier to achieving glycemic goals in patients with diabetes. Both acute and chronically recurrent hypoglycemic events appear to have long-term consequences for patients with type 2 diabetes mellitus (T2DM). Chronically recurrent hypoglycemia may lead to an impairment of the counterregulatory system, with the potential for the development of hypoglycemia unawareness syndrome, increased severe hypoglycemia-associated hospitalization, and increased mortality. Hypoglycemic events may also have negative implications in cardiovascular disease and/or dementia. Avoidance of hypoglycemia by treating with appropriate, individualized regimens for patients with T2DM should be a primary focus of physicians. Utilizing traditional agents (eg, metformin and thiazolidinediones) that do not promote hypoglycemia, in combination with newer agents such as dipeptidyl peptidase-4 inhibitors and incretin mimetics, could offer a therapeutic advantage when trying to help patients reach their hemoglobin A(1c) goal without the added risk of hypoglycemia.

Incretin mimetics and DPP-IV inhibitors: new paradigms for the treatment of type 2 diabetes

Incretin mimetics are a new class of pharmacological agents with multiple antihyperglycemic actions that mimic several of the actions of incretin hormones originating in the gut, such as glucagon-like peptide (GLP)-1. Dipeptidyl peptidase-IV (DPP-IV) inhibitors suppress the degradation of many peptides, including GLP-1, thereby extending their bioactivity. These agents seem to have multiple mechanisms of action for the treatment of type 2 diabetes mellitus (T2DM), including some or all the following: enhancement of glucose-dependent insulin secretion, suppression of inappropriately elevated glucagon secretion, slowing of gastric emptying, and decreased food intake. Exenatide (BYETTA) is the first incretin mimetic approved for clinical use by the US Food and Drug Administration. In phase 3 clinical trials, exenatide reduced HbA(1c) by approximately 1% and body weight by approximately 2 kg in T2DM patients failing to achieve glycemic control with metformin and/or a sulfonylurea, with mild-to-moderate nausea the most common side effect. Several GLP-1 analogues and DPP-IV inhibitors are in late-stage clinical testing and may soon become available for treating T2DM patients. The use of these agents may provide an opportunity to bring about new improvements in diabetes care.

A splice variant of estrogen receptor beta missing exon 3 displays altered subnuclear localization and capacity for transcriptional activation

There are two separate estrogen receptors (ERs), ERalpha and ERbeta. The ERbeta gene is variably spliced, and in some cases variant expression is high. Besides the full-length ERbeta (equivalent to ERbeta1), splice variants can encode proteins bearing an insert within the ligand-binding domain (beta2), a deletion of exon 3 (ERbeta1delta3) disrupting the DNA-binding domain, or both (ERbeta2delta3). Here we examine the intracellular localization and transcriptional properties of each of the ERbeta splice variants heterologously expressed in cultured cells. In accordance with ERalpha, ERbeta1 and ERbeta2 are both distributed in a reticular pattern within the nucleus after exposure to ligand. In contrast, ERbeta1delta3 and ERbeta2delta3 localize to discrete spots within the nucleus in the presence of ER agonists. In the presence of ER antagonists, the delta3 variants are distributed diffusely within the nucleus. We also show that the spots are stable nuclear structures to which the delta3 variants localize in a ligand-dependent manner. Coactivator proteins of ER colocalize with delta3 variants in the spots in the presence of agonists. The delta3 variants of ERbeta can activate luciferase reporter constructs containing an activator protein complex-1 site, but not an estrogen response element (ERE). These data suggest that without an intact DNA-binding domain, ERbeta is functionally altered, allowing localization to discrete nuclear spots and activation from activator protein-1-containing reporter genes.

Dynamic stabilization of nuclear receptor ligand binding domains by hormone or corepressor binding

We have developed a novel assembly assay to examine structural changes in the ligand binding domain (LBD) of the thyroid hormone receptor (TR). Fragments including the first helix of the TR LBD interact only weakly with the remainder of the LBD in the absence of hormone, but this interaction is strongly enhanced by the addition of either hormone or the corepressor NCoR. Since neither the ligand nor the corepressor shows direct interaction with this helix, we propose that both exert their effects by stabilizing the overall structure of the LBD. Current models of activation of nuclear hormone receptors focus on a ligand-induced allosteric shift in the position of the C-terminal helix 12 that generates the coactivator binding site. Our results suggest that ligand binding also has more global effects that dynamically alter the structure of the receptor LBD.

Paradoxical production of target protein using antisense RNA expression vectors

We used antisense RNA in a protocol designed to reduce estrogen receptor (ER) content in human breast cancer cells and observed paradoxical increases in ER levels. ER protein activity was measured using a highly sensitive reporter gene assay that relies on the ability of functional ER to bind a consensus estrogen response element (ERE) and drive the production of chloramphenicol acetyl-transferase (CAT). Upon transient transfection of ER-positive cell lines with three different vectors containing the full-length ER cDNA cloned in an antisense orientation, we observed unexpected increases in ER-driven CAT activity. To further investigate this phenomenon, expression from the antisense ER vectors was studied in an ER-negative breast tumor cell line, MDA-MB-453. ER activity was observed in these ER-negative cells upon transient transfection with each of three antisense ER vectors, but not from control vectors. Expression of ER from antisense constructs was 30-100-times less efficient than ER expression from isogenic sense constructs. The paradoxical ER activity was consistent with expected ER behavior in that it exhibited characteristic binding to the natural ligand, 17 beta-estradiol (E2), and it was inhibited by the antiestrogens, 4-hydroxy-tamoxifen (OHT) and ICI 164384 (ICI). Control vectors containing a truncated antisense ER cDNA produced no ER activity. Although the mechanism for this ER expression has not been determined, it appears likely that it is due to transcription off the opposite strand of the antisense construct.(ABSTRACT TRUNCATED AT 250 WORDS)

Topographical distribution of synaptic-associated proteins in the neuritic plaques of Alzheimer's disease hippocampus

Studies of the molecular composition of the abnormal neuritic processes of the plaques in Alzheimer's disease (AD) have shown that these structures are immunoreactive with antibodies against growth-related molecules, synaptic/axonal proteins, and cytoskeletal proteins. These studies suggest that a subpopulation of abnormal neurites in the plaque are sprouting axons that eventually degenerate. To test this hypothesis further we studied the regional distribution of plaques in the hippocampus using a panel of monoclonal antibodies against synaptic proteins. With these antibodies we found a greater proportion of immunoreactive plaques compared to previous studies where a monoclonal antibody against synaptophysin was used. The most sensitive antibodies to detect neuritic plaques were SP11 and anti-p65, and the largest number of positive plaques was found in the entorhinal cortex and CA1 region. These results further support the theory that synaptic and axonal damage are involved in plaque formation in AD.

Truncated forms of DNA-binding estrogen receptors in human breast cancer

The likelihood a breast cancer will respond to antiestrogen therapy depends on the tumor content of immunoreactive or ligand-binding estrogen receptor (ER). To investigate the failure of many ER-positive breast cancers to respond to antiestrogen therapy, we examined by gel-shift assay the ability of tumor ER to bind its cognate estrogen response element (ERE). Analysis of 38 primary breast cancers showed that some tumors containing abundant immunoreactive ER failed to demonstrate DNA binding ER. In many other ER-positive tumors, the fraction of DNA binding ER was low and consisted primarily of truncated receptor forms, which on Western analysis were revealed to be 50 kD homodimers and 67-50 kD ER heterodimers. The use of protease inhibitors during tumor extraction and the demonstration of nuclear-localizing ER and ERE-binding COUP (chicken ovalbumin upstream promoter) protein in these tumors indicated that the truncated forms of ER were likely present in vivo. The presence of intact DNA binding ER correlated with higher tumor content of immunoreactive sex steroid receptors (ER and/or PR), standard predictors of tumor responsiveness to antiestrogen, suggesting that loss or truncation of DNA binding ER may be an important prognostic parameter accounting for some forms of clinical resistance to antiestrogen therapy.

Characterization of human prorenin expressed in mammalian cells from cloned cDNA

Human preprorenin was synthesized in Chinese hamster ovary (CHO) cells transfected with an expression vector containing renin cDNA sequences. These cells secrete an inactive form of renin (EC 3.4.23.15) that can be activated by trypsin. This inactive renin is precipitable by antibody generated against purified human renal renin and also by antisera generated to a synthetic peptide derived from the amino acid sequence of the pro segment of preprorenin (anti-propeptide), indicating that the secreted inactive enzyme is a form of prorenin. Analysis of [35S]methionine-labeled proteins immunoprecipitated from CHO cell conditioned culture medium indicates that prorenin is expressed in CHO cells as two distinct forms that differ in their degree of glycosylation. In vitro trypsin activation of prorenin cleaves approximately 4.5 kDa from the protein, rendering it unreactive with the antipropeptide antiserum but still recognizable by anti-renal renin antibody. These results show directly that the prorenin expressed by CHO cells is an inactive enzyme that is activated by trypsin cleavage of the pro segment. The ability to express human renin in this form will allow for the purification of both active and inactive forms of the enzyme in quantities sufficient for detailed physiological and structural studies.

Defective gamma interferon production in leprosy. Reversal with antigen and interleukin 2

Antigen and mitogen-induced gamma interferon (gamma-IFN) production was studied in peripheral blood mononuclear cells from 34 leprosy patients. 17 of 18 lepromatous leprosy and borderline lepromatous patients (LL and BL) failed to release gamma-IFN in response to specific antigen (Mycobacterium leprae) and displayed reduced responses to mitogen (concanavalin A) stimulation. In contrast, cells from six tuberculoid and borderline tuberculoid patients (TT and BT) produced considerable levels of gamma-IFN under the same experimental conditions. Normal controls failed to respond to M. leprae and most displayed good responses to concanavalin A. Mid-borderline patients (BB) showed intermediate levels of gamma-IFN release. gamma-IFN release by lepromatous patients could be partially restored with purified interleukin 2 and M. leprae antigen but not with interleukin 2 alone.